AI Trajectory

Trajectory: (Expand/Collapse All)
Seq	Timestamp	Type	Name	Duration
0/0	2026/10/15 12:58	flow	patch-triage	8m Args: null Results: { "EnableConfigs": [ "INET", "IPV6", "IP_MULTICAST", "IP_MROUTE", "IPV6_MROUTE" ], "FocusSymbols": [ "do_ip_getsockopt", "ip_getsockopt", "do_ipv6_getsockopt", "ipv6_getsockopt", "ip_mc_gsfget", "ip_mc_msfget", "ip6_mc_msfget", "ip_mroute_getsockopt", "ip6_mroute_getsockopt" ], "KMSANReasoning": "The patch series refactors getsockopt handlers in IPv4 and IPv6 (including do_ip_getsockopt, do_ipv6_getsockopt, ip_mroute_getsockopt, ip6_mroute_getsockopt, and multicast filter helpers) to use the iterator-based `sockopt_t` abstraction instead of `sockptr_t`.\n\nEvaluation against KMSAN applicability criteria:\n1. Kernel-to-user copies: All kernel structures copied to user buffers (or iterators) are either completely zeroed beforehand (e.g., `memset(\u0026ss, 0, sizeof(ss))` in ip_mc_gsfget and ip6_mc_msfget, `memset(\u0026mtuinfo, 0, ...)` for IPV6_PATHMTU, `memset(\u0026freq, 0, ...)` for IPV6_FLOWLABEL_MGR), fully initialized from user input via copy_from_iter before write-back (e.g., `gsf` in ip_get_mcast_msfilter and ipv6_get_msfilter), or are fully initialized scalar types (`val`, `ucval`, `sopt.optlen`). No uninitialized stack or heap padding is exposed to userspace.\n2. Control flow / branching: Conditional branching does not depend on uninitialized variables or struct fields; `sockopt_t` structures are explicitly initialized by `sockopt_init_user`, `sockopt_set_user`, or `sockptr_to_sockopt`.\n3. Buffer lengths and bounds: Adjustments to lengths and iterator positioning (`iov_iter_advance`, `iov_iter_revert`, and bounds checking in `sockopt_expand_out`) affect user iterator offsets and buffer bounds. Any potential buffer miscalculations or memory safety issues here would be bounds/out-of-bounds errors detected by KASAN rather than uninitialized memory reads.\n\nBecause no uninitialized memory access or info-leak risks are introduced or exposed, dedicated KMSAN fuzzing is not required. Standard KASAN fuzzing is sufficient.", "NeedsKMSAN": false, "Reasoning": "The patch refactors the IPv4 (SOL_IP) and IPv6 (SOL_IPV6) getsockopt subsystem to use sockopt_t / iov_iter instead of sockptr_t. This touches reachable core networking code in net/ipv4, net/ipv6, and net/core, modifying buffer copying, optlen bounds handling, iterator advancement and reverting (iov_iter_revert, iov_iter_advance), multicast filter query logic (ip_mc_gsfget, ip6_mc_msfget), and BPF cgroup sockopt hooks (sol_ip_sockopt, sol_ipv6_sockopt). The modified code is directly reachable by unprivileged user space via getsockopt syscalls on standard AF_INET and AF_INET6 sockets.", "WorthFuzzing": true }
1/1	2026/10/15 12:58	action	read-patch-diff	0m Args: null Results: { "PatchDiff": "commit cadd503ae11ea00c223b192cf6ffc896572a18c1\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate: Thu Oct 15 12:58:45 2026 +0000\n\n syz-cluster: applied patch under review\n\ndiff --git a/include/linux/igmp.h b/include/linux/igmp.h\nindex e075611344ef3..0a1abf3552d2b 100644\n--- a/include/linux/igmp.h\n+++ b/include/linux/igmp.h\n@@ -276,7 +276,7 @@ extern int ip_mc_msfilter(struct sock sk, struct ip_msfilter msf,int ifindex);\n extern int ip_mc_msfget(struct sock sk, struct ip_msfilter msf,\n \t\t\tsockopt_t opt);\n extern int ip_mc_gsfget(struct sock sk, struct group_filter gsf,\n-\t\t\tsockptr_t optval, size_t offset);\n+\t\t\tsockopt_t opt, size_t offset);\n extern int ip_mc_sf_allow(const struct sock sk, __be32 local, __be32 rmt,\n \t\t\t int dif, int sdif);\n extern void ip_mc_init_dev(struct in_device );\ndiff --git a/include/linux/mroute.h b/include/linux/mroute.h\nindex 4c5003afee6c5..c1c21e61c81c3 100644\n--- a/include/linux/mroute.h\n+++ b/include/linux/mroute.h\n@@ -17,7 +17,7 @@ static inline int ip_mroute_opt(int opt)\n }\n \n int ip_mroute_setsockopt(struct sock , int, sockptr_t, unsigned int);\n-int ip_mroute_getsockopt(struct sock , int, sockptr_t, sockptr_t);\n+int ip_mroute_getsockopt(struct sock sk, int optname, sockopt_t opt);\n int ipmr_ioctl(struct sock sk, int cmd, void arg);\n int ipmr_compat_ioctl(struct sock sk, unsigned int cmd, void __user arg);\n int ip_mr_init(void);\n@@ -31,7 +31,7 @@ static inline int ip_mroute_setsockopt(struct sock sock, int optname,\n }\n \n static inline int ip_mroute_getsockopt(struct sock sk, int optname,\n-\t\t\t\t sockptr_t optval, sockptr_t optlen)\n+\t\t\t\t sockopt_t opt)\n {\n \treturn -ENOPROTOOPT;\n }\ndiff --git a/include/linux/mroute6.h b/include/linux/mroute6.h\nindex fddafdc168f73..ab4d206fb3206 100644\n--- a/include/linux/mroute6.h\n+++ b/include/linux/mroute6.h\n@@ -27,7 +27,7 @@ struct sock;\n \n #ifdef CONFIG_IPV6_MROUTE\n extern int ip6_mroute_setsockopt(struct sock , int, sockptr_t, unsigned int);\n-extern int ip6_mroute_getsockopt(struct sock , int, sockptr_t, sockptr_t);\n+int ip6_mroute_getsockopt(struct sock sk, int optname, sockopt_t sopt);\n extern int ip6_mr_input(struct sk_buff skb);\n extern int ip6mr_compat_ioctl(struct sock sk, unsigned int cmd, void __user arg);\n extern int ip6_mr_init(void);\n@@ -42,8 +42,7 @@ static inline int ip6_mroute_setsockopt(struct sock sock, int optname,\n }\n \n static inline\n-int ip6_mroute_getsockopt(struct sock sock,\n-\t\t\t int optname, sockptr_t optval, sockptr_t optlen)\n+int ip6_mroute_getsockopt(struct sock sock, int optname, sockopt_t sopt)\n {\n \treturn -ENOPROTOOPT;\n }\ndiff --git a/include/linux/net.h b/include/linux/net.h\nindex e2a866fbcfa5e..1d5b3524b0846 100644\n--- a/include/linux/net.h\n+++ b/include/linux/net.h\n@@ -50,6 +50,19 @@ typedef struct sockopt {\n int sockptr_to_sockopt(sockopt_t opt, sockptr_t optval, sockptr_t optlen,\n \t\t struct kvec kvec);\n \n+/\n+ Point a sockopt_t at a user-backed (optval, len) pair whose length is\n+ * already known, e.g. because the caller applied its own optlen quirks\n+ * before this point.\n+ /\n+static inline void sockopt_set_user(sockopt_t opt, char __user optval,\n+\t\t\t\t int len)\n+{\n+\tiov_iter_ubuf(\u0026opt-\u003eiter_out, ITER_DEST, optval, len);\n+\tiov_iter_ubuf(\u0026opt-\u003eiter_in, ITER_SOURCE, optval, len);\n+\topt-\u003eoptlen = len;\n+}\n+\n /\n * Initialize a user-backed sockopt_t from the (optval, optlen) __user pair of\n * a getsockopt() callback. Used by transitional __user getsockopt wrappers\n@@ -66,9 +79,7 @@ static inline int sockopt_init_user(sockopt_t opt, char __user optval,\n \tif (len \u003c 0)\n \t\treturn -EINVAL;\n \n-\tiov_iter_ubuf(\u0026opt-\u003eiter_out, ITER_DEST, optval, len);\n-\tiov_iter_ubuf(\u0026opt-\u003eiter_in, ITER_SOURCE, optval, len);\n-\topt-\u003eoptlen = len;\n+\tsockopt_set_user(opt, optval, len);\n \n \treturn 0;\n }\n@@ -80,16 +91,21 @@ static inline int sockopt_init_user(sockopt_t opt, char __user optval,\n \n Call it before writing through opt-\u003eiter_out: it re-anchors the iterator at\n * the head of optval. Only a user buffer can be longer than the optlen the\n- * caller declared, so a kernel-backed optval is refused with -EINVAL.\n+ * caller declared, so a kernel-backed optval is refused with -EINVAL. So is a\n+ * @size above MAX_RW_COUNT, which iov_iter_revert() could not unroll.\n /\n static inline int sockopt_expand_out(sockopt_t opt, size_t size)\n {\n+\t/* iov_iter_revert() refuses to unroll past MAX_RW_COUNT, so a size\n+\t * beyond that could never be reverted back to the fixed part later,\n+\t * even when optlen already covers it.\n+\t /\n+\tif (size \u003e MAX_RW_COUNT)\n+\t\treturn -EINVAL;\n+\n \tif (size \u003c= (size_t)opt-\u003eoptlen)\n \t\treturn 0;\n \n-\tif (size \u003e INT_MAX)\n-\t\treturn -EINVAL;\n-\n \t/ Re-anchoring reads iter_out.ubuf, so the iterator has to be a user\n \t * buffer that nothing has written through yet.\n \t /\ndiff --git a/include/net/ip.h b/include/net/ip.h\nindex 618b9806c10b0..c59ffb432b3ed 100644\n--- a/include/net/ip.h\n+++ b/include/net/ip.h\n@@ -833,8 +833,7 @@ int do_ip_setsockopt(struct sock sk, int level, int optname, sockptr_t optval,\n \t\t unsigned int optlen);\n int ip_setsockopt(struct sock sk, int level, int optname, sockptr_t optval,\n \t\t unsigned int optlen);\n-int do_ip_getsockopt(struct sock sk, int level, int optname,\n-\t\t sockptr_t optval, sockptr_t optlen);\n+int do_ip_getsockopt(struct sock sk, int level, int optname, sockopt_t sopt);\n int ip_getsockopt(struct sock sk, int level, int optname, char __user optval,\n \t\t int __user optlen);\n int ip_ra_control(struct sock sk, unsigned char on,\ndiff --git a/include/net/ipv6.h b/include/net/ipv6.h\nindex 3de07e738538f..a1e1de7da8c70 100644\n--- a/include/net/ipv6.h\n+++ b/include/net/ipv6.h\n@@ -1142,7 +1142,7 @@ int do_ipv6_setsockopt(struct sock sk, int level, int optname, sockptr_t optval\n int ipv6_setsockopt(struct sock sk, int level, int optname, sockptr_t optval,\n \t\t unsigned int optlen);\n int do_ipv6_getsockopt(struct sock sk, int level, int optname,\n-\t\t sockptr_t optval, sockptr_t optlen);\n+\t\t sockopt_t sopt);\n int ipv6_getsockopt(struct sock sk, int level, int optname,\n \t\t char __user optval, int __user optlen);\n \n@@ -1195,7 +1195,7 @@ int ip6_mc_source(int add, int omode, struct sock sk,\n int ip6_mc_msfilter(struct sock sk, struct group_filter gsf,\n \t\t struct sockaddr_storage list);\n int ip6_mc_msfget(struct sock sk, struct group_filter gsf,\n-\t\t sockptr_t optval, size_t ss_offset);\n+\t\t sockopt_t opt, size_t ss_offset);\n \n #ifdef CONFIG_PROC_FS\n int ac6_proc_init(struct net net);\ndiff --git a/net/core/filter.c b/net/core/filter.c\nindex 5e575981febec..03d4778ad99ac 100644\n--- a/net/core/filter.c\n+++ b/net/core/filter.c\n@@ -5737,10 +5737,20 @@ static int sol_ip_sockopt(struct sock sk, int optname,\n \t\treturn -EINVAL;\n \t}\n \n-\tif (getopt)\n-\t\treturn do_ip_getsockopt(sk, SOL_IP, optname,\n-\t\t\t\t\tKERNEL_SOCKPTR(optval),\n-\t\t\t\t\tKERNEL_SOCKPTR(optlen));\n+\tif (getopt) {\n+\t\tstruct kvec kvec;\n+\t\tsockopt_t opt;\n+\t\tint err;\n+\n+\t\terr = sockptr_to_sockopt(\u0026opt, KERNEL_SOCKPTR(optval),\n+\t\t\t\t\t KERNEL_SOCKPTR(optlen), \u0026kvec);\n+\t\tif (err)\n+\t\t\treturn err;\n+\n+\t\terr = do_ip_getsockopt(sk, SOL_IP, optname, \u0026opt);\n+\t\toptlen = opt.optlen;\n+\t\treturn err;\n+\t}\n \n \treturn do_ip_setsockopt(sk, SOL_IP, optname,\n \t\t\t\tKERNEL_SOCKPTR(optval), optlen);\n@@ -5764,10 +5774,20 @@ static int sol_ipv6_sockopt(struct sock sk, int optname,\n \t\treturn -EINVAL;\n \t}\n \n-\tif (getopt)\n-\t\treturn do_ipv6_getsockopt(sk, SOL_IPV6, optname,\n-\t\t\t\t\t KERNEL_SOCKPTR(optval),\n-\t\t\t\t\t KERNEL_SOCKPTR(optlen));\n+\tif (getopt) {\n+\t\tstruct kvec kvec;\n+\t\tsockopt_t opt;\n+\t\tint err;\n+\n+\t\terr = sockptr_to_sockopt(\u0026opt, KERNEL_SOCKPTR(optval),\n+\t\t\t\t\t KERNEL_SOCKPTR(optlen), \u0026kvec);\n+\t\tif (err)\n+\t\t\treturn err;\n+\n+\t\terr = do_ipv6_getsockopt(sk, SOL_IPV6, optname, \u0026opt);\n+\t\toptlen = opt.optlen;\n+\t\treturn err;\n+\t}\n \n \treturn do_ipv6_setsockopt(sk, SOL_IPV6, optname,\n \t\t\t\t KERNEL_SOCKPTR(optval), optlen);\ndiff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c\nindex 144fca158adcb..bf00810cdd7a1 100644\n--- a/net/ipv4/igmp.c\n+++ b/net/ipv4/igmp.c\n@@ -2763,21 +2763,22 @@ int ip_mc_msfget(struct sock sk, struct ip_msfilter msf, sockopt_t opt)\n \tif (err)\n \t\treturn err;\n \n-\topt-\u003eoptlen = msf_size;\n \tif (copy_to_iter(msf, IP_MSFILTER_SIZE(0), \u0026opt-\u003eiter_out) !=\n \t IP_MSFILTER_SIZE(0))\n \t\treturn -EFAULT;\n \tif (len \u0026\u0026 copy_to_iter(psl-\u003esl_addr, len, \u0026opt-\u003eiter_out) != len)\n \t\treturn -EFAULT;\n+\n+\topt-\u003eoptlen = msf_size;\n \treturn 0;\n done:\n \treturn err;\n }\n \n int ip_mc_gsfget(struct sock sk, struct group_filter gsf,\n-\t\t sockptr_t optval, size_t ss_offset)\n+\t\t sockopt_t opt, size_t ss_offset)\n {\n-\tint i, count, copycount;\n+\tint i, count, copycount, err;\n \tstruct sockaddr_in psin;\n \t__be32 addr;\n \tstruct ip_mc_socklist pmc;\n@@ -2805,6 +2806,18 @@ int ip_mc_gsfget(struct sock sk, struct group_filter gsf,\n \tcount = psl ? psl-\u003esl_count : 0;\n \tcopycount = count \u003c gsf-\u003egf_numsrc ? count : gsf-\u003egf_numsrc;\n \tgsf-\u003egf_numsrc = count;\n+\n+\t/ The source list is sized by the gf_numsrc the caller left in optval,\n+\t * not by optlen, which only has to cover the fixed part.\n+\t /\n+\terr = sockopt_expand_out(opt, ss_offset +\n+\t\t\t\t copycount sizeof(struct sockaddr_storage));\n+\tif (err)\n+\t\treturn err;\n+\n+\t/* The caller fills the fixed part in once it knows gf_numsrc. /\n+\tiov_iter_advance(\u0026opt-\u003eiter_out, ss_offset);\n+\n \tfor (i = 0; i \u003c copycount; i++) {\n \t\tstruct sockaddr_storage ss;\n \n@@ -2812,10 +2825,8 @@ int ip_mc_gsfget(struct sock sk, struct group_filter gsf,\n \t\tmemset(\u0026ss, 0, sizeof(ss));\n \t\tpsin-\u003esin_family = AF_INET;\n \t\tpsin-\u003esin_addr.s_addr = psl-\u003esl_addr[i];\n-\t\tif (copy_to_sockptr_offset(optval, ss_offset,\n-\t\t\t\t\t \u0026ss, sizeof(ss)))\n+\t\tif (copy_to_iter(\u0026ss, sizeof(ss), \u0026opt-\u003eiter_out) != sizeof(ss))\n \t\t\treturn -EFAULT;\n-\t\tss_offset += sizeof(ss);\n \t}\n \treturn 0;\n }\ndiff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c\nindex e06c1f48ecad6..90d0b5bee68b5 100644\n--- a/net/ipv4/ip_sockglue.c\n+++ b/net/ipv4/ip_sockglue.c\n@@ -1442,45 +1442,46 @@ static bool getsockopt_needs_rtnl(int optname)\n \treturn false;\n }\n \n-static int ip_get_mcast_msfilter(struct sock sk, sockptr_t optval,\n-\t\t\t\t sockptr_t optlen, int len)\n+static int ip_get_mcast_msfilter(struct sock sk, sockopt_t opt)\n {\n \tconst int size0 = offsetof(struct group_filter, gf_slist_flex);\n \tstruct group_filter gsf;\n \tint num, gsf_size;\n \tint err;\n \n-\tif (len \u003c size0)\n+\tif (opt-\u003eoptlen \u003c size0)\n \t\treturn -EINVAL;\n-\tif (copy_from_sockptr(\u0026gsf, optval, size0))\n+\tif (copy_from_iter(\u0026gsf, size0, \u0026opt-\u003eiter_in) != size0)\n \t\treturn -EFAULT;\n \n \tnum = gsf.gf_numsrc;\n-\terr = ip_mc_gsfget(sk, \u0026gsf, optval,\n+\terr = ip_mc_gsfget(sk, \u0026gsf, opt,\n \t\t\t offsetof(struct group_filter, gf_slist_flex));\n \tif (err)\n \t\treturn err;\n \tif (gsf.gf_numsrc \u003c num)\n \t\tnum = gsf.gf_numsrc;\n \tgsf_size = GROUP_FILTER_SIZE(num);\n-\tif (copy_to_sockptr(optlen, \u0026gsf_size, sizeof(int)) \|\|\n-\t copy_to_sockptr(optval, \u0026gsf, size0))\n+\n+\t/* ip_mc_gsfget() consumed the whole reply; rewind to the fixed part. /\n+\tiov_iter_revert(\u0026opt-\u003eiter_out, gsf_size);\n+\tif (copy_to_iter(\u0026gsf, size0, \u0026opt-\u003eiter_out) != size0)\n \t\treturn -EFAULT;\n+\topt-\u003eoptlen = gsf_size;\n \treturn 0;\n }\n \n-static int compat_ip_get_mcast_msfilter(struct sock sk, sockptr_t optval,\n-\t\t\t\t\tsockptr_t optlen, int len)\n+static int compat_ip_get_mcast_msfilter(struct sock sk, sockopt_t opt)\n {\n \tconst int size0 = offsetof(struct compat_group_filter, gf_slist_flex);\n \tstruct compat_group_filter gf32;\n \tstruct group_filter gf;\n-\tint num;\n+\tint num, len;\n \tint err;\n \n-\tif (len \u003c size0)\n+\tif (opt-\u003eoptlen \u003c size0)\n \t\treturn -EINVAL;\n-\tif (copy_from_sockptr(\u0026gf32, optval, size0))\n+\tif (copy_from_iter(\u0026gf32, size0, \u0026opt-\u003eiter_in) != size0)\n \t\treturn -EFAULT;\n \n \tgf.gf_interface = gf32.gf_interface;\n@@ -1488,24 +1489,27 @@ static int compat_ip_get_mcast_msfilter(struct sock sk, sockptr_t optval,\n \tnum = gf.gf_numsrc = gf32.gf_numsrc;\n \tgf.gf_group = gf32.gf_group;\n \n-\terr = ip_mc_gsfget(sk, \u0026gf, optval,\n+\terr = ip_mc_gsfget(sk, \u0026gf, opt,\n \t\t\t offsetof(struct compat_group_filter, gf_slist_flex));\n \tif (err)\n \t\treturn err;\n \tif (gf.gf_numsrc \u003c num)\n \t\tnum = gf.gf_numsrc;\n \tlen = GROUP_FILTER_SIZE(num) - (sizeof(gf) - sizeof(gf32));\n-\tif (copy_to_sockptr(optlen, \u0026len, sizeof(int)) \|\|\n-\t copy_to_sockptr_offset(optval, offsetof(struct compat_group_filter, gf_fmode),\n-\t\t\t\t \u0026gf.gf_fmode, sizeof(gf.gf_fmode)) \|\|\n-\t copy_to_sockptr_offset(optval, offsetof(struct compat_group_filter, gf_numsrc),\n-\t\t\t\t \u0026gf.gf_numsrc, sizeof(gf.gf_numsrc)))\n+\n+\t/ Rewind to gf_fmode, which gf_numsrc follows. /\n+\tiov_iter_revert(\u0026opt-\u003eiter_out,\n+\t\t\tlen - offsetof(struct compat_group_filter, gf_fmode));\n+\tif (copy_to_iter(\u0026gf.gf_fmode, sizeof(gf32.gf_fmode),\n+\t\t\t \u0026opt-\u003eiter_out) != sizeof(gf32.gf_fmode) \|\|\n+\t copy_to_iter(\u0026gf.gf_numsrc, sizeof(gf32.gf_numsrc),\n+\t\t\t \u0026opt-\u003eiter_out) != sizeof(gf32.gf_numsrc))\n \t\treturn -EFAULT;\n+\topt-\u003eoptlen = len;\n \treturn 0;\n }\n \n-int do_ip_getsockopt(struct sock sk, int level, int optname,\n-\t\t sockptr_t optval, sockptr_t optlen)\n+int do_ip_getsockopt(struct sock sk, int level, int optname, sockopt_t sopt)\n {\n \tstruct inet_sock inet = inet_sk(sk);\n \tbool needs_rtnl = getsockopt_needs_rtnl(optname);\n@@ -1516,10 +1520,9 @@ int do_ip_getsockopt(struct sock sk, int level, int optname,\n \t\treturn -EOPNOTSUPP;\n \n \tif (ip_mroute_opt(optname))\n-\t\treturn ip_mroute_getsockopt(sk, optname, optval, optlen);\n+\t\treturn ip_mroute_getsockopt(sk, optname, sopt);\n \n-\tif (copy_from_sockptr(\u0026len, optlen, sizeof(int)))\n-\t\treturn -EFAULT;\n+\tlen = sopt-\u003eoptlen;\n \tif (len \u003c 0)\n \t\treturn -EINVAL;\n \n@@ -1615,16 +1618,15 @@ int do_ip_getsockopt(struct sock sk, int level, int optname,\n \t\trcu_read_unlock();\n \n \t\tif (opt-\u003eoptlen == 0) {\n-\t\t\tlen = 0;\n-\t\t\treturn copy_to_sockptr(optlen, \u0026len, sizeof(int));\n+\t\t\tsopt-\u003eoptlen = 0;\n+\t\t\treturn 0;\n \t\t}\n \n \t\tip_options_undo(opt);\n \n \t\tlen = min_t(unsigned int, len, opt-\u003eoptlen);\n-\t\tif (copy_to_sockptr(optlen, \u0026len, sizeof(int)))\n-\t\t\treturn -EFAULT;\n-\t\tif (copy_to_sockptr(optval, opt-\u003e__data, len))\n+\t\tsopt-\u003eoptlen = len;\n+\t\tif (copy_to_iter(opt-\u003e__data, len, \u0026sopt-\u003eiter_out) != len)\n \t\t\treturn -EFAULT;\n \t\treturn 0;\n \t}\n@@ -1648,12 +1650,12 @@ int do_ip_getsockopt(struct sock sk, int level, int optname,\n \t\tif (sk-\u003esk_type != SOCK_STREAM)\n \t\t\treturn -ENOPROTOOPT;\n \n-\t\tif (optval.is_kernel) {\n+\t\tif (iov_iter_is_kvec(\u0026sopt-\u003eiter_out)) {\n \t\t\tmsg.msg_control_is_user = false;\n-\t\t\tmsg.msg_control = optval.kernel;\n+\t\t\tmsg.msg_control = sopt-\u003eiter_out.kvec-\u003eiov_base;\n \t\t} else {\n \t\t\tmsg.msg_control_is_user = true;\n-\t\t\tmsg.msg_control_user = optval.user;\n+\t\t\tmsg.msg_control_user = sopt-\u003eiter_out.ubuf;\n \t\t}\n \t\tmsg.msg_controllen = len;\n \t\tmsg.msg_flags = in_compat_syscall() ? MSG_CMSG_COMPAT : 0;\n@@ -1675,8 +1677,8 @@ int do_ip_getsockopt(struct sock sk, int level, int optname,\n \t\t\tint tos = READ_ONCE(inet-\u003ercv_tos);\n \t\t\tput_cmsg(\u0026msg, SOL_IP, IP_TOS, sizeof(tos), \u0026tos);\n \t\t}\n-\t\tlen -= msg.msg_controllen;\n-\t\treturn copy_to_sockptr(optlen, \u0026len, sizeof(int));\n+\t\tsopt-\u003eoptlen = len - msg.msg_controllen;\n+\t\treturn 0;\n \t}\n \tcase IP_UNICAST_IF:\n \t\tval = (__force int)htonl((__u32) READ_ONCE(inet-\u003euc_index));\n@@ -1687,9 +1689,8 @@ int do_ip_getsockopt(struct sock sk, int level, int optname,\n \t\tlen = min_t(unsigned int, len, sizeof(struct in_addr));\n \t\taddr.s_addr = READ_ONCE(inet-\u003emc_addr);\n \n-\t\tif (copy_to_sockptr(optlen, \u0026len, sizeof(int)))\n-\t\t\treturn -EFAULT;\n-\t\tif (copy_to_sockptr(optval, \u0026addr, len))\n+\t\tsopt-\u003eoptlen = len;\n+\t\tif (copy_to_iter(\u0026addr, len, \u0026sopt-\u003eiter_out) != len)\n \t\t\treturn -EFAULT;\n \t\treturn 0;\n \t}\n@@ -1706,32 +1707,24 @@ int do_ip_getsockopt(struct sock sk, int level, int optname,\n \tcase IP_MSFILTER:\n \t{\n \t\tstruct ip_msfilter msf;\n-\t\tstruct kvec kvec;\n-\t\tsockopt_t opt;\n \n \t\tif (len \u003c IP_MSFILTER_SIZE(0)) {\n \t\t\terr = -EINVAL;\n \t\t\tgoto out;\n \t\t}\n-\t\tif (copy_from_sockptr(\u0026msf, optval, IP_MSFILTER_SIZE(0))) {\n+\t\tif (copy_from_iter(\u0026msf, IP_MSFILTER_SIZE(0), \u0026sopt-\u003eiter_in) !=\n+\t\t IP_MSFILTER_SIZE(0)) {\n \t\t\terr = -EFAULT;\n \t\t\tgoto out;\n \t\t}\n-\t\terr = sockptr_to_sockopt(\u0026opt, optval, optlen, \u0026kvec);\n-\t\tif (err)\n-\t\t\tgoto out;\n-\n-\t\terr = ip_mc_msfget(sk, \u0026msf, \u0026opt);\n-\t\tif (!err \u0026\u0026 copy_to_sockptr(optlen, \u0026opt.optlen, sizeof(int)))\n-\t\t\terr = -EFAULT;\n+\t\terr = ip_mc_msfget(sk, \u0026msf, sopt);\n \t\tgoto out;\n \t}\n \tcase MCAST_MSFILTER:\n \t\tif (in_compat_syscall())\n-\t\t\terr = compat_ip_get_mcast_msfilter(sk, optval, optlen,\n-\t\t\t\t\t\t\t len);\n+\t\t\terr = compat_ip_get_mcast_msfilter(sk, sopt);\n \t\telse\n-\t\t\terr = ip_get_mcast_msfilter(sk, optval, optlen, len);\n+\t\t\terr = ip_get_mcast_msfilter(sk, sopt);\n \t\tgoto out;\n \tcase IP_PROTOCOL:\n \t\tval = inet_sk(sk)-\u003einet_num;\n@@ -1744,16 +1737,14 @@ int do_ip_getsockopt(struct sock sk, int level, int optname,\n copyval:\n \tif (len \u003c sizeof(int) \u0026\u0026 len \u003e 0 \u0026\u0026 val \u003e= 0 \u0026\u0026 val \u003c= 255) {\n \t\tunsigned char ucval = (unsigned char)val;\n-\t\tlen = 1;\n-\t\tif (copy_to_sockptr(optlen, \u0026len, sizeof(int)))\n-\t\t\treturn -EFAULT;\n-\t\tif (copy_to_sockptr(optval, \u0026ucval, 1))\n+\n+\t\tsopt-\u003eoptlen = 1;\n+\t\tif (copy_to_iter(\u0026ucval, 1, \u0026sopt-\u003eiter_out) != 1)\n \t\t\treturn -EFAULT;\n \t} else {\n \t\tlen = min_t(unsigned int, sizeof(int), len);\n-\t\tif (copy_to_sockptr(optlen, \u0026len, sizeof(int)))\n-\t\t\treturn -EFAULT;\n-\t\tif (copy_to_sockptr(optval, \u0026val, len))\n+\t\tsopt-\u003eoptlen = len;\n+\t\tif (copy_to_iter(\u0026val, len, \u0026sopt-\u003eiter_out) != len)\n \t\t\treturn -EFAULT;\n \t}\n \treturn 0;\n@@ -1768,19 +1759,22 @@ int do_ip_getsockopt(struct sock sk, int level, int optname,\n int ip_getsockopt(struct sock sk, int level,\n \t\t int optname, char __user optval, int __user optlen)\n {\n+\tsockopt_t opt;\n \tint err;\n \n-\terr = do_ip_getsockopt(sk, level, optname,\n-\t\t\t USER_SOCKPTR(optval), USER_SOCKPTR(optlen));\n+\terr = sockopt_init_user(\u0026opt, optval, optlen);\n+\tif (err)\n+\t\treturn err;\n+\n+\terr = do_ip_getsockopt(sk, level, optname, \u0026opt);\n+\tif (put_user(opt.optlen, optlen))\n+\t\treturn -EFAULT;\n \n #ifdef CONFIG_NETFILTER\n \t/* we need to exclude all possible ENOPROTOOPTs except default case /\n \tif (err == -ENOPROTOOPT \u0026\u0026 optname != IP_PKTOPTIONS \u0026\u0026\n \t\t\t!ip_mroute_opt(optname)) {\n-\t\tint len;\n-\n-\t\tif (get_user(len, optlen))\n-\t\t\treturn -EFAULT;\n+\t\tint len = opt.optlen;\n \n \t\terr = nf_getsockopt(sk, PF_INET, optname, optval, \u0026len);\n \t\tif (err \u003e= 0)\ndiff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c\nindex e4c51ca473019..f249569b4bf8b 100644\n--- a/net/ipv4/ipmr.c\n+++ b/net/ipv4/ipmr.c\n@@ -1638,8 +1638,7 @@ int ipmr_sk_ioctl(struct sock sk, unsigned int cmd, void __user arg)\n }\n \n / Getsock opt support for the multicast routing system. /\n-int ip_mroute_getsockopt(struct sock sk, int optname, sockptr_t optval,\n-\t\t\t sockptr_t optlen)\n+int ip_mroute_getsockopt(struct sock sk, int optname, sockopt_t opt)\n {\n \tint olr;\n \tint val;\n@@ -1670,16 +1669,14 @@ int ip_mroute_getsockopt(struct sock sk, int optname, sockptr_t optval,\n \t\treturn -ENOPROTOOPT;\n \t}\n \n-\tif (copy_from_sockptr(\u0026olr, optlen, sizeof(int)))\n-\t\treturn -EFAULT;\n+\tolr = opt-\u003eoptlen;\n \tif (olr \u003c 0)\n \t\treturn -EINVAL;\n \n \tolr = min_t(unsigned int, olr, sizeof(int));\n \n-\tif (copy_to_sockptr(optlen, \u0026olr, sizeof(int)))\n-\t\treturn -EFAULT;\n-\tif (copy_to_sockptr(optval, \u0026val, olr))\n+\topt-\u003eoptlen = olr;\n+\tif (copy_to_iter(\u0026val, olr, \u0026opt-\u003eiter_out) != olr)\n \t\treturn -EFAULT;\n \treturn 0;\n }\ndiff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c\nindex 36f117ad36708..9513258b95fb8 100644\n--- a/net/ipv6/ip6mr.c\n+++ b/net/ipv6/ip6mr.c\n@@ -1893,8 +1893,7 @@ int ip6_mroute_setsockopt(struct sock sk, int optname, sockptr_t optval,\n \tGetsock opt support for the multicast routing system.\n /\n \n-int ip6_mroute_getsockopt(struct sock sk, int optname, sockptr_t optval,\n-\t\t\t sockptr_t optlen)\n+int ip6_mroute_getsockopt(struct sock sk, int optname, sockopt_t sopt)\n {\n \tint olr;\n \tint val;\n@@ -1925,16 +1924,12 @@ int ip6_mroute_getsockopt(struct sock sk, int optname, sockptr_t optval,\n \t\treturn -ENOPROTOOPT;\n \t}\n \n-\tif (copy_from_sockptr(\u0026olr, optlen, sizeof(int)))\n-\t\treturn -EFAULT;\n-\n-\tolr = min_t(int, olr, sizeof(int));\n+\tolr = min_t(int, sopt-\u003eoptlen, sizeof(int));\n \tif (olr \u003c 0)\n \t\treturn -EINVAL;\n \n-\tif (copy_to_sockptr(optlen, \u0026olr, sizeof(int)))\n-\t\treturn -EFAULT;\n-\tif (copy_to_sockptr(optval, \u0026val, olr))\n+\tsopt-\u003eoptlen = olr;\n+\tif (copy_to_iter(\u0026val, olr, \u0026sopt-\u003eiter_out) != olr)\n \t\treturn -EFAULT;\n \treturn 0;\n }\ndiff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c\nindex 4b3536571c980..b1011319cd3ec 100644\n--- a/net/ipv6/ipv6_sockglue.c\n+++ b/net/ipv6/ipv6_sockglue.c\n@@ -889,7 +889,7 @@ int ipv6_setsockopt(struct sock sk, int level, int optname, sockptr_t optval,\n EXPORT_SYMBOL(ipv6_setsockopt);\n \n static int ipv6_getsockopt_sticky(struct sock sk, struct ipv6_txoptions opt,\n-\t\t\t\t int optname, sockptr_t optval, int len)\n+\t\t\t\t int optname, sockopt_t sopt, int len)\n {\n \tstruct ipv6_opt_hdr hdr;\n \n@@ -917,53 +917,57 @@ static int ipv6_getsockopt_sticky(struct sock sk, struct ipv6_txoptions opt,\n \t\treturn 0;\n \n \tlen = min_t(unsigned int, len, ipv6_optlen(hdr));\n-\tif (copy_to_sockptr(optval, hdr, len))\n+\tif (copy_to_iter(hdr, len, \u0026sopt-\u003eiter_out) != len)\n \t\treturn -EFAULT;\n \treturn len;\n }\n \n-static int ipv6_get_msfilter(struct sock sk, sockptr_t optval,\n-\t\t\t sockptr_t optlen, int len)\n+static int ipv6_get_msfilter(struct sock sk, sockopt_t opt)\n {\n \tconst int size0 = offsetof(struct group_filter, gf_slist_flex);\n \tstruct group_filter gsf;\n-\tint num;\n+\tint num, len;\n \tint err;\n \n-\tif (len \u003c size0)\n+\tif (opt-\u003eoptlen \u003c size0)\n \t\treturn -EINVAL;\n-\tif (copy_from_sockptr(\u0026gsf, optval, size0))\n+\tif (copy_from_iter(\u0026gsf, size0, \u0026opt-\u003eiter_in) != size0)\n \t\treturn -EFAULT;\n \tif (gsf.gf_group.ss_family != AF_INET6)\n \t\treturn -EADDRNOTAVAIL;\n \tnum = gsf.gf_numsrc;\n \tsockopt_lock_sock(sk);\n-\terr = ip6_mc_msfget(sk, \u0026gsf, optval, size0);\n+\terr = ip6_mc_msfget(sk, \u0026gsf, opt, size0);\n \tif (!err) {\n \t\tif (num \u003e gsf.gf_numsrc)\n \t\t\tnum = gsf.gf_numsrc;\n \t\tlen = GROUP_FILTER_SIZE(num);\n-\t\tif (copy_to_sockptr(optlen, \u0026len, sizeof(int)) \|\|\n-\t\t copy_to_sockptr(optval, \u0026gsf, size0))\n+\n+\t\t/* ip6_mc_msfget() consumed the whole reply; rewind to the\n+\t\t * fixed part.\n+\t\t /\n+\t\tiov_iter_revert(\u0026opt-\u003eiter_out, len);\n+\t\tif (copy_to_iter(\u0026gsf, size0, \u0026opt-\u003eiter_out) != size0)\n \t\t\terr = -EFAULT;\n+\t\telse\n+\t\t\topt-\u003eoptlen = len;\n \t}\n \tsockopt_release_sock(sk);\n \treturn err;\n }\n \n-static int compat_ipv6_get_msfilter(struct sock sk, sockptr_t optval,\n-\t\t\t\t sockptr_t optlen, int len)\n+static int compat_ipv6_get_msfilter(struct sock sk, sockopt_t opt)\n {\n \tconst int size0 = offsetof(struct compat_group_filter, gf_slist_flex);\n \tstruct compat_group_filter gf32;\n \tstruct group_filter gf;\n \tint err;\n-\tint num;\n+\tint num, len;\n \n-\tif (len \u003c size0)\n+\tif (opt-\u003eoptlen \u003c size0)\n \t\treturn -EINVAL;\n \n-\tif (copy_from_sockptr(\u0026gf32, optval, size0))\n+\tif (copy_from_iter(\u0026gf32, size0, \u0026opt-\u003eiter_in) != size0)\n \t\treturn -EFAULT;\n \tgf.gf_interface = gf32.gf_interface;\n \tgf.gf_fmode = gf32.gf_fmode;\n@@ -974,39 +978,41 @@ static int compat_ipv6_get_msfilter(struct sock sk, sockptr_t optval,\n \t\treturn -EADDRNOTAVAIL;\n \n \tsockopt_lock_sock(sk);\n-\terr = ip6_mc_msfget(sk, \u0026gf, optval, size0);\n+\terr = ip6_mc_msfget(sk, \u0026gf, opt, size0);\n \tsockopt_release_sock(sk);\n \tif (err)\n \t\treturn err;\n \tif (num \u003e gf.gf_numsrc)\n \t\tnum = gf.gf_numsrc;\n \tlen = GROUP_FILTER_SIZE(num) - (sizeof(gf)-sizeof(gf32));\n-\tif (copy_to_sockptr(optlen, \u0026len, sizeof(int)) \|\|\n-\t copy_to_sockptr_offset(optval, offsetof(struct compat_group_filter, gf_fmode),\n-\t\t\t\t \u0026gf.gf_fmode, sizeof(gf32.gf_fmode)) \|\|\n-\t copy_to_sockptr_offset(optval, offsetof(struct compat_group_filter, gf_numsrc),\n-\t\t\t\t \u0026gf.gf_numsrc, sizeof(gf32.gf_numsrc)))\n+\n+\t/ Rewind to gf_fmode, which gf_numsrc follows. /\n+\tiov_iter_revert(\u0026opt-\u003eiter_out,\n+\t\t\tlen - offsetof(struct compat_group_filter, gf_fmode));\n+\tif (copy_to_iter(\u0026gf.gf_fmode, sizeof(gf32.gf_fmode),\n+\t\t\t \u0026opt-\u003eiter_out) != sizeof(gf32.gf_fmode) \|\|\n+\t copy_to_iter(\u0026gf.gf_numsrc, sizeof(gf32.gf_numsrc),\n+\t\t\t \u0026opt-\u003eiter_out) != sizeof(gf32.gf_numsrc))\n \t\treturn -EFAULT;\n+\topt-\u003eoptlen = len;\n \treturn 0;\n }\n \n-int do_ipv6_getsockopt(struct sock sk, int level, int optname,\n-\t\t sockptr_t optval, sockptr_t optlen)\n+int do_ipv6_getsockopt(struct sock sk, int level, int optname, sockopt_t sopt)\n {\n \tstruct ipv6_pinfo np = inet6_sk(sk);\n \tint len;\n \tint val;\n \n \tif (ip6_mroute_opt(optname))\n-\t\treturn ip6_mroute_getsockopt(sk, optname, optval, optlen);\n+\t\treturn ip6_mroute_getsockopt(sk, optname, sopt);\n \n-\tif (copy_from_sockptr(\u0026len, optlen, sizeof(int)))\n-\t\treturn -EFAULT;\n+\tlen = sopt-\u003eoptlen;\n \tswitch (optname) {\n \tcase MCAST_MSFILTER:\n \t\tif (in_compat_syscall())\n-\t\t\treturn compat_ipv6_get_msfilter(sk, optval, optlen, len);\n-\t\treturn ipv6_get_msfilter(sk, optval, optlen, len);\n+\t\t\treturn compat_ipv6_get_msfilter(sk, sopt);\n+\t\treturn ipv6_get_msfilter(sk, sopt);\n \tcase IPV6_2292PKTOPTIONS:\n \t{\n \t\tstruct msghdr msg;\n@@ -1015,12 +1021,12 @@ int do_ipv6_getsockopt(struct sock sk, int level, int optname,\n \t\tif (sk-\u003esk_type != SOCK_STREAM)\n \t\t\treturn -ENOPROTOOPT;\n \n-\t\tif (optval.is_kernel) {\n+\t\tif (iov_iter_is_kvec(\u0026sopt-\u003eiter_out)) {\n \t\t\tmsg.msg_control_is_user = false;\n-\t\t\tmsg.msg_control = optval.kernel;\n+\t\t\tmsg.msg_control = sopt-\u003eiter_out.kvec-\u003eiov_base;\n \t\t} else {\n \t\t\tmsg.msg_control_is_user = true;\n-\t\t\tmsg.msg_control_user = optval.user;\n+\t\t\tmsg.msg_control_user = sopt-\u003eiter_out.ubuf;\n \t\t}\n \t\tmsg.msg_controllen = len;\n \t\tmsg.msg_flags = 0;\n@@ -1071,8 +1077,8 @@ int do_ipv6_getsockopt(struct sock sk, int level, int optname,\n \t\t\t\tput_cmsg(\u0026msg, SOL_IPV6, IPV6_FLOWINFO, sizeof(flowinfo), \u0026flowinfo);\n \t\t\t}\n \t\t}\n-\t\tlen -= msg.msg_controllen;\n-\t\treturn copy_to_sockptr(optlen, \u0026len, sizeof(int));\n+\t\tsopt-\u003eoptlen = len - msg.msg_controllen;\n+\t\treturn 0;\n \t}\n \tcase IPV6_MTU:\n \t{\n@@ -1127,12 +1133,13 @@ int do_ipv6_getsockopt(struct sock sk, int level, int optname,\n \t\tsockopt_lock_sock(sk);\n \t\topt = rcu_dereference_protected(np-\u003eopt,\n \t\t\t\t\t\tlockdep_sock_is_held(sk));\n-\t\tlen = ipv6_getsockopt_sticky(sk, opt, optname, optval, len);\n+\t\tlen = ipv6_getsockopt_sticky(sk, opt, optname, sopt, len);\n \t\tsockopt_release_sock(sk);\n \t\t/* check if ipv6_getsockopt_sticky() returns err code /\n \t\tif (len \u003c 0)\n \t\t\treturn len;\n-\t\treturn copy_to_sockptr(optlen, \u0026len, sizeof(int));\n+\t\tsopt-\u003eoptlen = len;\n+\t\treturn 0;\n \t}\n \n \tcase IPV6_RECVHOPOPTS:\n@@ -1186,9 +1193,8 @@ int do_ipv6_getsockopt(struct sock sk, int level, int optname,\n \t\tif (!mtuinfo.ip6m_mtu)\n \t\t\treturn -ENOTCONN;\n \n-\t\tif (copy_to_sockptr(optlen, \u0026len, sizeof(int)))\n-\t\t\treturn -EFAULT;\n-\t\tif (copy_to_sockptr(optval, \u0026mtuinfo, len))\n+\t\tsopt-\u003eoptlen = len;\n+\t\tif (copy_to_iter(\u0026mtuinfo, len, \u0026sopt-\u003eiter_out) != len)\n \t\t\treturn -EFAULT;\n \n \t\treturn 0;\n@@ -1265,7 +1271,8 @@ int do_ipv6_getsockopt(struct sock sk, int level, int optname,\n \t\tif (len \u003c sizeof(freq))\n \t\t\treturn -EINVAL;\n \n-\t\tif (copy_from_sockptr(\u0026freq, optval, sizeof(freq)))\n+\t\tif (copy_from_iter(\u0026freq, sizeof(freq), \u0026sopt-\u003eiter_in) !=\n+\t\t sizeof(freq))\n \t\t\treturn -EFAULT;\n \n \t\tif (freq.flr_action != IPV6_FL_A_GET)\n@@ -1280,9 +1287,8 @@ int do_ipv6_getsockopt(struct sock sk, int level, int optname,\n \t\tif (val \u003c 0)\n \t\t\treturn val;\n \n-\t\tif (copy_to_sockptr(optlen, \u0026len, sizeof(int)))\n-\t\t\treturn -EFAULT;\n-\t\tif (copy_to_sockptr(optval, \u0026freq, len))\n+\t\tsopt-\u003eoptlen = len;\n+\t\tif (copy_to_iter(\u0026freq, len, \u0026sopt-\u003eiter_out) != len)\n \t\t\treturn -EFAULT;\n \n \t\treturn 0;\n@@ -1340,9 +1346,8 @@ int do_ipv6_getsockopt(struct sock sk, int level, int optname,\n \t\treturn -ENOPROTOOPT;\n \t}\n \tlen = min_t(unsigned int, sizeof(int), len);\n-\tif (copy_to_sockptr(optlen, \u0026len, sizeof(int)))\n-\t\treturn -EFAULT;\n-\tif (copy_to_sockptr(optval, \u0026val, len))\n+\tsopt-\u003eoptlen = len;\n+\tif (copy_to_iter(\u0026val, len, \u0026sopt-\u003eiter_out) != len)\n \t\treturn -EFAULT;\n \treturn 0;\n }\n@@ -1350,7 +1355,8 @@ int do_ipv6_getsockopt(struct sock sk, int level, int optname,\n int ipv6_getsockopt(struct sock sk, int level, int optname,\n \t\t char __user optval, int __user optlen)\n {\n-\tint err;\n+\tsockopt_t sopt;\n+\tint len, err;\n \n \tif (level == SOL_IP \u0026\u0026 sk-\u003esk_type != SOCK_RAW)\n \t\treturn ip_getsockopt(sk, level, optname, optval, optlen);\n@@ -1358,15 +1364,25 @@ int ipv6_getsockopt(struct sock sk, int level, int optname,\n \tif (level != SOL_IPV6)\n \t\treturn -ENOPROTOOPT;\n \n-\terr = do_ipv6_getsockopt(sk, level, optname,\n-\t\t\t\t USER_SOCKPTR(optval), USER_SOCKPTR(optlen));\n+\tif (get_user(len, optlen))\n+\t\treturn -EFAULT;\n+\t/* Historic bug compatibility: take a negative optlen as 4, as the\n+\t * int options always did. MRT6_* has always rejected it instead.\n+\t /\n+\tif (len \u003c 0) {\n+\t\tif (ip6_mroute_opt(optname))\n+\t\t\treturn -EINVAL;\n+\t\tlen = 4;\n+\t}\n+\tsockopt_set_user(\u0026sopt, optval, len);\n+\n+\terr = do_ipv6_getsockopt(sk, level, optname, \u0026sopt);\n+\tif (put_user(sopt.optlen, optlen))\n+\t\treturn -EFAULT;\n #ifdef CONFIG_NETFILTER\n \t/ we need to exclude all possible ENOPROTOOPTs except default case /\n \tif (err == -ENOPROTOOPT \u0026\u0026 optname != IPV6_2292PKTOPTIONS) {\n-\t\tint len;\n-\n-\t\tif (get_user(len, optlen))\n-\t\t\treturn -EFAULT;\n+\t\tlen = sopt.optlen;\n \n \t\terr = nf_getsockopt(sk, PF_INET6, optname, optval, \u0026len);\n \t\tif (err \u003e= 0)\ndiff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c\nindex ecef55f261890..4ca2d77811f4e 100644\n--- a/net/ipv6/mcast.c\n+++ b/net/ipv6/mcast.c\n@@ -600,14 +600,14 @@ int ip6_mc_msfilter(struct sock sk, struct group_filter gsf,\n }\n \n int ip6_mc_msfget(struct sock sk, struct group_filter gsf,\n-\t\t sockptr_t optval, size_t ss_offset)\n+\t\t sockopt_t opt, size_t ss_offset)\n {\n \tstruct ipv6_pinfo inet6 = inet6_sk(sk);\n \tconst struct in6_addr group;\n \tstruct ipv6_mc_socklist pmc;\n \tstruct ip6_sf_socklist psl;\n+\tint i, copycount, err;\n \tunsigned int count;\n-\tint i, copycount;\n \n \tgroup = \u0026((struct sockaddr_in6 )\u0026gsf-\u003egf_group)-\u003esin6_addr;\n \n@@ -629,6 +629,18 @@ int ip6_mc_msfget(struct sock sk, struct group_filter gsf,\n \n \tcopycount = min(count, gsf-\u003egf_numsrc);\n \tgsf-\u003egf_numsrc = count;\n+\n+\t/ The source list is sized by the gf_numsrc the caller left in optval,\n+\t * not by optlen, which only has to cover the fixed part.\n+\t /\n+\terr = sockopt_expand_out(opt, ss_offset +\n+\t\t\t\t copycount sizeof(struct sockaddr_storage));\n+\tif (err)\n+\t\treturn err;\n+\n+\t/* The caller fills the fixed part in once it knows gf_numsrc. /\n+\tiov_iter_advance(\u0026opt-\u003eiter_out, ss_offset);\n+\n \tfor (i = 0; i \u003c copycount; i++) {\n \t\tstruct sockaddr_in6 psin6;\n \t\tstruct sockaddr_storage ss;\n@@ -637,9 +649,8 @@ int ip6_mc_msfget(struct sock sk, struct group_filter gsf,\n \t\tmemset(\u0026ss, 0, sizeof(ss));\n \t\tpsin6-\u003esin6_family = AF_INET6;\n \t\tpsin6-\u003esin6_addr = psl-\u003esl_addr[i];\n-\t\tif (copy_to_sockptr_offset(optval, ss_offset, \u0026ss, sizeof(ss)))\n+\t\tif (copy_to_iter(\u0026ss, sizeof(ss), \u0026opt-\u003eiter_out) != sizeof(ss))\n \t\t\treturn -EFAULT;\n-\t\tss_offset += sizeof(ss);\n \t}\n \treturn 0;\n }\ndiff --git a/tools/testing/selftests/net/config b/tools/testing/selftests/net/config\nindex d355cf9805977..07296f0df1394 100644\n--- a/tools/testing/selftests/net/config\n+++ b/tools/testing/selftests/net/config\n@@ -28,6 +28,7 @@ CONFIG_IP6_NF_MATCH_RPFILTER=m\n CONFIG_IP6_NF_NAT=m\n CONFIG_IP6_NF_RAW=m\n CONFIG_IP6_NF_TARGET_REJECT=m\n+CONFIG_IP_MROUTE=y\n CONFIG_IP_NF_FILTER=m\n CONFIG_IP_NF_IPTABLES=m\n CONFIG_IP_NF_IPTABLES_LEGACY=m\ndiff --git a/tools/testing/selftests/net/getsockopt_iter.c b/tools/testing/selftests/net/getsockopt_iter.c\nindex 6c2408df46123..2367fce226d4c 100644\n--- a/tools/testing/selftests/net/getsockopt_iter.c\n+++ b/tools/testing/selftests/net/getsockopt_iter.c\n@@ -55,6 +55,13 @@\n #ifndef TCP_ULP\n #define TCP_ULP 31\n #endif\n+/* linux/mroute.h does not coexist with netinet/in.h here. /\n+#ifndef MRT_VERSION\n+#define MRT_VERSION 206\n+#endif\n+#ifndef MRT6_VERSION\n+#define MRT6_VERSION 206\n+#endif\n \n / ---------- netlink ---------- /\n \n@@ -492,6 +499,371 @@ TEST_F(rawv6, bad_optname)\n \tASSERT_EQ(sizeof(val), optlen);\n }\n \n+/ ---------- ip (SOL_IP) ---------- /\n+\n+FIXTURE(ip)\n+{\n+\tint fd;\n+};\n+\n+FIXTURE_SETUP(ip)\n+{\n+\t/ a router alert option, so IP_OPTIONS has something to answer with /\n+\tstatic const unsigned char ipopts[4] = { 0x94, 0x04, 0x00, 0x00 };\n+\tint ttl = 42;\n+\n+\tself-\u003efd = socket(AF_INET, SOCK_DGRAM, 0);\n+\tif (self-\u003efd \u003c 0)\n+\t\tSKIP(return, \"AF_INET dgram socket: %s\", strerror(errno));\n+\n+\tif (setsockopt(self-\u003efd, SOL_IP, IP_TTL, \u0026ttl, sizeof(ttl)) \u003c 0)\n+\t\tSKIP(return, \"set IP_TTL: %s\", strerror(errno));\n+\n+\tif (setsockopt(self-\u003efd, SOL_IP, IP_OPTIONS, ipopts,\n+\t\t sizeof(ipopts)) \u003c 0)\n+\t\tSKIP(return, \"set IP_OPTIONS: %s\", strerror(errno));\n+}\n+\n+FIXTURE_TEARDOWN(ip)\n+{\n+\tif (self-\u003efd \u003e= 0)\n+\t\tclose(self-\u003efd);\n+}\n+\n+TEST_F(ip, ttl_exact)\n+{\n+\tsocklen_t optlen = sizeof(int);\n+\tint val = 0;\n+\n+\tASSERT_EQ(0, getsockopt(self-\u003efd, SOL_IP, IP_TTL, \u0026val, \u0026optlen));\n+\tASSERT_EQ(sizeof(int), optlen);\n+\tASSERT_EQ(42, val);\n+}\n+\n+TEST_F(ip, ttl_oversize_clamped)\n+{\n+\tsocklen_t optlen = 64;\n+\tint buf[16] = {};\n+\n+\tASSERT_EQ(0, getsockopt(self-\u003efd, SOL_IP, IP_TTL, buf, \u0026optlen));\n+\tASSERT_EQ(sizeof(int), optlen);\n+\tASSERT_EQ(42, buf[0]);\n+}\n+\n+/ SOL_IP answers a sub-int buffer with a single byte when the value fits\n+ * in one, rather than clamping the int down.\n+ /\n+TEST_F(ip, ttl_single_byte)\n+{\n+\tunsigned char buf[3] = {};\n+\tsocklen_t optlen = sizeof(buf);\n+\n+\tASSERT_EQ(0, getsockopt(self-\u003efd, SOL_IP, IP_TTL, buf, \u0026optlen));\n+\tASSERT_EQ(1, optlen);\n+\tASSERT_EQ(42, buf[0]);\n+}\n+\n+TEST_F(ip, ttl_zero_len)\n+{\n+\tsocklen_t optlen = 0;\n+\tint val;\n+\n+\tASSERT_EQ(0, getsockopt(self-\u003efd, SOL_IP, IP_TTL, \u0026val, \u0026optlen));\n+\tASSERT_EQ(0, optlen);\n+}\n+\n+TEST_F(ip, negative_optlen)\n+{\n+\tsocklen_t optlen = (socklen_t)-1;\n+\tint val;\n+\n+\tASSERT_EQ(-1, getsockopt(self-\u003efd, SOL_IP, IP_TTL, \u0026val, \u0026optlen));\n+\tASSERT_EQ(EINVAL, errno);\n+}\n+\n+TEST_F(ip, options_roundtrip)\n+{\n+\tstatic const unsigned char ipopts[4] = { 0x94, 0x04, 0x00, 0x00 };\n+\tunsigned char buf[40] = {};\n+\tsocklen_t optlen = sizeof(buf);\n+\n+\tASSERT_EQ(0, getsockopt(self-\u003efd, SOL_IP, IP_OPTIONS, buf, \u0026optlen));\n+\tASSERT_EQ(sizeof(ipopts), optlen);\n+\tASSERT_EQ(0, memcmp(buf, ipopts, sizeof(ipopts)));\n+}\n+\n+TEST_F(ip, options_undersize_clamped)\n+{\n+\tstatic const unsigned char ipopts[2] = { 0x94, 0x04 };\n+\tunsigned char buf[2] = {};\n+\tsocklen_t optlen = sizeof(buf);\n+\n+\tASSERT_EQ(0, getsockopt(self-\u003efd, SOL_IP, IP_OPTIONS, buf, \u0026optlen));\n+\tASSERT_EQ(sizeof(buf), optlen);\n+\tASSERT_EQ(0, memcmp(buf, ipopts, sizeof(buf)));\n+}\n+\n+/ With no option set the reply is empty and the call still succeeds. /\n+TEST_F(ip, options_absent)\n+{\n+\tunsigned char buf[40] = {};\n+\tsocklen_t optlen = sizeof(buf);\n+\tint fd;\n+\n+\tfd = socket(AF_INET, SOCK_DGRAM, 0);\n+\tif (fd \u003c 0)\n+\t\tSKIP(return, \"AF_INET dgram socket: %s\", strerror(errno));\n+\n+\tASSERT_EQ(0, getsockopt(fd, SOL_IP, IP_OPTIONS, buf, \u0026optlen));\n+\tASSERT_EQ(0, optlen);\n+\tclose(fd);\n+}\n+\n+TEST_F(ip, multicast_if_oversize_clamped)\n+{\n+\tstruct in_addr any = { .s_addr = INADDR_ANY };\n+\tsocklen_t optlen = 64;\n+\tunsigned char buf[64];\n+\n+\tmemset(buf, 0xaa, sizeof(buf));\n+\tASSERT_EQ(0, getsockopt(self-\u003efd, SOL_IP, IP_MULTICAST_IF, buf,\n+\t\t\t\t\u0026optlen));\n+\tASSERT_EQ(sizeof(struct in_addr), optlen);\n+\tASSERT_EQ(0, memcmp(buf, \u0026any, sizeof(any)));\n+\tASSERT_EQ(0xaa, buf[sizeof(any)]);\n+}\n+\n+/ IP_PKTOPTIONS only answers on a stream socket. /\n+TEST_F(ip, pktoptions_wrong_type)\n+{\n+\tsocklen_t optlen = 64;\n+\tchar buf[64];\n+\n+\tASSERT_EQ(-1, getsockopt(self-\u003efd, SOL_IP, IP_PKTOPTIONS, buf,\n+\t\t\t\t \u0026optlen));\n+\tASSERT_EQ(ENOPROTOOPT, errno);\n+}\n+\n+/ The MRT_* options are dispatched ahead of the rest of the switch and\n+ * want a raw IGMP socket. Without CONFIG_IP_MROUTE they are not\n+ * dispatched at all and the switch also answers ENOPROTOOPT, so the\n+ * config check has to come from somewhere other than this errno.\n+ /\n+TEST_F(ip, mroute_wrong_type)\n+{\n+\tsocklen_t optlen = sizeof(int);\n+\tint val;\n+\n+\tif (access(\"/proc/net/ip_mr_vif\", F_OK))\n+\t\tSKIP(return, \"CONFIG_IP_MROUTE disabled\");\n+\n+\tASSERT_EQ(-1, getsockopt(self-\u003efd, SOL_IP, MRT_VERSION, \u0026val,\n+\t\t\t\t \u0026optlen));\n+\tASSERT_EQ(EOPNOTSUPP, errno);\n+}\n+\n+TEST_F(ip, bad_optname)\n+{\n+\tsocklen_t optlen = sizeof(int);\n+\tint val;\n+\n+\tASSERT_EQ(-1, getsockopt(self-\u003efd, SOL_IP, 0x7fff, \u0026val, \u0026optlen));\n+\tASSERT_EQ(ENOPROTOOPT, errno);\n+\tASSERT_EQ(sizeof(int), optlen);\n+}\n+\n+/ ---------- ipv6 (SOL_IPV6) ---------- /\n+\n+/ an 8 byte hop-by-hop header, so the sticky options answer /\n+static const unsigned char hopopt[8] = { 0, 0, 1, 4, 0, 0, 0, 0 };\n+\n+FIXTURE(ipv6)\n+{\n+\tint fd;\n+};\n+\n+FIXTURE_SETUP(ipv6)\n+{\n+\tint hops = 42;\n+\n+\tself-\u003efd = socket(AF_INET6, SOCK_DGRAM, 0);\n+\tif (self-\u003efd \u003c 0)\n+\t\tSKIP(return, \"AF_INET6 dgram socket: %s\", strerror(errno));\n+\n+\tif (setsockopt(self-\u003efd, SOL_IPV6, IPV6_UNICAST_HOPS, \u0026hops,\n+\t\t sizeof(hops)) \u003c 0)\n+\t\tSKIP(return, \"set IPV6_UNICAST_HOPS: %s\", strerror(errno));\n+}\n+\n+FIXTURE_TEARDOWN(ipv6)\n+{\n+\tif (self-\u003efd \u003e= 0)\n+\t\tclose(self-\u003efd);\n+}\n+\n+TEST_F(ipv6, hops_exact)\n+{\n+\tsocklen_t optlen = sizeof(int);\n+\tint val = 0;\n+\n+\tASSERT_EQ(0, getsockopt(self-\u003efd, SOL_IPV6, IPV6_UNICAST_HOPS, \u0026val,\n+\t\t\t\t\u0026optlen));\n+\tASSERT_EQ(sizeof(int), optlen);\n+\tASSERT_EQ(42, val);\n+}\n+\n+TEST_F(ipv6, hops_oversize_clamped)\n+{\n+\tsocklen_t optlen = 64;\n+\tint buf[16] = {};\n+\n+\tASSERT_EQ(0, getsockopt(self-\u003efd, SOL_IPV6, IPV6_UNICAST_HOPS, buf,\n+\t\t\t\t\u0026optlen));\n+\tASSERT_EQ(sizeof(int), optlen);\n+\tASSERT_EQ(42, buf[0]);\n+}\n+\n+/ Unlike SOL_IP, SOL_IPV6 clamps a sub-int buffer down to what fits\n+ * rather than answering a single byte.\n+ /\n+TEST_F(ipv6, hops_sub_int)\n+{\n+\tunsigned char buf[3];\n+\tsocklen_t optlen = sizeof(buf);\n+\tint hops = 42;\n+\n+\tmemset(buf, 0xaa, sizeof(buf));\n+\tASSERT_EQ(0, getsockopt(self-\u003efd, SOL_IPV6, IPV6_UNICAST_HOPS, buf,\n+\t\t\t\t\u0026optlen));\n+\tASSERT_EQ(sizeof(buf), optlen);\n+\tASSERT_EQ(0, memcmp(buf, \u0026hops, sizeof(buf)));\n+}\n+\n+TEST_F(ipv6, hops_zero_len)\n+{\n+\tsocklen_t optlen = 0;\n+\tint val;\n+\n+\tASSERT_EQ(0, getsockopt(self-\u003efd, SOL_IPV6, IPV6_UNICAST_HOPS, \u0026val,\n+\t\t\t\t\u0026optlen));\n+\tASSERT_EQ(0, optlen);\n+}\n+\n+/ Unlike SOL_IP, a negative optlen is taken as 4 here, as the int options\n+ * always did.\n+ /\n+TEST_F(ipv6, negative_optlen)\n+{\n+\tsocklen_t optlen = (socklen_t)-1;\n+\tint val = 0;\n+\n+\tASSERT_EQ(0, getsockopt(self-\u003efd, SOL_IPV6, IPV6_UNICAST_HOPS, \u0026val,\n+\t\t\t\t\u0026optlen));\n+\tASSERT_EQ(sizeof(int), optlen);\n+\tASSERT_EQ(42, val);\n+}\n+\n+TEST_F(ipv6, hopopts_roundtrip)\n+{\n+\tunsigned char buf[64] = {};\n+\tsocklen_t optlen = sizeof(buf);\n+\n+\tif (setsockopt(self-\u003efd, SOL_IPV6, IPV6_HOPOPTS, hopopt,\n+\t\t sizeof(hopopt)) \u003c 0)\n+\t\tSKIP(return, \"set IPV6_HOPOPTS: %s\", strerror(errno));\n+\n+\tASSERT_EQ(0, getsockopt(self-\u003efd, SOL_IPV6, IPV6_HOPOPTS, buf,\n+\t\t\t\t\u0026optlen));\n+\tASSERT_EQ(sizeof(hopopt), optlen);\n+\tASSERT_EQ(0, memcmp(buf, hopopt, sizeof(hopopt)));\n+}\n+\n+TEST_F(ipv6, hopopts_undersize_clamped)\n+{\n+\tunsigned char buf[4] = {};\n+\tsocklen_t optlen = sizeof(buf);\n+\n+\tif (setsockopt(self-\u003efd, SOL_IPV6, IPV6_HOPOPTS, hopopt,\n+\t\t sizeof(hopopt)) \u003c 0)\n+\t\tSKIP(return, \"set IPV6_HOPOPTS: %s\", strerror(errno));\n+\n+\tASSERT_EQ(0, getsockopt(self-\u003efd, SOL_IPV6, IPV6_HOPOPTS, buf,\n+\t\t\t\t\u0026optlen));\n+\tASSERT_EQ(sizeof(buf), optlen);\n+\tASSERT_EQ(0, memcmp(buf, hopopt, sizeof(buf)));\n+}\n+\n+/ With no header set the reply is empty and the call still succeeds. /\n+TEST_F(ipv6, hopopts_absent)\n+{\n+\tunsigned char buf[64] = {};\n+\tsocklen_t optlen = sizeof(buf);\n+\tint fd;\n+\n+\tfd = socket(AF_INET6, SOCK_DGRAM, 0);\n+\tif (fd \u003c 0)\n+\t\tSKIP(return, \"AF_INET6 dgram socket: %s\", strerror(errno));\n+\n+\tASSERT_EQ(0, getsockopt(fd, SOL_IPV6, IPV6_HOPOPTS, buf, \u0026optlen));\n+\tASSERT_EQ(0, optlen);\n+\tclose(fd);\n+}\n+\n+/ IPV6_PATHMTU wants room for the whole struct ip6_mtuinfo. /\n+TEST_F(ipv6, pathmtu_undersize)\n+{\n+\tsocklen_t optlen = 8;\n+\tchar buf[8];\n+\n+\tASSERT_EQ(-1, getsockopt(self-\u003efd, SOL_IPV6, IPV6_PATHMTU, buf,\n+\t\t\t\t \u0026optlen));\n+\tASSERT_EQ(EINVAL, errno);\n+}\n+\n+/ A negative optlen is taken as 4, which is undersize for IPV6_PATHMTU. /\n+TEST_F(ipv6, pathmtu_negative_optlen)\n+{\n+\tsocklen_t optlen = (socklen_t)-1;\n+\tchar buf[64];\n+\n+\tASSERT_EQ(-1, getsockopt(self-\u003efd, SOL_IPV6, IPV6_PATHMTU, buf,\n+\t\t\t\t \u0026optlen));\n+\tASSERT_EQ(EINVAL, errno);\n+}\n+\n+TEST_F(ipv6, pktoptions_wrong_type)\n+{\n+\tsocklen_t optlen = 64;\n+\tchar buf[64];\n+\n+\tASSERT_EQ(-1, getsockopt(self-\u003efd, SOL_IPV6, IPV6_2292PKTOPTIONS, buf,\n+\t\t\t\t \u0026optlen));\n+\tASSERT_EQ(ENOPROTOOPT, errno);\n+}\n+\n+TEST_F(ipv6, mroute_wrong_type)\n+{\n+\tsocklen_t optlen = sizeof(int);\n+\tint val;\n+\n+\tif (access(\"/proc/net/ip6_mr_vif\", F_OK))\n+\t\tSKIP(return, \"CONFIG_IPV6_MROUTE disabled\");\n+\n+\tASSERT_EQ(-1, getsockopt(self-\u003efd, SOL_IPV6, MRT6_VERSION, \u0026val,\n+\t\t\t\t \u0026optlen));\n+\tASSERT_EQ(EOPNOTSUPP, errno);\n+}\n+\n+TEST_F(ipv6, bad_optname)\n+{\n+\tsocklen_t optlen = sizeof(int);\n+\tint val;\n+\n+\tASSERT_EQ(-1, getsockopt(self-\u003efd, SOL_IPV6, 0x7fff, \u0026val, \u0026optlen));\n+\tASSERT_EQ(ENOPROTOOPT, errno);\n+\tASSERT_EQ(sizeof(int), optlen);\n+}\n+\n / ---------- tls ---------- */\n \n FIXTURE(tls)\n" }
2/1	2026/10/15 12:58	agent	patch-evaluator	2m Model: core Args: null Results: { "EnableConfigs": [ "INET", "IPV6", "IP_MULTICAST", "IP_MROUTE", "IPV6_MROUTE" ], "FocusSymbols": [ "do_ip_getsockopt", "ip_getsockopt", "do_ipv6_getsockopt", "ipv6_getsockopt", "ip_mc_gsfget", "ip_mc_msfget", "ip6_mc_msfget", "ip_mroute_getsockopt", "ip6_mroute_getsockopt" ], "Reasoning": "The patch refactors the IPv4 (SOL_IP) and IPv6 (SOL_IPV6) getsockopt subsystem to use sockopt_t / iov_iter instead of sockptr_t. This touches reachable core networking code in net/ipv4, net/ipv6, and net/core, modifying buffer copying, optlen bounds handling, iterator advancement and reverting (iov_iter_revert, iov_iter_advance), multicast filter query logic (ip_mc_gsfget, ip6_mc_msfget), and BPF cgroup sockopt hooks (sol_ip_sockopt, sol_ipv6_sockopt). The modified code is directly reachable by unprivileged user space via getsockopt syscalls on standard AF_INET and AF_INET6 sockets.", "WorthFuzzing": true } Instruction: You are an expert Linux kernel maintainer and security engineer. Your job is to review a provided patch series and evaluate whether it warrants fuzzing with syzkaller. IMPORTANT: The changes have ALREADY been applied and committed as the HEAD commit in your workspace. Do NOT rely on internal assumptions. You must actively use your code access tools to inspect the actual source code, callers, and surrounding context. ================================================================================ 1. CORE TRIAGE PHILOSOPHY ================================================================================ The goal of patch fuzzing is to discover crashes, regressions, exposed latent bugs, and newly triggered assertions introduced by the patch series. - REACHABILITY IS THE PRIMARY GATE: Fuzzing can only discover bugs in code that can actually execute in standard virtualized environments (GCE or QEMU, utilizing software-emulated devices like USB gadgets, netdev, tun/tap). If the modified code is structurally unreachable (see Section 2), it MUST NOT be fuzzed, regardless of whether it adds assertions or complex logic. - DO NOT BLINDLY TRUST "NO FUNCTIONAL CHANGE" (NFCI) OR "REFACTORING" CLAIMS: Patch authors routinely label changes as "cleanups", "refactorings", or state "No functional change intended". Do NOT take these claims at face value. Code refactorings that rearrange logic, introduce helper functions, or alter state management in core subsystems frequently introduce subtle semantic shifts or uncover latent kernel bugs. If reachable executable code is modified or refactored, it MUST be fuzzed. - NEW OR MODIFIED ASSERTIONS IN REACHABLE CODE MUST BE FUZZED: When a patch introduces or modifies runtime checks or assertions (e.g., WARN_ON, VM_WARN_ON, BUG_ON, lockdep_assert) in reachable code paths, it enforces new or stricter invariants. Even if the author believes the invariant always holds, fuzzing is essential to verify whether an unusual sequence of operations can violate it. ================================================================================ 2. WHEN TO RETURN WorthFuzzing=false (NEGATIVE CRITERIA) ================================================================================ Return WorthFuzzing=false ONLY IF all modified code falls strictly into one or more of these categories: - Non-kernel and non-executable changes: * Modifications to Documentation/, comments, or spelling fixes. * User-space directories, self-tests, samples, or scripts (e.g., tools/, samples/, scripts/, usr/) that do not affect the compiled kernel image (vmlinux) or kernel modules. * Purely decorative logging (e.g., message strings in pr_err, printk, dev_info) or tracepoints that do not alter control flow or data structures. * Build system or Kconfig changes that do not alter compiled C logic. - Structurally unreachable hardware: * Vendor-specific PCIe switches, SmartNICs, or GPU drivers (e.g., mlxsw, pds_core, qed, ionic, amdgpu) requiring physical ASIC/PCIe cards not emulated in standard QEMU. - Unreachable execution paths: * Driver teardown callbacks (.remove, .shutdown, pci_unregister_driver) executed only during physical PCI hot-unplug or manual sysfs driver unbinding. * Code paths exclusive to architectures other than the target architecture. ================================================================================ 3. WHEN TO RETURN WorthFuzzing=true (POSITIVE CRITERIA) ================================================================================ Return WorthFuzzing=true whenever the patch touches reachable executable code, including: - Core Subsystems: * Any logic modifications in memory management (mm/), synchronization/locking (kernel/locking/), BPF, scheduler, core networking, VFS, or syscall handling. - Refactorings and Code Cleanups: * Any restructuring of reachable data structures, helper abstractions, or algorithm flows. - Runtime Assertions and Defensive Checks: * Any introduction or alteration of assertions (WARN_ON, VM_WARN_ON, BUG_ON, etc.) in reachable paths. - Reachable Drivers and Protocols: Drivers accessible via virtual buses (virtio, USB gadget, loopback, netlink, binder, sockets, etc.). ================================================================================ 4. EXTRACTING FocusSymbols (PREVENTING DILUTION) ================================================================================ When WorthFuzzing=true, you must extract specific kernel functions into FocusSymbols to guide the fuzzer: - AVOID UBIQUITOUS LIFECYCLE HOT-PATHS: Do NOT list generic, ubiquitous functions called by almost every program in the corpus (including, but not limited to: general memory allocators and deallocators, page fault and trap handlers, or core synchronization primitives; this is not an exhaustive list). Listing ubiquitous functions causes the fuzzer to classify thousands of unrelated tests as "focused", which severely dilutes fuzzing effort away from the actual changes. - TARGET SPECIFIC FEATURE LOGIC AND ENTRYPOINTS: List functions that specifically implement the logic being added or altered, or direct API entrypoints for the subsystem feature under review. - HANDLING STATIC INLINE FUNCTIONS IN HEADERS (.h): Compiler-inlined static functions (such as static inlines in mm/.h or include/linux/.h) lack distinct symbol addresses in vmlinux and cannot be targeted directly by symbol coverage filters. If the changes are primarily in static inline helpers, identify non-static, feature-specific caller functions in .c files that exercise them (avoiding ubiquitous lifecycle wrappers). ================================================================================ 5. IDENTIFYING EnableConfigs ================================================================================ Identify any specific CONFIG_ options required to properly compile and reach the modified code: - Inspect Kconfig files and #ifdef guards; do not make assumptions. - Check "depends on" lines in Kconfig to include any non-standard parent subsystem configs needed. - Strip any 'CONFIG_' prefix (e.g., return "NET_IPV4" instead of "CONFIG_NET_IPV4"). Prefer calling several tools at the same time to save round-trips. Use set-results tool to provide results of the analysis. It must be called exactly once before the final reply. Ignore results of this tool. Prompt: Target architecture: amd64 For your convenience, here is the diff of the changes: commit cadd503ae11ea00c223b192cf6ffc896572a18c1 Author: syz-cluster <triage@syzkaller.com> Date: Thu Oct 15 12:58:45 2026 +0000 syz-cluster: applied patch under review diff --git a/include/linux/igmp.h b/include/linux/igmp.h index e075611344ef3..0a1abf3552d2b 100644 --- a/include/linux/igmp.h +++ b/include/linux/igmp.h @@ -276,7 +276,7 @@ extern int ip_mc_msfilter(struct sock sk, struct ip_msfilter msf,int ifindex); extern int ip_mc_msfget(struct sock sk, struct ip_msfilter msf, sockopt_t opt); extern int ip_mc_gsfget(struct sock sk, struct group_filter gsf, - sockptr_t optval, size_t offset); + sockopt_t opt, size_t offset); extern int ip_mc_sf_allow(const struct sock sk, __be32 local, __be32 rmt, int dif, int sdif); extern void ip_mc_init_dev(struct in_device ); diff --git a/include/linux/mroute.h b/include/linux/mroute.h index 4c5003afee6c5..c1c21e61c81c3 100644 --- a/include/linux/mroute.h +++ b/include/linux/mroute.h @@ -17,7 +17,7 @@ static inline int ip_mroute_opt(int opt) } int ip_mroute_setsockopt(struct sock , int, sockptr_t, unsigned int); -int ip_mroute_getsockopt(struct sock , int, sockptr_t, sockptr_t); +int ip_mroute_getsockopt(struct sock sk, int optname, sockopt_t opt); int ipmr_ioctl(struct sock sk, int cmd, void arg); int ipmr_compat_ioctl(struct sock sk, unsigned int cmd, void __user arg); int ip_mr_init(void); @@ -31,7 +31,7 @@ static inline int ip_mroute_setsockopt(struct sock sock, int optname, } static inline int ip_mroute_getsockopt(struct sock sk, int optname, - sockptr_t optval, sockptr_t optlen) + sockopt_t opt) { return -ENOPROTOOPT; } diff --git a/include/linux/mroute6.h b/include/linux/mroute6.h index fddafdc168f73..ab4d206fb3206 100644 --- a/include/linux/mroute6.h +++ b/include/linux/mroute6.h @@ -27,7 +27,7 @@ struct sock; #ifdef CONFIG_IPV6_MROUTE extern int ip6_mroute_setsockopt(struct sock , int, sockptr_t, unsigned int); -extern int ip6_mroute_getsockopt(struct sock , int, sockptr_t, sockptr_t); +int ip6_mroute_getsockopt(struct sock sk, int optname, sockopt_t sopt); extern int ip6_mr_input(struct sk_buff skb); extern int ip6mr_compat_ioctl(struct sock sk, unsigned int cmd, void __user arg); extern int ip6_mr_init(void); @@ -42,8 +42,7 @@ static inline int ip6_mroute_setsockopt(struct sock sock, int optname, } static inline -int ip6_mroute_getsockopt(struct sock sock, - int optname, sockptr_t optval, sockptr_t optlen) +int ip6_mroute_getsockopt(struct sock sock, int optname, sockopt_t sopt) { return -ENOPROTOOPT; } diff --git a/include/linux/net.h b/include/linux/net.h index e2a866fbcfa5e..1d5b3524b0846 100644 --- a/include/linux/net.h +++ b/include/linux/net.h @@ -50,6 +50,19 @@ typedef struct sockopt { int sockptr_to_sockopt(sockopt_t opt, sockptr_t optval, sockptr_t optlen, struct kvec kvec); +/* + * Point a sockopt_t at a user-backed (optval, len) pair whose length is + * already known, e.g. because the caller applied its own optlen quirks + * before this point. + / +static inline void sockopt_set_user(sockopt_t opt, char __user optval, + int len) +{ + iov_iter_ubuf(&opt->iter_out, ITER_DEST, optval, len); + iov_iter_ubuf(&opt->iter_in, ITER_SOURCE, optval, len); + opt->optlen = len; +} + / * Initialize a user-backed sockopt_t from the (optval, optlen) __user pair of * a getsockopt() callback. Used by transitional __user getsockopt wrappers @@ -66,9 +79,7 @@ static inline int sockopt_init_user(sockopt_t opt, char __user optval, if (len < 0) return -EINVAL; - iov_iter_ubuf(&opt->iter_out, ITER_DEST, optval, len); - iov_iter_ubuf(&opt->iter_in, ITER_SOURCE, optval, len); - opt->optlen = len; + sockopt_set_user(opt, optval, len); return 0; } @@ -80,16 +91,21 @@ static inline int sockopt_init_user(sockopt_t opt, char __user optval, * * Call it before writing through opt->iter_out: it re-anchors the iterator at * the head of optval. Only a user buffer can be longer than the optlen the - * caller declared, so a kernel-backed optval is refused with -EINVAL. + * caller declared, so a kernel-backed optval is refused with -EINVAL. So is a + * @size above MAX_RW_COUNT, which iov_iter_revert() could not unroll. / static inline int sockopt_expand_out(sockopt_t opt, size_t size) { + /* iov_iter_revert() refuses to unroll past MAX_RW_COUNT, so a size + * beyond that could never be reverted back to the fixed part later, + * even when optlen already covers it. + / + if (size > MAX_RW_COUNT) + return -EINVAL; + if (size <= (size_t)opt->optlen) return 0; - if (size > INT_MAX) - return -EINVAL; - / Re-anchoring reads iter_out.ubuf, so the iterator has to be a user * buffer that nothing has written through yet. / diff --git a/include/net/ip.h b/include/net/ip.h index 618b9806c10b0..c59ffb432b3ed 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -833,8 +833,7 @@ int do_ip_setsockopt(struct sock sk, int level, int optname, sockptr_t optval, unsigned int optlen); int ip_setsockopt(struct sock sk, int level, int optname, sockptr_t optval, unsigned int optlen); -int do_ip_getsockopt(struct sock sk, int level, int optname, - sockptr_t optval, sockptr_t optlen); +int do_ip_getsockopt(struct sock sk, int level, int optname, sockopt_t sopt); int ip_getsockopt(struct sock sk, int level, int optname, char __user optval, int __user optlen); int ip_ra_control(struct sock sk, unsigned char on, diff --git a/include/net/ipv6.h b/include/net/ipv6.h index 3de07e738538f..a1e1de7da8c70 100644 --- a/include/net/ipv6.h +++ b/include/net/ipv6.h @@ -1142,7 +1142,7 @@ int do_ipv6_setsockopt(struct sock sk, int level, int optname, sockptr_t optval int ipv6_setsockopt(struct sock sk, int level, int optname, sockptr_t optval, unsigned int optlen); int do_ipv6_getsockopt(struct sock sk, int level, int optname, - sockptr_t optval, sockptr_t optlen); + sockopt_t sopt); int ipv6_getsockopt(struct sock sk, int level, int optname, char __user optval, int __user optlen); @@ -1195,7 +1195,7 @@ int ip6_mc_source(int add, int omode, struct sock sk, int ip6_mc_msfilter(struct sock sk, struct group_filter gsf, struct sockaddr_storage list); int ip6_mc_msfget(struct sock sk, struct group_filter gsf, - sockptr_t optval, size_t ss_offset); + sockopt_t opt, size_t ss_offset); #ifdef CONFIG_PROC_FS int ac6_proc_init(struct net net); diff --git a/net/core/filter.c b/net/core/filter.c index 5e575981febec..03d4778ad99ac 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -5737,10 +5737,20 @@ static int sol_ip_sockopt(struct sock sk, int optname, return -EINVAL; } - if (getopt) - return do_ip_getsockopt(sk, SOL_IP, optname, - KERNEL_SOCKPTR(optval), - KERNEL_SOCKPTR(optlen)); + if (getopt) { + struct kvec kvec; + sockopt_t opt; + int err; + + err = sockptr_to_sockopt(&opt, KERNEL_SOCKPTR(optval), + KERNEL_SOCKPTR(optlen), &kvec); + if (err) + return err; + + err = do_ip_getsockopt(sk, SOL_IP, optname, &opt); + optlen = opt.optlen; + return err; + } return do_ip_setsockopt(sk, SOL_IP, optname, KERNEL_SOCKPTR(optval), optlen); @@ -5764,10 +5774,20 @@ static int sol_ipv6_sockopt(struct sock sk, int optname, return -EINVAL; } - if (getopt) - return do_ipv6_getsockopt(sk, SOL_IPV6, optname, - KERNEL_SOCKPTR(optval), - KERNEL_SOCKPTR(optlen)); + if (getopt) { + struct kvec kvec; + sockopt_t opt; + int err; + + err = sockptr_to_sockopt(&opt, KERNEL_SOCKPTR(optval), + KERNEL_SOCKPTR(optlen), &kvec); + if (err) + return err; + + err = do_ipv6_getsockopt(sk, SOL_IPV6, optname, &opt); + optlen = opt.optlen; + return err; + } return do_ipv6_setsockopt(sk, SOL_IPV6, optname, KERNEL_SOCKPTR(optval), optlen); diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c index 144fca158adcb..bf00810cdd7a1 100644 --- a/net/ipv4/igmp.c +++ b/net/ipv4/igmp.c @@ -2763,21 +2763,22 @@ int ip_mc_msfget(struct sock sk, struct ip_msfilter msf, sockopt_t opt) if (err) return err; - opt->optlen = msf_size; if (copy_to_iter(msf, IP_MSFILTER_SIZE(0), &opt->iter_out) != IP_MSFILTER_SIZE(0)) return -EFAULT; if (len && copy_to_iter(psl->sl_addr, len, &opt->iter_out) != len) return -EFAULT; + + opt->optlen = msf_size; return 0; done: return err; } int ip_mc_gsfget(struct sock sk, struct group_filter gsf, - sockptr_t optval, size_t ss_offset) + sockopt_t opt, size_t ss_offset) { - int i, count, copycount; + int i, count, copycount, err; struct sockaddr_in psin; __be32 addr; struct ip_mc_socklist pmc; @@ -2805,6 +2806,18 @@ int ip_mc_gsfget(struct sock sk, struct group_filter gsf, count = psl ? psl->sl_count : 0; copycount = count < gsf->gf_numsrc ? count : gsf->gf_numsrc; gsf->gf_numsrc = count; + + / The source list is sized by the gf_numsrc the caller left in optval, + * not by optlen, which only has to cover the fixed part. + / + err = sockopt_expand_out(opt, ss_offset + + copycount sizeof(struct sockaddr_storage)); + if (err) + return err; + + /* The caller fills the fixed part in once it knows gf_numsrc. / + iov_iter_advance(&opt->iter_out, ss_offset); + for (i = 0; i < copycount; i++) { struct sockaddr_storage ss; @@ -2812,10 +2825,8 @@ int ip_mc_gsfget(struct sock sk, struct group_filter gsf, memset(&ss, 0, sizeof(ss)); psin->sin_family = AF_INET; psin->sin_addr.s_addr = psl->sl_addr[i]; - if (copy_to_sockptr_offset(optval, ss_offset, - &ss, sizeof(ss))) + if (copy_to_iter(&ss, sizeof(ss), &opt->iter_out) != sizeof(ss)) return -EFAULT; - ss_offset += sizeof(ss); } return 0; } diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index e06c1f48ecad6..90d0b5bee68b5 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -1442,45 +1442,46 @@ static bool getsockopt_needs_rtnl(int optname) return false; } -static int ip_get_mcast_msfilter(struct sock sk, sockptr_t optval, - sockptr_t optlen, int len) +static int ip_get_mcast_msfilter(struct sock sk, sockopt_t opt) { const int size0 = offsetof(struct group_filter, gf_slist_flex); struct group_filter gsf; int num, gsf_size; int err; - if (len < size0) + if (opt->optlen < size0) return -EINVAL; - if (copy_from_sockptr(&gsf, optval, size0)) + if (copy_from_iter(&gsf, size0, &opt->iter_in) != size0) return -EFAULT; num = gsf.gf_numsrc; - err = ip_mc_gsfget(sk, &gsf, optval, + err = ip_mc_gsfget(sk, &gsf, opt, offsetof(struct group_filter, gf_slist_flex)); if (err) return err; if (gsf.gf_numsrc < num) num = gsf.gf_numsrc; gsf_size = GROUP_FILTER_SIZE(num); - if (copy_to_sockptr(optlen, &gsf_size, sizeof(int)) \|\| - copy_to_sockptr(optval, &gsf, size0)) + + /* ip_mc_gsfget() consumed the whole reply; rewind to the fixed part. / + iov_iter_revert(&opt->iter_out, gsf_size); + if (copy_to_iter(&gsf, size0, &opt->iter_out) != size0) return -EFAULT; + opt->optlen = gsf_size; return 0; } -static int compat_ip_get_mcast_msfilter(struct sock sk, sockptr_t optval, - sockptr_t optlen, int len) +static int compat_ip_get_mcast_msfilter(struct sock sk, sockopt_t opt) { const int size0 = offsetof(struct compat_group_filter, gf_slist_flex); struct compat_group_filter gf32; struct group_filter gf; - int num; + int num, len; int err; - if (len < size0) + if (opt->optlen < size0) return -EINVAL; - if (copy_from_sockptr(&gf32, optval, size0)) + if (copy_from_iter(&gf32, size0, &opt->iter_in) != size0) return -EFAULT; gf.gf_interface = gf32.gf_interface; @@ -1488,24 +1489,27 @@ static int compat_ip_get_mcast_msfilter(struct sock sk, sockptr_t optval, num = gf.gf_numsrc = gf32.gf_numsrc; gf.gf_group = gf32.gf_group; - err = ip_mc_gsfget(sk, &gf, optval, + err = ip_mc_gsfget(sk, &gf, opt, offsetof(struct compat_group_filter, gf_slist_flex)); if (err) return err; if (gf.gf_numsrc < num) num = gf.gf_numsrc; len = GROUP_FILTER_SIZE(num) - (sizeof(gf) - sizeof(gf32)); - if (copy_to_sockptr(optlen, &len, sizeof(int)) \|\| - copy_to_sockptr_offset(optval, offsetof(struct compat_group_filter, gf_fmode), - &gf.gf_fmode, sizeof(gf.gf_fmode)) \|\| - copy_to_sockptr_offset(optval, offsetof(struct compat_group_filter, gf_numsrc), - &gf.gf_numsrc, sizeof(gf.gf_numsrc))) + + / Rewind to gf_fmode, which gf_numsrc follows. / + iov_iter_revert(&opt->iter_out, + len - offsetof(struct compat_group_filter, gf_fmode)); + if (copy_to_iter(&gf.gf_fmode, sizeof(gf32.gf_fmode), + &opt->iter_out) != sizeof(gf32.gf_fmode) \|\| + copy_to_iter(&gf.gf_numsrc, sizeof(gf32.gf_numsrc), + &opt->iter_out) != sizeof(gf32.gf_numsrc)) return -EFAULT; + opt->optlen = len; return 0; } -int do_ip_getsockopt(struct sock sk, int level, int optname, - sockptr_t optval, sockptr_t optlen) +int do_ip_getsockopt(struct sock sk, int level, int optname, sockopt_t sopt) { struct inet_sock inet = inet_sk(sk); bool needs_rtnl = getsockopt_needs_rtnl(optname); @@ -1516,10 +1520,9 @@ int do_ip_getsockopt(struct sock sk, int level, int optname, return -EOPNOTSUPP; if (ip_mroute_opt(optname)) - return ip_mroute_getsockopt(sk, optname, optval, optlen); + return ip_mroute_getsockopt(sk, optname, sopt); - if (copy_from_sockptr(&len, optlen, sizeof(int))) - return -EFAULT; + len = sopt->optlen; if (len < 0) return -EINVAL; @@ -1615,16 +1618,15 @@ int do_ip_getsockopt(struct sock sk, int level, int optname, rcu_read_unlock(); if (opt->optlen == 0) { - len = 0; - return copy_to_sockptr(optlen, &len, sizeof(int)); + sopt->optlen = 0; + return 0; } ip_options_undo(opt); len = min_t(unsigned int, len, opt->optlen); - if (copy_to_sockptr(optlen, &len, sizeof(int))) - return -EFAULT; - if (copy_to_sockptr(optval, opt->__data, len)) + sopt->optlen = len; + if (copy_to_iter(opt->__data, len, &sopt->iter_out) != len) return -EFAULT; return 0; } @@ -1648,12 +1650,12 @@ int do_ip_getsockopt(struct sock sk, int level, int optname, if (sk->sk_type != SOCK_STREAM) return -ENOPROTOOPT; - if (optval.is_kernel) { + if (iov_iter_is_kvec(&sopt->iter_out)) { msg.msg_control_is_user = false; - msg.msg_control = optval.kernel; + msg.msg_control = sopt->iter_out.kvec->iov_base; } else { msg.msg_control_is_user = true; - msg.msg_control_user = optval.user; + msg.msg_control_user = sopt->iter_out.ubuf; } msg.msg_controllen = len; msg.msg_flags = in_compat_syscall() ? MSG_CMSG_COMPAT : 0; @@ -1675,8 +1677,8 @@ int do_ip_getsockopt(struct sock sk, int level, int optname, int tos = READ_ONCE(inet->rcv_tos); put_cmsg(&msg, SOL_IP, IP_TOS, sizeof(tos), &tos); } - len -= msg.msg_controllen; - return copy_to_sockptr(optlen, &len, sizeof(int)); + sopt->optlen = len - msg.msg_controllen; + return 0; } case IP_UNICAST_IF: val = (__force int)htonl((__u32) READ_ONCE(inet->uc_index)); @@ -1687,9 +1689,8 @@ int do_ip_getsockopt(struct sock sk, int level, int optname, len = min_t(unsigned int, len, sizeof(struct in_addr)); addr.s_addr = READ_ONCE(inet->mc_addr); - if (copy_to_sockptr(optlen, &len, sizeof(int))) - return -EFAULT; - if (copy_to_sockptr(optval, &addr, len)) + sopt->optlen = len; + if (copy_to_iter(&addr, len, &sopt->iter_out) != len) return -EFAULT; return 0; } @@ -1706,32 +1707,24 @@ int do_ip_getsockopt(struct sock sk, int level, int optname, case IP_MSFILTER: { struct ip_msfilter msf; - struct kvec kvec; - sockopt_t opt; if (len < IP_MSFILTER_SIZE(0)) { err = -EINVAL; goto out; } - if (copy_from_sockptr(&msf, optval, IP_MSFILTER_SIZE(0))) { + if (copy_from_iter(&msf, IP_MSFILTER_SIZE(0), &sopt->iter_in) != + IP_MSFILTER_SIZE(0)) { err = -EFAULT; goto out; } - err = sockptr_to_sockopt(&opt, optval, optlen, &kvec); - if (err) - goto out; - - err = ip_mc_msfget(sk, &msf, &opt); - if (!err && copy_to_sockptr(optlen, &opt.optlen, sizeof(int))) - err = -EFAULT; + err = ip_mc_msfget(sk, &msf, sopt); goto out; } case MCAST_MSFILTER: if (in_compat_syscall()) - err = compat_ip_get_mcast_msfilter(sk, optval, optlen, - len); + err = compat_ip_get_mcast_msfilter(sk, sopt); else - err = ip_get_mcast_msfilter(sk, optval, optlen, len); + err = ip_get_mcast_msfilter(sk, sopt); goto out; case IP_PROTOCOL: val = inet_sk(sk)->inet_num; @@ -1744,16 +1737,14 @@ int do_ip_getsockopt(struct sock sk, int level, int optname, copyval: if (len < sizeof(int) && len > 0 && val >= 0 && val <= 255) { unsigned char ucval = (unsigned char)val; - len = 1; - if (copy_to_sockptr(optlen, &len, sizeof(int))) - return -EFAULT; - if (copy_to_sockptr(optval, &ucval, 1)) + + sopt->optlen = 1; + if (copy_to_iter(&ucval, 1, &sopt->iter_out) != 1) return -EFAULT; } else { len = min_t(unsigned int, sizeof(int), len); - if (copy_to_sockptr(optlen, &len, sizeof(int))) - return -EFAULT; - if (copy_to_sockptr(optval, &val, len)) + sopt->optlen = len; + if (copy_to_iter(&val, len, &sopt->iter_out) != len) return -EFAULT; } return 0; @@ -1768,19 +1759,22 @@ int do_ip_getsockopt(struct sock sk, int level, int optname, int ip_getsockopt(struct sock sk, int level, int optname, char __user optval, int __user optlen) { + sockopt_t opt; int err; - err = do_ip_getsockopt(sk, level, optname, - USER_SOCKPTR(optval), USER_SOCKPTR(optlen)); + err = sockopt_init_user(&opt, optval, optlen); + if (err) + return err; + + err = do_ip_getsockopt(sk, level, optname, &opt); + if (put_user(opt.optlen, optlen)) + return -EFAULT; #ifdef CONFIG_NETFILTER /* we need to exclude all possible ENOPROTOOPTs except default case / if (err == -ENOPROTOOPT && optname != IP_PKTOPTIONS && !ip_mroute_opt(optname)) { - int len; - - if (get_user(len, optlen)) - return -EFAULT; + int len = opt.optlen; err = nf_getsockopt(sk, PF_INET, optname, optval, &len); if (err >= 0) diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c index e4c51ca473019..f249569b4bf8b 100644 --- a/net/ipv4/ipmr.c +++ b/net/ipv4/ipmr.c @@ -1638,8 +1638,7 @@ int ipmr_sk_ioctl(struct sock sk, unsigned int cmd, void __user arg) } / Getsock opt support for the multicast routing system. / -int ip_mroute_getsockopt(struct sock sk, int optname, sockptr_t optval, - sockptr_t optlen) +int ip_mroute_getsockopt(struct sock sk, int optname, sockopt_t opt) { int olr; int val; @@ -1670,16 +1669,14 @@ int ip_mroute_getsockopt(struct sock sk, int optname, sockptr_t optval, return -ENOPROTOOPT; } - if (copy_from_sockptr(&olr, optlen, sizeof(int))) - return -EFAULT; + olr = opt->optlen; if (olr < 0) return -EINVAL; olr = min_t(unsigned int, olr, sizeof(int)); - if (copy_to_sockptr(optlen, &olr, sizeof(int))) - return -EFAULT; - if (copy_to_sockptr(optval, &val, olr)) + opt->optlen = olr; + if (copy_to_iter(&val, olr, &opt->iter_out) != olr) return -EFAULT; return 0; } diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c index 36f117ad36708..9513258b95fb8 100644 --- a/net/ipv6/ip6mr.c +++ b/net/ipv6/ip6mr.c @@ -1893,8 +1893,7 @@ int ip6_mroute_setsockopt(struct sock sk, int optname, sockptr_t optval, * Getsock opt support for the multicast routing system. / -int ip6_mroute_getsockopt(struct sock sk, int optname, sockptr_t optval, - sockptr_t optlen) +int ip6_mroute_getsockopt(struct sock sk, int optname, sockopt_t sopt) { int olr; int val; @@ -1925,16 +1924,12 @@ int ip6_mroute_getsockopt(struct sock sk, int optname, sockptr_t optval, return -ENOPROTOOPT; } - if (copy_from_sockptr(&olr, optlen, sizeof(int))) - return -EFAULT; - - olr = min_t(int, olr, sizeof(int)); + olr = min_t(int, sopt->optlen, sizeof(int)); if (olr < 0) return -EINVAL; - if (copy_to_sockptr(optlen, &olr, sizeof(int))) - return -EFAULT; - if (copy_to_sockptr(optval, &val, olr)) + sopt->optlen = olr; + if (copy_to_iter(&val, olr, &sopt->iter_out) != olr) return -EFAULT; return 0; } diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c index 4b3536571c980..b1011319cd3ec 100644 --- a/net/ipv6/ipv6_sockglue.c +++ b/net/ipv6/ipv6_sockglue.c @@ -889,7 +889,7 @@ int ipv6_setsockopt(struct sock sk, int level, int optname, sockptr_t optval, EXPORT_SYMBOL(ipv6_setsockopt); static int ipv6_getsockopt_sticky(struct sock sk, struct ipv6_txoptions opt, - int optname, sockptr_t optval, int len) + int optname, sockopt_t sopt, int len) { struct ipv6_opt_hdr hdr; @@ -917,53 +917,57 @@ static int ipv6_getsockopt_sticky(struct sock sk, struct ipv6_txoptions opt, return 0; len = min_t(unsigned int, len, ipv6_optlen(hdr)); - if (copy_to_sockptr(optval, hdr, len)) + if (copy_to_iter(hdr, len, &sopt->iter_out) != len) return -EFAULT; return len; } -static int ipv6_get_msfilter(struct sock sk, sockptr_t optval, - sockptr_t optlen, int len) +static int ipv6_get_msfilter(struct sock sk, sockopt_t opt) { const int size0 = offsetof(struct group_filter, gf_slist_flex); struct group_filter gsf; - int num; + int num, len; int err; - if (len < size0) + if (opt->optlen < size0) return -EINVAL; - if (copy_from_sockptr(&gsf, optval, size0)) + if (copy_from_iter(&gsf, size0, &opt->iter_in) != size0) return -EFAULT; if (gsf.gf_group.ss_family != AF_INET6) return -EADDRNOTAVAIL; num = gsf.gf_numsrc; sockopt_lock_sock(sk); - err = ip6_mc_msfget(sk, &gsf, optval, size0); + err = ip6_mc_msfget(sk, &gsf, opt, size0); if (!err) { if (num > gsf.gf_numsrc) num = gsf.gf_numsrc; len = GROUP_FILTER_SIZE(num); - if (copy_to_sockptr(optlen, &len, sizeof(int)) \|\| - copy_to_sockptr(optval, &gsf, size0)) + + / ip6_mc_msfget() consumed the whole reply; rewind to the + * fixed part. + / + iov_iter_revert(&opt->iter_out, len); + if (copy_to_iter(&gsf, size0, &opt->iter_out) != size0) err = -EFAULT; + else + opt->optlen = len; } sockopt_release_sock(sk); return err; } -static int compat_ipv6_get_msfilter(struct sock sk, sockptr_t optval, - sockptr_t optlen, int len) +static int compat_ipv6_get_msfilter(struct sock sk, sockopt_t opt) { const int size0 = offsetof(struct compat_group_filter, gf_slist_flex); struct compat_group_filter gf32; struct group_filter gf; int err; - int num; + int num, len; - if (len < size0) + if (opt->optlen < size0) return -EINVAL; - if (copy_from_sockptr(&gf32, optval, size0)) + if (copy_from_iter(&gf32, size0, &opt->iter_in) != size0) return -EFAULT; gf.gf_interface = gf32.gf_interface; gf.gf_fmode = gf32.gf_fmode; @@ -974,39 +978,41 @@ static int compat_ipv6_get_msfilter(struct sock sk, sockptr_t optval, return -EADDRNOTAVAIL; sockopt_lock_sock(sk); - err = ip6_mc_msfget(sk, &gf, optval, size0); + err = ip6_mc_msfget(sk, &gf, opt, size0); sockopt_release_sock(sk); if (err) return err; if (num > gf.gf_numsrc) num = gf.gf_numsrc; len = GROUP_FILTER_SIZE(num) - (sizeof(gf)-sizeof(gf32)); - if (copy_to_sockptr(optlen, &len, sizeof(int)) \|\| - copy_to_sockptr_offset(optval, offsetof(struct compat_group_filter, gf_fmode), - &gf.gf_fmode, sizeof(gf32.gf_fmode)) \|\| - copy_to_sockptr_offset(optval, offsetof(struct compat_group_filter, gf_numsrc), - &gf.gf_numsrc, sizeof(gf32.gf_numsrc))) + + / Rewind to gf_fmode, which gf_numsrc follows. / + iov_iter_revert(&opt->iter_out, + len - offsetof(struct compat_group_filter, gf_fmode)); + if (copy_to_iter(&gf.gf_fmode, sizeof(gf32.gf_fmode), + &opt->iter_out) != sizeof(gf32.gf_fmode) \|\| + copy_to_iter(&gf.gf_numsrc, sizeof(gf32.gf_numsrc), + &opt->iter_out) != sizeof(gf32.gf_numsrc)) return -EFAULT; + opt->optlen = len; return 0; } -int do_ipv6_getsockopt(struct sock sk, int level, int optname, - sockptr_t optval, sockptr_t optlen) +int do_ipv6_getsockopt(struct sock sk, int level, int optname, sockopt_t sopt) { struct ipv6_pinfo np = inet6_sk(sk); int len; int val; if (ip6_mroute_opt(optname)) - return ip6_mroute_getsockopt(sk, optname, optval, optlen); + return ip6_mroute_getsockopt(sk, optname, sopt); - if (copy_from_sockptr(&len, optlen, sizeof(int))) - return -EFAULT; + len = sopt->optlen; switch (optname) { case MCAST_MSFILTER: if (in_compat_syscall()) - return compat_ipv6_get_msfilter(sk, optval, optlen, len); - return ipv6_get_msfilter(sk, optval, optlen, len); + return compat_ipv6_get_msfilter(sk, sopt); + return ipv6_get_msfilter(sk, sopt); case IPV6_2292PKTOPTIONS: { struct msghdr msg; @@ -1015,12 +1021,12 @@ int do_ipv6_getsockopt(struct sock sk, int level, int optname, if (sk->sk_type != SOCK_STREAM) return -ENOPROTOOPT; - if (optval.is_kernel) { + if (iov_iter_is_kvec(&sopt->iter_out)) { msg.msg_control_is_user = false; - msg.msg_control = optval.kernel; + msg.msg_control = sopt->iter_out.kvec->iov_base; } else { msg.msg_control_is_user = true; - msg.msg_control_user = optval.user; + msg.msg_control_user = sopt->iter_out.ubuf; } msg.msg_controllen = len; msg.msg_flags = 0; @@ -1071,8 +1077,8 @@ int do_ipv6_getsockopt(struct sock sk, int level, int optname, put_cmsg(&msg, SOL_IPV6, IPV6_FLOWINFO, sizeof(flowinfo), &flowinfo); } } - len -= msg.msg_controllen; - return copy_to_sockptr(optlen, &len, sizeof(int)); + sopt->optlen = len - msg.msg_controllen; + return 0; } case IPV6_MTU: { @@ -1127,12 +1133,13 @@ int do_ipv6_getsockopt(struct sock sk, int level, int optname, sockopt_lock_sock(sk); opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk)); - len = ipv6_getsockopt_sticky(sk, opt, optname, optval, len); + len = ipv6_getsockopt_sticky(sk, opt, optname, sopt, len); sockopt_release_sock(sk); /* check if ipv6_getsockopt_sticky() returns err code / if (len < 0) return len; - return copy_to_sockptr(optlen, &len, sizeof(int)); + sopt->optlen = len; + return 0; } case IPV6_RECVHOPOPTS: @@ -1186,9 +1193,8 @@ int do_ipv6_getsockopt(struct sock sk, int level, int optname, if (!mtuinfo.ip6m_mtu) return -ENOTCONN; - if (copy_to_sockptr(optlen, &len, sizeof(int))) - return -EFAULT; - if (copy_to_sockptr(optval, &mtuinfo, len)) + sopt->optlen = len; + if (copy_to_iter(&mtuinfo, len, &sopt->iter_out) != len) return -EFAULT; return 0; @@ -1265,7 +1271,8 @@ int do_ipv6_getsockopt(struct sock sk, int level, int optname, if (len < sizeof(freq)) return -EINVAL; - if (copy_from_sockptr(&freq, optval, sizeof(freq))) + if (copy_from_iter(&freq, sizeof(freq), &sopt->iter_in) != + sizeof(freq)) return -EFAULT; if (freq.flr_action != IPV6_FL_A_GET) @@ -1280,9 +1287,8 @@ int do_ipv6_getsockopt(struct sock sk, int level, int optname, if (val < 0) return val; - if (copy_to_sockptr(optlen, &len, sizeof(int))) - return -EFAULT; - if (copy_to_sockptr(optval, &freq, len)) + sopt->optlen = len; + if (copy_to_iter(&freq, len, &sopt->iter_out) != len) return -EFAULT; return 0; @@ -1340,9 +1346,8 @@ int do_ipv6_getsockopt(struct sock sk, int level, int optname, return -ENOPROTOOPT; } len = min_t(unsigned int, sizeof(int), len); - if (copy_to_sockptr(optlen, &len, sizeof(int))) - return -EFAULT; - if (copy_to_sockptr(optval, &val, len)) + sopt->optlen = len; + if (copy_to_iter(&val, len, &sopt->iter_out) != len) return -EFAULT; return 0; } @@ -1350,7 +1355,8 @@ int do_ipv6_getsockopt(struct sock sk, int level, int optname, int ipv6_getsockopt(struct sock sk, int level, int optname, char __user optval, int __user optlen) { - int err; + sockopt_t sopt; + int len, err; if (level == SOL_IP && sk->sk_type != SOCK_RAW) return ip_getsockopt(sk, level, optname, optval, optlen); @@ -1358,15 +1364,25 @@ int ipv6_getsockopt(struct sock sk, int level, int optname, if (level != SOL_IPV6) return -ENOPROTOOPT; - err = do_ipv6_getsockopt(sk, level, optname, - USER_SOCKPTR(optval), USER_SOCKPTR(optlen)); + if (get_user(len, optlen)) + return -EFAULT; + /* Historic bug compatibility: take a negative optlen as 4, as the + * int options always did. MRT6_* has always rejected it instead. + / + if (len < 0) { + if (ip6_mroute_opt(optname)) + return -EINVAL; + len = 4; + } + sockopt_set_user(&sopt, optval, len); + + err = do_ipv6_getsockopt(sk, level, optname, &sopt); + if (put_user(sopt.optlen, optlen)) + return -EFAULT; #ifdef CONFIG_NETFILTER / we need to exclude all possible ENOPROTOOPTs except default case / if (err == -ENOPROTOOPT && optname != IPV6_2292PKTOPTIONS) { - int len; - - if (get_user(len, optlen)) - return -EFAULT; + len = sopt.optlen; err = nf_getsockopt(sk, PF_INET6, optname, optval, &len); if (err >= 0) diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c index ecef55f261890..4ca2d77811f4e 100644 --- a/net/ipv6/mcast.c +++ b/net/ipv6/mcast.c @@ -600,14 +600,14 @@ int ip6_mc_msfilter(struct sock sk, struct group_filter gsf, } int ip6_mc_msfget(struct sock sk, struct group_filter gsf, - sockptr_t optval, size_t ss_offset) + sockopt_t opt, size_t ss_offset) { struct ipv6_pinfo inet6 = inet6_sk(sk); const struct in6_addr group; struct ipv6_mc_socklist pmc; struct ip6_sf_socklist psl; + int i, copycount, err; unsigned int count; - int i, copycount; group = &((struct sockaddr_in6 )&gsf->gf_group)->sin6_addr; @@ -629,6 +629,18 @@ int ip6_mc_msfget(struct sock sk, struct group_filter gsf, copycount = min(count, gsf->gf_numsrc); gsf->gf_numsrc = count; + + / The source list is sized by the gf_numsrc the caller left in optval, + * not by optlen, which only has to cover the fixed part. + / + err = sockopt_expand_out(opt, ss_offset + + copycount sizeof(struct sockaddr_storage)); + if (err) + return err; + + /* The caller fills the fixed part in once it knows gf_numsrc. / + iov_iter_advance(&opt->iter_out, ss_offset); + for (i = 0; i < copycount; i++) { struct sockaddr_in6 psin6; struct sockaddr_storage ss; @@ -637,9 +649,8 @@ int ip6_mc_msfget(struct sock sk, struct group_filter gsf, memset(&ss, 0, sizeof(ss)); psin6->sin6_family = AF_INET6; psin6->sin6_addr = psl->sl_addr[i]; - if (copy_to_sockptr_offset(optval, ss_offset, &ss, sizeof(ss))) + if (copy_to_iter(&ss, sizeof(ss), &opt->iter_out) != sizeof(ss)) return -EFAULT; - ss_offset += sizeof(ss); } return 0; } diff --git a/tools/testing/selftests/net/config b/tools/testing/selftests/net/config index d355cf9805977..07296f0df1394 100644 --- a/tools/testing/selftests/net/config +++ b/tools/testing/selftests/net/config @@ -28,6 +28,7 @@ CONFIG_IP6_NF_MATCH_RPFILTER=m CONFIG_IP6_NF_NAT=m CONFIG_IP6_NF_RAW=m CONFIG_IP6_NF_TARGET_REJECT=m +CONFIG_IP_MROUTE=y CONFIG_IP_NF_FILTER=m CONFIG_IP_NF_IPTABLES=m CONFIG_IP_NF_IPTABLES_LEGACY=m diff --git a/tools/testing/selftests/net/getsockopt_iter.c b/tools/testing/selftests/net/getsockopt_iter.c index 6c2408df46123..2367fce226d4c 100644 --- a/tools/testing/selftests/net/getsockopt_iter.c +++ b/tools/testing/selftests/net/getsockopt_iter.c @@ -55,6 +55,13 @@ #ifndef TCP_ULP #define TCP_ULP 31 #endif +/* linux/mroute.h does not coexist with netinet/in.h here. / +#ifndef MRT_VERSION +#define MRT_VERSION 206 +#endif +#ifndef MRT6_VERSION +#define MRT6_VERSION 206 +#endif / ---------- netlink ---------- / @@ -492,6 +499,371 @@ TEST_F(rawv6, bad_optname) ASSERT_EQ(sizeof(val), optlen); } +/ ---------- ip (SOL_IP) ---------- / + +FIXTURE(ip) +{ + int fd; +}; + +FIXTURE_SETUP(ip) +{ + / a router alert option, so IP_OPTIONS has something to answer with / + static const unsigned char ipopts[4] = { 0x94, 0x04, 0x00, 0x00 }; + int ttl = 42; + + self->fd = socket(AF_INET, SOCK_DGRAM, 0); + if (self->fd < 0) + SKIP(return, "AF_INET dgram socket: %s", strerror(errno)); + + if (setsockopt(self->fd, SOL_IP, IP_TTL, &ttl, sizeof(ttl)) < 0) + SKIP(return, "set IP_TTL: %s", strerror(errno)); + + if (setsockopt(self->fd, SOL_IP, IP_OPTIONS, ipopts, + sizeof(ipopts)) < 0) + SKIP(return, "set IP_OPTIONS: %s", strerror(errno)); +} + +FIXTURE_TEARDOWN(ip) +{ + if (self->fd >= 0) + close(self->fd); +} + +TEST_F(ip, ttl_exact) +{ + socklen_t optlen = sizeof(int); + int val = 0; + + ASSERT_EQ(0, getsockopt(self->fd, SOL_IP, IP_TTL, &val, &optlen)); + ASSERT_EQ(sizeof(int), optlen); + ASSERT_EQ(42, val); +} + +TEST_F(ip, ttl_oversize_clamped) +{ + socklen_t optlen = 64; + int buf[16] = {}; + + ASSERT_EQ(0, getsockopt(self->fd, SOL_IP, IP_TTL, buf, &optlen)); + ASSERT_EQ(sizeof(int), optlen); + ASSERT_EQ(42, buf[0]); +} + +/ SOL_IP answers a sub-int buffer with a single byte when the value fits + * in one, rather than clamping the int down. + / +TEST_F(ip, ttl_single_byte) +{ + unsigned char buf[3] = {}; + socklen_t optlen = sizeof(buf); + + ASSERT_EQ(0, getsockopt(self->fd, SOL_IP, IP_TTL, buf, &optlen)); + ASSERT_EQ(1, optlen); + ASSERT_EQ(42, buf[0]); +} + +TEST_F(ip, ttl_zero_len) +{ + socklen_t optlen = 0; + int val; + + ASSERT_EQ(0, getsockopt(self->fd, SOL_IP, IP_TTL, &val, &optlen)); + ASSERT_EQ(0, optlen); +} + +TEST_F(ip, negative_optlen) +{ + socklen_t optlen = (socklen_t)-1; + int val; + + ASSERT_EQ(-1, getsockopt(self->fd, SOL_IP, IP_TTL, &val, &optlen)); + ASSERT_EQ(EINVAL, errno); +} + +TEST_F(ip, options_roundtrip) +{ + static const unsigned char ipopts[4] = { 0x94, 0x04, 0x00, 0x00 }; + unsigned char buf[40] = {}; + socklen_t optlen = sizeof(buf); + + ASSERT_EQ(0, getsockopt(self->fd, SOL_IP, IP_OPTIONS, buf, &optlen)); + ASSERT_EQ(sizeof(ipopts), optlen); + ASSERT_EQ(0, memcmp(buf, ipopts, sizeof(ipopts))); +} + +TEST_F(ip, options_undersize_clamped) +{ + static const unsigned char ipopts[2] = { 0x94, 0x04 }; + unsigned char buf[2] = {}; + socklen_t optlen = sizeof(buf); + + ASSERT_EQ(0, getsockopt(self->fd, SOL_IP, IP_OPTIONS, buf, &optlen)); + ASSERT_EQ(sizeof(buf), optlen); + ASSERT_EQ(0, memcmp(buf, ipopts, sizeof(buf))); +} + +/ With no option set the reply is empty and the call still succeeds. / +TEST_F(ip, options_absent) +{ + unsigned char buf[40] = {}; + socklen_t optlen = sizeof(buf); + int fd; + + fd = socket(AF_INET, SOCK_DGRAM, 0); + if (fd < 0) + SKIP(return, "AF_INET dgram socket: %s", strerror(errno)); + + ASSERT_EQ(0, getsockopt(fd, SOL_IP, IP_OPTIONS, buf, &optlen)); + ASSERT_EQ(0, optlen); + close(fd); +} + +TEST_F(ip, multicast_if_oversize_clamped) +{ + struct in_addr any = { .s_addr = INADDR_ANY }; + socklen_t optlen = 64; + unsigned char buf[64]; + + memset(buf, 0xaa, sizeof(buf)); + ASSERT_EQ(0, getsockopt(self->fd, SOL_IP, IP_MULTICAST_IF, buf, + &optlen)); + ASSERT_EQ(sizeof(struct in_addr), optlen); + ASSERT_EQ(0, memcmp(buf, &any, sizeof(any))); + ASSERT_EQ(0xaa, buf[sizeof(any)]); +} + +/ IP_PKTOPTIONS only answers on a stream socket. / +TEST_F(ip, pktoptions_wrong_type) +{ + socklen_t optlen = 64; + char buf[64]; + + ASSERT_EQ(-1, getsockopt(self->fd, SOL_IP, IP_PKTOPTIONS, buf, + &optlen)); + ASSERT_EQ(ENOPROTOOPT, errno); +} + +/ The MRT_* options are dispatched ahead of the rest of the switch and + * want a raw IGMP socket. Without CONFIG_IP_MROUTE they are not + * dispatched at all and the switch also answers ENOPROTOOPT, so the + * config check has to come from somewhere other than this errno. + / +TEST_F(ip, mroute_wrong_type) +{ + socklen_t optlen = sizeof(int); + int val; + + if (access("/proc/net/ip_mr_vif", F_OK)) + SKIP(return, "CONFIG_IP_MROUTE disabled"); + + ASSERT_EQ(-1, getsockopt(self->fd, SOL_IP, MRT_VERSION, &val, + &optlen)); + ASSERT_EQ(EOPNOTSUPP, errno); +} + +TEST_F(ip, bad_optname) +{ + socklen_t optlen = sizeof(int); + int val; + + ASSERT_EQ(-1, getsockopt(self->fd, SOL_IP, 0x7fff, &val, &optlen)); + ASSERT_EQ(ENOPROTOOPT, errno); + ASSERT_EQ(sizeof(int), optlen); +} + +/ ---------- ipv6 (SOL_IPV6) ---------- / + +/ an 8 byte hop-by-hop header, so the sticky options answer / +static const unsigned char hopopt[8] = { 0, 0, 1, 4, 0, 0, 0, 0 }; + +FIXTURE(ipv6) +{ + int fd; +}; + +FIXTURE_SETUP(ipv6) +{ + int hops = 42; + + self->fd = socket(AF_INET6, SOCK_DGRAM, 0); + if (self->fd < 0) + SKIP(return, "AF_INET6 dgram socket: %s", strerror(errno)); + + if (setsockopt(self->fd, SOL_IPV6, IPV6_UNICAST_HOPS, &hops, + sizeof(hops)) < 0) + SKIP(return, "set IPV6_UNICAST_HOPS: %s", strerror(errno)); +} + +FIXTURE_TEARDOWN(ipv6) +{ + if (self->fd >= 0) + close(self->fd); +} + +TEST_F(ipv6, hops_exact) +{ + socklen_t optlen = sizeof(int); + int val = 0; + + ASSERT_EQ(0, getsockopt(self->fd, SOL_IPV6, IPV6_UNICAST_HOPS, &val, + &optlen)); + ASSERT_EQ(sizeof(int), optlen); + ASSERT_EQ(42, val); +} + +TEST_F(ipv6, hops_oversize_clamped) +{ + socklen_t optlen = 64; + int buf[16] = {}; + + ASSERT_EQ(0, getsockopt(self->fd, SOL_IPV6, IPV6_UNICAST_HOPS, buf, + &optlen)); + ASSERT_EQ(sizeof(int), optlen); + ASSERT_EQ(42, buf[0]); +} + +/ Unlike SOL_IP, SOL_IPV6 clamps a sub-int buffer down to what fits + * rather than answering a single byte. + / +TEST_F(ipv6, hops_sub_int) +{ + unsigned char buf[3]; + socklen_t optlen = sizeof(buf); + int hops = 42; + + memset(buf, 0xaa, sizeof(buf)); + ASSERT_EQ(0, getsockopt(self->fd, SOL_IPV6, IPV6_UNICAST_HOPS, buf, + &optlen)); + ASSERT_EQ(sizeof(buf), optlen); + ASSERT_EQ(0, memcmp(buf, &hops, sizeof(buf))); +} + +TEST_F(ipv6, hops_zero_len) +{ + socklen_t optlen = 0; + int val; + + ASSERT_EQ(0, getsockopt(self->fd, SOL_IPV6, IPV6_UNICAST_HOPS, &val, + &optlen)); + ASSERT_EQ(0, optlen); +} + +/ Unlike SOL_IP, a negative optlen is taken as 4 here, as the int options + * always did. + / +TEST_F(ipv6, negative_optlen) +{ + socklen_t optlen = (socklen_t)-1; + int val = 0; + + ASSERT_EQ(0, getsockopt(self->fd, SOL_IPV6, IPV6_UNICAST_HOPS, &val, + &optlen)); + ASSERT_EQ(sizeof(int), optlen); + ASSERT_EQ(42, val); +} + +TEST_F(ipv6, hopopts_roundtrip) +{ + unsigned char buf[64] = {}; + socklen_t optlen = sizeof(buf); + + if (setsockopt(self->fd, SOL_IPV6, IPV6_HOPOPTS, hopopt, + sizeof(hopopt)) < 0) + SKIP(return, "set IPV6_HOPOPTS: %s", strerror(errno)); + + ASSERT_EQ(0, getsockopt(self->fd, SOL_IPV6, IPV6_HOPOPTS, buf, + &optlen)); + ASSERT_EQ(sizeof(hopopt), optlen); + ASSERT_EQ(0, memcmp(buf, hopopt, sizeof(hopopt))); +} + +TEST_F(ipv6, hopopts_undersize_clamped) +{ + unsigned char buf[4] = {}; + socklen_t optlen = sizeof(buf); + + if (setsockopt(self->fd, SOL_IPV6, IPV6_HOPOPTS, hopopt, + sizeof(hopopt)) < 0) + SKIP(return, "set IPV6_HOPOPTS: %s", strerror(errno)); + + ASSERT_EQ(0, getsockopt(self->fd, SOL_IPV6, IPV6_HOPOPTS, buf, + &optlen)); + ASSERT_EQ(sizeof(buf), optlen); + ASSERT_EQ(0, memcmp(buf, hopopt, sizeof(buf))); +} + +/ With no header set the reply is empty and the call still succeeds. / +TEST_F(ipv6, hopopts_absent) +{ + unsigned char buf[64] = {}; + socklen_t optlen = sizeof(buf); + int fd; + + fd = socket(AF_INET6, SOCK_DGRAM, 0); + if (fd < 0) + SKIP(return, "AF_INET6 dgram socket: %s", strerror(errno)); + + ASSERT_EQ(0, getsockopt(fd, SOL_IPV6, IPV6_HOPOPTS, buf, &optlen)); + ASSERT_EQ(0, optlen); + close(fd); +} + +/ IPV6_PATHMTU wants room for the whole struct ip6_mtuinfo. / +TEST_F(ipv6, pathmtu_undersize) +{ + socklen_t optlen = 8; + char buf[8]; + + ASSERT_EQ(-1, getsockopt(self->fd, SOL_IPV6, IPV6_PATHMTU, buf, + &optlen)); + ASSERT_EQ(EINVAL, errno); +} + +/ A negative optlen is taken as 4, which is undersize for IPV6_PATHMTU. / +TEST_F(ipv6, pathmtu_negative_optlen) +{ + socklen_t optlen = (socklen_t)-1; + char buf[64]; + + ASSERT_EQ(-1, getsockopt(self->fd, SOL_IPV6, IPV6_PATHMTU, buf, + &optlen)); + ASSERT_EQ(EINVAL, errno); +} + +TEST_F(ipv6, pktoptions_wrong_type) +{ + socklen_t optlen = 64; + char buf[64]; + + ASSERT_EQ(-1, getsockopt(self->fd, SOL_IPV6, IPV6_2292PKTOPTIONS, buf, + &optlen)); + ASSERT_EQ(ENOPROTOOPT, errno); +} + +TEST_F(ipv6, mroute_wrong_type) +{ + socklen_t optlen = sizeof(int); + int val; + + if (access("/proc/net/ip6_mr_vif", F_OK)) + SKIP(return, "CONFIG_IPV6_MROUTE disabled"); + + ASSERT_EQ(-1, getsockopt(self->fd, SOL_IPV6, MRT6_VERSION, &val, + &optlen)); + ASSERT_EQ(EOPNOTSUPP, errno); +} + +TEST_F(ipv6, bad_optname) +{ + socklen_t optlen = sizeof(int); + int val; + + ASSERT_EQ(-1, getsockopt(self->fd, SOL_IPV6, 0x7fff, &val, &optlen)); + ASSERT_EQ(ENOPROTOOPT, errno); + ASSERT_EQ(sizeof(int), optlen); +} + / ---------- tls ---------- */ FIXTURE(tls)
3/2	2026/10/15 12:58	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 20752 output: 95 thoughts: 2346 Thoughts: My Analysis of the Linux Kernel Patch Series Okay, so I'm looking at this patch series targeting amd64. My initial assessment is that this is a significant refactoring of `getsockopt` handling within the Linux kernel, specifically related to IP and IPv6 socket options and multicast. Let's dig in. The diff touches various header and source files, including `include/linux/igmp.h`, `include/linux/mroute.h`, `include/linux/mroute6.h`, `include/linux/net.h`, `include/net/ip.h`, `include/net/ipv6.h`, and files in `net/core`, `net/ipv4`, `net/ipv6`, along with selftests. Seems quite broad. My first thought: this series replaces `sockptr_t` and `optlen` with `sockopt_t sopt`. This has the potential for significant impact, particularly since it refactors `do_ip_getsockopt` and `do_ipv6_getsockopt`, which are fundamental. And I see a lot of other calls touched by the refactoring as well. This isn't just a minor tweak. The changes impact how `getsockopt` handles IPv4 (SOL_IP) and IPv6 (SOL_IPV6) options, including BPF cgroup hooks. I see changes to multicast source filtering (`ip_mc_msfget`, `ip_mc_gsfget`, etc.), multicast routing (`MRT_`, `MRT6_`), and general IP/IPv6 sockopts (`IP_OPTIONS`, `IP_PKTOPTIONS`, `IPV6_2292PKTOPTIONS`). This is core networking code! I see some use of `iov_iter` and a refactoring of `sockopt_expand_out`, which are worth a closer look. Hold on, there's some interesting rewind and advance logic using `iov_iter_revert` and `iov_iter_advance`* alongside `sockopt_expand_out`. Any subtle memory safety issues here? Any off-by-one errors? Buffer handling changes are definitely important here, particularly in the context of user-supplied data. I need to understand this logic very carefully. The `copy_to_iter` and size checks are also important. The selftests should catch most of it. Given the scope, this is definitely worth fuzzing. It's core kernel code, easily reachable via standard `getsockopt` syscalls on AF_INET and AF_INET6 sockets. This is easily exploitable in a standard QEMU environment. Now, which functions should be `FocusSymbols`? I need to be careful not to list ubiquitous functions. These functions aren't called by every program, only ones using `getsockopt(SOL_IP)` or `getsockopt(SOL_IPV6)`. So it's not a generic memory allocator or trap handler. I should try to limit the functions I focus on, to improve fuzzing efficiency. I need to make a good decision on whether to focus on the common entry points (like `ip_getsockopt`, `do_ip_getsockopt`, `ipv6_getsockopt`, `do_ipv6_getsockopt`), or some of the inner calls that are affected. The important thing is that `FocusSymbols` should focus the fuzzer. The functions specifically implemented, or are API entry points for the feature altered: - `do_ip_getsockopt` - `ip_getsockopt` - `do_ipv6_getsockopt` - `ipv6_getsockopt` - `ip_get_mcast_msfilter` - `compat_ip_get_mcast_msfilter` - `ipv6_get_msfilter` - `compat_ipv6_get_msfilter` - `ip_mc_msfget` - `ip_mc_gsfget` - `ip6_mc_msfget` - `ip_mroute_getsockopt` - `ip6_mroute_getsockopt` - `ipv6_getsockopt_sticky` - `sol_ip_sockopt` - `sol_ipv6_sockopt` - `sockopt_set_user` (static inline) - `sockopt_expand_out` (static inline) I'll need to double-check that the symbols are not static, and reachable via syzkaller. Specifically, I'll check that `ip_getsockopt` is not the same as `do_ip_getsockopt`.
4/2	2026/10/15 12:59	tool	grepper	0m Args: { "Expression": "(ip_mc_gsfget\|ip6_mc_msfget\|ip_get_mcast_msfilter\|ipv6_get_msfilter\|ip_mroute_getsockopt\|ip6_mroute_getsockopt\|do_ip_getsockopt\|do_ipv6_getsockopt)", "PathPrefixes": [ "net/" ] } Results: { "Output": "net/core/filter.c=5723=static int sol_ip_sockopt(struct sock sk, int optname,\n--\nnet/core/filter.c-5749-\nnet/core/filter.c:5750:\t\terr = do_ip_getsockopt(sk, SOL_IP, optname, \u0026opt);\nnet/core/filter.c-5751-\t\toptlen = opt.optlen;\n--\nnet/core/filter.c=5759=static int sol_ipv6_sockopt(struct sock sk, int optname,\n--\nnet/core/filter.c-5786-\nnet/core/filter.c:5787:\t\terr = do_ipv6_getsockopt(sk, SOL_IPV6, optname, \u0026opt);\nnet/core/filter.c-5788-\t\toptlen = opt.optlen;\n--\nnet/ipv4/igmp.c=2713=int ip_mc_msfget(struct sock sk, struct ip_msfilter msf, sockopt_t opt)\n--\nnet/ipv4/igmp.c-2777-\nnet/ipv4/igmp.c:2778:int ip_mc_gsfget(struct sock sk, struct group_filter gsf,\nnet/ipv4/igmp.c-2779-\t\t sockopt_t opt, size_t ss_offset)\n--\nnet/ipv4/ip_sockglue.c=1435=static bool getsockopt_needs_rtnl(int optname)\n--\nnet/ipv4/ip_sockglue.c-1444-\nnet/ipv4/ip_sockglue.c:1445:static int ip_get_mcast_msfilter(struct sock sk, sockopt_t opt)\nnet/ipv4/ip_sockglue.c-1446-{\n--\nnet/ipv4/ip_sockglue.c-1457-\tnum = gsf.gf_numsrc;\nnet/ipv4/ip_sockglue.c:1458:\terr = ip_mc_gsfget(sk, \u0026gsf, opt,\nnet/ipv4/ip_sockglue.c-1459-\t\t\t offsetof(struct group_filter, gf_slist_flex));\n--\nnet/ipv4/ip_sockglue.c-1465-\nnet/ipv4/ip_sockglue.c:1466:\t/* ip_mc_gsfget() consumed the whole reply; rewind to the fixed part. /\nnet/ipv4/ip_sockglue.c-1467-\tiov_iter_revert(\u0026opt-\u003eiter_out, gsf_size);\n--\nnet/ipv4/ip_sockglue.c-1473-\nnet/ipv4/ip_sockglue.c:1474:static int compat_ip_get_mcast_msfilter(struct sock sk, sockopt_t opt)\nnet/ipv4/ip_sockglue.c-1475-{\n--\nnet/ipv4/ip_sockglue.c-1491-\nnet/ipv4/ip_sockglue.c:1492:\terr = ip_mc_gsfget(sk, \u0026gf, opt,\nnet/ipv4/ip_sockglue.c-1493-\t\t\t offsetof(struct compat_group_filter, gf_slist_flex));\n--\nnet/ipv4/ip_sockglue.c-1511-\nnet/ipv4/ip_sockglue.c:1512:int do_ip_getsockopt(struct sock sk, int level, int optname, sockopt_t sopt)\nnet/ipv4/ip_sockglue.c-1513-{\n--\nnet/ipv4/ip_sockglue.c-1522-\tif (ip_mroute_opt(optname))\nnet/ipv4/ip_sockglue.c:1523:\t\treturn ip_mroute_getsockopt(sk, optname, sopt);\nnet/ipv4/ip_sockglue.c-1524-\n--\nnet/ipv4/ip_sockglue.c-1724-\t\tif (in_compat_syscall())\nnet/ipv4/ip_sockglue.c:1725:\t\t\terr = compat_ip_get_mcast_msfilter(sk, sopt);\nnet/ipv4/ip_sockglue.c-1726-\t\telse\nnet/ipv4/ip_sockglue.c:1727:\t\t\terr = ip_get_mcast_msfilter(sk, sopt);\nnet/ipv4/ip_sockglue.c-1728-\t\tgoto out;\n--\nnet/ipv4/ip_sockglue.c=1759=int ip_getsockopt(struct sock sk, int level,\n--\nnet/ipv4/ip_sockglue.c-1768-\nnet/ipv4/ip_sockglue.c:1769:\terr = do_ip_getsockopt(sk, level, optname, \u0026opt);\nnet/ipv4/ip_sockglue.c-1770-\tif (put_user(opt.optlen, optlen))\n--\nnet/ipv4/ipmr.c=1619=int ipmr_sk_ioctl(struct sock sk, unsigned int cmd, void __user arg)\n--\nnet/ipv4/ipmr.c-1640-/* Getsock opt support for the multicast routing system. /\nnet/ipv4/ipmr.c:1641:int ip_mroute_getsockopt(struct sock sk, int optname, sockopt_t opt)\nnet/ipv4/ipmr.c-1642-{\n--\nnet/ipv6/ip6mr.c=1713=int ip6_mroute_setsockopt(struct sock sk, int optname, sockptr_t optval,\n--\nnet/ipv6/ip6mr.c-1895-\nnet/ipv6/ip6mr.c:1896:int ip6_mroute_getsockopt(struct sock sk, int optname, sockopt_t sopt)\nnet/ipv6/ip6mr.c-1897-{\n--\nnet/ipv6/ipv6_sockglue.c=891=static int ipv6_getsockopt_sticky(struct sock sk, struct ipv6_txoptions opt,\n--\nnet/ipv6/ipv6_sockglue.c-924-\nnet/ipv6/ipv6_sockglue.c:925:static int ipv6_get_msfilter(struct sock sk, sockopt_t opt)\nnet/ipv6/ipv6_sockglue.c-926-{\n--\nnet/ipv6/ipv6_sockglue.c-939-\tsockopt_lock_sock(sk);\nnet/ipv6/ipv6_sockglue.c:940:\terr = ip6_mc_msfget(sk, \u0026gsf, opt, size0);\nnet/ipv6/ipv6_sockglue.c-941-\tif (!err) {\n--\nnet/ipv6/ipv6_sockglue.c-945-\nnet/ipv6/ipv6_sockglue.c:946:\t\t/* ip6_mc_msfget() consumed the whole reply; rewind to the\nnet/ipv6/ipv6_sockglue.c-947-\t\t * fixed part.\n--\nnet/ipv6/ipv6_sockglue.c-958-\nnet/ipv6/ipv6_sockglue.c:959:static int compat_ipv6_get_msfilter(struct sock sk, sockopt_t opt)\nnet/ipv6/ipv6_sockglue.c-960-{\n--\nnet/ipv6/ipv6_sockglue.c-980-\tsockopt_lock_sock(sk);\nnet/ipv6/ipv6_sockglue.c:981:\terr = ip6_mc_msfget(sk, \u0026gf, opt, size0);\nnet/ipv6/ipv6_sockglue.c-982-\tsockopt_release_sock(sk);\n--\nnet/ipv6/ipv6_sockglue.c-1000-\nnet/ipv6/ipv6_sockglue.c:1001:int do_ipv6_getsockopt(struct sock sk, int level, int optname, sockopt_t sopt)\nnet/ipv6/ipv6_sockglue.c-1002-{\n--\nnet/ipv6/ipv6_sockglue.c-1007-\tif (ip6_mroute_opt(optname))\nnet/ipv6/ipv6_sockglue.c:1008:\t\treturn ip6_mroute_getsockopt(sk, optname, sopt);\nnet/ipv6/ipv6_sockglue.c-1009-\n--\nnet/ipv6/ipv6_sockglue.c-1013-\t\tif (in_compat_syscall())\nnet/ipv6/ipv6_sockglue.c:1014:\t\t\treturn compat_ipv6_get_msfilter(sk, sopt);\nnet/ipv6/ipv6_sockglue.c:1015:\t\treturn ipv6_get_msfilter(sk, sopt);\nnet/ipv6/ipv6_sockglue.c-1016-\tcase IPV6_2292PKTOPTIONS:\n--\nnet/ipv6/ipv6_sockglue.c=1355=int ipv6_getsockopt(struct sock sk, int level, int optname,\n--\nnet/ipv6/ipv6_sockglue.c-1378-\nnet/ipv6/ipv6_sockglue.c:1379:\terr = do_ipv6_getsockopt(sk, level, optname, \u0026sopt);\nnet/ipv6/ipv6_sockglue.c-1380-\tif (put_user(sopt.optlen, optlen))\n--\nnet/ipv6/mcast.c=504=int ip6_mc_msfilter(struct sock sk, struct group_filter gsf,\n--\nnet/ipv6/mcast.c-601-\nnet/ipv6/mcast.c:602:int ip6_mc_msfget(struct sock sk, struct group_filter gsf,\nnet/ipv6/mcast.c-603-\t\t sockopt_t opt, size_t ss_offset)\n" }
5/2	2026/10/15 12:59	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 26827 output: 55 thoughts: 45 Thoughts: Okay, here's my take on those thoughts, tailored for an expert audience: Kconfig Dependency Audit: IPv6 and Multicast Alright, time to get down to brass tacks. I need to nail down the precise Kconfig dependencies for this code change. No guessing, no assumptions. My immediate strategy? Let's aggressively use `grep`. I'll run a quick sweep through the affected files, specifically targeting the `CONFIG_IPV6`, `CONFIG_IP_MROUTE`, and `CONFIG_IPV6_MROUTE` Kconfig symbols. These are the usual suspects when dealing with IPv6-related modifications and multicast functionality. The goal is pinpoint exactly what needs to be enabled or potentially adjusted to ensure this new code integrates seamlessly and doesn't introduce any surprises downstream. This is a crucial step to maintain build integrity and avoid runtime issues. I expect to be able to quickly determine if there are any new dependencies or if existing settings need to be revisited. Let's get to it.
6/2	2026/10/15 12:59	tool	grepper	0m Args: { "Expression": "CONFIG_(IP_MROUTE\|IPV6_MROUTE\|IPV6)", "PathPrefixes": [ "net/ipv4/", "net/ipv6/", "include/" ] } Results: { "Output": "\nFull output is too long, showing 200 out of 2599 lines.\nUse more precise expression or PathPrefixes if possible.\n\nNumber of matching lines per file (129 files in total):\ninclude/linux/errqueue.h:2\ninclude/linux/filter.h:2\ninclude/linux/icmpv6.h:1\ninclude/linux/if_bridge.h:2\ninclude/linux/indirect_call_wrapper.h:1\ninclude/linux/inet_diag.h:1\ninclude/linux/ipv6.h:9\ninclude/linux/lsm_audit.h:2\ninclude/linux/mroute.h:1\ninclude/linux/mroute6.h:4\ninclude/linux/mroute_base.h:2\ninclude/linux/netdevice.h:2\ninclude/linux/netfilter_ipv6.h:6\ninclude/linux/skbuff.h:1\ninclude/linux/sunrpc/addr.h:3\ninclude/linux/udp.h:2\ninclude/net/addrconf.h:1\ninclude/net/amt.h:1\ninclude/net/bond_options.h:1\ninclude/net/bonding.h:3\ninclude/net/dst_cache.h:2\ninclude/net/hotdata.h:1\ninclude/net/inet6_hashtables.h:2\ninclude/net/inet_hashtables.h:6\ninclude/net/inet_sock.h:3\ninclude/net/ioam6.h:1\ninclude/net/ip.h:2\ninclude/net/ip6_fib.h:12\ninclude/net/ip6_route.h:5\ninclude/net/ip_tunnels.h:5\ninclude/net/ipv6.h:4\ninclude/net/ipv6_frag.h:1\ninclude/net/libeth/rx.h:1\ninclude/net/mac80211.h:1\ninclude/net/mptcp.h:1\ninclude/net/ndisc.h:5\ninclude/net/net_namespace.h:2\ninclude/net/netfilter/br_netfilter.h:1\ninclude/net/netfilter/nf_synproxy.h:2\ninclude/net/netfilter/nf_tables_ipv6.h:2\ninclude/net/netns/ipv4.h:2\ninclude/net/netns/ipv6.h:4\ninclude/net/netns/mib.h:3\ninclude/net/netns/xfrm.h:1\ninclude/net/ping.h:1\ninclude/net/protocol.h:4\ninclude/net/rawv6.h:1\ninclude/net/rpl.h:1\ninclude/net/sctp/sctp.h:4\ninclude/net/sctp/structs.h:3\n... and 79 more files\n\ninclude/linux/errqueue.h-6-#include \u003cnet/ip.h\u003e\ninclude/linux/errqueue.h:7:#if IS_ENABLED(CONFIG_IPV6)\ninclude/linux/errqueue.h-8-#include \u003clinux/ipv6.h\u003e\n--\ninclude/linux/errqueue.h=14=struct sock_exterr_skb {\n--\ninclude/linux/errqueue.h-16-\t\tstruct inet_skb_parm\th4;\ninclude/linux/errqueue.h:17:#if IS_ENABLED(CONFIG_IPV6)\ninclude/linux/errqueue.h-18-\t\tstruct inet6_skb_parm\th6;\n--\ninclude/linux/filter.h=1827=static inline bool bpf_sk_lookup_run_v4(const struct net net, int protocol,\n--\ninclude/linux/filter.h-1862-\ninclude/linux/filter.h:1863:#if IS_ENABLED(CONFIG_IPV6)\ninclude/linux/filter.h-1864-static inline bool bpf_sk_lookup_run_v6(const struct net net, int protocol,\n--\ninclude/linux/filter.h-1900-}\ninclude/linux/filter.h:1901:#endif /* IS_ENABLED(CONFIG_IPV6) /\ninclude/linux/filter.h-1902-\n--\ninclude/linux/icmpv6.h=9=static inline struct icmp6hdr icmp6_hdr(const struct sk_buff skb)\n--\ninclude/linux/icmpv6.h-15-\ninclude/linux/icmpv6.h:16:#if IS_ENABLED(CONFIG_IPV6)\ninclude/linux/icmpv6.h-17-\n--\ninclude/linux/if_bridge.h=16=struct br_ip {\n--\ninclude/linux/if_bridge.h-18-\t\t__be32\tip4;\ninclude/linux/if_bridge.h:19:#if IS_ENABLED(CONFIG_IPV6)\ninclude/linux/if_bridge.h-20-\t\tstruct in6_addr ip6;\n--\ninclude/linux/if_bridge.h-24-\t\t__be32\tip4;\ninclude/linux/if_bridge.h:25:#if IS_ENABLED(CONFIG_IPV6)\ninclude/linux/if_bridge.h-26-\t\tstruct in6_addr ip6;\n--\ninclude/linux/indirect_call_wrapper.h-59- /\ninclude/linux/indirect_call_wrapper.h:60:#if IS_ENABLED(CONFIG_IPV6)\ninclude/linux/indirect_call_wrapper.h-61-#define INDIRECT_CALL_INET(f, f2, f1, ...) \\\n--\ninclude/linux/inet_diag.h=58=static inline size_t inet_diag_msg_attrs_size(void)\n--\ninclude/linux/inet_diag.h-61-\t\t+ nla_total_size(1) /* INET_DIAG_TOS /\ninclude/linux/inet_diag.h:62:#if IS_ENABLED(CONFIG_IPV6)\ninclude/linux/inet_diag.h-63-\t\t+ nla_total_size(1) / INET_DIAG_TCLASS /\n--\ninclude/linux/ipv6.h=13=struct ipv6_devconf {\n--\ninclude/linux/ipv6.h-48-\t__s32\t\tignore_routes_with_linkdown;\ninclude/linux/ipv6.h:49:#ifdef CONFIG_IPV6_ROUTER_PREF\ninclude/linux/ipv6.h-50-\t__s32\t\taccept_ra_rtr_pref;\ninclude/linux/ipv6.h-51-\t__s32\t\trtr_probe_interval;\ninclude/linux/ipv6.h:52:#ifdef CONFIG_IPV6_ROUTE_INFO\ninclude/linux/ipv6.h-53-\t__s32\t\taccept_ra_rt_info_min_plen;\n--\ninclude/linux/ipv6.h-58-\t__s32\t\taccept_ra_from_local;\ninclude/linux/ipv6.h:59:#ifdef CONFIG_IPV6_OPTIMISTIC_DAD\ninclude/linux/ipv6.h-60-\t__s32\t\toptimistic_dad;\n--\ninclude/linux/ipv6.h-62-#endif\ninclude/linux/ipv6.h:63:#ifdef CONFIG_IPV6_MROUTE\ninclude/linux/ipv6.h-64-\tatomic_t\tmc_forwarding;\n--\ninclude/linux/ipv6.h-80-\t__s32\t\tseg6_enabled;\ninclude/linux/ipv6.h:81:#ifdef CONFIG_IPV6_SEG6_HMAC\ninclude/linux/ipv6.h-82-\t__s32\t\tseg6_require_hmac;\n--\ninclude/linux/ipv6.h=156=struct inet6_skb_parm {\n--\ninclude/linux/ipv6.h-164-\t__u16\t\t\tflags;\ninclude/linux/ipv6.h:165:#if defined(CONFIG_IPV6_MIP6) \|\| defined(CONFIG_IPV6_MIP6_MODULE)\ninclude/linux/ipv6.h-166-\t__u16\t\t\tdsthao;\n--\ninclude/linux/ipv6.h=230=struct ipv6_pinfo {\n--\ninclude/linux/ipv6.h-242-\tu8\t\t\ttclass;\ninclude/linux/ipv6.h:243:#ifdef CONFIG_IPV6_SUBTREES\ninclude/linux/ipv6.h-244-\tbool\t\t\tsaddr_cache;\n--\ninclude/linux/ipv6.h=331=struct tcp6_timewait_sock {\n--\ninclude/linux/ipv6.h-334-\ninclude/linux/ipv6.h:335:#if IS_ENABLED(CONFIG_IPV6)\ninclude/linux/ipv6.h-336-extern int disable_ipv6_mod;\n--\ninclude/linux/ipv6.h=380=static inline struct raw6_sock raw6_sk(const struct sock sk)\n--\ninclude/linux/ipv6.h-386-#define inet_v6_ipv6only(__sk)\t\t0\ninclude/linux/ipv6.h:387:#endif / IS_ENABLED(CONFIG_IPV6) /\ninclude/linux/ipv6.h-388-#endif / _IPV6_H /\n--\ninclude/linux/lsm_audit.h=128=int ipv4_skb_to_auditdata(struct sk_buff skb,\n--\ninclude/linux/lsm_audit.h-130-\ninclude/linux/lsm_audit.h:131:#if IS_ENABLED(CONFIG_IPV6)\ninclude/linux/lsm_audit.h-132-int ipv6_skb_to_auditdata(struct sk_buff skb,\ninclude/linux/lsm_audit.h-133-\t\tstruct common_audit_data ad, u8 proto);\ninclude/linux/lsm_audit.h:134:#endif / IS_ENABLED(CONFIG_IPV6) /\ninclude/linux/lsm_audit.h-135-\n--\ninclude/linux/mroute.h-12-\ninclude/linux/mroute.h:13:#ifdef CONFIG_IP_MROUTE\ninclude/linux/mroute.h-14-static inline int ip_mroute_opt(int opt)\n--\ninclude/linux/mroute6.h-13-\ninclude/linux/mroute6.h:14:#ifdef CONFIG_IPV6_MROUTE\ninclude/linux/mroute6.h-15-static inline int ip6_mroute_opt(int opt)\n--\ninclude/linux/mroute6.h=26=struct sock;\ninclude/linux/mroute6.h-27-\ninclude/linux/mroute6.h:28:#ifdef CONFIG_IPV6_MROUTE\ninclude/linux/mroute6.h-29-extern int ip6_mroute_setsockopt(struct sock , int, sockptr_t, unsigned int);\n--\ninclude/linux/mroute6.h=67=static inline void ip6_mr_cleanup(void)\n--\ninclude/linux/mroute6.h-72-\ninclude/linux/mroute6.h:73:#ifdef CONFIG_IPV6_MROUTE_MULTIPLE_TABLES\ninclude/linux/mroute6.h-74-bool ip6mr_rule_default(const struct fib_rule rule);\n--\ninclude/linux/mroute6.h=103=extern int ip6mr_get_route(struct net net, struct sk_buff skb,\n--\ninclude/linux/mroute6.h-105-\ninclude/linux/mroute6.h:106:#ifdef CONFIG_IPV6_MROUTE\ninclude/linux/mroute6.h-107-bool mroute6_is_socket(struct net net, struct sk_buff skb);\n--\ninclude/linux/mroute_base.h=266=static inline bool mr_can_free_table(struct net net)\n--\ninclude/linux/mroute_base.h-270-\ninclude/linux/mroute_base.h:271:#ifdef CONFIG_IP_MROUTE_COMMON\ninclude/linux/mroute_base.h-272-void vif_device_init(struct vif_device v,\n--\ninclude/linux/mroute_base.h=391=struct mr_mfc_iter {\n--\ninclude/linux/mroute_base.h-399-\ninclude/linux/mroute_base.h:400:#ifdef CONFIG_IP_MROUTE_COMMON\ninclude/linux/mroute_base.h-401-void mr_vif_seq_idx(struct net net, struct mr_vif_iter iter, loff_t pos);\n--\ninclude/linux/netdevice.h=144=static inline bool dev_xmit_complete(int rc)\n--\ninclude/linux/netdevice.h-175-#if !IS_ENABLED(CONFIG_NET_IPIP) \u0026\u0026 !IS_ENABLED(CONFIG_NET_IPGRE) \u0026\u0026 \\\ninclude/linux/netdevice.h:176: !IS_ENABLED(CONFIG_IPV6_SIT) \u0026\u0026 !IS_ENABLED(CONFIG_IPV6_TUNNEL)\ninclude/linux/netdevice.h-177-#define MAX_HEADER LL_MAX_HEADER\n--\ninclude/linux/netdevice.h=2160=struct net_device {\n--\ninclude/linux/netdevice.h-2306-#endif\ninclude/linux/netdevice.h:2307:#if IS_ENABLED(CONFIG_IPV6)\ninclude/linux/netdevice.h-2308-\tconst struct ndisc_ops ndisc_ops;\n--\ninclude/linux/netfilter_ipv6.h=40=static inline int nf_ipv6_chk_addr(struct net net, const struct in6_addr addr,\n--\ninclude/linux/netfilter_ipv6.h-42-{\ninclude/linux/netfilter_ipv6.h:43:#if IS_ENABLED(CONFIG_IPV6)\ninclude/linux/netfilter_ipv6.h-44-\treturn ipv6_chk_addr(net, addr, dev, strict);\n--\ninclude/linux/netfilter_ipv6.h=53=static inline int nf_ip6_route(struct net net, struct dst_entry *dst,\n--\ninclude/linux/netfilter_ipv6.h-55-{\ninclude/linux/netfilter_ipv6.h:56:#if IS_ENABLED(CONFIG_IPV6)\ninclude/linux/netfilter_ipv6.h-57-\treturn __nf_ip6_route(net, dst, fl, strict);\n--\ninclude/linux/netfilter_ipv6.h=71=static inline int nf_br_ip6_fragment(struct net net, struct sock sk,\n--\ninclude/linux/netfilter_ipv6.h-77-{\ninclude/linux/netfilter_ipv6.h:78:#if IS_ENABLED(CONFIG_IPV6)\ninclude/linux/netfilter_ipv6.h-79-\treturn br_ip6_fragment(net, sk, skb, data, output);\n--\ninclude/linux/netfilter_ipv6.h=87=static inline int nf_ip6_route_me_harder(struct net net, struct sock sk, struct sk_buff skb)\ninclude/linux/netfilter_ipv6.h-88-{\ninclude/linux/netfilter_ipv6.h:89:#if IS_ENABLED(CONFIG_IPV6)\ninclude/linux/netfilter_ipv6.h-90-\treturn ip6_route_me_harder(net, sk, skb);\n--\ninclude/linux/netfilter_ipv6.h=96=static inline u32 nf_ipv6_cookie_init_sequence(const struct ipv6hdr iph,\n--\ninclude/linux/netfilter_ipv6.h-99-{\ninclude/linux/netfilter_ipv6.h:100:#if IS_ENABLED(CONFIG_IPV6) \u0026\u0026 IS_ENABLED(CONFIG_SYN_COOKIES)\ninclude/linux/netfilter_ipv6.h-101-\treturn __cookie_v6_init_sequence(iph, th, mssp);\n--\ninclude/linux/netfilter_ipv6.h=106=static inline int nf_cookie_v6_check(const struct ipv6hdr iph,\n--\ninclude/linux/netfilter_ipv6.h-108-{\ninclude/linux/netfilter_ipv6.h:109:#if IS_ENABLED(CONFIG_IPV6) \u0026\u0026 IS_ENABLED(CONFIG_SYN_COOKIES)\ninclude/linux/netfilter_ipv6.h-110-\treturn __cookie_v6_check(iph, th);\n--\ninclude/linux/skbuff.h=886=struct sk_buff {\n--\ninclude/linux/skbuff.h-1004-\t__u8\t\t\tcsum_valid:1;\ninclude/linux/skbuff.h:1005:#ifdef CONFIG_IPV6_NDISC_NODETYPE\ninclude/linux/skbuff.h-1006-\t__u8\t\t\tndisc_nodetype:2;\n--\ninclude/linux/sunrpc/addr.h=59=static inline bool __rpc_copy_addr4(struct sockaddr dst,\n--\ninclude/linux/sunrpc/addr.h-69-\ninclude/linux/sunrpc/addr.h:70:#if IS_ENABLED(CONFIG_IPV6)\ninclude/linux/sunrpc/addr.h-71-static inline bool rpc_cmp_addr6(const struct sockaddr sap1,\n--\ninclude/linux/sunrpc/addr.h=85=static inline bool __rpc_copy_addr6(struct sockaddr dst,\n--\ninclude/linux/sunrpc/addr.h-95-}\ninclude/linux/sunrpc/addr.h:96:#else\t/ !(IS_ENABLED(CONFIG_IPV6) */\n\n" }
7/2	2026/10/15 12:59	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 31566 output: 42 thoughts: 34 Thoughts: Here's my take on the thought process: Diving into Multicast Routing Code Okay, so I need to understand how multicast routing is handled in this kernel. Where's the best place to start? I immediately think, "Check the build system!" Specifically, the `Makefile` and `Kconfig` files are going to be critical. They'll tell me how `net/ipv4/ipmr.c` and `net/ipv6/ip6mr.c` are brought into the build. What are the dependencies? Are there specific configuration options that enable them? I need to understand the conditional compilation and how these modules fit into the bigger picture. Time to dig in and unravel the build process for these crucial files. Let's see how the kernel is setting the stage for multicast!
8/2	2026/10/15 12:59	tool	grepper	0m Args: { "Expression": "ipmr\|ip6mr", "PathPrefixes": [ "net/ipv4/Makefile", "net/ipv6/Makefile" ] } Results: { "Output": "net/ipv4/Makefile=22=obj-$(CONFIG_IP_MULTIPLE_TABLES) += fib_rules.o\nnet/ipv4/Makefile:23:obj-$(CONFIG_IP_MROUTE) += ipmr.o\nnet/ipv4/Makefile:24:obj-$(CONFIG_IP_MROUTE_COMMON) += ipmr_base.o\nnet/ipv4/Makefile-25-obj-$(CONFIG_NET_IPIP) += ipip.o\n--\nnet/ipv6/Makefile=15=ipv6-$(CONFIG_SYSCTL) += sysctl_net_ipv6.o\nnet/ipv6/Makefile:16:ipv6-$(CONFIG_IPV6_MROUTE) += ip6mr.o\nnet/ipv6/Makefile-17-\n" }
9/2	2026/10/15 12:59	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 32008 output: 49 thoughts: 26 Thoughts: Okay, here's my take on those thoughts, tailored for an expert audience: Investigating Multicast Routing Configuration Alright, let's dive in. Before I even start looking at the code, my initial thought is always to confirm the underlying configuration. I need to quickly establish the relevant Kconfig options. Specifically, I'm thinking about `CONFIG_IP_MROUTE` for IPv4 multicast routing, and naturally, `CONFIG_IPV6_MROUTE` for the IPv6 counterpart. I need to verify that these are enabled or disabled, or perhaps even set to a module configuration. I'll need to know whether the functionality is even baked into this build. Understanding the base configuration before poking around in the kernel's guts always saves time. I need to make sure that whatever I'm troubleshooting, or looking to improve, is actually enabled within this particular build. Let's see what's what.
10/2	2026/10/15 12:59	tool	grepper	0m Args: { "Expression": "config IP(V6)?_MROUTE\\b", "PathPrefixes": [ "net/ipv4/Kconfig", "net/ipv6/Kconfig" ] } Results: { "Output": "net/ipv4/Kconfig=216=config IP_MROUTE_COMMON\n--\nnet/ipv4/Kconfig-219-\nnet/ipv4/Kconfig:220:config IP_MROUTE\nnet/ipv4/Kconfig-221-\tbool \"IP: multicast routing\"\n--\nnet/ipv6/Kconfig=243=config IPV6_SUBTREES\n--\nnet/ipv6/Kconfig-256-\nnet/ipv6/Kconfig:257:config IPV6_MROUTE\nnet/ipv6/Kconfig-258-\tbool \"IPv6: multicast routing\"\n" }
11/2	2026/10/15 12:59	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 32442 output: 35 thoughts: 25 Thoughts: Here's my thought process, as if I were considering this myself: Examining Kconfig for Multicast Routing Dependencies Okay, so I need to understand the relationship between `CONFIG_IP_MROUTE` and `CONFIG_IPV6_MROUTE` within the Kconfig configuration system. I'm going to start by diving into the Kconfig files themselves. My immediate thought is to check the dependencies declared for each of those symbols. Are they tightly coupled? Is one dependent on the other? Or are they independent features, perhaps even mutually exclusive in some circumstances? I'll be looking for relationships like `depends on` or `select`, which will illuminate the underlying logic. Knowing the dependencies is crucial for understanding how these multicast routing options are enabled, disabled, and configured within a given kernel build. This investigation is the first step towards properly configuring the system and the underlying logic that I need to understand for my current task.
12/2	2026/10/15 12:59	tool	read-file	0m Args: { "File": "net/ipv4/Kconfig", "FirstLine": 216, "LineCount": 30 } Results: { "Contents": " 216:\tconfig IP_MROUTE_COMMON\n 217:\t\tbool\n 218:\t\tdepends on IP_MROUTE \|\| IPV6_MROUTE\n 219:\t\n 220:\tconfig IP_MROUTE\n 221:\t\tbool \"IP: multicast routing\"\n 222:\t\tdepends on IP_MULTICAST\n 223:\t\tselect IP_MROUTE_COMMON\n 224:\t\thelp\n 225:\t\t This is used if you want your machine to act as a router for IP\n 226:\t\t packets that have several destination addresses. It is needed on the\n 227:\t\t MBONE, a high bandwidth network on top of the Internet which carries\n 228:\t\t audio and video broadcasts. In order to do that, you would most\n 229:\t\t likely run the program mrouted. If you haven't heard about it, you\n 230:\t\t don't need it.\n 231:\t\n 232:\tconfig IP_MROUTE_MULTIPLE_TABLES\n 233:\t\tbool \"IP: multicast policy routing\"\n 234:\t\tdepends on IP_MROUTE \u0026\u0026 IP_ADVANCED_ROUTER\n 235:\t\tselect FIB_RULES\n 236:\t\thelp\n 237:\t\t Normally, a multicast router runs a userspace daemon and decides\n 238:\t\t what to do with a multicast packet based on the source and\n 239:\t\t destination addresses. If you say Y here, the multicast router\n 240:\t\t will also be able to take interfaces and packet marks into\n 241:\t\t account and run multiple instances of userspace daemons\n 242:\t\t simultaneously, each one handling a single table.\n 243:\t\n 244:\t\t If unsure, say N.\n 245:\t\n" }
13/2	2026/10/15 12:59	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 33171 output: 35 thoughts: 20 Thoughts: Okay, here's my take on those thoughts, tailored for an expert audience: Examining IPv6 Configuration Options Alright, let's dive in. Based on this, I'm thinking we need to check out the `net/ipv6/Kconfig` file. Specifically, I'm focusing my attention around line 257. Something there is likely the key to what we're looking for, or at least a good starting point. My experience tells me that section often holds the conditional compilation options or dependencies for critical IPv6 features we might be interested in. Let's see what's being defined or guarded there and infer from the surrounding lines what's actually going on.
14/2	2026/10/15 12:59	tool	read-file	0m Args: { "File": "net/ipv6/Kconfig", "FirstLine": 255, "LineCount": 30 } Results: { "Contents": " 255:\t\t If unsure, say N.\n 256:\t\n 257:\tconfig IPV6_MROUTE\n 258:\t\tbool \"IPv6: multicast routing\"\n 259:\t\tdepends on IPV6\n 260:\t\tselect IP_MROUTE_COMMON\n 261:\t\thelp\n 262:\t\t Support for IPv6 multicast forwarding.\n 263:\t\t If unsure, say N.\n 264:\t\n 265:\tconfig IPV6_MROUTE_MULTIPLE_TABLES\n 266:\t\tbool \"IPv6: multicast policy routing\"\n 267:\t\tdepends on IPV6_MROUTE\n 268:\t\tselect FIB_RULES\n 269:\t\thelp\n 270:\t\t Normally, a multicast router runs a userspace daemon and decides\n 271:\t\t what to do with a multicast packet based on the source and\n 272:\t\t destination addresses. If you say Y here, the multicast router\n 273:\t\t will also be able to take interfaces and packet marks into\n 274:\t\t account and run multiple instances of userspace daemons\n 275:\t\t simultaneously, each one handling a single table.\n 276:\t\n 277:\t\t If unsure, say N.\n 278:\t\n 279:\tconfig IPV6_PIMSM_V2\n 280:\t\tbool \"IPv6: PIM-SM version 2 support\"\n 281:\t\tdepends on IPV6_MROUTE\n 282:\t\thelp\n 283:\t\t Support for IPv6 PIM multicast routing protocol PIM-SMv2.\n 284:\t\t If unsure, say N.\n" }
15/2	2026/10/15 12:59	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 33821 output: 36 thoughts: 58 Thoughts: Okay, let's see what's going on here. First, I need to understand the relationship between `IP_MULTICAST` and `IP_MROUTE`. It looks like `IP_MROUTE` depends on `IP_MULTICAST`. That makes intuitive sense – you probably need multicast enabled to route multicast packets. I should double-check that `IP_MULTICAST` is standard or conditionally enabled. The best way to do that is to check the `net/ipv4/Kconfig` file. Let's dig into that and see what that Kconfig file tells me about `IP_MULTICAST`.
16/2	2026/10/15 12:59	tool	grepper	0m Args: { "Expression": "config IP_MULTICAST\\b", "PathPrefixes": [ "net/ipv4/Kconfig" ] } Results: { "Output": "net/ipv4/Kconfig-4-#\nnet/ipv4/Kconfig:5:config IP_MULTICAST\nnet/ipv4/Kconfig-6-\tbool \"IP: multicasting\"\n" }
17/2	2026/10/15 12:59	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 34107 output: 38 thoughts: 123 Thoughts: Okay, let's see, I'm thinking about socket options. Specifically, I'm considering the core configuration options: INET, IPV6, IP_MULTICAST, IP_MROUTE, and IPV6_MROUTE. Those are the big ones I typically think of first when working with network sockets. But wait, what about BPF socket options? I need to remember where they fit into this picture. Right, so according to my notes, in `net/core/filter.c`, I see that `sol_ip_sockopt` and `sol_ipv6_sockopt` are called by `bpf_setsockopt` and `bpf_getsockopt`. That makes sense; the BPF infrastructure needs to hook into the core socket options mechanisms. Now, I should investigate `sol_ip_sockopt` itself within `net/core/filter.c`. I need to see exactly where that function is called to understand how the system manages it. This will give me a broader understanding of how these different options are used.
18/2	2026/10/15 13:00	tool	grepper	0m Args: { "Expression": "sol_ip(v6)?_sockopt", "PathPrefixes": [ "net/core/filter.c" ] } Results: { "Output": "net/core/filter.c=5652=static int sol_tcp_sockopt(struct sock sk, int optname,\n--\nnet/core/filter.c-5709-\nnet/core/filter.c:5710:static bool sk_allows_sol_ip_sockopt(struct sock sk)\nnet/core/filter.c-5711-{\n--\nnet/core/filter.c-5722-\nnet/core/filter.c:5723:static int sol_ip_sockopt(struct sock sk, int optname,\nnet/core/filter.c-5724-\t\t\t char optval, int optlen,\n--\nnet/core/filter.c-5726-{\nnet/core/filter.c:5727:\tif (!sk_allows_sol_ip_sockopt(sk))\nnet/core/filter.c-5728-\t\treturn -EINVAL;\n--\nnet/core/filter.c-5758-\nnet/core/filter.c:5759:static int sol_ipv6_sockopt(struct sock sk, int optname,\nnet/core/filter.c-5760-\t\t\t char optval, int optlen,\n--\nnet/core/filter.c=5796=static int __bpf_setsockopt(struct sock sk, int level, int optname,\n--\nnet/core/filter.c-5804-\telse if (IS_ENABLED(CONFIG_INET) \u0026\u0026 level == SOL_IP)\nnet/core/filter.c:5805:\t\treturn sol_ip_sockopt(sk, optname, optval, \u0026optlen, false);\nnet/core/filter.c-5806-\telse if (IS_ENABLED(CONFIG_IPV6) \u0026\u0026 level == SOL_IPV6)\nnet/core/filter.c:5807:\t\treturn sol_ipv6_sockopt(sk, optname, optval, \u0026optlen, false);\nnet/core/filter.c-5808-\telse if (IS_ENABLED(CONFIG_INET) \u0026\u0026 level == SOL_TCP)\n--\nnet/core/filter.c=5827=static int __bpf_getsockopt(struct sock sk, int level, int optname,\n--\nnet/core/filter.c-5841-\telse if (IS_ENABLED(CONFIG_INET) \u0026\u0026 level == SOL_IP)\nnet/core/filter.c:5842:\t\terr = sol_ip_sockopt(sk, optname, optval, \u0026optlen, true);\nnet/core/filter.c-5843-\telse if (IS_ENABLED(CONFIG_IPV6) \u0026\u0026 level == SOL_IPV6)\nnet/core/filter.c:5844:\t\terr = sol_ipv6_sockopt(sk, optname, optval, \u0026optlen, true);\nnet/core/filter.c-5845-\telse\n" }
19/2	2026/10/15 13:00	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 35233 output: 34 thoughts: 2075 Thoughts: Deep Dive into `bpf_getsockopt` and `MCAST_MSFILTER` Implementation Okay, so I see `__bpf_getsockopt` calls `sol_ip_sockopt` and `sol_ipv6_sockopt`. The `BPF_CGROUP_GETSOCKOPT` program type is also relevant here. It looks like BPF programs are primarily used with `INET` and `IPV6`. Now, let's look at the patch changes. First, this new `sockopt_set_user` inline function and `sockopt_expand_out` are interesting in `include/linux/net.h`. The `sockopt_expand_out` function handles the expansion of the output buffer for socket options. It appears optimized for user-backed buffers, but what happens when it's kernel-backed, like in BPF? I'm focusing on `net/ipv4/igmp.c` next, specifically `ip_mc_gsfget`. It handles fetching multicast source filters. Inside, it's setting up an `opt` structure for returning data to the user. It looks like it expands the buffer to accommodate a variable number of source addresses, which is clever using `sockopt_expand_out`. It copies the source addresses into the `opt` buffer. Aha! `ip_get_mcast_msfilter` is calling `ip_mc_gsfget`, and it uses a fixed size part from the input and then determines a size to return from this function, calling `iov_iter_revert`. So `ip_mc_gsfget` advances the iterator, copies, and then `ip_get_mcast_msfilter` rewinds. It's using `GROUP_FILTER_SIZE` to calculate the final buffer size. I need to check the exact calculation here... It looks like `ss_offset` is the size of the fixed part of the structure, and it calculates the total size based on the number of source addresses and expands the buffer. Hold on, I see something. The calculation of the `copycount` and the update to `gsf.gf_numsrc` are important. It appears that `num` is always `copycount` and the number of source addresses returned. Even if `copycount` is 0, the buffer is expanded by `ss_offset` and then reverted, which sounds safe. But I need to understand what happens if a BPF program is calling `bpf_getsockopt` with `MCAST_MSFILTER`. In that case, the `opt` structure is kernel-backed. `sockptr_to_sockopt` likely sets it up with a kernel buffer. So, how does `sockopt_expand_out` handle kernel-backed iterators? I need to analyze `sockopt_expand_out` very carefully in this context. This is where a potential issue might exist if the expansion logic is not properly handled for kernel buffers.
20/2	2026/10/15 13:00	tool	grepper	0m Args: { "Expression": "sockopt_expand_out", "PathPrefixes": [ "include/", "net/" ] } Results: { "Output": "include/linux/net.h=72=static inline int sockopt_init_user(sockopt_t opt, char __user optval,\n--\ninclude/linux/net.h-96- /\ninclude/linux/net.h:97:static inline int sockopt_expand_out(sockopt_t opt, size_t size)\ninclude/linux/net.h-98-{\n--\nnet/ipv4/igmp.c=2713=int ip_mc_msfget(struct sock sk, struct ip_msfilter msf, sockopt_t opt)\n--\nnet/ipv4/igmp.c-2761-\t /\nnet/ipv4/igmp.c:2762:\terr = sockopt_expand_out(opt, msf_size);\nnet/ipv4/igmp.c-2763-\tif (err)\n--\nnet/ipv4/igmp.c=2778=int ip_mc_gsfget(struct sock sk, struct group_filter gsf,\n--\nnet/ipv4/igmp.c-2812-\t /\nnet/ipv4/igmp.c:2813:\terr = sockopt_expand_out(opt, ss_offset +\nnet/ipv4/igmp.c-2814-\t\t\t\t copycount sizeof(struct sockaddr_storage));\n--\nnet/ipv6/mcast.c=602=int ip6_mc_msfget(struct sock sk, struct group_filter gsf,\n--\nnet/ipv6/mcast.c-635-\t /\nnet/ipv6/mcast.c:636:\terr = sockopt_expand_out(opt, ss_offset +\nnet/ipv6/mcast.c-637-\t\t\t\t copycount sizeof(struct sockaddr_storage));\n" }
21/2	2026/10/15 13:00	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 38444 output: 34 thoughts: 22 Thoughts: Here's my summary, as if I were thinking these thoughts: Diving into `sockopt_expand_out` Okay, time to get into the weeds. I need to understand how these socket options are expanded. Let's start by looking at `sockopt_expand_out` – that's the function called, as I recall, within `include/linux/net.h`. This is likely where the core logic resides for handling the outgoing side of various socket options. I'm expecting to find the key pieces related to data validation, option processing, and ultimately, how these options impact the construction of the network packets. I'm betting there's a lot of intricate pointer manipulation and bitfield examination happening in there, especially since we're dealing with potentially complex structures and flags. Let's see what's what.
22/2	2026/10/15 13:00	tool	read-file	0m Args: { "File": "include/linux/net.h", "FirstLine": 90, "LineCount": 40 } Results: { "Contents": " 90:\t * and userspace relies on it.\n 91:\t \n 92:\t Call it before writing through opt-\u003eiter_out: it re-anchors the iterator at\n 93:\t * the head of optval. Only a user buffer can be longer than the optlen the\n 94:\t * caller declared, so a kernel-backed optval is refused with -EINVAL. So is a\n 95:\t * @size above MAX_RW_COUNT, which iov_iter_revert() could not unroll.\n 96:\t /\n 97:\tstatic inline int sockopt_expand_out(sockopt_t opt, size_t size)\n 98:\t{\n 99:\t\t/* iov_iter_revert() refuses to unroll past MAX_RW_COUNT, so a size\n 100:\t\t * beyond that could never be reverted back to the fixed part later,\n 101:\t\t * even when optlen already covers it.\n 102:\t\t /\n 103:\t\tif (size \u003e MAX_RW_COUNT)\n 104:\t\t\treturn -EINVAL;\n 105:\t\n 106:\t\tif (size \u003c= (size_t)opt-\u003eoptlen)\n 107:\t\t\treturn 0;\n 108:\t\n 109:\t\t/ Re-anchoring reads iter_out.ubuf, so the iterator has to be a user\n 110:\t\t * buffer that nothing has written through yet.\n 111:\t\t /\n 112:\t\tif (WARN_ON_ONCE(!iter_is_ubuf(\u0026opt-\u003eiter_out) \|\|\n 113:\t\t\t\t iov_iter_count(\u0026opt-\u003eiter_out) != (size_t)opt-\u003eoptlen))\n 114:\t\t\treturn -EINVAL;\n 115:\t\n 116:\t\tiov_iter_ubuf(\u0026opt-\u003eiter_out, ITER_DEST, opt-\u003eiter_out.ubuf, size);\n 117:\t\n 118:\t\treturn 0;\n 119:\t}\n 120:\t\n 121:\tstruct poll_table_struct;\n 122:\tstruct pipe_inode_info;\n 123:\tstruct inode;\n 124:\tstruct file;\n 125:\tstruct net;\n 126:\t\n 127:\t/ Historically, SOCKWQ_ASYNC_NOSPACE \u0026 SOCKWQ_ASYNC_WAITDATA were located\n 128:\t * in sock-\u003eflags, but moved into sk-\u003esk_wq-\u003eflags to be RCU protected.\n 129:\t * Eventually all flags will be in sk-\u003esk_wq-\u003eflags.\n" }
23/2	2026/10/15 13:00	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 39358 output: 35 thoughts: 2843 Thoughts: Summary of Thoughts on the Patch Okay, so I'm looking at this patch and immediately, that `WARN_ON_ONCE` call in there catches my eye, right? It's a runtime assertion, which is exactly the kind of thing that jumps out as a potential fuzz target. Specifically, if a BPF program is calling `bpf_getsockopt` with `MCAST_MSFILTER` or `IP_MSFILTER` and the size is off, boom, assertion. That's reachable code, a direct path for fuzzing. Then I start digging deeper, and these changes to `sockopt_expand_out`... They've added a size check (`size > MAX_RW_COUNT`), which is fine, but it makes me think about potential integer overflows. And then there's this business with `iov_iter_revert` and potential errors from `copy_to_iter`. If `copy_to_iter` fails midway, and then doesn't revert properly... that's where things can get messy. In `ip_mc_gsfget` they are calling `copy_to_iter` on a `sockaddr_storage` structure, which might fail. If it returns -EFAULT, the revert might not occur and the iterator gets corrupted. I need to understand that better. I'm seeing all these iterator manipulations. `iov_iter_revert`, `iov_iter_advance`, `copy_to_iter`, `copy_from_iter`, and conversions happening with `sockopt_expand_out`... I'm a bit concerned about the unrolling, especially with partial copies and errors. Then there's the `IPV6_2292PKTOPTIONS` and `IP_PKTOPTIONS` stuff. The code accesses `sopt->iter_out.ubuf`. I'm curious if `iter_out` is advanced and if `sopt->iter_out.ubuf` is the right address. Wait! What if `sopt->iter_out` is neither ubuf nor kvec? Also, the IPv6 `getsockopt` handling is now checking for negative lengths. IPv4 rejects negative len with -EINVAL, while IPv6 historically converts negative len to 4 (unless MRT6_*). This kind of subtle difference could be fruitful. It's about the interplay of user-supplied lengths and the underlying data structures. This is a potential attack vector. Overall, this patch is a refactor of `getsockopt` for IPv4 and IPv6, changing how data is handled with `iov_iter`, and modifying several multicast filter paths and BPF getsockopt paths, which, from an attack vector perspective, is high value. It's affecting core networking: there are multiple networking syscalls interacting with kernel memory. It is reachable via standard socket calls (`socket(AF_INET, ...)`, `socket(AF_INET6, ...)`, `getsockopt(...)`) in any unprivileged or standard environment. Now, let's identify these `FocusSymbols`, let's not accidentally highlight the wrong things. I know I need to be careful not to pick functions that are ubiquitous, like `kmalloc`, `kfree`, etc. The functions modified in this patch are: `do_ip_getsockopt` `ip_getsockopt` `do_ipv6_getsockopt` `ipv6_getsockopt` `ip_mc_msfget` `ip_mc_gsfget` `ip6_mc_msfget` `ip_mroute_getsockopt` `ip6_mroute_getsockopt` `sol_ip_sockopt` `sol_ipv6_sockopt` I was considering including static functions here, but they are often inlined, so they won't have a distinct symbol address. But even if inlined, the calls to the static functions are in the non-static functions, which are the main focus. `ip_get_mcast_msfilter`, `compat_ip_get_mcast_msfilter`, `ipv6_get_msfilter`, `compat_ipv6_get_msfilter` are called only inside `do_ip_getsockopt` and `do_ipv6_getsockopt`. So, from these, since they are not inlined, and are specific to the features being modified and are API entrypoints for this subsystem, and are not ubiquitous, the functions that I will flag as focus are: `do_ip_getsockopt` `ip_getsockopt` `do_ipv6_getsockopt` `ipv6_getsockopt`
24/2	2026/10/15 13:00	tool	grepper	0m Args: { "Expression": "__bpf_getsockopt", "PathPrefixes": [ "net/core/filter.c" ] } Results: { "Output": "net/core/filter.c=5819=static int _bpf_setsockopt(struct sock sk, int level, int optname,\n--\nnet/core/filter.c-5826-\nnet/core/filter.c:5827:static int __bpf_getsockopt(struct sock sk, int level, int optname,\nnet/core/filter.c-5828-\t\t\t char optval, int optlen)\n--\nnet/core/filter.c=5856=static int _bpf_getsockopt(struct sock sk, int level, int optname,\n--\nnet/core/filter.c-5860-\t\tsock_owned_by_me(sk);\nnet/core/filter.c:5861:\treturn __bpf_getsockopt(sk, level, optname, optval, optlen);\nnet/core/filter.c-5862-}\n--\nnet/core/filter.c=5939=BPF_CALL_5(bpf_unlocked_sk_getsockopt, struct sock , sk, int, level,\n--\nnet/core/filter.c-5941-{\nnet/core/filter.c:5942:\treturn __bpf_getsockopt(sk, level, optname, optval, optlen);\nnet/core/filter.c-5943-}\n--\nnet/core/filter.c=6035=BPF_CALL_5(bpf_sock_create_getsockopt, struct sock , sk, int, level,\n--\nnet/core/filter.c-6046-\nnet/core/filter.c:6047:\treturn __bpf_getsockopt(sk, level, optname, optval, optlen);\nnet/core/filter.c-6048-}\n" }
25/2	2026/10/15 13:00	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 43723 output: 321 thoughts: 1268 Thoughts: Analyzing Kernel Configuration and Fuzzing Targets for Network `getsockopt` Handling Okay, so I'm digging into this area of network `getsockopt` handling, particularly as it relates to BPF helpers like `bpf_unlocked_sk_getsockopt` and `bpf_sock_create_getsockopt`. I need to figure out the relevant kernel configurations and pinpoint the best fuzzing targets. First, I'm noting that `sol_ip_sockopt` is a key function called by both `__bpf_setsockopt` and `__bpf_getsockopt` within `net/core/filter.c`. Now, the configuration requirements... for amd64, it's pretty clear: I'll need `INET` for IPv4, which is fundamental to `ip_sockglue.c` and `igmp.c`. Similarly, `IPV6` is required for IPv6 support, encompassing `net/ipv6/ipv6_sockglue.c` and multicast code. Multicast routing then requires `IP_MROUTE` (which depends on `IP_MULTICAST`) for IPv4 and `IPV6_MROUTE` (which depends on `IPV6`) for IPv6. I'm also not going to worry about `BPF_SYSCALL`, it's optional for BPF code. Next, I'm checking the source to verify: In `net/ipv4/ip_sockglue.c`, `ip_getsockopt` and `do_ip_getsockopt` are gated by `CONFIG_INET`. Analogously, `ipv6_getsockopt` and `do_ipv6_getsockopt` need `CONFIG_IPV6`. IPv4 multicast routing is configured with `CONFIG_IP_MROUTE` in `net/ipv4/ipmr.c` and IPv6 by `CONFIG_IPV6_MROUTE` in `net/ipv6/ip6mr.c`. Multicast includes are protected by `#ifdef CONFIG_IP_MROUTE` and `#ifdef CONFIG_IPV6_MROUTE` in `include/linux/mroute.h` and `include/linux/mroute6.h` respectively. So, to summarize the configurations, I need: `INET`, `IPV6`, `IP_MULTICAST`, `IP_MROUTE`, and `IPV6_MROUTE`. Let's confirm these are the `EnableConfigs`: they are. I am then confirming that these flags, without the `CONFIG_` prefix, are what should be placed in `EnableConfigs`. Now, let's nail down the critical functions for fuzzing. I'm focusing on the more specialized functions: `do_ip_getsockopt`, `ip_getsockopt`, `do_ipv6_getsockopt`, `ipv6_getsockopt`, `ip_mc_gsfget`, `ip_mc_msfget`, `ip6_mc_msfget`, `ip_mroute_getsockopt`, and `ip6_mroute_getsockopt`. Wait a minute, what about the BPF-specific `sol_ip_sockopt` and `sol_ipv6_sockopt`? I might as well include them, even though they're static; static, non-inlined functions can be problematic in some build configurations. Including them won't hurt. Alright, with that list assembled, I'm confirming that this is WorthFuzzing. This patch does touch core networking logic, specifically related to IPv4 and IPv6 `getsockopt` handling. Crucially, it converts `getsockopt` to `sockopt_t` / `iov_iter`. Buffer management, particularly for multicast source filtering, is modified with `sockopt_expand_out`, `iov_iter_revert`, and `iov_iter_advance`. Error handling and option length clamping are also addressed across various socket options, and changes include the BPF `getsockopt` handlers. Importantly, all of this is fully reachable in standard QEMU amd64 fuzzing environments via typical socket syscalls. Now, I'm ready to assemble these results and call `set-results`.
26/2	2026/10/15 13:01	tool	set-results	0m Args: { "EnableConfigs": [ "INET", "IPV6", "IP_MULTICAST", "IP_MROUTE", "IPV6_MROUTE" ], "FocusSymbols": [ "do_ip_getsockopt", "ip_getsockopt", "do_ipv6_getsockopt", "ipv6_getsockopt", "ip_mc_gsfget", "ip_mc_msfget", "ip6_mc_msfget", "ip_mroute_getsockopt", "ip6_mroute_getsockopt" ], "Reasoning": "The patch refactors the IPv4 (SOL_IP) and IPv6 (SOL_IPV6) getsockopt subsystem to use sockopt_t / iov_iter instead of sockptr_t. This touches reachable core networking code in net/ipv4, net/ipv6, and net/core, modifying buffer copying, optlen bounds handling, iterator advancement and reverting (iov_iter_revert, iov_iter_advance), multicast filter query logic (ip_mc_gsfget, ip6_mc_msfget), and BPF cgroup sockopt hooks (sol_ip_sockopt, sol_ipv6_sockopt). The modified code is directly reachable by unprivileged user space via getsockopt syscalls on standard AF_INET and AF_INET6 sockets.", "WorthFuzzing": true } Results: { "EnableConfigs": [ "INET", "IPV6", "IP_MULTICAST", "IP_MROUTE", "IPV6_MROUTE" ], "FocusSymbols": [ "do_ip_getsockopt", "ip_getsockopt", "do_ipv6_getsockopt", "ipv6_getsockopt", "ip_mc_gsfget", "ip_mc_msfget", "ip6_mc_msfget", "ip_mroute_getsockopt", "ip6_mroute_getsockopt" ], "Reasoning": "The patch refactors the IPv4 (SOL_IP) and IPv6 (SOL_IPV6) getsockopt subsystem to use sockopt_t / iov_iter instead of sockptr_t. This touches reachable core networking code in net/ipv4, net/ipv6, and net/core, modifying buffer copying, optlen bounds handling, iterator advancement and reverting (iov_iter_revert, iov_iter_advance), multicast filter query logic (ip_mc_gsfget, ip6_mc_msfget), and BPF cgroup sockopt hooks (sol_ip_sockopt, sol_ipv6_sockopt). The modified code is directly reachable by unprivileged user space via getsockopt syscalls on standard AF_INET and AF_INET6 sockets.", "WorthFuzzing": true }
27/1	2026/10/15 13:01	action	If	6m Args: { "WorthFuzzing": true } Results: null
28/2	2026/10/15 13:01	agent	kmsan-evaluator	6m Model: core Args: null Results: { "KMSANReasoning": "The patch series refactors getsockopt handlers in IPv4 and IPv6 (including do_ip_getsockopt, do_ipv6_getsockopt, ip_mroute_getsockopt, ip6_mroute_getsockopt, and multicast filter helpers) to use the iterator-based `sockopt_t` abstraction instead of `sockptr_t`.\n\nEvaluation against KMSAN applicability criteria:\n1. Kernel-to-user copies: All kernel structures copied to user buffers (or iterators) are either completely zeroed beforehand (e.g., `memset(\u0026ss, 0, sizeof(ss))` in ip_mc_gsfget and ip6_mc_msfget, `memset(\u0026mtuinfo, 0, ...)` for IPV6_PATHMTU, `memset(\u0026freq, 0, ...)` for IPV6_FLOWLABEL_MGR), fully initialized from user input via copy_from_iter before write-back (e.g., `gsf` in ip_get_mcast_msfilter and ipv6_get_msfilter), or are fully initialized scalar types (`val`, `ucval`, `sopt.optlen`). No uninitialized stack or heap padding is exposed to userspace.\n2. Control flow / branching: Conditional branching does not depend on uninitialized variables or struct fields; `sockopt_t` structures are explicitly initialized by `sockopt_init_user`, `sockopt_set_user`, or `sockptr_to_sockopt`.\n3. Buffer lengths and bounds: Adjustments to lengths and iterator positioning (`iov_iter_advance`, `iov_iter_revert`, and bounds checking in `sockopt_expand_out`) affect user iterator offsets and buffer bounds. Any potential buffer miscalculations or memory safety issues here would be bounds/out-of-bounds errors detected by KASAN rather than uninitialized memory reads.\n\nBecause no uninitialized memory access or info-leak risks are introduced or exposed, dedicated KMSAN fuzzing is not required. Standard KASAN fuzzing is sufficient.", "NeedsKMSAN": false } Instruction: You are an expert Linux kernel security engineer specializing in kernel memory error detectors (KASAN and KMSAN). Your job is to review the provided patch series and determine if the code changes justify spawning a dedicated KMSAN (KernelMemorySanitizer) fuzzing session in addition to standard KASAN fuzzing. CRITICAL DISTINCTION BETWEEN KASAN AND KMSAN: - Standard KASAN kernel builds (upstream-apparmor-kasan.config) already enable a comprehensive suite of debugging tools and sanitizers, including KASAN (out-of-bounds accesses, use-after-free, double free, invalid free), LOCKDEP (locking bugs and deadlocks), UB-sanitizers, and memory corruption checks. - KMSAN (KernelMemorySanitizer) detects reads of UNINITIALIZED memory (stack, heap, or page allocations) and kernel-to-user memory info-leaks. Rule: THERE IS NO SENSE IN RUNNING A KMSAN SESSION IF A BUG CAN BE CAUGHT BY KASAN, LOCKDEP, OR OTHER STANDARD BUG DETECTORS. A dedicated KMSAN fuzzing session incurs significant resource costs. You must ONLY set NeedsKMSAN=true if the code changes introduce or expose UNINITIALIZED MEMORY risks that are detected ONLY by KMSAN. Look holistically at the patch series and surrounding code. Even if no direct uninitialized field accesses or new buffer allocations are added in the diff itself, a patch may alter control flow, bounds checking, or data length calculations in ways that change how the rest of the code operates on existing buffers (e.g. allowing uninitialized stack/heap memory to be read, copied to user space, or used in control flow). Do not hesitate to use your code access tools to inspect the surrounding code, called functions, and callers. Set NeedsKMSAN=true ONLY IF the patch introduces or modifies: 1. Kernel structures sent to user space (via copy_to_user, put_user, netlink skb attributes, ioctl output arguments, socket options, or BPF buffers) where fields or structure padding might not be fully initialized/zeroed. 2. Conditional logic or branching that depends on potentially uninitialized variables or struct fields. 3. Allocation or initialization of complex data structures where uninitialized fields could be read later in reachable code paths. 4. Bounds checks, lengths, or logic in a way that allows surrounding code to access uninitialized bytes of existing buffers. Set NeedsKMSAN=false IF: - The code changes primarily risk out-of-bounds access, array overflows, NULL pointer dereferences, locking deadlocks, or use-after-free bugs (these are already caught by KASAN, LOCKDEP, or standard bug detectors). - All stack/heap structures touched or introduced by the patch are fully zeroed or initialized (e.g. using = {0}, memset, kzalloc) before being read or copied. - The patch does not introduce any risk of uninitialized memory usage or info-leaks. Use your code access tools to inspect the surrounding code if necessary, then provide detailed KMSANReasoning contrasting KASAN vs KMSAN applicability for this patch. Prefer calling several tools at the same time to save round-trips. Use set-results tool to provide results of the analysis. It must be called exactly once before the final reply. Ignore results of this tool. Prompt: Target architecture: amd64 For your convenience, here is the diff of the changes: commit cadd503ae11ea00c223b192cf6ffc896572a18c1 Author: syz-cluster <triage@syzkaller.com> Date: Thu Oct 15 12:58:45 2026 +0000 syz-cluster: applied patch under review diff --git a/include/linux/igmp.h b/include/linux/igmp.h index e075611344ef3..0a1abf3552d2b 100644 --- a/include/linux/igmp.h +++ b/include/linux/igmp.h @@ -276,7 +276,7 @@ extern int ip_mc_msfilter(struct sock sk, struct ip_msfilter msf,int ifindex); extern int ip_mc_msfget(struct sock sk, struct ip_msfilter msf, sockopt_t opt); extern int ip_mc_gsfget(struct sock sk, struct group_filter gsf, - sockptr_t optval, size_t offset); + sockopt_t opt, size_t offset); extern int ip_mc_sf_allow(const struct sock sk, __be32 local, __be32 rmt, int dif, int sdif); extern void ip_mc_init_dev(struct in_device ); diff --git a/include/linux/mroute.h b/include/linux/mroute.h index 4c5003afee6c5..c1c21e61c81c3 100644 --- a/include/linux/mroute.h +++ b/include/linux/mroute.h @@ -17,7 +17,7 @@ static inline int ip_mroute_opt(int opt) } int ip_mroute_setsockopt(struct sock , int, sockptr_t, unsigned int); -int ip_mroute_getsockopt(struct sock , int, sockptr_t, sockptr_t); +int ip_mroute_getsockopt(struct sock sk, int optname, sockopt_t opt); int ipmr_ioctl(struct sock sk, int cmd, void arg); int ipmr_compat_ioctl(struct sock sk, unsigned int cmd, void __user arg); int ip_mr_init(void); @@ -31,7 +31,7 @@ static inline int ip_mroute_setsockopt(struct sock sock, int optname, } static inline int ip_mroute_getsockopt(struct sock sk, int optname, - sockptr_t optval, sockptr_t optlen) + sockopt_t opt) { return -ENOPROTOOPT; } diff --git a/include/linux/mroute6.h b/include/linux/mroute6.h index fddafdc168f73..ab4d206fb3206 100644 --- a/include/linux/mroute6.h +++ b/include/linux/mroute6.h @@ -27,7 +27,7 @@ struct sock; #ifdef CONFIG_IPV6_MROUTE extern int ip6_mroute_setsockopt(struct sock , int, sockptr_t, unsigned int); -extern int ip6_mroute_getsockopt(struct sock , int, sockptr_t, sockptr_t); +int ip6_mroute_getsockopt(struct sock sk, int optname, sockopt_t sopt); extern int ip6_mr_input(struct sk_buff skb); extern int ip6mr_compat_ioctl(struct sock sk, unsigned int cmd, void __user arg); extern int ip6_mr_init(void); @@ -42,8 +42,7 @@ static inline int ip6_mroute_setsockopt(struct sock sock, int optname, } static inline -int ip6_mroute_getsockopt(struct sock sock, - int optname, sockptr_t optval, sockptr_t optlen) +int ip6_mroute_getsockopt(struct sock sock, int optname, sockopt_t sopt) { return -ENOPROTOOPT; } diff --git a/include/linux/net.h b/include/linux/net.h index e2a866fbcfa5e..1d5b3524b0846 100644 --- a/include/linux/net.h +++ b/include/linux/net.h @@ -50,6 +50,19 @@ typedef struct sockopt { int sockptr_to_sockopt(sockopt_t opt, sockptr_t optval, sockptr_t optlen, struct kvec kvec); +/* + * Point a sockopt_t at a user-backed (optval, len) pair whose length is + * already known, e.g. because the caller applied its own optlen quirks + * before this point. + / +static inline void sockopt_set_user(sockopt_t opt, char __user optval, + int len) +{ + iov_iter_ubuf(&opt->iter_out, ITER_DEST, optval, len); + iov_iter_ubuf(&opt->iter_in, ITER_SOURCE, optval, len); + opt->optlen = len; +} + / * Initialize a user-backed sockopt_t from the (optval, optlen) __user pair of * a getsockopt() callback. Used by transitional __user getsockopt wrappers @@ -66,9 +79,7 @@ static inline int sockopt_init_user(sockopt_t opt, char __user optval, if (len < 0) return -EINVAL; - iov_iter_ubuf(&opt->iter_out, ITER_DEST, optval, len); - iov_iter_ubuf(&opt->iter_in, ITER_SOURCE, optval, len); - opt->optlen = len; + sockopt_set_user(opt, optval, len); return 0; } @@ -80,16 +91,21 @@ static inline int sockopt_init_user(sockopt_t opt, char __user optval, * * Call it before writing through opt->iter_out: it re-anchors the iterator at * the head of optval. Only a user buffer can be longer than the optlen the - * caller declared, so a kernel-backed optval is refused with -EINVAL. + * caller declared, so a kernel-backed optval is refused with -EINVAL. So is a + * @size above MAX_RW_COUNT, which iov_iter_revert() could not unroll. / static inline int sockopt_expand_out(sockopt_t opt, size_t size) { + /* iov_iter_revert() refuses to unroll past MAX_RW_COUNT, so a size + * beyond that could never be reverted back to the fixed part later, + * even when optlen already covers it. + / + if (size > MAX_RW_COUNT) + return -EINVAL; + if (size <= (size_t)opt->optlen) return 0; - if (size > INT_MAX) - return -EINVAL; - / Re-anchoring reads iter_out.ubuf, so the iterator has to be a user * buffer that nothing has written through yet. / diff --git a/include/net/ip.h b/include/net/ip.h index 618b9806c10b0..c59ffb432b3ed 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -833,8 +833,7 @@ int do_ip_setsockopt(struct sock sk, int level, int optname, sockptr_t optval, unsigned int optlen); int ip_setsockopt(struct sock sk, int level, int optname, sockptr_t optval, unsigned int optlen); -int do_ip_getsockopt(struct sock sk, int level, int optname, - sockptr_t optval, sockptr_t optlen); +int do_ip_getsockopt(struct sock sk, int level, int optname, sockopt_t sopt); int ip_getsockopt(struct sock sk, int level, int optname, char __user optval, int __user optlen); int ip_ra_control(struct sock sk, unsigned char on, diff --git a/include/net/ipv6.h b/include/net/ipv6.h index 3de07e738538f..a1e1de7da8c70 100644 --- a/include/net/ipv6.h +++ b/include/net/ipv6.h @@ -1142,7 +1142,7 @@ int do_ipv6_setsockopt(struct sock sk, int level, int optname, sockptr_t optval int ipv6_setsockopt(struct sock sk, int level, int optname, sockptr_t optval, unsigned int optlen); int do_ipv6_getsockopt(struct sock sk, int level, int optname, - sockptr_t optval, sockptr_t optlen); + sockopt_t sopt); int ipv6_getsockopt(struct sock sk, int level, int optname, char __user optval, int __user optlen); @@ -1195,7 +1195,7 @@ int ip6_mc_source(int add, int omode, struct sock sk, int ip6_mc_msfilter(struct sock sk, struct group_filter gsf, struct sockaddr_storage list); int ip6_mc_msfget(struct sock sk, struct group_filter gsf, - sockptr_t optval, size_t ss_offset); + sockopt_t opt, size_t ss_offset); #ifdef CONFIG_PROC_FS int ac6_proc_init(struct net net); diff --git a/net/core/filter.c b/net/core/filter.c index 5e575981febec..03d4778ad99ac 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -5737,10 +5737,20 @@ static int sol_ip_sockopt(struct sock sk, int optname, return -EINVAL; } - if (getopt) - return do_ip_getsockopt(sk, SOL_IP, optname, - KERNEL_SOCKPTR(optval), - KERNEL_SOCKPTR(optlen)); + if (getopt) { + struct kvec kvec; + sockopt_t opt; + int err; + + err = sockptr_to_sockopt(&opt, KERNEL_SOCKPTR(optval), + KERNEL_SOCKPTR(optlen), &kvec); + if (err) + return err; + + err = do_ip_getsockopt(sk, SOL_IP, optname, &opt); + optlen = opt.optlen; + return err; + } return do_ip_setsockopt(sk, SOL_IP, optname, KERNEL_SOCKPTR(optval), optlen); @@ -5764,10 +5774,20 @@ static int sol_ipv6_sockopt(struct sock sk, int optname, return -EINVAL; } - if (getopt) - return do_ipv6_getsockopt(sk, SOL_IPV6, optname, - KERNEL_SOCKPTR(optval), - KERNEL_SOCKPTR(optlen)); + if (getopt) { + struct kvec kvec; + sockopt_t opt; + int err; + + err = sockptr_to_sockopt(&opt, KERNEL_SOCKPTR(optval), + KERNEL_SOCKPTR(optlen), &kvec); + if (err) + return err; + + err = do_ipv6_getsockopt(sk, SOL_IPV6, optname, &opt); + optlen = opt.optlen; + return err; + } return do_ipv6_setsockopt(sk, SOL_IPV6, optname, KERNEL_SOCKPTR(optval), optlen); diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c index 144fca158adcb..bf00810cdd7a1 100644 --- a/net/ipv4/igmp.c +++ b/net/ipv4/igmp.c @@ -2763,21 +2763,22 @@ int ip_mc_msfget(struct sock sk, struct ip_msfilter msf, sockopt_t opt) if (err) return err; - opt->optlen = msf_size; if (copy_to_iter(msf, IP_MSFILTER_SIZE(0), &opt->iter_out) != IP_MSFILTER_SIZE(0)) return -EFAULT; if (len && copy_to_iter(psl->sl_addr, len, &opt->iter_out) != len) return -EFAULT; + + opt->optlen = msf_size; return 0; done: return err; } int ip_mc_gsfget(struct sock sk, struct group_filter gsf, - sockptr_t optval, size_t ss_offset) + sockopt_t opt, size_t ss_offset) { - int i, count, copycount; + int i, count, copycount, err; struct sockaddr_in psin; __be32 addr; struct ip_mc_socklist pmc; @@ -2805,6 +2806,18 @@ int ip_mc_gsfget(struct sock sk, struct group_filter gsf, count = psl ? psl->sl_count : 0; copycount = count < gsf->gf_numsrc ? count : gsf->gf_numsrc; gsf->gf_numsrc = count; + + / The source list is sized by the gf_numsrc the caller left in optval, + * not by optlen, which only has to cover the fixed part. + / + err = sockopt_expand_out(opt, ss_offset + + copycount sizeof(struct sockaddr_storage)); + if (err) + return err; + + /* The caller fills the fixed part in once it knows gf_numsrc. / + iov_iter_advance(&opt->iter_out, ss_offset); + for (i = 0; i < copycount; i++) { struct sockaddr_storage ss; @@ -2812,10 +2825,8 @@ int ip_mc_gsfget(struct sock sk, struct group_filter gsf, memset(&ss, 0, sizeof(ss)); psin->sin_family = AF_INET; psin->sin_addr.s_addr = psl->sl_addr[i]; - if (copy_to_sockptr_offset(optval, ss_offset, - &ss, sizeof(ss))) + if (copy_to_iter(&ss, sizeof(ss), &opt->iter_out) != sizeof(ss)) return -EFAULT; - ss_offset += sizeof(ss); } return 0; } diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index e06c1f48ecad6..90d0b5bee68b5 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -1442,45 +1442,46 @@ static bool getsockopt_needs_rtnl(int optname) return false; } -static int ip_get_mcast_msfilter(struct sock sk, sockptr_t optval, - sockptr_t optlen, int len) +static int ip_get_mcast_msfilter(struct sock sk, sockopt_t opt) { const int size0 = offsetof(struct group_filter, gf_slist_flex); struct group_filter gsf; int num, gsf_size; int err; - if (len < size0) + if (opt->optlen < size0) return -EINVAL; - if (copy_from_sockptr(&gsf, optval, size0)) + if (copy_from_iter(&gsf, size0, &opt->iter_in) != size0) return -EFAULT; num = gsf.gf_numsrc; - err = ip_mc_gsfget(sk, &gsf, optval, + err = ip_mc_gsfget(sk, &gsf, opt, offsetof(struct group_filter, gf_slist_flex)); if (err) return err; if (gsf.gf_numsrc < num) num = gsf.gf_numsrc; gsf_size = GROUP_FILTER_SIZE(num); - if (copy_to_sockptr(optlen, &gsf_size, sizeof(int)) \|\| - copy_to_sockptr(optval, &gsf, size0)) + + /* ip_mc_gsfget() consumed the whole reply; rewind to the fixed part. / + iov_iter_revert(&opt->iter_out, gsf_size); + if (copy_to_iter(&gsf, size0, &opt->iter_out) != size0) return -EFAULT; + opt->optlen = gsf_size; return 0; } -static int compat_ip_get_mcast_msfilter(struct sock sk, sockptr_t optval, - sockptr_t optlen, int len) +static int compat_ip_get_mcast_msfilter(struct sock sk, sockopt_t opt) { const int size0 = offsetof(struct compat_group_filter, gf_slist_flex); struct compat_group_filter gf32; struct group_filter gf; - int num; + int num, len; int err; - if (len < size0) + if (opt->optlen < size0) return -EINVAL; - if (copy_from_sockptr(&gf32, optval, size0)) + if (copy_from_iter(&gf32, size0, &opt->iter_in) != size0) return -EFAULT; gf.gf_interface = gf32.gf_interface; @@ -1488,24 +1489,27 @@ static int compat_ip_get_mcast_msfilter(struct sock sk, sockptr_t optval, num = gf.gf_numsrc = gf32.gf_numsrc; gf.gf_group = gf32.gf_group; - err = ip_mc_gsfget(sk, &gf, optval, + err = ip_mc_gsfget(sk, &gf, opt, offsetof(struct compat_group_filter, gf_slist_flex)); if (err) return err; if (gf.gf_numsrc < num) num = gf.gf_numsrc; len = GROUP_FILTER_SIZE(num) - (sizeof(gf) - sizeof(gf32)); - if (copy_to_sockptr(optlen, &len, sizeof(int)) \|\| - copy_to_sockptr_offset(optval, offsetof(struct compat_group_filter, gf_fmode), - &gf.gf_fmode, sizeof(gf.gf_fmode)) \|\| - copy_to_sockptr_offset(optval, offsetof(struct compat_group_filter, gf_numsrc), - &gf.gf_numsrc, sizeof(gf.gf_numsrc))) + + / Rewind to gf_fmode, which gf_numsrc follows. / + iov_iter_revert(&opt->iter_out, + len - offsetof(struct compat_group_filter, gf_fmode)); + if (copy_to_iter(&gf.gf_fmode, sizeof(gf32.gf_fmode), + &opt->iter_out) != sizeof(gf32.gf_fmode) \|\| + copy_to_iter(&gf.gf_numsrc, sizeof(gf32.gf_numsrc), + &opt->iter_out) != sizeof(gf32.gf_numsrc)) return -EFAULT; + opt->optlen = len; return 0; } -int do_ip_getsockopt(struct sock sk, int level, int optname, - sockptr_t optval, sockptr_t optlen) +int do_ip_getsockopt(struct sock sk, int level, int optname, sockopt_t sopt) { struct inet_sock inet = inet_sk(sk); bool needs_rtnl = getsockopt_needs_rtnl(optname); @@ -1516,10 +1520,9 @@ int do_ip_getsockopt(struct sock sk, int level, int optname, return -EOPNOTSUPP; if (ip_mroute_opt(optname)) - return ip_mroute_getsockopt(sk, optname, optval, optlen); + return ip_mroute_getsockopt(sk, optname, sopt); - if (copy_from_sockptr(&len, optlen, sizeof(int))) - return -EFAULT; + len = sopt->optlen; if (len < 0) return -EINVAL; @@ -1615,16 +1618,15 @@ int do_ip_getsockopt(struct sock sk, int level, int optname, rcu_read_unlock(); if (opt->optlen == 0) { - len = 0; - return copy_to_sockptr(optlen, &len, sizeof(int)); + sopt->optlen = 0; + return 0; } ip_options_undo(opt); len = min_t(unsigned int, len, opt->optlen); - if (copy_to_sockptr(optlen, &len, sizeof(int))) - return -EFAULT; - if (copy_to_sockptr(optval, opt->__data, len)) + sopt->optlen = len; + if (copy_to_iter(opt->__data, len, &sopt->iter_out) != len) return -EFAULT; return 0; } @@ -1648,12 +1650,12 @@ int do_ip_getsockopt(struct sock sk, int level, int optname, if (sk->sk_type != SOCK_STREAM) return -ENOPROTOOPT; - if (optval.is_kernel) { + if (iov_iter_is_kvec(&sopt->iter_out)) { msg.msg_control_is_user = false; - msg.msg_control = optval.kernel; + msg.msg_control = sopt->iter_out.kvec->iov_base; } else { msg.msg_control_is_user = true; - msg.msg_control_user = optval.user; + msg.msg_control_user = sopt->iter_out.ubuf; } msg.msg_controllen = len; msg.msg_flags = in_compat_syscall() ? MSG_CMSG_COMPAT : 0; @@ -1675,8 +1677,8 @@ int do_ip_getsockopt(struct sock sk, int level, int optname, int tos = READ_ONCE(inet->rcv_tos); put_cmsg(&msg, SOL_IP, IP_TOS, sizeof(tos), &tos); } - len -= msg.msg_controllen; - return copy_to_sockptr(optlen, &len, sizeof(int)); + sopt->optlen = len - msg.msg_controllen; + return 0; } case IP_UNICAST_IF: val = (__force int)htonl((__u32) READ_ONCE(inet->uc_index)); @@ -1687,9 +1689,8 @@ int do_ip_getsockopt(struct sock sk, int level, int optname, len = min_t(unsigned int, len, sizeof(struct in_addr)); addr.s_addr = READ_ONCE(inet->mc_addr); - if (copy_to_sockptr(optlen, &len, sizeof(int))) - return -EFAULT; - if (copy_to_sockptr(optval, &addr, len)) + sopt->optlen = len; + if (copy_to_iter(&addr, len, &sopt->iter_out) != len) return -EFAULT; return 0; } @@ -1706,32 +1707,24 @@ int do_ip_getsockopt(struct sock sk, int level, int optname, case IP_MSFILTER: { struct ip_msfilter msf; - struct kvec kvec; - sockopt_t opt; if (len < IP_MSFILTER_SIZE(0)) { err = -EINVAL; goto out; } - if (copy_from_sockptr(&msf, optval, IP_MSFILTER_SIZE(0))) { + if (copy_from_iter(&msf, IP_MSFILTER_SIZE(0), &sopt->iter_in) != + IP_MSFILTER_SIZE(0)) { err = -EFAULT; goto out; } - err = sockptr_to_sockopt(&opt, optval, optlen, &kvec); - if (err) - goto out; - - err = ip_mc_msfget(sk, &msf, &opt); - if (!err && copy_to_sockptr(optlen, &opt.optlen, sizeof(int))) - err = -EFAULT; + err = ip_mc_msfget(sk, &msf, sopt); goto out; } case MCAST_MSFILTER: if (in_compat_syscall()) - err = compat_ip_get_mcast_msfilter(sk, optval, optlen, - len); + err = compat_ip_get_mcast_msfilter(sk, sopt); else - err = ip_get_mcast_msfilter(sk, optval, optlen, len); + err = ip_get_mcast_msfilter(sk, sopt); goto out; case IP_PROTOCOL: val = inet_sk(sk)->inet_num; @@ -1744,16 +1737,14 @@ int do_ip_getsockopt(struct sock sk, int level, int optname, copyval: if (len < sizeof(int) && len > 0 && val >= 0 && val <= 255) { unsigned char ucval = (unsigned char)val; - len = 1; - if (copy_to_sockptr(optlen, &len, sizeof(int))) - return -EFAULT; - if (copy_to_sockptr(optval, &ucval, 1)) + + sopt->optlen = 1; + if (copy_to_iter(&ucval, 1, &sopt->iter_out) != 1) return -EFAULT; } else { len = min_t(unsigned int, sizeof(int), len); - if (copy_to_sockptr(optlen, &len, sizeof(int))) - return -EFAULT; - if (copy_to_sockptr(optval, &val, len)) + sopt->optlen = len; + if (copy_to_iter(&val, len, &sopt->iter_out) != len) return -EFAULT; } return 0; @@ -1768,19 +1759,22 @@ int do_ip_getsockopt(struct sock sk, int level, int optname, int ip_getsockopt(struct sock sk, int level, int optname, char __user optval, int __user optlen) { + sockopt_t opt; int err; - err = do_ip_getsockopt(sk, level, optname, - USER_SOCKPTR(optval), USER_SOCKPTR(optlen)); + err = sockopt_init_user(&opt, optval, optlen); + if (err) + return err; + + err = do_ip_getsockopt(sk, level, optname, &opt); + if (put_user(opt.optlen, optlen)) + return -EFAULT; #ifdef CONFIG_NETFILTER /* we need to exclude all possible ENOPROTOOPTs except default case / if (err == -ENOPROTOOPT && optname != IP_PKTOPTIONS && !ip_mroute_opt(optname)) { - int len; - - if (get_user(len, optlen)) - return -EFAULT; + int len = opt.optlen; err = nf_getsockopt(sk, PF_INET, optname, optval, &len); if (err >= 0) diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c index e4c51ca473019..f249569b4bf8b 100644 --- a/net/ipv4/ipmr.c +++ b/net/ipv4/ipmr.c @@ -1638,8 +1638,7 @@ int ipmr_sk_ioctl(struct sock sk, unsigned int cmd, void __user arg) } / Getsock opt support for the multicast routing system. / -int ip_mroute_getsockopt(struct sock sk, int optname, sockptr_t optval, - sockptr_t optlen) +int ip_mroute_getsockopt(struct sock sk, int optname, sockopt_t opt) { int olr; int val; @@ -1670,16 +1669,14 @@ int ip_mroute_getsockopt(struct sock sk, int optname, sockptr_t optval, return -ENOPROTOOPT; } - if (copy_from_sockptr(&olr, optlen, sizeof(int))) - return -EFAULT; + olr = opt->optlen; if (olr < 0) return -EINVAL; olr = min_t(unsigned int, olr, sizeof(int)); - if (copy_to_sockptr(optlen, &olr, sizeof(int))) - return -EFAULT; - if (copy_to_sockptr(optval, &val, olr)) + opt->optlen = olr; + if (copy_to_iter(&val, olr, &opt->iter_out) != olr) return -EFAULT; return 0; } diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c index 36f117ad36708..9513258b95fb8 100644 --- a/net/ipv6/ip6mr.c +++ b/net/ipv6/ip6mr.c @@ -1893,8 +1893,7 @@ int ip6_mroute_setsockopt(struct sock sk, int optname, sockptr_t optval, * Getsock opt support for the multicast routing system. / -int ip6_mroute_getsockopt(struct sock sk, int optname, sockptr_t optval, - sockptr_t optlen) +int ip6_mroute_getsockopt(struct sock sk, int optname, sockopt_t sopt) { int olr; int val; @@ -1925,16 +1924,12 @@ int ip6_mroute_getsockopt(struct sock sk, int optname, sockptr_t optval, return -ENOPROTOOPT; } - if (copy_from_sockptr(&olr, optlen, sizeof(int))) - return -EFAULT; - - olr = min_t(int, olr, sizeof(int)); + olr = min_t(int, sopt->optlen, sizeof(int)); if (olr < 0) return -EINVAL; - if (copy_to_sockptr(optlen, &olr, sizeof(int))) - return -EFAULT; - if (copy_to_sockptr(optval, &val, olr)) + sopt->optlen = olr; + if (copy_to_iter(&val, olr, &sopt->iter_out) != olr) return -EFAULT; return 0; } diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c index 4b3536571c980..b1011319cd3ec 100644 --- a/net/ipv6/ipv6_sockglue.c +++ b/net/ipv6/ipv6_sockglue.c @@ -889,7 +889,7 @@ int ipv6_setsockopt(struct sock sk, int level, int optname, sockptr_t optval, EXPORT_SYMBOL(ipv6_setsockopt); static int ipv6_getsockopt_sticky(struct sock sk, struct ipv6_txoptions opt, - int optname, sockptr_t optval, int len) + int optname, sockopt_t sopt, int len) { struct ipv6_opt_hdr hdr; @@ -917,53 +917,57 @@ static int ipv6_getsockopt_sticky(struct sock sk, struct ipv6_txoptions opt, return 0; len = min_t(unsigned int, len, ipv6_optlen(hdr)); - if (copy_to_sockptr(optval, hdr, len)) + if (copy_to_iter(hdr, len, &sopt->iter_out) != len) return -EFAULT; return len; } -static int ipv6_get_msfilter(struct sock sk, sockptr_t optval, - sockptr_t optlen, int len) +static int ipv6_get_msfilter(struct sock sk, sockopt_t opt) { const int size0 = offsetof(struct group_filter, gf_slist_flex); struct group_filter gsf; - int num; + int num, len; int err; - if (len < size0) + if (opt->optlen < size0) return -EINVAL; - if (copy_from_sockptr(&gsf, optval, size0)) + if (copy_from_iter(&gsf, size0, &opt->iter_in) != size0) return -EFAULT; if (gsf.gf_group.ss_family != AF_INET6) return -EADDRNOTAVAIL; num = gsf.gf_numsrc; sockopt_lock_sock(sk); - err = ip6_mc_msfget(sk, &gsf, optval, size0); + err = ip6_mc_msfget(sk, &gsf, opt, size0); if (!err) { if (num > gsf.gf_numsrc) num = gsf.gf_numsrc; len = GROUP_FILTER_SIZE(num); - if (copy_to_sockptr(optlen, &len, sizeof(int)) \|\| - copy_to_sockptr(optval, &gsf, size0)) + + / ip6_mc_msfget() consumed the whole reply; rewind to the + * fixed part. + / + iov_iter_revert(&opt->iter_out, len); + if (copy_to_iter(&gsf, size0, &opt->iter_out) != size0) err = -EFAULT; + else + opt->optlen = len; } sockopt_release_sock(sk); return err; } -static int compat_ipv6_get_msfilter(struct sock sk, sockptr_t optval, - sockptr_t optlen, int len) +static int compat_ipv6_get_msfilter(struct sock sk, sockopt_t opt) { const int size0 = offsetof(struct compat_group_filter, gf_slist_flex); struct compat_group_filter gf32; struct group_filter gf; int err; - int num; + int num, len; - if (len < size0) + if (opt->optlen < size0) return -EINVAL; - if (copy_from_sockptr(&gf32, optval, size0)) + if (copy_from_iter(&gf32, size0, &opt->iter_in) != size0) return -EFAULT; gf.gf_interface = gf32.gf_interface; gf.gf_fmode = gf32.gf_fmode; @@ -974,39 +978,41 @@ static int compat_ipv6_get_msfilter(struct sock sk, sockptr_t optval, return -EADDRNOTAVAIL; sockopt_lock_sock(sk); - err = ip6_mc_msfget(sk, &gf, optval, size0); + err = ip6_mc_msfget(sk, &gf, opt, size0); sockopt_release_sock(sk); if (err) return err; if (num > gf.gf_numsrc) num = gf.gf_numsrc; len = GROUP_FILTER_SIZE(num) - (sizeof(gf)-sizeof(gf32)); - if (copy_to_sockptr(optlen, &len, sizeof(int)) \|\| - copy_to_sockptr_offset(optval, offsetof(struct compat_group_filter, gf_fmode), - &gf.gf_fmode, sizeof(gf32.gf_fmode)) \|\| - copy_to_sockptr_offset(optval, offsetof(struct compat_group_filter, gf_numsrc), - &gf.gf_numsrc, sizeof(gf32.gf_numsrc))) + + / Rewind to gf_fmode, which gf_numsrc follows. / + iov_iter_revert(&opt->iter_out, + len - offsetof(struct compat_group_filter, gf_fmode)); + if (copy_to_iter(&gf.gf_fmode, sizeof(gf32.gf_fmode), + &opt->iter_out) != sizeof(gf32.gf_fmode) \|\| + copy_to_iter(&gf.gf_numsrc, sizeof(gf32.gf_numsrc), + &opt->iter_out) != sizeof(gf32.gf_numsrc)) return -EFAULT; + opt->optlen = len; return 0; } -int do_ipv6_getsockopt(struct sock sk, int level, int optname, - sockptr_t optval, sockptr_t optlen) +int do_ipv6_getsockopt(struct sock sk, int level, int optname, sockopt_t sopt) { struct ipv6_pinfo np = inet6_sk(sk); int len; int val; if (ip6_mroute_opt(optname)) - return ip6_mroute_getsockopt(sk, optname, optval, optlen); + return ip6_mroute_getsockopt(sk, optname, sopt); - if (copy_from_sockptr(&len, optlen, sizeof(int))) - return -EFAULT; + len = sopt->optlen; switch (optname) { case MCAST_MSFILTER: if (in_compat_syscall()) - return compat_ipv6_get_msfilter(sk, optval, optlen, len); - return ipv6_get_msfilter(sk, optval, optlen, len); + return compat_ipv6_get_msfilter(sk, sopt); + return ipv6_get_msfilter(sk, sopt); case IPV6_2292PKTOPTIONS: { struct msghdr msg; @@ -1015,12 +1021,12 @@ int do_ipv6_getsockopt(struct sock sk, int level, int optname, if (sk->sk_type != SOCK_STREAM) return -ENOPROTOOPT; - if (optval.is_kernel) { + if (iov_iter_is_kvec(&sopt->iter_out)) { msg.msg_control_is_user = false; - msg.msg_control = optval.kernel; + msg.msg_control = sopt->iter_out.kvec->iov_base; } else { msg.msg_control_is_user = true; - msg.msg_control_user = optval.user; + msg.msg_control_user = sopt->iter_out.ubuf; } msg.msg_controllen = len; msg.msg_flags = 0; @@ -1071,8 +1077,8 @@ int do_ipv6_getsockopt(struct sock sk, int level, int optname, put_cmsg(&msg, SOL_IPV6, IPV6_FLOWINFO, sizeof(flowinfo), &flowinfo); } } - len -= msg.msg_controllen; - return copy_to_sockptr(optlen, &len, sizeof(int)); + sopt->optlen = len - msg.msg_controllen; + return 0; } case IPV6_MTU: { @@ -1127,12 +1133,13 @@ int do_ipv6_getsockopt(struct sock sk, int level, int optname, sockopt_lock_sock(sk); opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk)); - len = ipv6_getsockopt_sticky(sk, opt, optname, optval, len); + len = ipv6_getsockopt_sticky(sk, opt, optname, sopt, len); sockopt_release_sock(sk); /* check if ipv6_getsockopt_sticky() returns err code / if (len < 0) return len; - return copy_to_sockptr(optlen, &len, sizeof(int)); + sopt->optlen = len; + return 0; } case IPV6_RECVHOPOPTS: @@ -1186,9 +1193,8 @@ int do_ipv6_getsockopt(struct sock sk, int level, int optname, if (!mtuinfo.ip6m_mtu) return -ENOTCONN; - if (copy_to_sockptr(optlen, &len, sizeof(int))) - return -EFAULT; - if (copy_to_sockptr(optval, &mtuinfo, len)) + sopt->optlen = len; + if (copy_to_iter(&mtuinfo, len, &sopt->iter_out) != len) return -EFAULT; return 0; @@ -1265,7 +1271,8 @@ int do_ipv6_getsockopt(struct sock sk, int level, int optname, if (len < sizeof(freq)) return -EINVAL; - if (copy_from_sockptr(&freq, optval, sizeof(freq))) + if (copy_from_iter(&freq, sizeof(freq), &sopt->iter_in) != + sizeof(freq)) return -EFAULT; if (freq.flr_action != IPV6_FL_A_GET) @@ -1280,9 +1287,8 @@ int do_ipv6_getsockopt(struct sock sk, int level, int optname, if (val < 0) return val; - if (copy_to_sockptr(optlen, &len, sizeof(int))) - return -EFAULT; - if (copy_to_sockptr(optval, &freq, len)) + sopt->optlen = len; + if (copy_to_iter(&freq, len, &sopt->iter_out) != len) return -EFAULT; return 0; @@ -1340,9 +1346,8 @@ int do_ipv6_getsockopt(struct sock sk, int level, int optname, return -ENOPROTOOPT; } len = min_t(unsigned int, sizeof(int), len); - if (copy_to_sockptr(optlen, &len, sizeof(int))) - return -EFAULT; - if (copy_to_sockptr(optval, &val, len)) + sopt->optlen = len; + if (copy_to_iter(&val, len, &sopt->iter_out) != len) return -EFAULT; return 0; } @@ -1350,7 +1355,8 @@ int do_ipv6_getsockopt(struct sock sk, int level, int optname, int ipv6_getsockopt(struct sock sk, int level, int optname, char __user optval, int __user optlen) { - int err; + sockopt_t sopt; + int len, err; if (level == SOL_IP && sk->sk_type != SOCK_RAW) return ip_getsockopt(sk, level, optname, optval, optlen); @@ -1358,15 +1364,25 @@ int ipv6_getsockopt(struct sock sk, int level, int optname, if (level != SOL_IPV6) return -ENOPROTOOPT; - err = do_ipv6_getsockopt(sk, level, optname, - USER_SOCKPTR(optval), USER_SOCKPTR(optlen)); + if (get_user(len, optlen)) + return -EFAULT; + /* Historic bug compatibility: take a negative optlen as 4, as the + * int options always did. MRT6_* has always rejected it instead. + / + if (len < 0) { + if (ip6_mroute_opt(optname)) + return -EINVAL; + len = 4; + } + sockopt_set_user(&sopt, optval, len); + + err = do_ipv6_getsockopt(sk, level, optname, &sopt); + if (put_user(sopt.optlen, optlen)) + return -EFAULT; #ifdef CONFIG_NETFILTER / we need to exclude all possible ENOPROTOOPTs except default case / if (err == -ENOPROTOOPT && optname != IPV6_2292PKTOPTIONS) { - int len; - - if (get_user(len, optlen)) - return -EFAULT; + len = sopt.optlen; err = nf_getsockopt(sk, PF_INET6, optname, optval, &len); if (err >= 0) diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c index ecef55f261890..4ca2d77811f4e 100644 --- a/net/ipv6/mcast.c +++ b/net/ipv6/mcast.c @@ -600,14 +600,14 @@ int ip6_mc_msfilter(struct sock sk, struct group_filter gsf, } int ip6_mc_msfget(struct sock sk, struct group_filter gsf, - sockptr_t optval, size_t ss_offset) + sockopt_t opt, size_t ss_offset) { struct ipv6_pinfo inet6 = inet6_sk(sk); const struct in6_addr group; struct ipv6_mc_socklist pmc; struct ip6_sf_socklist psl; + int i, copycount, err; unsigned int count; - int i, copycount; group = &((struct sockaddr_in6 )&gsf->gf_group)->sin6_addr; @@ -629,6 +629,18 @@ int ip6_mc_msfget(struct sock sk, struct group_filter gsf, copycount = min(count, gsf->gf_numsrc); gsf->gf_numsrc = count; + + / The source list is sized by the gf_numsrc the caller left in optval, + * not by optlen, which only has to cover the fixed part. + / + err = sockopt_expand_out(opt, ss_offset + + copycount sizeof(struct sockaddr_storage)); + if (err) + return err; + + /* The caller fills the fixed part in once it knows gf_numsrc. / + iov_iter_advance(&opt->iter_out, ss_offset); + for (i = 0; i < copycount; i++) { struct sockaddr_in6 psin6; struct sockaddr_storage ss; @@ -637,9 +649,8 @@ int ip6_mc_msfget(struct sock sk, struct group_filter gsf, memset(&ss, 0, sizeof(ss)); psin6->sin6_family = AF_INET6; psin6->sin6_addr = psl->sl_addr[i]; - if (copy_to_sockptr_offset(optval, ss_offset, &ss, sizeof(ss))) + if (copy_to_iter(&ss, sizeof(ss), &opt->iter_out) != sizeof(ss)) return -EFAULT; - ss_offset += sizeof(ss); } return 0; } diff --git a/tools/testing/selftests/net/config b/tools/testing/selftests/net/config index d355cf9805977..07296f0df1394 100644 --- a/tools/testing/selftests/net/config +++ b/tools/testing/selftests/net/config @@ -28,6 +28,7 @@ CONFIG_IP6_NF_MATCH_RPFILTER=m CONFIG_IP6_NF_NAT=m CONFIG_IP6_NF_RAW=m CONFIG_IP6_NF_TARGET_REJECT=m +CONFIG_IP_MROUTE=y CONFIG_IP_NF_FILTER=m CONFIG_IP_NF_IPTABLES=m CONFIG_IP_NF_IPTABLES_LEGACY=m diff --git a/tools/testing/selftests/net/getsockopt_iter.c b/tools/testing/selftests/net/getsockopt_iter.c index 6c2408df46123..2367fce226d4c 100644 --- a/tools/testing/selftests/net/getsockopt_iter.c +++ b/tools/testing/selftests/net/getsockopt_iter.c @@ -55,6 +55,13 @@ #ifndef TCP_ULP #define TCP_ULP 31 #endif +/* linux/mroute.h does not coexist with netinet/in.h here. / +#ifndef MRT_VERSION +#define MRT_VERSION 206 +#endif +#ifndef MRT6_VERSION +#define MRT6_VERSION 206 +#endif / ---------- netlink ---------- / @@ -492,6 +499,371 @@ TEST_F(rawv6, bad_optname) ASSERT_EQ(sizeof(val), optlen); } +/ ---------- ip (SOL_IP) ---------- / + +FIXTURE(ip) +{ + int fd; +}; + +FIXTURE_SETUP(ip) +{ + / a router alert option, so IP_OPTIONS has something to answer with / + static const unsigned char ipopts[4] = { 0x94, 0x04, 0x00, 0x00 }; + int ttl = 42; + + self->fd = socket(AF_INET, SOCK_DGRAM, 0); + if (self->fd < 0) + SKIP(return, "AF_INET dgram socket: %s", strerror(errno)); + + if (setsockopt(self->fd, SOL_IP, IP_TTL, &ttl, sizeof(ttl)) < 0) + SKIP(return, "set IP_TTL: %s", strerror(errno)); + + if (setsockopt(self->fd, SOL_IP, IP_OPTIONS, ipopts, + sizeof(ipopts)) < 0) + SKIP(return, "set IP_OPTIONS: %s", strerror(errno)); +} + +FIXTURE_TEARDOWN(ip) +{ + if (self->fd >= 0) + close(self->fd); +} + +TEST_F(ip, ttl_exact) +{ + socklen_t optlen = sizeof(int); + int val = 0; + + ASSERT_EQ(0, getsockopt(self->fd, SOL_IP, IP_TTL, &val, &optlen)); + ASSERT_EQ(sizeof(int), optlen); + ASSERT_EQ(42, val); +} + +TEST_F(ip, ttl_oversize_clamped) +{ + socklen_t optlen = 64; + int buf[16] = {}; + + ASSERT_EQ(0, getsockopt(self->fd, SOL_IP, IP_TTL, buf, &optlen)); + ASSERT_EQ(sizeof(int), optlen); + ASSERT_EQ(42, buf[0]); +} + +/ SOL_IP answers a sub-int buffer with a single byte when the value fits + * in one, rather than clamping the int down. + / +TEST_F(ip, ttl_single_byte) +{ + unsigned char buf[3] = {}; + socklen_t optlen = sizeof(buf); + + ASSERT_EQ(0, getsockopt(self->fd, SOL_IP, IP_TTL, buf, &optlen)); + ASSERT_EQ(1, optlen); + ASSERT_EQ(42, buf[0]); +} + +TEST_F(ip, ttl_zero_len) +{ + socklen_t optlen = 0; + int val; + + ASSERT_EQ(0, getsockopt(self->fd, SOL_IP, IP_TTL, &val, &optlen)); + ASSERT_EQ(0, optlen); +} + +TEST_F(ip, negative_optlen) +{ + socklen_t optlen = (socklen_t)-1; + int val; + + ASSERT_EQ(-1, getsockopt(self->fd, SOL_IP, IP_TTL, &val, &optlen)); + ASSERT_EQ(EINVAL, errno); +} + +TEST_F(ip, options_roundtrip) +{ + static const unsigned char ipopts[4] = { 0x94, 0x04, 0x00, 0x00 }; + unsigned char buf[40] = {}; + socklen_t optlen = sizeof(buf); + + ASSERT_EQ(0, getsockopt(self->fd, SOL_IP, IP_OPTIONS, buf, &optlen)); + ASSERT_EQ(sizeof(ipopts), optlen); + ASSERT_EQ(0, memcmp(buf, ipopts, sizeof(ipopts))); +} + +TEST_F(ip, options_undersize_clamped) +{ + static const unsigned char ipopts[2] = { 0x94, 0x04 }; + unsigned char buf[2] = {}; + socklen_t optlen = sizeof(buf); + + ASSERT_EQ(0, getsockopt(self->fd, SOL_IP, IP_OPTIONS, buf, &optlen)); + ASSERT_EQ(sizeof(buf), optlen); + ASSERT_EQ(0, memcmp(buf, ipopts, sizeof(buf))); +} + +/ With no option set the reply is empty and the call still succeeds. / +TEST_F(ip, options_absent) +{ + unsigned char buf[40] = {}; + socklen_t optlen = sizeof(buf); + int fd; + + fd = socket(AF_INET, SOCK_DGRAM, 0); + if (fd < 0) + SKIP(return, "AF_INET dgram socket: %s", strerror(errno)); + + ASSERT_EQ(0, getsockopt(fd, SOL_IP, IP_OPTIONS, buf, &optlen)); + ASSERT_EQ(0, optlen); + close(fd); +} + +TEST_F(ip, multicast_if_oversize_clamped) +{ + struct in_addr any = { .s_addr = INADDR_ANY }; + socklen_t optlen = 64; + unsigned char buf[64]; + + memset(buf, 0xaa, sizeof(buf)); + ASSERT_EQ(0, getsockopt(self->fd, SOL_IP, IP_MULTICAST_IF, buf, + &optlen)); + ASSERT_EQ(sizeof(struct in_addr), optlen); + ASSERT_EQ(0, memcmp(buf, &any, sizeof(any))); + ASSERT_EQ(0xaa, buf[sizeof(any)]); +} + +/ IP_PKTOPTIONS only answers on a stream socket. / +TEST_F(ip, pktoptions_wrong_type) +{ + socklen_t optlen = 64; + char buf[64]; + + ASSERT_EQ(-1, getsockopt(self->fd, SOL_IP, IP_PKTOPTIONS, buf, + &optlen)); + ASSERT_EQ(ENOPROTOOPT, errno); +} + +/ The MRT_* options are dispatched ahead of the rest of the switch and + * want a raw IGMP socket. Without CONFIG_IP_MROUTE they are not + * dispatched at all and the switch also answers ENOPROTOOPT, so the + * config check has to come from somewhere other than this errno. + / +TEST_F(ip, mroute_wrong_type) +{ + socklen_t optlen = sizeof(int); + int val; + + if (access("/proc/net/ip_mr_vif", F_OK)) + SKIP(return, "CONFIG_IP_MROUTE disabled"); + + ASSERT_EQ(-1, getsockopt(self->fd, SOL_IP, MRT_VERSION, &val, + &optlen)); + ASSERT_EQ(EOPNOTSUPP, errno); +} + +TEST_F(ip, bad_optname) +{ + socklen_t optlen = sizeof(int); + int val; + + ASSERT_EQ(-1, getsockopt(self->fd, SOL_IP, 0x7fff, &val, &optlen)); + ASSERT_EQ(ENOPROTOOPT, errno); + ASSERT_EQ(sizeof(int), optlen); +} + +/ ---------- ipv6 (SOL_IPV6) ---------- / + +/ an 8 byte hop-by-hop header, so the sticky options answer / +static const unsigned char hopopt[8] = { 0, 0, 1, 4, 0, 0, 0, 0 }; + +FIXTURE(ipv6) +{ + int fd; +}; + +FIXTURE_SETUP(ipv6) +{ + int hops = 42; + + self->fd = socket(AF_INET6, SOCK_DGRAM, 0); + if (self->fd < 0) + SKIP(return, "AF_INET6 dgram socket: %s", strerror(errno)); + + if (setsockopt(self->fd, SOL_IPV6, IPV6_UNICAST_HOPS, &hops, + sizeof(hops)) < 0) + SKIP(return, "set IPV6_UNICAST_HOPS: %s", strerror(errno)); +} + +FIXTURE_TEARDOWN(ipv6) +{ + if (self->fd >= 0) + close(self->fd); +} + +TEST_F(ipv6, hops_exact) +{ + socklen_t optlen = sizeof(int); + int val = 0; + + ASSERT_EQ(0, getsockopt(self->fd, SOL_IPV6, IPV6_UNICAST_HOPS, &val, + &optlen)); + ASSERT_EQ(sizeof(int), optlen); + ASSERT_EQ(42, val); +} + +TEST_F(ipv6, hops_oversize_clamped) +{ + socklen_t optlen = 64; + int buf[16] = {}; + + ASSERT_EQ(0, getsockopt(self->fd, SOL_IPV6, IPV6_UNICAST_HOPS, buf, + &optlen)); + ASSERT_EQ(sizeof(int), optlen); + ASSERT_EQ(42, buf[0]); +} + +/ Unlike SOL_IP, SOL_IPV6 clamps a sub-int buffer down to what fits + * rather than answering a single byte. + / +TEST_F(ipv6, hops_sub_int) +{ + unsigned char buf[3]; + socklen_t optlen = sizeof(buf); + int hops = 42; + + memset(buf, 0xaa, sizeof(buf)); + ASSERT_EQ(0, getsockopt(self->fd, SOL_IPV6, IPV6_UNICAST_HOPS, buf, + &optlen)); + ASSERT_EQ(sizeof(buf), optlen); + ASSERT_EQ(0, memcmp(buf, &hops, sizeof(buf))); +} + +TEST_F(ipv6, hops_zero_len) +{ + socklen_t optlen = 0; + int val; + + ASSERT_EQ(0, getsockopt(self->fd, SOL_IPV6, IPV6_UNICAST_HOPS, &val, + &optlen)); + ASSERT_EQ(0, optlen); +} + +/ Unlike SOL_IP, a negative optlen is taken as 4 here, as the int options + * always did. + / +TEST_F(ipv6, negative_optlen) +{ + socklen_t optlen = (socklen_t)-1; + int val = 0; + + ASSERT_EQ(0, getsockopt(self->fd, SOL_IPV6, IPV6_UNICAST_HOPS, &val, + &optlen)); + ASSERT_EQ(sizeof(int), optlen); + ASSERT_EQ(42, val); +} + +TEST_F(ipv6, hopopts_roundtrip) +{ + unsigned char buf[64] = {}; + socklen_t optlen = sizeof(buf); + + if (setsockopt(self->fd, SOL_IPV6, IPV6_HOPOPTS, hopopt, + sizeof(hopopt)) < 0) + SKIP(return, "set IPV6_HOPOPTS: %s", strerror(errno)); + + ASSERT_EQ(0, getsockopt(self->fd, SOL_IPV6, IPV6_HOPOPTS, buf, + &optlen)); + ASSERT_EQ(sizeof(hopopt), optlen); + ASSERT_EQ(0, memcmp(buf, hopopt, sizeof(hopopt))); +} + +TEST_F(ipv6, hopopts_undersize_clamped) +{ + unsigned char buf[4] = {}; + socklen_t optlen = sizeof(buf); + + if (setsockopt(self->fd, SOL_IPV6, IPV6_HOPOPTS, hopopt, + sizeof(hopopt)) < 0) + SKIP(return, "set IPV6_HOPOPTS: %s", strerror(errno)); + + ASSERT_EQ(0, getsockopt(self->fd, SOL_IPV6, IPV6_HOPOPTS, buf, + &optlen)); + ASSERT_EQ(sizeof(buf), optlen); + ASSERT_EQ(0, memcmp(buf, hopopt, sizeof(buf))); +} + +/ With no header set the reply is empty and the call still succeeds. / +TEST_F(ipv6, hopopts_absent) +{ + unsigned char buf[64] = {}; + socklen_t optlen = sizeof(buf); + int fd; + + fd = socket(AF_INET6, SOCK_DGRAM, 0); + if (fd < 0) + SKIP(return, "AF_INET6 dgram socket: %s", strerror(errno)); + + ASSERT_EQ(0, getsockopt(fd, SOL_IPV6, IPV6_HOPOPTS, buf, &optlen)); + ASSERT_EQ(0, optlen); + close(fd); +} + +/ IPV6_PATHMTU wants room for the whole struct ip6_mtuinfo. / +TEST_F(ipv6, pathmtu_undersize) +{ + socklen_t optlen = 8; + char buf[8]; + + ASSERT_EQ(-1, getsockopt(self->fd, SOL_IPV6, IPV6_PATHMTU, buf, + &optlen)); + ASSERT_EQ(EINVAL, errno); +} + +/ A negative optlen is taken as 4, which is undersize for IPV6_PATHMTU. / +TEST_F(ipv6, pathmtu_negative_optlen) +{ + socklen_t optlen = (socklen_t)-1; + char buf[64]; + + ASSERT_EQ(-1, getsockopt(self->fd, SOL_IPV6, IPV6_PATHMTU, buf, + &optlen)); + ASSERT_EQ(EINVAL, errno); +} + +TEST_F(ipv6, pktoptions_wrong_type) +{ + socklen_t optlen = 64; + char buf[64]; + + ASSERT_EQ(-1, getsockopt(self->fd, SOL_IPV6, IPV6_2292PKTOPTIONS, buf, + &optlen)); + ASSERT_EQ(ENOPROTOOPT, errno); +} + +TEST_F(ipv6, mroute_wrong_type) +{ + socklen_t optlen = sizeof(int); + int val; + + if (access("/proc/net/ip6_mr_vif", F_OK)) + SKIP(return, "CONFIG_IPV6_MROUTE disabled"); + + ASSERT_EQ(-1, getsockopt(self->fd, SOL_IPV6, MRT6_VERSION, &val, + &optlen)); + ASSERT_EQ(EOPNOTSUPP, errno); +} + +TEST_F(ipv6, bad_optname) +{ + socklen_t optlen = sizeof(int); + int val; + + ASSERT_EQ(-1, getsockopt(self->fd, SOL_IPV6, 0x7fff, &val, &optlen)); + ASSERT_EQ(ENOPROTOOPT, errno); + ASSERT_EQ(sizeof(int), optlen); +} + / ---------- tls ---------- */ FIXTURE(tls)
29/3	2026/10/15 13:01	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 19964 output: 38 thoughts: 1398 Thoughts: KMSAN Fuzzing Session Justification Okay, so I need to decide if this patch series warrants a dedicated KMSAN fuzzing session. The goal is to catch uninitialized memory reads or leaks to userspace. Let's break this down. First, this is a refactoring of `getsockopt` with iterators, specifically looking at changes in the IGMP, mroute, and IPv6 mroute functionalities. It modifies the signatures of several functions and introduces `sockopt_t` which is now passed around instead of the more raw `sockptr_t`. There are a lot of changes touching includes and various `net` files. This touches on kernel structures passed to userspace, which is where KMSAN becomes relevant. The patch updates how data is copied to userspace using functions like `copy_to_iter` and `put_user`. This is interesting. Now, according to the KMSAN rules, I only need to consider a session if the changes introduce or expose risks that are only detected by KMSAN. Standard KASAN should handle anything that can be easily detected. Looking at the guidelines: 1. Kernel structures sent to user space? Check. We are dealing with socket options. 2. Conditional logic or branching dependent on uninitialized data? Potentially. Need to look closer. 3. Complex data structure initialization with potential uninitialized fields? Possible. 4. Bounds checks that could lead to uninitialized memory access? Worth investigating. The crux of the matter is whether this patch changes how `getsockopt` copies data to userspace, and if this could lead to the exposure of uninitialized memory. I need to dive into the code and look for places where data is copied to userspace via `copy_to_iter`, `put_user`, and where buffers are written. Okay, let's start with `net/ipv4/igmp.c`. I'm looking at `ip_mc_msfget`: ```c int ip_mc_msfget(struct sock sk, struct ip_msfilter msf, sockopt_t opt) { ... if (copy_to_iter(msf, IP_MSFILTER_SIZE(0), &opt->iter_out) != IP_MSFILTER_SIZE(0)) return -EFAULT; if (len && copy_to_iter(psl->sl_addr, len, &opt->iter_out) != len) return -EFAULT; opt->optlen = msf_size; return 0; } ``` This immediately* draws my attention. The function is using `copy_to_iter` to send `msf` and `psl->sl_addr` to userspace. My concern is whether `msf` and `psl->sl_addr` are fully initialized before this copy happens. This is the critical point. Was it fully initialized before? Was this always the code path? Time to check the history of this code. What did it look like before the patch, especially around the same line of code. Time to dig in and compare.
30/3	2026/10/15 13:01	tool	read-file	0m Args: { "File": "net/ipv4/igmp.c", "FirstLine": 2740, "LineCount": 50 } Results: { "Contents": "2740:\t\tfor_each_pmc_rtnl(inet, pmc) {\n2741:\t\t\tif (pmc-\u003emulti.imr_multiaddr.s_addr == msf-\u003eimsf_multiaddr \u0026\u0026\n2742:\t\t\t pmc-\u003emulti.imr_ifindex == imr.imr_ifindex)\n2743:\t\t\t\tbreak;\n2744:\t\t}\n2745:\t\tif (!pmc)\t\t/* must have a prior join /\n2746:\t\t\tgoto done;\n2747:\t\tmsf-\u003eimsf_fmode = pmc-\u003esfmode;\n2748:\t\tpsl = rtnl_dereference(pmc-\u003esflist);\n2749:\t\tif (!psl) {\n2750:\t\t\tcount = 0;\n2751:\t\t} else {\n2752:\t\t\tcount = psl-\u003esl_count;\n2753:\t\t}\n2754:\t\tcopycount = count \u003c msf-\u003eimsf_numsrc ? count : msf-\u003eimsf_numsrc;\n2755:\t\tlen = flex_array_size(psl, sl_addr, copycount);\n2756:\t\tmsf-\u003eimsf_numsrc = count;\n2757:\t\tmsf_size = IP_MSFILTER_SIZE(copycount);\n2758:\t\n2759:\t\t/ The source list is sized by the imsf_numsrc the caller left in\n2760:\t\t * optval, not by optlen, which only has to cover the fixed part.\n2761:\t\t /\n2762:\t\terr = sockopt_expand_out(opt, msf_size);\n2763:\t\tif (err)\n2764:\t\t\treturn err;\n2765:\t\n2766:\t\tif (copy_to_iter(msf, IP_MSFILTER_SIZE(0), \u0026opt-\u003eiter_out) !=\n2767:\t\t IP_MSFILTER_SIZE(0))\n2768:\t\t\treturn -EFAULT;\n2769:\t\tif (len \u0026\u0026 copy_to_iter(psl-\u003esl_addr, len, \u0026opt-\u003eiter_out) != len)\n2770:\t\t\treturn -EFAULT;\n2771:\t\n2772:\t\topt-\u003eoptlen = msf_size;\n2773:\t\treturn 0;\n2774:\tdone:\n2775:\t\treturn err;\n2776:\t}\n2777:\t\n2778:\tint ip_mc_gsfget(struct sock sk, struct group_filter gsf,\n2779:\t\t\t sockopt_t opt, size_t ss_offset)\n2780:\t{\n2781:\t\tint i, count, copycount, err;\n2782:\t\tstruct sockaddr_in psin;\n2783:\t\t__be32 addr;\n2784:\t\tstruct ip_mc_socklist pmc;\n2785:\t\tstruct inet_sock inet = inet_sk(sk);\n2786:\t\tstruct ip_sf_socklist psl;\n2787:\t\n2788:\t\tASSERT_RTNL();\n2789:\t\n" }
31/3	2026/10/15 13:01	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 22918 output: 19 thoughts: 1109 Thoughts: Analyzing Multicast Source Filtering: A Deep Dive Okay, let's break this down. First, I'm looking at `ip_mc_gsfget`. It seems to be the core function for retrieving multicast source filtering information. I'm seeing it takes a socket, a `group_filter` structure, and a `sockopt_t` structure as arguments, along with an offset. The first thing that jumps out is the use of `rtnl_dereference`, which suggests this function interacts with the routing netlink layer – that's expected. I see it's looking for a specific multicast group (`addr`) and interface (`gsf->gf_interface`) associated with the socket. It's iterating through a list of multicast memberships (`for_each_pmc_rtnl`). If it doesn't find a matching entry, it returns `-EADDRNOTAVAIL` – which makes sense; you can't get filter information for a group you haven't joined. Then, the code updates the `gf_fmode` in the `group_filter` structure, and gets the source list using `rtnl_dereference`. Now, the important part: it determines how many sources to copy (`copycount`), limited by both the actual number of sources and the caller's requested number (`gf_numsrc`). It expands the output buffer with `sockopt_expand_out`, which is crucial for handling variable-length data, using an offset to skip the fixed part. It then advances the iterator, copies the source addresses one by one. Now, let's shift to `ip_get_mcast_msfilter`, and the structure `group_filter gsf`. It's calling `ip_mc_gsfget` to do the real work. What's interesting is how it handles the input and output `group_filter` structure. I see that the code first copies the fixed part of the `group_filter` struct (`size0`) from the input iterator (`opt->iter_in`) to the stack, using `copy_from_iter`. Then it calls `ip_mc_gsfget` to populate this structure with the actual source list. Crucially, I see that the `gsf` structure is on the stack, and copied to from `opt->iter_in`. Also, it calls `iov_iter_revert` to rewind to the fixed part, which is interesting. What I'm wondering now is, is `struct group_filter` padded, or will the contents of `gsf` remain valid? I need to check the exact size of `struct group_filter` to confirm this.
32/3	2026/10/15 13:01	tool	grepper	0m Args: { "Expression": "struct group_filter \\{" } Results: { "Output": "include/uapi/linux/in.h=219=struct group_source_req {\n--\ninclude/uapi/linux/in.h-224-\ninclude/uapi/linux/in.h:225:struct group_filter {\ninclude/uapi/linux/in.h-226-\tunion {\n--\ntools/include/uapi/linux/in.h=219=struct group_source_req {\n--\ntools/include/uapi/linux/in.h-224-\ntools/include/uapi/linux/in.h:225:struct group_filter {\ntools/include/uapi/linux/in.h-226-\tunion {\n" }
33/3	2026/10/15 13:01	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 24794 output: 38 thoughts: 23 Thoughts: Okay, let's dive into this. Here's my take on those instructions, as if they're my internal thought process: Diving into `in.h` for IP-related Structures Right, so we're talking about network headers. The instruction is to check out `include/uapi/linux/in.h` around line 225. I already know this file—it's the standard header for internet address definitions in the Linux kernel userspace API. It's the go-to place for structs like `sockaddr_in`, `in_addr`, and the constants that define network addressing parameters. My mental map probably already has it filed away with `netinet/in.h` and the various socket-related system calls. Let me see... I wonder what the focus is on that specific line? It's probably something like a struct definition or a macro related to IPv4 addressing. The line number suggests we're likely dealing with the foundational data structures and their respective offsets, possibly the definitions of the `sockaddr_in` struct or parts of the `in_addr` or `in6_addr` structs. That is likely where the IPv4 structures and constant definitions are. I'm curious what detail we are looking at. I'll take a look!
34/3	2026/10/15 13:01	tool	read-file	0m Args: { "File": "include/uapi/linux/in.h", "FirstLine": 220, "LineCount": 40 } Results: { "Contents": " 220:\t\t__u32\t\t\t\t gsr_interface;\t/* interface index /\n 221:\t\tstruct __kernel_sockaddr_storage gsr_group;\t/ group address /\n 222:\t\tstruct __kernel_sockaddr_storage gsr_source;\t/ source address /\n 223:\t};\n 224:\t\n 225:\tstruct group_filter {\n 226:\t\tunion {\n 227:\t\t\tstruct {\n 228:\t\t\t\t__u32\t\t\t\t gf_interface_aux; / interface index /\n 229:\t\t\t\tstruct __kernel_sockaddr_storage gf_group_aux;\t / multicast address /\n 230:\t\t\t\t__u32\t\t\t\t gf_fmode_aux;\t / filter mode /\n 231:\t\t\t\t__u32\t\t\t\t gf_numsrc_aux;\t / number of sources /\n 232:\t\t\t\tstruct __kernel_sockaddr_storage gf_slist[1];\t / interface index /\n 233:\t\t\t};\n 234:\t\t\tstruct {\n 235:\t\t\t\t__u32\t\t\t\t gf_interface;\t / interface index /\n 236:\t\t\t\tstruct __kernel_sockaddr_storage gf_group;\t / multicast address /\n 237:\t\t\t\t__u32\t\t\t\t gf_fmode;\t / filter mode /\n 238:\t\t\t\t__u32\t\t\t\t gf_numsrc;\t / number of sources /\n 239:\t\t\t\tstruct __kernel_sockaddr_storage gf_slist_flex[]; / interface index /\n 240:\t\t\t};\n 241:\t\t};\n 242:\t};\n 243:\t\n 244:\t#define GROUP_FILTER_SIZE(numsrc) \\\n 245:\t\t(sizeof(struct group_filter) - sizeof(struct __kernel_sockaddr_storage) \\\n 246:\t\t+ (numsrc) sizeof(struct __kernel_sockaddr_storage))\n 247:\t#endif\n 248:\t\n 249:\t#if __UAPI_DEF_IN_PKTINFO\n 250:\tstruct in_pktinfo {\n 251:\t\tint\t\tipi_ifindex;\n 252:\t\tstruct in_addr\tipi_spec_dst;\n 253:\t\tstruct in_addr\tipi_addr;\n 254:\t};\n 255:\t#endif\n 256:\t\n 257:\t/* Structure describing an Internet (IP) socket address. /\n 258:\t#if __UAPI_DEF_SOCKADDR_IN\n 259:\t#define __SOCK_SIZE__\t16\t\t/ sizeof(struct sockaddr)\t*/\n" }
35/3	2026/10/15 13:01	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 25815 output: 32 thoughts: 783 Thoughts: Analyzing the Group Filter Structure for Potential Padding Issues Okay, so I'm looking at this `struct group_filter` definition, and immediately, my expert eye hones in on the union and those nested structs. I'm seeing potential alignment issues, and my gut tells me there's padding in play. Specifically, I'm noting `gf_interface` is a `__u32` (4 bytes), and I know `struct __kernel_sockaddr_storage` typically requires 8-byte alignment (I'll double-check this for certainty though!). That means there's probably 4 bytes of padding inserted between `gf_interface` and `gf_group`! This is definitely a red flag. Before I go further, I want to see what the original code was doing. I need to understand the prior logic to fully grasp the impact of the change. Ah, right... it was using `offsetof` to calculate a `size0` and then using that to copy the data: `copy_from_sockptr(&gsf, optval, size0)` and then copy it back: `copy_to_sockptr(optval, &gsf, size0)`. Now I'm looking at the patch's implementation. It's using iterators now, `copy_from_iter` and `copy_to_iter`, with the same `size0`. So, they're still copying `size0` bytes from user space into a local `gsf` and then back. Hmm, now I'm curious about the interaction of `iov_iter_revert` which is often a point of interest for these types of changes. Let me see how these `opt->iter_in` and `opt->iter_out` are being used. Time to dive into the `ip_getsockopt` function from `net/ipv4/ip_sockglue.c`. Okay, so it looks like `ip_getsockopt` calls `sockopt_init_user`, and I know I need to know the definition of the `sockopt_t` struct, which should be defined in `include/linux/net.h`. Let's see what that looks like. I need to understand this `sockopt_t` and how it interacts with the user-provided buffers and lengths. I suspect this is where the actual copy logic resides, and potentially where the padding issues could cause problems in the patched code, especially if `size0` isn't accounting for this padding. That's where I need to focus my analysis.
36/3	2026/10/15 13:02	tool	grepper	0m Args: { "Expression": "typedef struct sockopt", "PathPrefixes": [ "include/linux/net.h" ] } Results: { "Output": "include/linux/net.h-43- */\ninclude/linux/net.h:44:typedef struct sockopt {\ninclude/linux/net.h-45-\tstruct iov_iter iter_in;\n" }
37/3	2026/10/15 13:02	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 27257 output: 34 thoughts: 19 Thoughts: Here's a first-person summary, tailored for an expert audience, based on your instructions: Diving into `include/linux/net.h` Okay, time to dig in. I'm focusing on the heart of the Linux network stack – let's open up `include/linux/net.h` and take a look around line 44. I have a feeling there will be something interesting there. I always like to start with the fundamental definitions and data structures to get a handle on the overall organization. Let's see what core elements are being defined near that point.
38/3	2026/10/15 13:02	tool	read-file	0m Args: { "File": "include/linux/net.h", "FirstLine": 40, "LineCount": 70 } Results: { "Contents": " 40:\t \n 41:\t The optlen field allows callbacks to return a specific length value\n 42:\t * independent of the bytes written via copy_to_iter().\n 43:\t /\n 44:\ttypedef struct sockopt {\n 45:\t\tstruct iov_iter iter_in;\n 46:\t\tstruct iov_iter iter_out;\n 47:\t\tint optlen;\n 48:\t} sockopt_t;\n 49:\t\n 50:\tint sockptr_to_sockopt(sockopt_t opt, sockptr_t optval, sockptr_t optlen,\n 51:\t\t\t struct kvec kvec);\n 52:\t\n 53:\t/\n 54:\t * Point a sockopt_t at a user-backed (optval, len) pair whose length is\n 55:\t * already known, e.g. because the caller applied its own optlen quirks\n 56:\t * before this point.\n 57:\t /\n 58:\tstatic inline void sockopt_set_user(sockopt_t opt, char __user optval,\n 59:\t\t\t\t\t int len)\n 60:\t{\n 61:\t\tiov_iter_ubuf(\u0026opt-\u003eiter_out, ITER_DEST, optval, len);\n 62:\t\tiov_iter_ubuf(\u0026opt-\u003eiter_in, ITER_SOURCE, optval, len);\n 63:\t\topt-\u003eoptlen = len;\n 64:\t}\n 65:\t\n 66:\t/\n 67:\t * Initialize a user-backed sockopt_t from the (optval, optlen) __user pair of\n 68:\t * a getsockopt() callback. Used by transitional __user getsockopt wrappers\n 69:\t * while the proto-layer callbacks are converted to take a sockopt_t; the\n 70:\t * caller writes opt-\u003eoptlen back to the user optlen after the callback.\n 71:\t /\n 72:\tstatic inline int sockopt_init_user(sockopt_t opt, char __user optval,\n 73:\t\t\t\t\t int __user optlen)\n 74:\t{\n 75:\t\tint len;\n 76:\t\n 77:\t\tif (get_user(len, optlen))\n 78:\t\t\treturn -EFAULT;\n 79:\t\tif (len \u003c 0)\n 80:\t\t\treturn -EINVAL;\n 81:\t\n 82:\t\tsockopt_set_user(opt, optval, len);\n 83:\t\n 84:\t\treturn 0;\n 85:\t}\n 86:\t\n 87:\t/\n 88:\t Grow optval to @size, for the options whose reply is sized by a count the\n 89:\t * caller left in optval rather than by optlen. Those write past optlen today\n 90:\t * and userspace relies on it.\n 91:\t \n 92:\t Call it before writing through opt-\u003eiter_out: it re-anchors the iterator at\n 93:\t * the head of optval. Only a user buffer can be longer than the optlen the\n 94:\t * caller declared, so a kernel-backed optval is refused with -EINVAL. So is a\n 95:\t * @size above MAX_RW_COUNT, which iov_iter_revert() could not unroll.\n 96:\t /\n 97:\tstatic inline int sockopt_expand_out(sockopt_t opt, size_t size)\n 98:\t{\n 99:\t\t/* iov_iter_revert() refuses to unroll past MAX_RW_COUNT, so a size\n 100:\t\t * beyond that could never be reverted back to the fixed part later,\n 101:\t\t * even when optlen already covers it.\n 102:\t\t /\n 103:\t\tif (size \u003e MAX_RW_COUNT)\n 104:\t\t\treturn -EINVAL;\n 105:\t\n 106:\t\tif (size \u003c= (size_t)opt-\u003eoptlen)\n 107:\t\t\treturn 0;\n 108:\t\n 109:\t\t/ Re-anchoring reads iter_out.ubuf, so the iterator has to be a user\n" }
39/3	2026/10/15 13:02	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 28522 output: 35 thoughts: 32 Thoughts: Okay, let's dive into this. Here's how I'd approach that snippet, considering my expertise: Examining `sockopt_expand_out` in `include/linux/net.h` Alright, I need to get a better handle on how this system works. I'm going to head down into the heart of things, specifically line 110 of `include/linux/net.h` and investigate the `sockopt_expand_out` function. Given my experience, I'm expecting this is where the expansion logic for socket options resides, particularly for output (or potentially, both input and output), when dealing with the kernel's network stack. I'm curious about how it handles option data structures, and the potential for memory management issues. I'll need to look for things like buffer handling, data copying, and any checks for size limitations or invalid option configurations. It is unlikely to involve anything groundbreaking, but a good understanding is essential before any changes or optimization. This is where I'll get the context I need.
40/3	2026/10/15 13:02	tool	read-file	0m Args: { "File": "include/linux/net.h", "FirstLine": 105, "LineCount": 35 } Results: { "Contents": " 105:\t\n 106:\t\tif (size \u003c= (size_t)opt-\u003eoptlen)\n 107:\t\t\treturn 0;\n 108:\t\n 109:\t\t/* Re-anchoring reads iter_out.ubuf, so the iterator has to be a user\n 110:\t\t * buffer that nothing has written through yet.\n 111:\t\t /\n 112:\t\tif (WARN_ON_ONCE(!iter_is_ubuf(\u0026opt-\u003eiter_out) \|\|\n 113:\t\t\t\t iov_iter_count(\u0026opt-\u003eiter_out) != (size_t)opt-\u003eoptlen))\n 114:\t\t\treturn -EINVAL;\n 115:\t\n 116:\t\tiov_iter_ubuf(\u0026opt-\u003eiter_out, ITER_DEST, opt-\u003eiter_out.ubuf, size);\n 117:\t\n 118:\t\treturn 0;\n 119:\t}\n 120:\t\n 121:\tstruct poll_table_struct;\n 122:\tstruct pipe_inode_info;\n 123:\tstruct inode;\n 124:\tstruct file;\n 125:\tstruct net;\n 126:\t\n 127:\t/ Historically, SOCKWQ_ASYNC_NOSPACE \u0026 SOCKWQ_ASYNC_WAITDATA were located\n 128:\t * in sock-\u003eflags, but moved into sk-\u003esk_wq-\u003eflags to be RCU protected.\n 129:\t * Eventually all flags will be in sk-\u003esk_wq-\u003eflags.\n 130:\t */\n 131:\tenum socket_flags {\n 132:\t\tSOCKWQ_ASYNC_NOSPACE,\n 133:\t\tSOCKWQ_ASYNC_WAITDATA,\n 134:\t\tSOCK_NOSPACE,\n 135:\t\tSOCK_SUPPORT_ZC,\n 136:\t\tSOCK_CUSTOM_SOCKOPT,\n 137:\t};\n 138:\t\n 139:\t#ifndef ARCH_HAS_SOCKET_TYPES\n" }
41/3	2026/10/15 13:02	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 29343 output: 22 thoughts: 23 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: Analyzing `sockptr_to_sockopt` Alright, let's dive into this `sockptr_to_sockopt` function. I need to understand its functionality within this context. My first step is clear: I need to locate its definition. Where's this function declared? I'll need to trace it to its source code to unravel its purpose and how it fits into the broader picture. Let's see what the implementation reveals. I'm expecting to find insights into how socket pointer data is being translated into socket option structures, or perhaps some form of argument validation, or even some low-level network manipulation.
42/3	2026/10/15 13:02	tool	grepper	0m Args: { "Expression": "int sockptr_to_sockopt" } Results: { "Output": "include/linux/net.h=44=typedef struct sockopt {\n--\ninclude/linux/net.h-49-\ninclude/linux/net.h:50:int sockptr_to_sockopt(sockopt_t opt, sockptr_t optval, sockptr_t optlen,\ninclude/linux/net.h-51-\t\t struct kvec kvec);\n--\nnet/socket.c=2433=INDIRECT_CALLABLE_DECLARE(bool tcp_bpf_bypass_getsockopt(int level,\n--\nnet/socket.c-2441- /\nnet/socket.c:2442:int sockptr_to_sockopt(sockopt_t opt, sockptr_t optval,\nnet/socket.c-2443-\t\t sockptr_t optlen, struct kvec *kvec)\n" }
43/3	2026/10/15 13:02	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 29760 output: 34 thoughts: 18 Thoughts: Okay, let's dive into this. Here's my thought process on the matter: Delving into `net/socket.c` - Line 2442 Alright, the objective is pretty clear. I need to get a handle on a specific section of the kernel's network socket implementation. The place to start is `net/socket.c`, and specifically, around line 2442. I'm going to carefully analyze what's happening at that juncture. I'm assuming, given the context, that I'm likely to find some crucial function call, data structure manipulation, or maybe even a critical locking mechanism in play around that area. Knowing the codebase, the exact line may not be the critical component, but a relevant section of code surrounding that line. I'll need to figure out what functionality is happening in this particular area. Let's dig in and see what treasures we can unearth!
44/3	2026/10/15 13:02	tool	read-file	0m Args: { "File": "net/socket.c", "FirstLine": 2440, "LineCount": 40 } Results: { "Contents": "2440:\t * .iter_in is read-only and .iter_out is write-only by the protocol callbacks\n2441:\t /\n2442:\tint sockptr_to_sockopt(sockopt_t opt, sockptr_t optval,\n2443:\t\t\t sockptr_t optlen, struct kvec kvec)\n2444:\t{\n2445:\t\tint koptlen;\n2446:\t\n2447:\t\tif (copy_from_sockptr(\u0026koptlen, optlen, sizeof(int)))\n2448:\t\t\treturn -EFAULT;\n2449:\t\n2450:\t\tif (koptlen \u003c 0)\n2451:\t\t\treturn -EINVAL;\n2452:\t\n2453:\t\tif (optval.is_kernel) {\n2454:\t\t\tkvec-\u003eiov_base = optval.kernel;\n2455:\t\t\tkvec-\u003eiov_len = koptlen;\n2456:\t\t\tiov_iter_kvec(\u0026opt-\u003eiter_out, ITER_DEST, kvec, 1, koptlen);\n2457:\t\t\tiov_iter_kvec(\u0026opt-\u003eiter_in, ITER_SOURCE, kvec, 1, koptlen);\n2458:\t\t} else {\n2459:\t\t\tiov_iter_ubuf(\u0026opt-\u003eiter_out, ITER_DEST, optval.user, koptlen);\n2460:\t\t\tiov_iter_ubuf(\u0026opt-\u003eiter_in, ITER_SOURCE, optval.user,\n2461:\t\t\t\t koptlen);\n2462:\t\t}\n2463:\t\topt-\u003eoptlen = koptlen;\n2464:\t\n2465:\t\treturn 0;\n2466:\t}\n2467:\t\n2468:\tint do_sock_getsockopt(struct socket sock, bool compat, int level,\n2469:\t\t\t int optname, sockptr_t optval, sockptr_t optlen)\n2470:\t{\n2471:\t\tint max_optlen __maybe_unused = 0;\n2472:\t\tconst struct proto_ops *ops;\n2473:\t\tstruct kvec kvec;\n2474:\t\tsockopt_t opt;\n2475:\t\tint err;\n2476:\t\n2477:\t\terr = security_socket_getsockopt(sock, level, optname);\n2478:\t\tif (err)\n2479:\t\t\treturn err;\n" }
45/3	2026/10/15 13:02	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 30667 output: 36 thoughts: 329 Thoughts: Examining the Socket Option Handling Okay, I'm looking at this patch and immediately my eye is drawn to `net/core/filter.c`, specifically how it's handling socket options. I see these two snippets, one for IP and the other for IPv6. They both seem to follow a similar pattern: they check if it's a `getopt` operation, and then use `sockptr_to_sockopt` to convert the user-provided pointers (`optval` and `optlen`) into a `sockopt_t` structure. Then, they call `do_ip_getsockopt` or `do_ipv6_getsockopt` respectively, to perform the actual get option operation. Finally, they update `*optlen` and return. But wait a minute, I need to remind myself how this is getting done. I'm slightly fuzzy on the role of `optval` and `optlen` here, so I need to understand them. Let me take a look at the surrounding code to refresh my memory on where these are defined. Okay, let's jump back up to around line 5737 in `net/core/filter.c`! I should be able to get a better handle on the context of those variables.
46/3	2026/10/15 13:02	tool	read-file	0m Args: { "File": "net/core/filter.c", "FirstLine": 5730, "LineCount": 50 } Results: { "Contents": "5730:\t\tswitch (optname) {\n5731:\t\tcase IP_TOS:\n5732:\t\tcase IP_TRANSPARENT:\n5733:\t\t\tif (optlen != sizeof(int))\n5734:\t\t\t\treturn -EINVAL;\n5735:\t\t\tbreak;\n5736:\t\tdefault:\n5737:\t\t\treturn -EINVAL;\n5738:\t\t}\n5739:\t\n5740:\t\tif (getopt) {\n5741:\t\t\tstruct kvec kvec;\n5742:\t\t\tsockopt_t opt;\n5743:\t\t\tint err;\n5744:\t\n5745:\t\t\terr = sockptr_to_sockopt(\u0026opt, KERNEL_SOCKPTR(optval),\n5746:\t\t\t\t\t\t KERNEL_SOCKPTR(optlen), \u0026kvec);\n5747:\t\t\tif (err)\n5748:\t\t\t\treturn err;\n5749:\t\n5750:\t\t\terr = do_ip_getsockopt(sk, SOL_IP, optname, \u0026opt);\n5751:\t\t\toptlen = opt.optlen;\n5752:\t\t\treturn err;\n5753:\t\t}\n5754:\t\n5755:\t\treturn do_ip_setsockopt(sk, SOL_IP, optname,\n5756:\t\t\t\t\tKERNEL_SOCKPTR(optval), optlen);\n5757:\t}\n5758:\t\n5759:\tstatic int sol_ipv6_sockopt(struct sock sk, int optname,\n5760:\t\t\t\t char optval, int optlen,\n5761:\t\t\t\t bool getopt)\n5762:\t{\n5763:\t\tif (sk-\u003esk_family != AF_INET6)\n5764:\t\t\treturn -EINVAL;\n5765:\t\n5766:\t\tswitch (optname) {\n5767:\t\tcase IPV6_TCLASS:\n5768:\t\tcase IPV6_AUTOFLOWLABEL:\n5769:\t\tcase IPV6_TRANSPARENT:\n5770:\t\t\tif (*optlen != sizeof(int))\n5771:\t\t\t\treturn -EINVAL;\n5772:\t\t\tbreak;\n5773:\t\tdefault:\n5774:\t\t\treturn -EINVAL;\n5775:\t\t}\n5776:\t\n5777:\t\tif (getopt) {\n5778:\t\t\tstruct kvec kvec;\n5779:\t\t\tsockopt_t opt;\n" }
47/3	2026/10/15 13:02	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 31969 output: 27 thoughts: 106 Thoughts: Analyzing the Transition to `sockopt_t` Okay, so we're looking at a change where `do_ip_getsockopt` and `do_ipv6_getsockopt` are moving away from `sockptr_t optval, sockptr_t optlen` and adopting `sockopt_t` instead. My initial instinct is to dig into the git history and surrounding context to get a handle on the bigger picture. I need to understand the why behind this conversion. Is this part of a larger subsystem overhaul? What other changes are happening concurrently? My next step is to understand this new `sockopt_t`. What's the rationale behind its introduction? What advantages does it offer over the previous approach? I'll need to search the git log, any relevant documentation, and any other project references to get a better understanding of how `sockopt_t` is intended to be used and the problems it's designed to solve. The aim here is to understand the scope and implications of this change.
48/3	2026/10/15 13:02	tool	grepper	0m Args: { "Expression": "sockopt_t", "PathPrefixes": [ "net/" ] } Results: { "Output": "\nFull output is too long, showing 200 out of 354 lines.\nUse more precise expression or PathPrefixes if possible.\n\nNumber of matching lines per file (39 files in total):\nnet/atm/common.c:1\nnet/atm/common.h:1\nnet/atm/pvc.c:1\nnet/bluetooth/hci_sock.c:2\nnet/bluetooth/iso.c:1\nnet/bluetooth/l2cap_sock.c:2\nnet/bluetooth/rfcomm/sock.c:2\nnet/bluetooth/sco.c:2\nnet/can/raw.c:1\nnet/core/filter.c:2\nnet/ieee802154/socket.c:2\nnet/ipv4/igmp.c:2\nnet/ipv4/ip_sockglue.c:4\nnet/ipv4/ipmr.c:1\nnet/ipv4/raw.c:3\nnet/ipv4/udp.c:4\nnet/ipv6/ip6mr.c:1\nnet/ipv6/ipv6_sockglue.c:5\nnet/ipv6/mcast.c:1\nnet/ipv6/raw.c:2\nnet/ipv6/udp.c:1\nnet/iucv/af_iucv.c:1\nnet/kcm/kcmsock.c:1\nnet/l2tp/l2tp_ppp.c:1\nnet/mctp/af_mctp.c:1\nnet/mptcp/sockopt.c:2\nnet/netlink/af_netlink.c:1\nnet/packet/af_packet.c:1\nnet/phonet/pep.c:2\nnet/rds/af_rds.c:1\nnet/rds/info.c:1\nnet/rds/info.h:1\nnet/rxrpc/af_rxrpc.c:1\nnet/socket.c:3\nnet/tipc/socket.c:1\nnet/tls/tls_main.c:12\nnet/vmw_vsock/af_vsock.c:1\nnet/x25/af_x25.c:1\nnet/xdp/xsk.c:1\n\nnet/atm/common.c=756=int vcc_getsockopt(struct socket sock, int level, int optname,\nnet/atm/common.c:757:\t\t sockopt_t opt)\nnet/atm/common.c-758-{\n--\nnet/atm/common.h=25=int vcc_getsockopt(struct socket sock, int level, int optname,\nnet/atm/common.h:26:\t\t sockopt_t opt);\nnet/atm/common.h-27-void vcc_process_recv_queue(struct atm_vcc vcc);\n--\nnet/atm/pvc.c=77=static int pvc_getsockopt(struct socket sock, int level, int optname,\nnet/atm/pvc.c:78:\t\t\t sockopt_t opt)\nnet/atm/pvc.c-79-{\n--\nnet/bluetooth/hci_sock.c=2085=static int hci_sock_getsockopt_old(struct socket sock, int level, int optname,\nnet/bluetooth/hci_sock.c:2086:\t\t\t\t sockopt_t sopt)\nnet/bluetooth/hci_sock.c-2087-{\n--\nnet/bluetooth/hci_sock.c=2152=static int hci_sock_getsockopt(struct socket sock, int level, int optname,\nnet/bluetooth/hci_sock.c:2153:\t\t\t sockopt_t sopt)\nnet/bluetooth/hci_sock.c-2154-{\n--\nnet/bluetooth/iso.c=2047=static int iso_sock_getsockopt(struct socket sock, int level, int optname,\nnet/bluetooth/iso.c:2048:\t\t\t sockopt_t opt)\nnet/bluetooth/iso.c-2049-{\n--\nnet/bluetooth/l2cap_sock.c=455=static int l2cap_sock_getsockopt_old(struct socket sock, int optname,\nnet/bluetooth/l2cap_sock.c:456:\t\t\t\t sockopt_t sopt)\nnet/bluetooth/l2cap_sock.c-457-{\n--\nnet/bluetooth/l2cap_sock.c=585=static int l2cap_sock_getsockopt(struct socket sock, int level, int optname,\nnet/bluetooth/l2cap_sock.c:586:\t\t\t\t sockopt_t sopt)\nnet/bluetooth/l2cap_sock.c-587-{\n--\nnet/bluetooth/rfcomm/sock.c=740=static int rfcomm_sock_getsockopt_old(struct socket sock, int optname,\nnet/bluetooth/rfcomm/sock.c:741:\t\t\t\t sockopt_t sopt)\nnet/bluetooth/rfcomm/sock.c-742-{\n--\nnet/bluetooth/rfcomm/sock.c=819=static int rfcomm_sock_getsockopt(struct socket sock, int level, int optname,\nnet/bluetooth/rfcomm/sock.c:820:\t\t\t\t sockopt_t sopt)\nnet/bluetooth/rfcomm/sock.c-821-{\n--\nnet/bluetooth/sco.c=1145=static int sco_sock_getsockopt_old(struct socket sock, int optname,\nnet/bluetooth/sco.c:1146:\t\t\t\t sockopt_t opt)\nnet/bluetooth/sco.c-1147-{\n--\nnet/bluetooth/sco.c=1206=static int sco_sock_getsockopt(struct socket sock, int level, int optname,\nnet/bluetooth/sco.c:1207:\t\t\t sockopt_t opt)\nnet/bluetooth/sco.c-1208-{\n--\nnet/can/raw.c=770=static int raw_getsockopt(struct socket sock, int level, int optname,\nnet/can/raw.c:771:\t\t\t sockopt_t opt)\nnet/can/raw.c-772-{\n--\nnet/core/filter.c=5723=static int sol_ip_sockopt(struct sock sk, int optname,\n--\nnet/core/filter.c-5741-\t\tstruct kvec kvec;\nnet/core/filter.c:5742:\t\tsockopt_t opt;\nnet/core/filter.c-5743-\t\tint err;\n--\nnet/core/filter.c=5759=static int sol_ipv6_sockopt(struct sock sk, int optname,\n--\nnet/core/filter.c-5778-\t\tstruct kvec kvec;\nnet/core/filter.c:5779:\t\tsockopt_t opt;\nnet/core/filter.c-5780-\t\tint err;\n--\nnet/ieee802154/socket.c=794=static int ieee802154_dgram_deliver(struct net_device dev, struct sk_buff skb)\n--\nnet/ieee802154/socket.c-834-\nnet/ieee802154/socket.c:835:static int do_dgram_getsockopt(struct sock sk, int optname, sockopt_t opt)\nnet/ieee802154/socket.c-836-{\n--\nnet/ieee802154/socket.c=873=static int dgram_getsockopt(struct sock sk, int level, int optname,\n--\nnet/ieee802154/socket.c-875-{\nnet/ieee802154/socket.c:876:\tsockopt_t opt;\nnet/ieee802154/socket.c-877-\tint err;\n--\nnet/ipv4/igmp.c=2622=int ip_mc_msfilter(struct sock sk, struct ip_msfilter msf, int ifindex)\n--\nnet/ipv4/igmp.c-2712-\nnet/ipv4/igmp.c:2713:int ip_mc_msfget(struct sock sk, struct ip_msfilter msf, sockopt_t opt)\nnet/ipv4/igmp.c-2714-{\n--\nnet/ipv4/igmp.c=2778=int ip_mc_gsfget(struct sock sk, struct group_filter gsf,\nnet/ipv4/igmp.c:2779:\t\t sockopt_t opt, size_t ss_offset)\nnet/ipv4/igmp.c-2780-{\n--\nnet/ipv4/ip_sockglue.c=1435=static bool getsockopt_needs_rtnl(int optname)\n--\nnet/ipv4/ip_sockglue.c-1444-\nnet/ipv4/ip_sockglue.c:1445:static int ip_get_mcast_msfilter(struct sock sk, sockopt_t opt)\nnet/ipv4/ip_sockglue.c-1446-{\n--\nnet/ipv4/ip_sockglue.c-1473-\nnet/ipv4/ip_sockglue.c:1474:static int compat_ip_get_mcast_msfilter(struct sock sk, sockopt_t opt)\nnet/ipv4/ip_sockglue.c-1475-{\n--\nnet/ipv4/ip_sockglue.c-1511-\nnet/ipv4/ip_sockglue.c:1512:int do_ip_getsockopt(struct sock sk, int level, int optname, sockopt_t sopt)\nnet/ipv4/ip_sockglue.c-1513-{\n--\nnet/ipv4/ip_sockglue.c=1759=int ip_getsockopt(struct sock sk, int level,\n--\nnet/ipv4/ip_sockglue.c-1761-{\nnet/ipv4/ip_sockglue.c:1762:\tsockopt_t opt;\nnet/ipv4/ip_sockglue.c-1763-\tint err;\n--\nnet/ipv4/ipmr.c=1619=int ipmr_sk_ioctl(struct sock sk, unsigned int cmd, void __user arg)\n--\nnet/ipv4/ipmr.c-1640-/ Getsock opt support for the multicast routing system. /\nnet/ipv4/ipmr.c:1641:int ip_mroute_getsockopt(struct sock sk, int optname, sockopt_t opt)\nnet/ipv4/ipmr.c-1642-{\n--\nnet/ipv4/raw.c=812=static int raw_seticmpfilter(struct sock sk, sockptr_t optval, int optlen)\n--\nnet/ipv4/raw.c-820-\nnet/ipv4/raw.c:821:static int raw_geticmpfilter(struct sock sk, sockopt_t opt)\nnet/ipv4/raw.c-822-{\n--\nnet/ipv4/raw.c=847=static int raw_setsockopt(struct sock sk, int level, int optname,\n--\nnet/ipv4/raw.c-854-\nnet/ipv4/raw.c:855:static int do_raw_getsockopt(struct sock sk, int optname, sockopt_t opt)\nnet/ipv4/raw.c-856-{\n--\nnet/ipv4/raw.c=866=static int raw_getsockopt(struct sock sk, int level, int optname,\n--\nnet/ipv4/raw.c-868-{\nnet/ipv4/raw.c:869:\tsockopt_t opt;\nnet/ipv4/raw.c-870-\tint err;\n--\nnet/ipv4/udp.c=3044=int udp_lib_getsockopt(struct sock sk, int level, int optname,\nnet/ipv4/udp.c:3045:\t\t sockopt_t opt)\nnet/ipv4/udp.c-3046-{\n--\nnet/ipv4/udp.c-3050-\tlen = opt-\u003eoptlen;\nnet/ipv4/udp.c:3051:\t/* keep the check so direct sockopt_t callers stay covered. /\nnet/ipv4/udp.c-3052-\tif (len \u003c 0)\n--\nnet/ipv4/udp.c=3092=static int udp_getsockopt(struct sock sk, int level, int optname,\n--\nnet/ipv4/udp.c-3094-{\nnet/ipv4/udp.c:3095:\tsockopt_t opt;\nnet/ipv4/udp.c-3096-\tint err;\n--\nnet/ipv4/udp.c-3099-\t * keep the old __user pointers, until ip_getsockopt() moves\nnet/ipv4/udp.c:3100:\t * to sockopt_t\nnet/ipv4/udp.c-3101-\t /\n--\nnet/ipv6/ip6mr.c=1713=int ip6_mroute_setsockopt(struct sock sk, int optname, sockptr_t optval,\n--\nnet/ipv6/ip6mr.c-1895-\nnet/ipv6/ip6mr.c:1896:int ip6_mroute_getsockopt(struct sock sk, int optname, sockopt_t sopt)\nnet/ipv6/ip6mr.c-1897-{\n--\nnet/ipv6/ipv6_sockglue.c=891=static int ipv6_getsockopt_sticky(struct sock sk, struct ipv6_txoptions opt,\nnet/ipv6/ipv6_sockglue.c:892:\t\t\t\t int optname, sockopt_t sopt, int len)\nnet/ipv6/ipv6_sockglue.c-893-{\n--\nnet/ipv6/ipv6_sockglue.c-924-\nnet/ipv6/ipv6_sockglue.c:925:static int ipv6_get_msfilter(struct sock sk, sockopt_t opt)\nnet/ipv6/ipv6_sockglue.c-926-{\n--\nnet/ipv6/ipv6_sockglue.c-958-\nnet/ipv6/ipv6_sockglue.c:959:static int compat_ipv6_get_msfilter(struct sock sk, sockopt_t opt)\nnet/ipv6/ipv6_sockglue.c-960-{\n--\nnet/ipv6/ipv6_sockglue.c-1000-\nnet/ipv6/ipv6_sockglue.c:1001:int do_ipv6_getsockopt(struct sock sk, int level, int optname, sockopt_t sopt)\nnet/ipv6/ipv6_sockglue.c-1002-{\n--\nnet/ipv6/ipv6_sockglue.c=1355=int ipv6_getsockopt(struct sock sk, int level, int optname,\n--\nnet/ipv6/ipv6_sockglue.c-1357-{\nnet/ipv6/ipv6_sockglue.c:1358:\tsockopt_t sopt;\nnet/ipv6/ipv6_sockglue.c-1359-\tint len, err;\n--\nnet/ipv6/mcast.c=602=int ip6_mc_msfget(struct sock sk, struct group_filter gsf,\nnet/ipv6/mcast.c:603:\t\t sockopt_t opt, size_t ss_offset)\nnet/ipv6/mcast.c-604-{\n--\nnet/ipv6/raw.c=1031=static int rawv6_setsockopt(struct sock sk, int level, int optname,\n--\nnet/ipv6/raw.c-1053-\nnet/ipv6/raw.c:1054:static int do_rawv6_getsockopt(struct sock sk, int optname, sockopt_t opt)\nnet/ipv6/raw.c-1055-{\n--\nnet/ipv6/raw.c=1089=static int rawv6_getsockopt(struct sock sk, int level, int optname,\n--\nnet/ipv6/raw.c-1091-{\nnet/ipv6/raw.c:1092:\tsockopt_t opt;\nnet/ipv6/raw.c-1093-\tint err;\n--\nnet/ipv6/udp.c=1836=static int udpv6_getsockopt(struct sock sk, int level, int optname,\n--\nnet/ipv6/udp.c-1838-{\nnet/ipv6/udp.c:1839:\tsockopt_t opt;\nnet/ipv6/udp.c-1840-\tint err;\n--\nnet/iucv/af_iucv.c=1568=static int iucv_sock_getsockopt(struct socket sock, int level, int optname,\nnet/iucv/af_iucv.c:1569:\t\t\t\tsockopt_t opt)\n\n" }
49/3	2026/10/15 13:02	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 36739 output: 34 thoughts: 3549 Thoughts: Thorough Analysis of `getsockopt` Conversion to `sockopt_t` Alright, let's dissect this refactoring meticulously, focusing on potential uninitialized memory issues and leaks. The goal here is to ensure that the conversion from raw user pointers to `sockopt_t` with `iov_iter` maintains data integrity and doesn't introduce any new vulnerabilities. I've already examined similar changes in `udp_getsockopt`, `raw_getsockopt`, etc., so now it's time to tackle `do_ip_getsockopt` and `do_ipv6_getsockopt`, along with related multicast helpers. First, I examined `include/linux/net.h` to see how `sockopt_t` is initialized, specifically how user-provided buffers are handled through `sockopt_set_user` and `sockopt_init_user`. These functions use `iov_iter_ubuf` for user buffers and I confirmed that `sockopt_expand_out` would not expand beyond allowable buffer size. Next, I looked at the implementation within `net/core/filter.c` for `sol_ip_sockopt` and `sol_ipv6_sockopt`. In `sol_ip_sockopt`, `sockptr_to_sockopt` is used to convert the raw user pointers to `sockopt_t` and `kvec` is initialized. The size of the `kvec` is initialized with data retrieved earlier, and then is passed as arguments to `iov_iter_kvec`. Then `do_ip_getsockopt` is called with the initialized `sockopt_t`. I verified that the length of the buffers passed into the kernel is initialized, and that no uninitialized memory could be leaked. Then I examined `net/ipv4/igmp.c` for `ip_mc_msfget`. Here the original `opt->optlen` setting was moved after the `copy_to_iter`. However, initialization looks unchanged. Then, I looked at `net/ipv4/ip_sockglue.c` to examine `ip_mc_gsfget`. It initializes `struct sockaddr_storage ss` and uses `memset` to zero it out, before filling the structure and copying data via `copy_to_iter`. This means any data copied to the user is initialized. I also checked `net/ipv6/mcast.c` to see if there are similar calls with `memset` for `ip6_mc_msfget`. The same initialization pattern is followed. Finally, I analyzed the flow in `ip_get_mcast_msfilter`. This function reads a `struct group_filter` from the user-provided buffer, and then uses a helper function. In particular, I followed the logic of `iov_iter_revert` and `copy_to_iter`. This function calculates the required buffer size and then rewinds the output iterator to the beginning to write the fixed portion of the struct back to the user-space buffer. This looked like a point that would be prone to uninitialized reads or memory corruption. The critical point is the `copy_from_iter` that reads user data into `gsf`. I verified that all `size0` bytes of the struct are initialized and that subsequent writes to the user buffer only contain properly initialized data. I'm confident that the code is free of uninitialized memory reads or leaks.
50/3	2026/10/15 13:03	tool	grepper	0m Args: { "Expression": "out:", "PathPrefixes": [ "net/ipv4/ip_sockglue.c" ] } Results: { "Output": "net/ipv4/ip_sockglue.c=523=int ip_recv_error(struct sock sk, struct msghdr msg, int len)\n--\nnet/ipv4/ip_sockglue.c-581-\tconsume_skb(skb);\nnet/ipv4/ip_sockglue.c:582:out:\nnet/ipv4/ip_sockglue.c-583-\treturn err;\n--\nnet/ipv4/ip_sockglue.c=1512=int do_ip_getsockopt(struct sock sk, int level, int optname, sockopt_t sopt)\n--\nnet/ipv4/ip_sockglue.c-1751-\nnet/ipv4/ip_sockglue.c:1752:out:\nnet/ipv4/ip_sockglue.c-1753-\tsockopt_release_sock(sk);\n" }
51/3	2026/10/15 13:03	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 41292 output: 40 thoughts: 25 Thoughts: Okay, here's my attempt at summarizing the thought process, as if it were my own, targeted to an expert audience and starting with a bolded header: Diving into `net/ipv4/ip_sockglue.c` Around Line 1750 Alright, let's zero in on line 1750 within `net/ipv4/ip_sockglue.c`. My immediate thought is, "What's the context here? What's the surrounding code doing?" I'm expecting to find some crucial glue code. Given the filename, this is likely where IPv4 socket-related functionality interfaces with the broader networking stack. I'm mentally filing this as a point where socket operations probably touch upon IP-level details. I'll be looking for key function calls, data structures, and conditional logic. Is it socket creation? Connection establishment? Data transmission or reception path? Likely one of these, or some combination thereof. I anticipate functions like `inet_get_local_port` or interactions with `sock` and `inet_sock` structures, but it could equally be packet processing flow and so may be relevant to the implementation of the TCP or UDP protocol. I need to quickly grasp the surrounding code's purpose to understand the role of this specific line. Are there any preceding comments? Any interesting variable initializations? Any error handling? I need to build a mental map of what's happening at this point in the control flow. My gut feeling is that this could be a spot where IP address and port bindings are checked, or perhaps where raw sockets are initialized. Or maybe it's packet routing decisions based on IP headers. The specific operation is dependent on the code around line 1750, so I will analyze this carefully. Time to dig in!
52/3	2026/10/15 13:03	tool	read-file	0m Args: { "File": "net/ipv4/ip_sockglue.c", "FirstLine": 1745, "LineCount": 40 } Results: { "Contents": "1745:\t\t\tlen = min_t(unsigned int, sizeof(int), len);\n1746:\t\t\tsopt-\u003eoptlen = len;\n1747:\t\t\tif (copy_to_iter(\u0026val, len, \u0026sopt-\u003eiter_out) != len)\n1748:\t\t\t\treturn -EFAULT;\n1749:\t\t}\n1750:\t\treturn 0;\n1751:\t\n1752:\tout:\n1753:\t\tsockopt_release_sock(sk);\n1754:\t\tif (needs_rtnl)\n1755:\t\t\trtnl_unlock();\n1756:\t\treturn err;\n1757:\t}\n1758:\t\n1759:\tint ip_getsockopt(struct sock sk, int level,\n1760:\t\t\t int optname, char __user optval, int __user optlen)\n1761:\t{\n1762:\t\tsockopt_t opt;\n1763:\t\tint err;\n1764:\t\n1765:\t\terr = sockopt_init_user(\u0026opt, optval, optlen);\n1766:\t\tif (err)\n1767:\t\t\treturn err;\n1768:\t\n1769:\t\terr = do_ip_getsockopt(sk, level, optname, \u0026opt);\n1770:\t\tif (put_user(opt.optlen, optlen))\n1771:\t\t\treturn -EFAULT;\n1772:\t\n1773:\t#ifdef CONFIG_NETFILTER\n1774:\t\t/ we need to exclude all possible ENOPROTOOPTs except default case */\n1775:\t\tif (err == -ENOPROTOOPT \u0026\u0026 optname != IP_PKTOPTIONS \u0026\u0026\n1776:\t\t\t\t!ip_mroute_opt(optname)) {\n1777:\t\t\tint len = opt.optlen;\n1778:\t\n1779:\t\t\terr = nf_getsockopt(sk, PF_INET, optname, optval, \u0026len);\n1780:\t\t\tif (err \u003e= 0)\n1781:\t\t\t\terr = put_user(len, optlen);\n1782:\t\t\treturn err;\n1783:\t\t}\n1784:\t#endif\n" }
53/3	2026/10/15 13:03	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 42329 output: 33 thoughts: 298 Thoughts: Analyzing the Getsockopt System Call Okay, let's break this down. I'm focusing on the `ip_getsockopt` function and the surrounding calls. The initial observation is the direct use of `put_user` with `opt.optlen`, implying a direct write to userspace memory. But the key is how data is actually populated for that `opt.optlen`. I'm seeing `copy_to_iter` being used to handle the actual byte-level transfer. Now, jumping into `ip_get_mcast_msfilter`, things get more interesting. We're advancing with `ip_mc_gsfget`, then writing, importantly, multiple `struct sockaddr_storage` elements, each zeroed and initialized. The `iov_iter_revert` call is critical here, rewinding the iterator, effectively repositioning it. The following `copy_to_iter` writes data that was previously read and potentially modified from userspace via `copy_from_iter`. I need to emphasize, at this point, that the value of `opt.optlen`, which ends up being what's written to userspace by `put_user`, appears to be set to `gsf_size`. The crucial question is, does anything else write to `opt->iter_out` after the revert? The answer is no. So it really does look like it's just this `gsf_size` value and nothing else! Okay, let's step back and consider the bigger picture. When a `getsockopt` call comes from userspace, how does it all link up? What if the underlying socket operation (`ops->getsockopt`) does its own thing? I'm going to track how `do_sock_getsockopt` handles all this user-space interaction. I need to understand how the data makes it from userland, via `copy_from_iter`, get used, and then eventually makes it back to userland via the mechanisms described above. I need to review `do_sock_getsockopt` to be sure I am not missing any subtle interactions!
54/3	2026/10/15 13:03	tool	grepper	0m Args: { "Expression": "do_sock_getsockopt", "PathPrefixes": [ "net/socket.c" ] } Results: { "Output": "net/socket.c=2442=int sockptr_to_sockopt(sockopt_t opt, sockptr_t optval,\n--\nnet/socket.c-2467-\nnet/socket.c:2468:int do_sock_getsockopt(struct socket sock, bool compat, int level,\nnet/socket.c-2469-\t\t int optname, sockptr_t optval, sockptr_t optlen)\n--\nnet/socket.c-2517-}\nnet/socket.c:2518:EXPORT_SYMBOL(do_sock_getsockopt);\nnet/socket.c-2519-\n--\nnet/socket.c=2524=int __sys_getsockopt(int fd, int level, int optname, char __user *optval,\n--\nnet/socket.c-2535-\nnet/socket.c:2536:\treturn do_sock_getsockopt(sock, in_compat_syscall(), level, optname,\nnet/socket.c-2537-\t\t\t\t USER_SOCKPTR(optval), USER_SOCKPTR(optlen));\n" }
55/3	2026/10/15 13:03	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 43406 output: 34 thoughts: 37 Thoughts: Okay, let's dive into this. Here's my take on understanding this code snippet: Diving into `do_sock_getsockopt` Implementation Alright, I need to get a clear picture of how `do_sock_getsockopt` functions. I'll focus on lines 2468 through 2520 in `net/socket.c`. I expect to see the meat and potatoes of the function's logic there. I'm especially interested in how it handles the different socket options and the data retrieval process for each. I'll be looking for things like: * How it validates the input parameters, `sock`, `level`, `optname`, and `optval`. This is crucial for preventing security vulnerabilities and ensuring correct behavior. * The overall control flow: what checks are performed early on to determine the appropriate path for the specific `optname` requested. Are there any early exits or error conditions I should watch out for? * The data retrieval logic for the different socket options it supports. Are there helper functions called to handle specific options, or is it all handled inline? How is the retrieved data formatted and copied into `optval`? Is there any memory management I should be aware of? * How the function handles errors. Is there a clear error handling strategy? Are specific `errno` values used to signal different error conditions? * The overall structure of the code. Is it well-organized and readable, or is it a bit of a mess? Are there any obvious areas for potential optimization or improvement? By focusing on these points, I should get a solid grasp of how `do_sock_getsockopt` works and its role in the kernel's socket implementation. It's time to dig in and see what's actually happening in that code.
56/3	2026/10/15 13:03	tool	read-file	0m Args: { "File": "net/socket.c", "FirstLine": 2468, "LineCount": 55 } Results: { "Contents": "2468:\tint do_sock_getsockopt(struct socket sock, bool compat, int level,\n2469:\t\t\t int optname, sockptr_t optval, sockptr_t optlen)\n2470:\t{\n2471:\t\tint max_optlen __maybe_unused = 0;\n2472:\t\tconst struct proto_ops ops;\n2473:\t\tstruct kvec kvec;\n2474:\t\tsockopt_t opt;\n2475:\t\tint err;\n2476:\t\n2477:\t\terr = security_socket_getsockopt(sock, level, optname);\n2478:\t\tif (err)\n2479:\t\t\treturn err;\n2480:\t\n2481:\t\tif (!compat)\n2482:\t\t\tcopy_from_sockptr(\u0026max_optlen, optlen, sizeof(int));\n2483:\t\n2484:\t\tops = READ_ONCE(sock-\u003eops);\n2485:\t\tif (level == SOL_SOCKET) {\n2486:\t\t\terr = sk_getsockopt(sock-\u003esk, level, optname, optval, optlen);\n2487:\t\t} else if (ops-\u003egetsockopt_iter) {\n2488:\t\t\terr = sockptr_to_sockopt(\u0026opt, optval, optlen, \u0026kvec);\n2489:\t\t\tif (err)\n2490:\t\t\t\treturn err;\n2491:\t\n2492:\t\t\terr = ops-\u003egetsockopt_iter(sock, level, optname, \u0026opt);\n2493:\t\n2494:\t\t\t/* Always write back optlen, even on failure. Some protocols\n2495:\t\t\t * (e.g. CAN raw) return -ERANGE and set optlen to the\n2496:\t\t\t * required buffer size so userspace can discover it.\n2497:\t\t\t /\n2498:\t\t\tif (copy_to_sockptr(optlen, \u0026opt.optlen, sizeof(int)))\n2499:\t\t\t\treturn -EFAULT;\n2500:\t\t} else if (ops-\u003egetsockopt) {\n2501:\t\t\tif (WARN_ONCE(optval.is_kernel \|\| optlen.is_kernel,\n2502:\t\t\t\t \"Invalid argument type\"))\n2503:\t\t\t\treturn -EOPNOTSUPP;\n2504:\t\n2505:\t\t\terr = ops-\u003egetsockopt(sock, level, optname, optval.user,\n2506:\t\t\t\t\t optlen.user);\n2507:\t\t} else {\n2508:\t\t\terr = -EOPNOTSUPP;\n2509:\t\t}\n2510:\t\n2511:\t\tif (!compat)\n2512:\t\t\terr = BPF_CGROUP_RUN_PROG_GETSOCKOPT(sock-\u003esk, level, optname,\n2513:\t\t\t\t\t\t\t optval, optlen, max_optlen,\n2514:\t\t\t\t\t\t\t err);\n2515:\t\n2516:\t\treturn err;\n2517:\t}\n2518:\tEXPORT_SYMBOL(do_sock_getsockopt);\n2519:\t\n2520:\t/\n2521:\t \tGet a socket option. Because we don't know the option lengths we have\n2522:\t \tto pass a user mode parameter for the protocols to sort out.\n" }
57/3	2026/10/15 13:03	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 44744 output: 20 thoughts: 75 Thoughts: Here's my summary, as I understand it: Verifying the Sockopt Flow for IPv4/IPv6 Okay, so I'm digging into how `getsockopt` is implemented, specifically for IPv4 and IPv6. I know that even with the evolution of the networking stack, the `ops->getsockopt` function pointer in the `socket` structure is still being used for these protocols. The reason is that `ops->getsockopt` ultimately dispatches to either `inet_getsockopt` or `inet6_getsockopt`, depending on the address family, and those in turn call down to the core IP-specific implementations, `ip_getsockopt` and `ipv6_getsockopt` respectively. The current architecture allows for this dispatch and the maintenance of the existing code flow. My primary concern right now is verifying the behavior of `inet_getsockopt`. I need to ensure it's behaving as expected and correctly routing the control flow to either `ip_getsockopt` or `ipv6_getsockopt` based on the socket type. I want to confirm the logic there is sound. I want to understand how it handles the different socket options and the data associated with them.
58/3	2026/10/15 13:04	tool	grepper	0m Error: no matches Args: { "Expression": "int inet_getsockopt" } Results: { "error": "no matches" }
59/3	2026/10/15 13:04	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 45114 output: 20 thoughts: 15 Thoughts: Okay, here's my take on those thoughts, tailored for an expert audience: Hunting for the Network Datagram Operations Alright, let's get down to brass tacks. I'm thinking, where's the best place to start poking around in this networking code? Given the context, my initial hunch is to track down the `inet_dgram_ops` structure, or something very much like it. It's the standard entry point, the central dispatch table, that should handle the datagram-oriented operations in the internet domain. That struct should point to the functions that manage UDP, RAW, and any other datagram socket types we might encounter. Let's see if we can find where it's declared, initialized, and used. That should give me a solid foundation for understanding the datagram data flow, and figuring out what's going on behind the scenes. Finding it should rapidly help narrow down the system in question.
60/3	2026/10/15 13:04	tool	grepper	0m Args: { "Expression": "inet_dgram_ops" } Results: { "Output": "include/net/inet_common.h=11=extern const struct proto_ops inet_stream_ops;\ninclude/net/inet_common.h:12:extern const struct proto_ops inet_dgram_ops;\ninclude/net/inet_common.h-13-\n--\nnet/ipv4/af_inet.c=1092=EXPORT_SYMBOL(inet_stream_ops);\nnet/ipv4/af_inet.c-1093-\nnet/ipv4/af_inet.c:1094:const struct proto_ops inet_dgram_ops = {\nnet/ipv4/af_inet.c-1095-\t.family\t\t = PF_INET,\n--\nnet/ipv4/af_inet.c-1119-};\nnet/ipv4/af_inet.c:1120:EXPORT_SYMBOL(inet_dgram_ops);\nnet/ipv4/af_inet.c-1121-\nnet/ipv4/af_inet.c-1122-/\nnet/ipv4/af_inet.c:1123: For SOCK_RAW sockets; should be the same as inet_dgram_ops but without\nnet/ipv4/af_inet.c-1124- * udp_poll\n--\nnet/ipv4/af_inet.c=1160=static struct inet_protosw inetsw_array[] =\n--\nnet/ipv4/af_inet.c-1174-\t\t.prot = \u0026udp_prot,\nnet/ipv4/af_inet.c:1175:\t\t.ops = \u0026inet_dgram_ops,\nnet/ipv4/af_inet.c-1176-\t\t.flags = INET_PROTOSW_PERMANENT,\n--\nnet/packet/af_packet.c=4320=static int packet_ioctl(struct socket *sock, unsigned int cmd,\n--\nnet/packet/af_packet.c-4358-\tcase SIOCSIFFLAGS:\nnet/packet/af_packet.c:4359:\t\treturn inet_dgram_ops.ioctl(sock, cmd, arg);\nnet/packet/af_packet.c-4360-#endif\n" }
61/3	2026/10/15 13:04	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 45904 output: 39 thoughts: 45 Thoughts: Here's a summary of my thought process, as requested: Diving into `inet_dgram_ops`'s `getsockopt` Implementation Okay, so I'm trying to understand how `getsockopt` functions within the `inet_dgram_ops` structure. My instinct is to trace this back to the core implementation. Let's start with `net/ipv4/af_inet.c`. I'll need to locate the definition of `inet_dgram_ops`, and then within that, pinpoint how `.getsockopt` is defined. Specifically, I'm aiming for lines 1094 through 1115. Those lines should contain the relevant code. From there, I can analyze the logic and see what options are supported and how they're handled. This should give me a solid foundation for understanding the behavior of `getsockopt` in this context. Time to dig in.
62/3	2026/10/15 13:04	tool	read-file	0m Args: { "File": "net/ipv4/af_inet.c", "FirstLine": 1094, "LineCount": 25 } Results: { "Contents": "1094:\tconst struct proto_ops inet_dgram_ops = {\n1095:\t\t.family\t\t = PF_INET,\n1096:\t\t.owner\t\t = THIS_MODULE,\n1097:\t\t.release\t = inet_release,\n1098:\t\t.bind\t\t = inet_bind,\n1099:\t\t.connect\t = inet_dgram_connect,\n1100:\t\t.socketpair\t = sock_no_socketpair,\n1101:\t\t.accept\t\t = sock_no_accept,\n1102:\t\t.getname\t = inet_getname,\n1103:\t\t.poll\t\t = udp_poll,\n1104:\t\t.ioctl\t\t = inet_ioctl,\n1105:\t\t.gettstamp\t = sock_gettstamp,\n1106:\t\t.listen\t\t = sock_no_listen,\n1107:\t\t.shutdown\t = inet_shutdown,\n1108:\t\t.setsockopt\t = sock_common_setsockopt,\n1109:\t\t.getsockopt\t = sock_common_getsockopt,\n1110:\t\t.sendmsg\t = inet_sendmsg,\n1111:\t\t.read_skb\t = udp_read_skb,\n1112:\t\t.recvmsg\t = inet_recvmsg,\n1113:\t\t.mmap\t\t = sock_no_mmap,\n1114:\t\t.splice_eof\t = inet_splice_eof,\n1115:\t\t.set_peek_off\t = udp_set_peek_off,\n1116:\t#ifdef CONFIG_COMPAT\n1117:\t\t.compat_ioctl\t = inet_compat_ioctl,\n1118:\t#endif\n" }
63/3	2026/10/15 13:04	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 46653 output: 40 thoughts: 867 Thoughts: Analyzing `getsockopt` Implementation for UDP/RAW Sockets Okay, so I'm diving into the `getsockopt` implementation, specifically for UDP and RAW sockets. I'm following the call chain: `sock_common_getsockopt` goes down to `sk->sk_prot->getsockopt`. For IPv4, I need to see how `ip_getsockopt` is called. Let's start by looking at `net/ipv4/ip_sockglue.c`. I see `ip_getsockopt` has the signature `ip_getsockopt(struct sock sk, int level, int optname, char __user optval, int __user optlen)`. It initializes a `sockopt_t` struct, then calls `do_ip_getsockopt`. Importantly, the code handles `ENOPROTOOPT` with `nf_getsockopt`, but only* if the `optname` is not `IP_PKTOPTIONS` and it's not an mroute option. Got to keep that in mind. Now, let's look at the IPv6 counterpart, `ipv6_getsockopt`. The function `ipv6_getsockopt(sock sk, int level, int optname, char __user optval, int __user optlen)` includes a check: if the level is `SOL_IP` but the socket isn't RAW, then it calls the IPv4 implementation `ip_getsockopt`. If the level isn't `SOL_IPV6`, it returns `-ENOPROTOOPT`. I note that there is special treatment for a negative optlen, potentially handling legacy compatibility. Similar to the IPv4 case, it handles `ENOPROTOOPT` via `nf_getsockopt`, excluding the `IPV6_2292PKTOPTIONS` option. To really understand what's going on, I need to methodically check every single* option handled in both `do_ip_getsockopt` and `do_ipv6_getsockopt`. I'll go through `net/ipv4/ip_sockglue.c` to start. This is the core of how the socket options are actually retrieved.
64/3	2026/10/15 13:04	tool	read-file	0m Args: { "File": "net/ipv4/ip_sockglue.c", "FirstLine": 1515, "LineCount": 80 } Results: { "Contents": "1515:\t\tbool needs_rtnl = getsockopt_needs_rtnl(optname);\n1516:\t\tint val, err = 0;\n1517:\t\tint len;\n1518:\t\n1519:\t\tif (level != SOL_IP)\n1520:\t\t\treturn -EOPNOTSUPP;\n1521:\t\n1522:\t\tif (ip_mroute_opt(optname))\n1523:\t\t\treturn ip_mroute_getsockopt(sk, optname, sopt);\n1524:\t\n1525:\t\tlen = sopt-\u003eoptlen;\n1526:\t\tif (len \u003c 0)\n1527:\t\t\treturn -EINVAL;\n1528:\t\n1529:\t\t/* Handle options that can be read without locking the socket. */\n1530:\t\tswitch (optname) {\n1531:\t\tcase IP_PKTINFO:\n1532:\t\t\tval = inet_test_bit(PKTINFO, sk);\n1533:\t\t\tgoto copyval;\n1534:\t\tcase IP_RECVTTL:\n1535:\t\t\tval = inet_test_bit(TTL, sk);\n1536:\t\t\tgoto copyval;\n1537:\t\tcase IP_RECVTOS:\n1538:\t\t\tval = inet_test_bit(TOS, sk);\n1539:\t\t\tgoto copyval;\n1540:\t\tcase IP_RECVOPTS:\n1541:\t\t\tval = inet_test_bit(RECVOPTS, sk);\n1542:\t\t\tgoto copyval;\n1543:\t\tcase IP_RETOPTS:\n1544:\t\t\tval = inet_test_bit(RETOPTS, sk);\n1545:\t\t\tgoto copyval;\n1546:\t\tcase IP_PASSSEC:\n1547:\t\t\tval = inet_test_bit(PASSSEC, sk);\n1548:\t\t\tgoto copyval;\n1549:\t\tcase IP_RECVORIGDSTADDR:\n1550:\t\t\tval = inet_test_bit(ORIGDSTADDR, sk);\n1551:\t\t\tgoto copyval;\n1552:\t\tcase IP_CHECKSUM:\n1553:\t\t\tval = inet_test_bit(CHECKSUM, sk);\n1554:\t\t\tgoto copyval;\n1555:\t\tcase IP_RECVFRAGSIZE:\n1556:\t\t\tval = inet_test_bit(RECVFRAGSIZE, sk);\n1557:\t\t\tgoto copyval;\n1558:\t\tcase IP_RECVERR:\n1559:\t\t\tval = inet_test_bit(RECVERR, sk);\n1560:\t\t\tgoto copyval;\n1561:\t\tcase IP_RECVERR_RFC4884:\n1562:\t\t\tval = inet_test_bit(RECVERR_RFC4884, sk);\n1563:\t\t\tgoto copyval;\n1564:\t\tcase IP_FREEBIND:\n1565:\t\t\tval = inet_test_bit(FREEBIND, sk);\n1566:\t\t\tgoto copyval;\n1567:\t\tcase IP_HDRINCL:\n1568:\t\t\tval = inet_test_bit(HDRINCL, sk);\n1569:\t\t\tgoto copyval;\n1570:\t\tcase IP_MULTICAST_LOOP:\n1571:\t\t\tval = inet_test_bit(MC_LOOP, sk);\n1572:\t\t\tgoto copyval;\n1573:\t\tcase IP_MULTICAST_ALL:\n1574:\t\t\tval = inet_test_bit(MC_ALL, sk);\n1575:\t\t\tgoto copyval;\n1576:\t\tcase IP_TRANSPARENT:\n1577:\t\t\tval = inet_test_bit(TRANSPARENT, sk);\n1578:\t\t\tgoto copyval;\n1579:\t\tcase IP_NODEFRAG:\n1580:\t\t\tval = inet_test_bit(NODEFRAG, sk);\n1581:\t\t\tgoto copyval;\n1582:\t\tcase IP_BIND_ADDRESS_NO_PORT:\n1583:\t\t\tval = inet_test_bit(BIND_ADDRESS_NO_PORT, sk);\n1584:\t\t\tgoto copyval;\n1585:\t\tcase IP_ROUTER_ALERT:\n1586:\t\t\tval = inet_test_bit(RTALERT, sk);\n1587:\t\t\tgoto copyval;\n1588:\t\tcase IP_TTL:\n1589:\t\t\tval = READ_ONCE(inet-\u003euc_ttl);\n1590:\t\t\tif (val \u003c 0)\n1591:\t\t\t\tval = READ_ONCE(sock_net(sk)-\u003eipv4.sysctl_ip_default_ttl);\n1592:\t\t\tgoto copyval;\n1593:\t\tcase IP_MINTTL:\n1594:\t\t\tval = READ_ONCE(inet-\u003emin_ttl);\n" }
65/3	2026/10/15 13:04	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 49307 output: 40 thoughts: 33 Thoughts: Okay, here's my interpretation of what's going through my mind as I approach this section of `net/ipv4/ip_sockglue.c`: Diving into `ip_sockglue.c` for Context Alright, time to dig deeper. I'm going to scan down to lines 1595 through 1750 in `net/ipv4/ip_sockglue.c`. This usually means there's some interesting stuff happening – likely related to the interaction between the generic socket layer and the IPv4 implementation, which is always fun. Given the file's name, I'm expecting to see glue code, potentially bridging different layers or handling specific socket operations that require IPv4-specific logic. I'm hoping to get a clearer picture of how a particular function or set of functions behaves, and its implications to other interacting structures. I wonder if there might be something related to socket options, address binding, connection establishment, or perhaps even error handling within that range. It will be helpful to see the specific calls to this section of code so I can see what is using this section of code, and how. Time to get my hands dirty.
66/3	2026/10/15 13:04	tool	read-file	0m Args: { "File": "net/ipv4/ip_sockglue.c", "FirstLine": 1595, "LineCount": 80 } Results: { "Contents": "1595:\t\t\tgoto copyval;\n1596:\t\tcase IP_MULTICAST_TTL:\n1597:\t\t\tval = READ_ONCE(inet-\u003emc_ttl);\n1598:\t\t\tgoto copyval;\n1599:\t\tcase IP_MTU_DISCOVER:\n1600:\t\t\tval = READ_ONCE(inet-\u003epmtudisc);\n1601:\t\t\tgoto copyval;\n1602:\t\tcase IP_TOS:\n1603:\t\t\tval = READ_ONCE(inet-\u003etos);\n1604:\t\t\tgoto copyval;\n1605:\t\tcase IP_OPTIONS:\n1606:\t\t{\n1607:\t\t\tunsigned char optbuf[sizeof(struct ip_options)+40];\n1608:\t\t\tstruct ip_options opt = (struct ip_options )optbuf;\n1609:\t\t\tstruct ip_options_rcu inet_opt;\n1610:\t\n1611:\t\t\trcu_read_lock();\n1612:\t\t\tinet_opt = rcu_dereference(inet-\u003einet_opt);\n1613:\t\t\topt-\u003eoptlen = 0;\n1614:\t\t\tif (inet_opt)\n1615:\t\t\t\tmemcpy(optbuf, \u0026inet_opt-\u003eopt,\n1616:\t\t\t\t sizeof(struct ip_options) +\n1617:\t\t\t\t inet_opt-\u003eopt.optlen);\n1618:\t\t\trcu_read_unlock();\n1619:\t\n1620:\t\t\tif (opt-\u003eoptlen == 0) {\n1621:\t\t\t\tsopt-\u003eoptlen = 0;\n1622:\t\t\t\treturn 0;\n1623:\t\t\t}\n1624:\t\n1625:\t\t\tip_options_undo(opt);\n1626:\t\n1627:\t\t\tlen = min_t(unsigned int, len, opt-\u003eoptlen);\n1628:\t\t\tsopt-\u003eoptlen = len;\n1629:\t\t\tif (copy_to_iter(opt-\u003e__data, len, \u0026sopt-\u003eiter_out) != len)\n1630:\t\t\t\treturn -EFAULT;\n1631:\t\t\treturn 0;\n1632:\t\t}\n1633:\t\tcase IP_MTU:\n1634:\t\t{\n1635:\t\t\tstruct dst_entry dst;\n1636:\t\t\tval = 0;\n1637:\t\t\tdst = sk_dst_get(sk);\n1638:\t\t\tif (dst) {\n1639:\t\t\t\tval = dst4_mtu(dst);\n1640:\t\t\t\tdst_release(dst);\n1641:\t\t\t}\n1642:\t\t\tif (!val)\n1643:\t\t\t\treturn -ENOTCONN;\n1644:\t\t\tgoto copyval;\n1645:\t\t}\n1646:\t\tcase IP_PKTOPTIONS:\n1647:\t\t{\n1648:\t\t\tstruct msghdr msg;\n1649:\t\n1650:\t\t\tif (sk-\u003esk_type != SOCK_STREAM)\n1651:\t\t\t\treturn -ENOPROTOOPT;\n1652:\t\n1653:\t\t\tif (iov_iter_is_kvec(\u0026sopt-\u003eiter_out)) {\n1654:\t\t\t\tmsg.msg_control_is_user = false;\n1655:\t\t\t\tmsg.msg_control = sopt-\u003eiter_out.kvec-\u003eiov_base;\n1656:\t\t\t} else {\n1657:\t\t\t\tmsg.msg_control_is_user = true;\n1658:\t\t\t\tmsg.msg_control_user = sopt-\u003eiter_out.ubuf;\n1659:\t\t\t}\n1660:\t\t\tmsg.msg_controllen = len;\n1661:\t\t\tmsg.msg_flags = in_compat_syscall() ? MSG_CMSG_COMPAT : 0;\n1662:\t\n1663:\t\t\tif (inet_test_bit(PKTINFO, sk)) {\n1664:\t\t\t\tstruct in_pktinfo info;\n1665:\t\n1666:\t\t\t\tinfo.ipi_addr.s_addr = READ_ONCE(inet-\u003einet_rcv_saddr);\n1667:\t\t\t\tinfo.ipi_spec_dst.s_addr = READ_ONCE(inet-\u003einet_rcv_saddr);\n1668:\t\t\t\tinfo.ipi_ifindex = READ_ONCE(inet-\u003emc_index);\n1669:\t\t\t\tput_cmsg(\u0026msg, SOL_IP, IP_PKTINFO, sizeof(info), \u0026info);\n1670:\t\t\t}\n1671:\t\t\tif (inet_test_bit(TTL, sk)) {\n1672:\t\t\t\tint hlim = READ_ONCE(inet-\u003emc_ttl);\n1673:\t\n1674:\t\t\t\tput_cmsg(\u0026msg, SOL_IP, IP_TTL, sizeof(hlim), \u0026hlim);\n" }
67/3	2026/10/15 13:04	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 50883 output: 40 thoughts: 31 Thoughts: Okay, here's my summary, taking on the persona you requested: Diving into `ip_sockglue.c` – Lines 1675-1750 Alright, let's keep going. Time to dive back into the bowels of the IPv4 socket glue code, specifically lines 1675 through 1750 of `net/ipv4/ip_sockglue.c`. My immediate thought is, "Okay, what critical data structure or interaction am I going to be dealing with in this stretch?". Given the location within `ip_sockglue.c`, I'm primed for details on how the kernel interfaces with the socket layer at the IP level. It's likely involved with memory allocation, socket options, or perhaps even error handling related to IPv4 sockets. I need to keep an eye out for any unusual function calls or data structure manipulations that deviate from typical socket behavior, or for any areas that could introduce potential performance bottlenecks. I also want to observe if any unusual error handling is employed, as this can be a frequent source of issues. Given the line range, my intuition says I am probably looking at a specific socket option or flag, and the associated read/write actions. Got to read closely! Let's get to it.
68/3	2026/10/15 13:04	tool	read-file	0m Args: { "File": "net/ipv4/ip_sockglue.c", "FirstLine": 1675, "LineCount": 75 } Results: { "Contents": "1675:\t\t\t}\n1676:\t\t\tif (inet_test_bit(TOS, sk)) {\n1677:\t\t\t\tint tos = READ_ONCE(inet-\u003ercv_tos);\n1678:\t\t\t\tput_cmsg(\u0026msg, SOL_IP, IP_TOS, sizeof(tos), \u0026tos);\n1679:\t\t\t}\n1680:\t\t\tsopt-\u003eoptlen = len - msg.msg_controllen;\n1681:\t\t\treturn 0;\n1682:\t\t}\n1683:\t\tcase IP_UNICAST_IF:\n1684:\t\t\tval = (__force int)htonl((__u32) READ_ONCE(inet-\u003euc_index));\n1685:\t\t\tgoto copyval;\n1686:\t\tcase IP_MULTICAST_IF:\n1687:\t\t{\n1688:\t\t\tstruct in_addr addr;\n1689:\t\t\tlen = min_t(unsigned int, len, sizeof(struct in_addr));\n1690:\t\t\taddr.s_addr = READ_ONCE(inet-\u003emc_addr);\n1691:\t\n1692:\t\t\tsopt-\u003eoptlen = len;\n1693:\t\t\tif (copy_to_iter(\u0026addr, len, \u0026sopt-\u003eiter_out) != len)\n1694:\t\t\t\treturn -EFAULT;\n1695:\t\t\treturn 0;\n1696:\t\t}\n1697:\t\tcase IP_LOCAL_PORT_RANGE:\n1698:\t\t\tval = READ_ONCE(inet-\u003elocal_port_range);\n1699:\t\t\tgoto copyval;\n1700:\t\t}\n1701:\t\n1702:\t\tif (needs_rtnl)\n1703:\t\t\trtnl_lock();\n1704:\t\tsockopt_lock_sock(sk);\n1705:\t\n1706:\t\tswitch (optname) {\n1707:\t\tcase IP_MSFILTER:\n1708:\t\t{\n1709:\t\t\tstruct ip_msfilter msf;\n1710:\t\n1711:\t\t\tif (len \u003c IP_MSFILTER_SIZE(0)) {\n1712:\t\t\t\terr = -EINVAL;\n1713:\t\t\t\tgoto out;\n1714:\t\t\t}\n1715:\t\t\tif (copy_from_iter(\u0026msf, IP_MSFILTER_SIZE(0), \u0026sopt-\u003eiter_in) !=\n1716:\t\t\t IP_MSFILTER_SIZE(0)) {\n1717:\t\t\t\terr = -EFAULT;\n1718:\t\t\t\tgoto out;\n1719:\t\t\t}\n1720:\t\t\terr = ip_mc_msfget(sk, \u0026msf, sopt);\n1721:\t\t\tgoto out;\n1722:\t\t}\n1723:\t\tcase MCAST_MSFILTER:\n1724:\t\t\tif (in_compat_syscall())\n1725:\t\t\t\terr = compat_ip_get_mcast_msfilter(sk, sopt);\n1726:\t\t\telse\n1727:\t\t\t\terr = ip_get_mcast_msfilter(sk, sopt);\n1728:\t\t\tgoto out;\n1729:\t\tcase IP_PROTOCOL:\n1730:\t\t\tval = inet_sk(sk)-\u003einet_num;\n1731:\t\t\tbreak;\n1732:\t\tdefault:\n1733:\t\t\tsockopt_release_sock(sk);\n1734:\t\t\treturn -ENOPROTOOPT;\n1735:\t\t}\n1736:\t\tsockopt_release_sock(sk);\n1737:\tcopyval:\n1738:\t\tif (len \u003c sizeof(int) \u0026\u0026 len \u003e 0 \u0026\u0026 val \u003e= 0 \u0026\u0026 val \u003c= 255) {\n1739:\t\t\tunsigned char ucval = (unsigned char)val;\n1740:\t\n1741:\t\t\tsopt-\u003eoptlen = 1;\n1742:\t\t\tif (copy_to_iter(\u0026ucval, 1, \u0026sopt-\u003eiter_out) != 1)\n1743:\t\t\t\treturn -EFAULT;\n1744:\t\t} else {\n1745:\t\t\tlen = min_t(unsigned int, sizeof(int), len);\n1746:\t\t\tsopt-\u003eoptlen = len;\n1747:\t\t\tif (copy_to_iter(\u0026val, len, \u0026sopt-\u003eiter_out) != len)\n1748:\t\t\t\treturn -EFAULT;\n1749:\t\t}\n" }
69/3	2026/10/15 13:04	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 52371 output: 41 thoughts: 36 Thoughts: Okay, here's my interpretation of that thought process, tailored for an expert audience: Diving into IPv6 Socket Options Alright, so we're talking IPv6 socket options here, and I have a feeling we need to dig a little deeper. We've got a situation, and my gut says the issue might lie within the core socket glue code. Specifically, I'm thinking we should take a look at `net/ipv6/ipv6_sockglue.c`. That file is where a lot of the fundamental IPv6 socket interactions are handled, so it's a natural place to start looking for potential problems. My immediate focus will be the `do_ipv6_getsockopt` function. This function handles the getsockopt operations for IPv6 sockets. I need to understand how different options are parsed, how their values are retrieved, and what internal structures are involved. I'll be looking for any potential logic errors, race conditions, or incorrect data handling within that function. Essentially, I'm trying to trace the path of a getsockopt call through the IPv6 stack to see where things might be going wrong.
70/3	2026/10/15 13:04	tool	read-file	0m Args: { "File": "net/ipv6/ipv6_sockglue.c", "FirstLine": 1000, "LineCount": 80 } Results: { "Contents": "1000:\t\n1001:\tint do_ipv6_getsockopt(struct sock sk, int level, int optname, sockopt_t sopt)\n1002:\t{\n1003:\t\tstruct ipv6_pinfo np = inet6_sk(sk);\n1004:\t\tint len;\n1005:\t\tint val;\n1006:\t\n1007:\t\tif (ip6_mroute_opt(optname))\n1008:\t\t\treturn ip6_mroute_getsockopt(sk, optname, sopt);\n1009:\t\n1010:\t\tlen = sopt-\u003eoptlen;\n1011:\t\tswitch (optname) {\n1012:\t\tcase MCAST_MSFILTER:\n1013:\t\t\tif (in_compat_syscall())\n1014:\t\t\t\treturn compat_ipv6_get_msfilter(sk, sopt);\n1015:\t\t\treturn ipv6_get_msfilter(sk, sopt);\n1016:\t\tcase IPV6_2292PKTOPTIONS:\n1017:\t\t{\n1018:\t\t\tstruct msghdr msg;\n1019:\t\t\tstruct sk_buff skb;\n1020:\t\n1021:\t\t\tif (sk-\u003esk_type != SOCK_STREAM)\n1022:\t\t\t\treturn -ENOPROTOOPT;\n1023:\t\n1024:\t\t\tif (iov_iter_is_kvec(\u0026sopt-\u003eiter_out)) {\n1025:\t\t\t\tmsg.msg_control_is_user = false;\n1026:\t\t\t\tmsg.msg_control = sopt-\u003eiter_out.kvec-\u003eiov_base;\n1027:\t\t\t} else {\n1028:\t\t\t\tmsg.msg_control_is_user = true;\n1029:\t\t\t\tmsg.msg_control_user = sopt-\u003eiter_out.ubuf;\n1030:\t\t\t}\n1031:\t\t\tmsg.msg_controllen = len;\n1032:\t\t\tmsg.msg_flags = 0;\n1033:\t\n1034:\t\t\tsockopt_lock_sock(sk);\n1035:\t\t\tskb = np-\u003epktoptions;\n1036:\t\t\tif (skb)\n1037:\t\t\t\tip6_datagram_recv_ctl(sk, \u0026msg, skb);\n1038:\t\t\tsockopt_release_sock(sk);\n1039:\t\t\tif (!skb) {\n1040:\t\t\t\tif (np-\u003erxopt.bits.rxinfo) {\n1041:\t\t\t\t\tint mcast_oif = READ_ONCE(np-\u003emcast_oif);\n1042:\t\t\t\t\tstruct in6_pktinfo src_info;\n1043:\t\n1044:\t\t\t\t\tsrc_info.ipi6_ifindex = mcast_oif ? :\n1045:\t\t\t\t\t\tnp-\u003esticky_pktinfo.ipi6_ifindex;\n1046:\t\t\t\t\tsrc_info.ipi6_addr = mcast_oif ? sk-\u003esk_v6_daddr : np-\u003esticky_pktinfo.ipi6_addr;\n1047:\t\t\t\t\tput_cmsg(\u0026msg, SOL_IPV6, IPV6_PKTINFO, sizeof(src_info), \u0026src_info);\n1048:\t\t\t\t}\n1049:\t\t\t\tif (np-\u003erxopt.bits.rxhlim) {\n1050:\t\t\t\t\tint hlim = READ_ONCE(np-\u003emcast_hops);\n1051:\t\n1052:\t\t\t\t\tput_cmsg(\u0026msg, SOL_IPV6, IPV6_HOPLIMIT, sizeof(hlim), \u0026hlim);\n1053:\t\t\t\t}\n1054:\t\t\t\tif (np-\u003erxopt.bits.rxtclass) {\n1055:\t\t\t\t\tint tclass = (int)ip6_tclass(np-\u003ercv_flowinfo);\n1056:\t\n1057:\t\t\t\t\tput_cmsg(\u0026msg, SOL_IPV6, IPV6_TCLASS, sizeof(tclass), \u0026tclass);\n1058:\t\t\t\t}\n1059:\t\t\t\tif (np-\u003erxopt.bits.rxoinfo) {\n1060:\t\t\t\t\tint mcast_oif = READ_ONCE(np-\u003emcast_oif);\n1061:\t\t\t\t\tstruct in6_pktinfo src_info;\n1062:\t\n1063:\t\t\t\t\tsrc_info.ipi6_ifindex = mcast_oif ? :\n1064:\t\t\t\t\t\tnp-\u003esticky_pktinfo.ipi6_ifindex;\n1065:\t\t\t\t\tsrc_info.ipi6_addr = mcast_oif ? sk-\u003esk_v6_daddr :\n1066:\t\t\t\t\t\t\t\t\t np-\u003esticky_pktinfo.ipi6_addr;\n1067:\t\t\t\t\tput_cmsg(\u0026msg, SOL_IPV6, IPV6_2292PKTINFO, sizeof(src_info), \u0026src_info);\n1068:\t\t\t\t}\n1069:\t\t\t\tif (np-\u003erxopt.bits.rxohlim) {\n1070:\t\t\t\t\tint hlim = READ_ONCE(np-\u003emcast_hops);\n1071:\t\n1072:\t\t\t\t\tput_cmsg(\u0026msg, SOL_IPV6, IPV6_2292HOPLIMIT, sizeof(hlim), \u0026hlim);\n1073:\t\t\t\t}\n1074:\t\t\t\tif (np-\u003erxopt.bits.rxflow) {\n1075:\t\t\t\t\t__be32 flowinfo = np-\u003ercv_flowinfo;\n1076:\t\n1077:\t\t\t\t\tput_cmsg(\u0026msg, SOL_IPV6, IPV6_FLOWINFO, sizeof(flowinfo), \u0026flowinfo);\n1078:\t\t\t\t}\n1079:\t\t\t}\n" }
71/3	2026/10/15 13:04	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 54149 output: 41 thoughts: 33 Thoughts: Here's a summary of my thought process, as requested: Diving Deeper into `ipv6_sockglue.c` Okay, so we're dealing with IPv6 socket glue, and to get a more complete picture, I think it's worth taking a look at a specific section of the code. Let's dig into `net/ipv6/ipv6_sockglue.c`, specifically lines 1080 to 1200. This area likely handles a specific aspect of how IPv6 sockets are managed within the kernel. It could be related to connection establishment, data flow control, error handling, or perhaps even address mapping. By examining this particular chunk of code, I'm hoping to understand a particular behavior in greater detail, or potentially pinpoint a specific location related to the issue I'm investigating. I'm expecting some standard socket management, interaction with the networking stack or possibly some interaction with the routing subsystems. Time to roll up the sleeves.
72/3	2026/10/15 13:04	tool	read-file	0m Args: { "File": "net/ipv6/ipv6_sockglue.c", "FirstLine": 1080, "LineCount": 80 } Results: { "Contents": "1080:\t\t\tsopt-\u003eoptlen = len - msg.msg_controllen;\n1081:\t\t\treturn 0;\n1082:\t\t}\n1083:\t\tcase IPV6_MTU:\n1084:\t\t{\n1085:\t\t\tstruct dst_entry dst;\n1086:\t\n1087:\t\t\tval = 0;\n1088:\t\t\trcu_read_lock();\n1089:\t\t\tdst = __sk_dst_get(sk);\n1090:\t\t\tif (dst)\n1091:\t\t\t\tval = dst6_mtu(dst);\n1092:\t\t\trcu_read_unlock();\n1093:\t\t\tif (!val)\n1094:\t\t\t\treturn -ENOTCONN;\n1095:\t\t\tbreak;\n1096:\t\t}\n1097:\t\n1098:\t\tcase IPV6_V6ONLY:\n1099:\t\t\tval = sk-\u003esk_ipv6only;\n1100:\t\t\tbreak;\n1101:\t\n1102:\t\tcase IPV6_RECVPKTINFO:\n1103:\t\t\tval = np-\u003erxopt.bits.rxinfo;\n1104:\t\t\tbreak;\n1105:\t\n1106:\t\tcase IPV6_2292PKTINFO:\n1107:\t\t\tval = np-\u003erxopt.bits.rxoinfo;\n1108:\t\t\tbreak;\n1109:\t\n1110:\t\tcase IPV6_RECVHOPLIMIT:\n1111:\t\t\tval = np-\u003erxopt.bits.rxhlim;\n1112:\t\t\tbreak;\n1113:\t\n1114:\t\tcase IPV6_2292HOPLIMIT:\n1115:\t\t\tval = np-\u003erxopt.bits.rxohlim;\n1116:\t\t\tbreak;\n1117:\t\n1118:\t\tcase IPV6_RECVRTHDR:\n1119:\t\t\tval = np-\u003erxopt.bits.srcrt;\n1120:\t\t\tbreak;\n1121:\t\n1122:\t\tcase IPV6_2292RTHDR:\n1123:\t\t\tval = np-\u003erxopt.bits.osrcrt;\n1124:\t\t\tbreak;\n1125:\t\n1126:\t\tcase IPV6_HOPOPTS:\n1127:\t\tcase IPV6_RTHDRDSTOPTS:\n1128:\t\tcase IPV6_RTHDR:\n1129:\t\tcase IPV6_DSTOPTS:\n1130:\t\t{\n1131:\t\t\tstruct ipv6_txoptions opt;\n1132:\t\n1133:\t\t\tsockopt_lock_sock(sk);\n1134:\t\t\topt = rcu_dereference_protected(np-\u003eopt,\n1135:\t\t\t\t\t\t\tlockdep_sock_is_held(sk));\n1136:\t\t\tlen = ipv6_getsockopt_sticky(sk, opt, optname, sopt, len);\n1137:\t\t\tsockopt_release_sock(sk);\n1138:\t\t\t/* check if ipv6_getsockopt_sticky() returns err code */\n1139:\t\t\tif (len \u003c 0)\n1140:\t\t\t\treturn len;\n1141:\t\t\tsopt-\u003eoptlen = len;\n1142:\t\t\treturn 0;\n1143:\t\t}\n1144:\t\n1145:\t\tcase IPV6_RECVHOPOPTS:\n1146:\t\t\tval = np-\u003erxopt.bits.hopopts;\n1147:\t\t\tbreak;\n1148:\t\n1149:\t\tcase IPV6_2292HOPOPTS:\n1150:\t\t\tval = np-\u003erxopt.bits.ohopopts;\n1151:\t\t\tbreak;\n1152:\t\n1153:\t\tcase IPV6_RECVDSTOPTS:\n1154:\t\t\tval = np-\u003erxopt.bits.dstopts;\n1155:\t\t\tbreak;\n1156:\t\n1157:\t\tcase IPV6_2292DSTOPTS:\n1158:\t\t\tval = np-\u003erxopt.bits.odstopts;\n1159:\t\t\tbreak;\n" }
73/3	2026/10/15 13:04	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 55535 output: 20 thoughts: 948 Thoughts: Diving into IPv6 and Multicast Socket Options Alright, let's take a look at what's happening with these socket options. First, I'm checking `ipv6_getsockopt_sticky` in `net/ipv6/ipv6_sockglue.c`. This function seems straightforward enough. It retrieves IPv6 extension headers based on the `optname` passed. The key point here is that the `hdr` (the header itself) comes from a `struct ipv6_txoptions opt`, which I know is allocated and initialized when `setsockopt` is called. So, the data source is well-defined. Now, let's move on to `compat_ip_get_mcast_msfilter` and `compat_ipv6_get_msfilter`. This area is interesting because of the "compat" prefix. It looks like we're dealing with a compatibility layer for multicast filters. The function `compat_ip_get_mcast_msfilter` immediately catches my eye. It copies data to and from a `struct compat_group_filter`. I need to understand what's actually* being copied. I see the `copy_to_iter` calls, and specifically: `copy_to_iter(&gf.gf_fmode, sizeof(gf32.gf_fmode), &opt->iter_out)`. This is where I need to be precise. The important question now is, what are the types of `gf.gf_fmode` and `gf32.gf_fmode`? I need to know the underlying structures to be sure how the data is being handled. This is likely where the "compatibility" aspect comes into play. I'll need to check the definition of `struct compat_group_filter` to understand the exact types and sizes involved in that copy.
74/3	2026/10/15 13:05	tool	grepper	0m Args: { "Expression": "struct compat_group_filter" } Results: { "Output": "include/net/compat.h=64=struct compat_group_source_req {\n--\ninclude/net/compat.h-71-\ninclude/net/compat.h:72:struct compat_group_filter {\ninclude/net/compat.h-73-\tunion {\n--\nnet/ipv4/ip_sockglue.c=801=static int compat_ip_set_mcast_msfilter(struct sock sk, sockptr_t optval,\n--\nnet/ipv4/ip_sockglue.c-803-{\nnet/ipv4/ip_sockglue.c:804:\tconst int size0 = offsetof(struct compat_group_filter, gf_slist_flex);\nnet/ipv4/ip_sockglue.c:805:\tstruct compat_group_filter gf32;\nnet/ipv4/ip_sockglue.c-806-\tunsigned int n;\n--\nnet/ipv4/ip_sockglue.c-830-\terr = -EINVAL;\nnet/ipv4/ip_sockglue.c:831:\tif (offsetof(struct compat_group_filter, gf_slist_flex[n]) \u003e optlen)\nnet/ipv4/ip_sockglue.c-832-\t\tgoto out_free_gsf;\n--\nnet/ipv4/ip_sockglue.c=1474=static int compat_ip_get_mcast_msfilter(struct sock sk, sockopt_t opt)\nnet/ipv4/ip_sockglue.c-1475-{\nnet/ipv4/ip_sockglue.c:1476:\tconst int size0 = offsetof(struct compat_group_filter, gf_slist_flex);\nnet/ipv4/ip_sockglue.c:1477:\tstruct compat_group_filter gf32;\nnet/ipv4/ip_sockglue.c-1478-\tstruct group_filter gf;\n--\nnet/ipv4/ip_sockglue.c-1492-\terr = ip_mc_gsfget(sk, \u0026gf, opt,\nnet/ipv4/ip_sockglue.c:1493:\t\t\t offsetof(struct compat_group_filter, gf_slist_flex));\nnet/ipv4/ip_sockglue.c-1494-\tif (err)\n--\nnet/ipv4/ip_sockglue.c-1501-\tiov_iter_revert(\u0026opt-\u003eiter_out,\nnet/ipv4/ip_sockglue.c:1502:\t\t\tlen - offsetof(struct compat_group_filter, gf_fmode));\nnet/ipv4/ip_sockglue.c-1503-\tif (copy_to_iter(\u0026gf.gf_fmode, sizeof(gf32.gf_fmode),\n--\nnet/ipv6/ipv6_sockglue.c=218=static int compat_ipv6_set_mcast_msfilter(struct sock sk, sockptr_t optval,\n--\nnet/ipv6/ipv6_sockglue.c-220-{\nnet/ipv6/ipv6_sockglue.c:221:\tconst int size0 = offsetof(struct compat_group_filter, gf_slist_flex);\nnet/ipv6/ipv6_sockglue.c:222:\tstruct compat_group_filter gf32;\nnet/ipv6/ipv6_sockglue.c-223-\tvoid p;\n--\nnet/ipv6/ipv6_sockglue.c-247-\tret = -EINVAL;\nnet/ipv6/ipv6_sockglue.c:248:\tif (offsetof(struct compat_group_filter, gf_slist_flex[n]) \u003e optlen)\nnet/ipv6/ipv6_sockglue.c-249-\t\tgoto out_free_p;\n--\nnet/ipv6/ipv6_sockglue.c=959=static int compat_ipv6_get_msfilter(struct sock sk, sockopt_t *opt)\nnet/ipv6/ipv6_sockglue.c-960-{\nnet/ipv6/ipv6_sockglue.c:961:\tconst int size0 = offsetof(struct compat_group_filter, gf_slist_flex);\nnet/ipv6/ipv6_sockglue.c:962:\tstruct compat_group_filter gf32;\nnet/ipv6/ipv6_sockglue.c-963-\tstruct group_filter gf;\n--\nnet/ipv6/ipv6_sockglue.c-990-\tiov_iter_revert(\u0026opt-\u003eiter_out,\nnet/ipv6/ipv6_sockglue.c:991:\t\t\tlen - offsetof(struct compat_group_filter, gf_fmode));\nnet/ipv6/ipv6_sockglue.c-992-\tif (copy_to_iter(\u0026gf.gf_fmode, sizeof(gf32.gf_fmode),\n" }
75/3	2026/10/15 13:05	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 58128 output: 34 thoughts: 19 Thoughts: Here's a summary of my thought process, as requested: Diving into `net/compat.h` Okay, let's zero in on `include/net/compat.h`. My immediate interest is likely centered around the potential for some compatibility handling, and the header's location suggests it's related to network code. I'm going to scan around line 72, as that seems like a good starting point to explore. There, I'm expecting to find either a: * Definition: A structure, macro or a function with its definition. * A Conditional: Some preprocessor directives using `#ifdef`, `#ifndef`, `#if` or `#endif` that could affect behavior based on the kernel version or architecture. * Documentation: Some inline comments that might reveal the reason for its existence, intended behavior or potential pitfalls. My focus is to quickly understand the what and the why of this particular section of code. Depending on what I find, my next steps will be determined. Are there API changes across versions? Is it for legacy support? Is it there to ensure forward compatibility? Hopefully, I can determine why this code is important.
76/3	2026/10/15 13:05	tool	read-file	0m Args: { "File": "include/net/compat.h", "FirstLine": 60, "LineCount": 40 } Results: { "Contents": " 60:\t\tstruct __kernel_sockaddr_storage gr_group\n 61:\t\t\t__aligned(4);\n 62:\t} __packed;\n 63:\t\n 64:\tstruct compat_group_source_req {\n 65:\t\t__u32\t\t\t\t gsr_interface;\n 66:\t\tstruct __kernel_sockaddr_storage gsr_group\n 67:\t\t\t__aligned(4);\n 68:\t\tstruct __kernel_sockaddr_storage gsr_source\n 69:\t\t\t__aligned(4);\n 70:\t} __packed;\n 71:\t\n 72:\tstruct compat_group_filter {\n 73:\t\tunion {\n 74:\t\t\tstruct {\n 75:\t\t\t\t__u32\t\t\t\t gf_interface_aux;\n 76:\t\t\t\tstruct __kernel_sockaddr_storage gf_group_aux\n 77:\t\t\t\t\t__aligned(4);\n 78:\t\t\t\t__u32\t\t\t\t gf_fmode_aux;\n 79:\t\t\t\t__u32\t\t\t\t gf_numsrc_aux;\n 80:\t\t\t\tstruct __kernel_sockaddr_storage gf_slist[1]\n 81:\t\t\t\t\t__aligned(4);\n 82:\t\t\t} __packed;\n 83:\t\t\tstruct {\n 84:\t\t\t\t__u32\t\t\t\t gf_interface;\n 85:\t\t\t\tstruct __kernel_sockaddr_storage gf_group\n 86:\t\t\t\t\t__aligned(4);\n 87:\t\t\t\t__u32\t\t\t\t gf_fmode;\n 88:\t\t\t\t__u32\t\t\t\t gf_numsrc;\n 89:\t\t\t\tstruct __kernel_sockaddr_storage gf_slist_flex[]\n 90:\t\t\t\t\t__aligned(4);\n 91:\t\t\t} __packed;\n 92:\t\t};\n 93:\t} __packed;\n 94:\t\n 95:\t#endif /* NET_COMPAT_H */\n" }
77/3	2026/10/15 13:05	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 58915 output: 38 thoughts: 777 Thoughts: Analyzing the Compatibility Revert and `getsockopt` Implementation Okay, let's break this down. I need to understand why this compatibility revert in the code works as intended. First, I'm examining the revert in the compatibility code. The goal is to ensure the same data is written, even with potential differences in the underlying structures. The key here is the `iov_iter_revert` function and what it does in relation to the `compat_group_filter` structure. My initial code block shows this: ```c /* Rewind to gf_fmode, which gf_numsrc follows. / iov_iter_revert(&opt->iter_out, len - offsetof(struct compat_group_filter, gf_fmode)); if (copy_to_iter(&gf.gf_fmode, sizeof(gf32.gf_fmode), &opt->iter_out) != sizeof(gf32.gf_fmode) \|\| copy_to_iter(&gf.gf_numsrc, sizeof(gf32.gf_numsrc), &opt->iter_out) != sizeof(gf32.gf_numsrc)) return -EFAULT; opt->optlen = len; ``` I'm thinking: The code rewinds the iterator to `gf_fmode` using `offsetof`. Then, it copies the contents of `gf_fmode` and `gf_numsrc` to the iterator. The key observation is that both `gf.gf_fmode` and `gf32.gf_fmode` are the same size (`__u32`, 4 bytes), and `gf_numsrc` immediately follows `gf_fmode` in the struct. Therefore, reverting the iterator back to `gf_fmode` and then copying `gf_fmode` and `gf_numsrc` to the iterator should write the same data as before the patch. Then I look at the "before patch" code to understand this logic. It used a different method with `copy_to_sockptr`: ```c if (copy_to_sockptr(optlen, &len, sizeof(int)) \|\| copy_to_sockptr_offset(optval, offsetof(struct compat_group_filter, gf_fmode), &gf.gf_fmode, sizeof(gf.gf_fmode)) \|\| copy_to_sockptr_offset(optval, offsetof(struct compat_group_filter, gf_numsrc), &gf.gf_numsrc, sizeof(gf.gf_numsrc))) ``` The code then writes `gf_fmode` and `gf_numsrc`. Since the sizes and positions are the same, the two methods are doing the same thing. I then think, the `ip_mc_gsfget` function had written up to `len`, so after the two copies, the iterator is where it should be (at `gf_slist_flex`). My next concern is `ip_mroute_getsockopt`: ```c int ip_mroute_getsockopt(struct sock sk, int optname, sockopt_t *opt) { int olr; int val; ... olr = opt->optlen; if (olr < 0) return -EINVAL; olr = min_t(unsigned int, olr, sizeof(int)); opt->optlen = olr; if (copy_to_iter(&val, olr, &opt->iter_out) != olr) return -EFAULT; return 0; } ``` I wonder if `val` is initialized. Let's check `net/ipv4/ipmr.c` lines 1640-1675 to verify. This is important to ensure no garbage data is being returned.
78/3	2026/10/15 13:05	tool	read-file	0m Args: { "File": "net/ipv4/ipmr.c", "FirstLine": 1640, "LineCount": 35 } Results: { "Contents": "1640:\t/* Getsock opt support for the multicast routing system. /\n1641:\tint ip_mroute_getsockopt(struct sock sk, int optname, sockopt_t opt)\n1642:\t{\n1643:\t\tint olr;\n1644:\t\tint val;\n1645:\t\tstruct net net = sock_net(sk);\n1646:\t\tstruct mr_table *mrt;\n1647:\t\n1648:\t\tif (sk-\u003esk_type != SOCK_RAW \|\|\n1649:\t\t inet_sk(sk)-\u003einet_num != IPPROTO_IGMP)\n1650:\t\t\treturn -EOPNOTSUPP;\n1651:\t\n1652:\t\tmrt = ipmr_get_table(net, raw_sk(sk)-\u003eipmr_table ? : RT_TABLE_DEFAULT);\n1653:\t\tif (!mrt)\n1654:\t\t\treturn -ENOENT;\n1655:\t\n1656:\t\tswitch (optname) {\n1657:\t\tcase MRT_VERSION:\n1658:\t\t\tval = 0x0305;\n1659:\t\t\tbreak;\n1660:\t\tcase MRT_PIM:\n1661:\t\t\tif (!ipmr_pimsm_enabled())\n1662:\t\t\t\treturn -ENOPROTOOPT;\n1663:\t\t\tval = READ_ONCE(mrt-\u003emroute_do_pim);\n1664:\t\t\tbreak;\n1665:\t\tcase MRT_ASSERT:\n1666:\t\t\tval = READ_ONCE(mrt-\u003emroute_do_assert);\n1667:\t\t\tbreak;\n1668:\t\tdefault:\n1669:\t\t\treturn -ENOPROTOOPT;\n1670:\t\t}\n1671:\t\n1672:\t\tolr = opt-\u003eoptlen;\n1673:\t\tif (olr \u003c 0)\n1674:\t\t\treturn -EINVAL;\n" }
79/3	2026/10/15 13:05	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 61133 output: 39 thoughts: 122 Thoughts: Analyzing Variable Initialization in `ip6_mroute_getsockopt` Alright, let's break this down. The core concern is ensuring a variable, specifically `val` in this case, is initialized before a switch statement completes or a return statement is reached. This is crucial for avoiding undefined behavior, particularly in C. To illustrate this, I'm going to examine the `ip6_mroute_getsockopt` function. Let's start by looking at its definition in `net/ipv6/ip6mr.c`. I need to ensure that `val` is properly handled here. Specifically, I'm interested in the lines related to `ip6_mroute_getsockopt`. So, the first thing I'll do is check that `val` is actually initialized, which should be the case. I'll read through lines 1895-1935 in `net/ipv6/ip6mr.c` to see how it's used within the context of the function and make sure there are no issues.
80/3	2026/10/15 13:05	tool	read-file	0m Args: { "File": "net/ipv6/ip6mr.c", "FirstLine": 1895, "LineCount": 40 } Results: { "Contents": "1895:\t\n1896:\tint ip6_mroute_getsockopt(struct sock sk, int optname, sockopt_t sopt)\n1897:\t{\n1898:\t\tint olr;\n1899:\t\tint val;\n1900:\t\tstruct net net = sock_net(sk);\n1901:\t\tstruct mr_table mrt;\n1902:\t\n1903:\t\tif (sk-\u003esk_type != SOCK_RAW \|\|\n1904:\t\t inet_sk(sk)-\u003einet_num != IPPROTO_ICMPV6)\n1905:\t\t\treturn -EOPNOTSUPP;\n1906:\t\n1907:\t\tmrt = ip6mr_get_table(net, raw6_sk(sk)-\u003eip6mr_table ? : RT6_TABLE_DFLT);\n1908:\t\tif (!mrt)\n1909:\t\t\treturn -ENOENT;\n1910:\t\n1911:\t\tswitch (optname) {\n1912:\t\tcase MRT6_VERSION:\n1913:\t\t\tval = 0x0305;\n1914:\t\t\tbreak;\n1915:\t#ifdef CONFIG_IPV6_PIMSM_V2\n1916:\t\tcase MRT6_PIM:\n1917:\t\t\tval = READ_ONCE(mrt-\u003emroute_do_pim);\n1918:\t\t\tbreak;\n1919:\t#endif\n1920:\t\tcase MRT6_ASSERT:\n1921:\t\t\tval = READ_ONCE(mrt-\u003emroute_do_assert);\n1922:\t\t\tbreak;\n1923:\t\tdefault:\n1924:\t\t\treturn -ENOPROTOOPT;\n1925:\t\t}\n1926:\t\n1927:\t\tolr = min_t(int, sopt-\u003eoptlen, sizeof(int));\n1928:\t\tif (olr \u003c 0)\n1929:\t\t\treturn -EINVAL;\n1930:\t\n1931:\t\tsopt-\u003eoptlen = olr;\n1932:\t\tif (copy_to_iter(\u0026val, olr, \u0026sopt-\u003eiter_out) != olr)\n1933:\t\t\treturn -EFAULT;\n1934:\t\treturn 0;\n" }
81/3	2026/10/15 13:05	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 62130 output: 41 thoughts: 781 Thoughts: Analyzing Socket Option Initialization Okay, so I'm looking at how socket options are handled, particularly the `getsockopt` calls. First, I see that `val` is fully initialized, which is good. I need to dive deeper into `sol_ip_sockopt` and `sol_ipv6_sockopt` in `net/core/filter.c` though. Wait, let's look at `sol_ip_sockopt` specifically, and how the `sockptr_to_sockopt` function works. I see that `int optlen` is passed as a pointer. Then `KERNEL_SOCKPTR(optlen)` points to `int optlen`. The `sockptr_to_sockopt` function then reads `koptlen` from `optlen`. Next, the `kvec` is initialized: `kvec->iov_base = optval` and `kvec->iov_len = koptlen`. After that, `iov_iter_kvec` initializes `&opt->iter_out` and `&opt->iter_in`. Finally, `opt->optlen = koptlen`. Then, we have the `do_ip_getsockopt(sk, SOL_IP, optname, &opt)` call. If `optname` is IP_TOS or IP_TRANSPARENT (which are the only ones allowed by `sol_ip_sockopt`), `val` is an `int`, copied to `&sopt->iter_out`. And finally, `optlen = opt.optlen;`. So, from what I can tell, everything is initialized correctly in the `sol_ip_sockopt` flow. Now, I really need to check `do_ipv6_getsockopt`, though. I'll need to look at lines 1260 to 1350 of `net/ipv6/ipv6_sockglue.c` to be sure.
82/3	2026/10/15 13:05	tool	read-file	0m Args: { "File": "net/ipv6/ipv6_sockglue.c", "FirstLine": 1260, "LineCount": 80 } Results: { "Contents": "1260:\t\t\tbreak;\n1261:\t\n1262:\t\tcase IPV6_FLOWINFO_SEND:\n1263:\t\t\tval = inet6_test_bit(SNDFLOW, sk);\n1264:\t\t\tbreak;\n1265:\t\n1266:\t\tcase IPV6_FLOWLABEL_MGR:\n1267:\t\t{\n1268:\t\t\tstruct in6_flowlabel_req freq;\n1269:\t\t\tint flags;\n1270:\t\n1271:\t\t\tif (len \u003c sizeof(freq))\n1272:\t\t\t\treturn -EINVAL;\n1273:\t\n1274:\t\t\tif (copy_from_iter(\u0026freq, sizeof(freq), \u0026sopt-\u003eiter_in) !=\n1275:\t\t\t sizeof(freq))\n1276:\t\t\t\treturn -EFAULT;\n1277:\t\n1278:\t\t\tif (freq.flr_action != IPV6_FL_A_GET)\n1279:\t\t\t\treturn -EINVAL;\n1280:\t\n1281:\t\t\tlen = sizeof(freq);\n1282:\t\t\tflags = freq.flr_flags;\n1283:\t\n1284:\t\t\tmemset(\u0026freq, 0, sizeof(freq));\n1285:\t\n1286:\t\t\tval = ipv6_flowlabel_opt_get(sk, \u0026freq, flags);\n1287:\t\t\tif (val \u003c 0)\n1288:\t\t\t\treturn val;\n1289:\t\n1290:\t\t\tsopt-\u003eoptlen = len;\n1291:\t\t\tif (copy_to_iter(\u0026freq, len, \u0026sopt-\u003eiter_out) != len)\n1292:\t\t\t\treturn -EFAULT;\n1293:\t\n1294:\t\t\treturn 0;\n1295:\t\t}\n1296:\t\n1297:\t\tcase IPV6_ADDR_PREFERENCES:\n1298:\t\t\t{\n1299:\t\t\tu8 srcprefs = READ_ONCE(np-\u003esrcprefs);\n1300:\t\t\tval = 0;\n1301:\t\n1302:\t\t\tif (srcprefs \u0026 IPV6_PREFER_SRC_TMP)\n1303:\t\t\t\tval \|= IPV6_PREFER_SRC_TMP;\n1304:\t\t\telse if (srcprefs \u0026 IPV6_PREFER_SRC_PUBLIC)\n1305:\t\t\t\tval \|= IPV6_PREFER_SRC_PUBLIC;\n1306:\t\t\telse {\n1307:\t\t\t\t/* XXX: should we return system default? */\n1308:\t\t\t\tval \|= IPV6_PREFER_SRC_PUBTMP_DEFAULT;\n1309:\t\t\t}\n1310:\t\n1311:\t\t\tif (srcprefs \u0026 IPV6_PREFER_SRC_COA)\n1312:\t\t\t\tval \|= IPV6_PREFER_SRC_COA;\n1313:\t\t\telse\n1314:\t\t\t\tval \|= IPV6_PREFER_SRC_HOME;\n1315:\t\t\tbreak;\n1316:\t\t\t}\n1317:\t\tcase IPV6_MINHOPCOUNT:\n1318:\t\t\tval = READ_ONCE(np-\u003emin_hopcount);\n1319:\t\t\tbreak;\n1320:\t\n1321:\t\tcase IPV6_DONTFRAG:\n1322:\t\t\tval = inet6_test_bit(DONTFRAG, sk);\n1323:\t\t\tbreak;\n1324:\t\n1325:\t\tcase IPV6_AUTOFLOWLABEL:\n1326:\t\t\tval = ip6_autoflowlabel(sock_net(sk), sk);\n1327:\t\t\tbreak;\n1328:\t\n1329:\t\tcase IPV6_RECVFRAGSIZE:\n1330:\t\t\tval = np-\u003erxopt.bits.recvfragsize;\n1331:\t\t\tbreak;\n1332:\t\n1333:\t\tcase IPV6_ROUTER_ALERT:\n1334:\t\t\tval = inet6_test_bit(RTALERT, sk);\n1335:\t\t\tbreak;\n1336:\t\n1337:\t\tcase IPV6_ROUTER_ALERT_ISOLATE:\n1338:\t\t\tval = inet6_test_bit(RTALERT_ISOLATE, sk);\n1339:\t\t\tbreak;\n" }
83/3	2026/10/15 13:05	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 64509 output: 41 thoughts: 209 Thoughts: Here's my analysis of the provided code snippet and the potential area of concern, presented as my own thought process: Examining IPv6 Flow Label Handling and a Potential Gotcha Okay, let's break this down. I'm looking at the `IPV6_FLOWLABEL_MGR` path, specifically how the flow label option is handled. The code clearly initializes `freq` to zero using `memset`. This is crucial. It's initializing a structure before calling the function `ipv6_flowlabel_opt_get` to populate the `freq` structure, and the code explicitly zeroing out `freq` guarantees that any garbage data is wiped out. The returned data, if any, is then copied to `iter_out` if `ipv6_flowlabel_opt_get` returned successfully. That’s standard, safe practice. But wait a minute… that's got me thinking. Is the same initialization pattern used everywhere? I need to quickly cross-reference this with other parts of the IPv6 stack, particularly where similar data is passed from the kernel. I should see if this pattern is universal. I know! What about `IPV6_PATHMTU` in `do_ipv6_getsockopt`? Let's check it out. I'm going to jump straight to lines 1180-1210 of `net/ipv6/ipv6_sockglue.c` to verify the pattern. This seems like it could open up a security vulnerability if not handled properly.
84/3	2026/10/15 13:06	tool	read-file	0m Args: { "File": "net/ipv6/ipv6_sockglue.c", "FirstLine": 1180, "LineCount": 40 } Results: { "Contents": "1180:\t\t\tstruct ip6_mtuinfo mtuinfo;\n1181:\t\n1182:\t\t\tif (len \u003c sizeof(mtuinfo))\n1183:\t\t\t\treturn -EINVAL;\n1184:\t\n1185:\t\t\tlen = sizeof(mtuinfo);\n1186:\t\t\tmemset(\u0026mtuinfo, 0, sizeof(mtuinfo));\n1187:\t\n1188:\t\t\trcu_read_lock();\n1189:\t\t\tdst = __sk_dst_get(sk);\n1190:\t\t\tif (dst)\n1191:\t\t\t\tmtuinfo.ip6m_mtu = dst6_mtu(dst);\n1192:\t\t\trcu_read_unlock();\n1193:\t\t\tif (!mtuinfo.ip6m_mtu)\n1194:\t\t\t\treturn -ENOTCONN;\n1195:\t\n1196:\t\t\tsopt-\u003eoptlen = len;\n1197:\t\t\tif (copy_to_iter(\u0026mtuinfo, len, \u0026sopt-\u003eiter_out) != len)\n1198:\t\t\t\treturn -EFAULT;\n1199:\t\n1200:\t\t\treturn 0;\n1201:\t\t}\n1202:\t\n1203:\t\tcase IPV6_TRANSPARENT:\n1204:\t\t\tval = inet_test_bit(TRANSPARENT, sk);\n1205:\t\t\tbreak;\n1206:\t\n1207:\t\tcase IPV6_FREEBIND:\n1208:\t\t\tval = inet_test_bit(FREEBIND, sk);\n1209:\t\t\tbreak;\n1210:\t\n1211:\t\tcase IPV6_RECVORIGDSTADDR:\n1212:\t\t\tval = np-\u003erxopt.bits.rxorigdstaddr;\n1213:\t\t\tbreak;\n1214:\t\n1215:\t\tcase IPV6_UNICAST_HOPS:\n1216:\t\tcase IPV6_MULTICAST_HOPS:\n1217:\t\t{\n1218:\t\t\tstruct dst_entry *dst;\n1219:\t\n" }
85/3	2026/10/15 13:06	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 65646 output: 25 thoughts: 6794 Thoughts: Analysis of Potential Uninitialized Memory Reads in Socket Option Retrieval Okay, let's break this down. My primary concern is ensuring that socket option retrieval routines don't inadvertently leak uninitialized kernel memory to user space or exhibit other exploitable behaviors. The focus is on finding all potential issues in this code. First, I identified the pattern of initializing a `sockopt_t` structure, then potentially modifying its `iter_out` member via functions like `sockopt_expand_out`, and finally, using `copy_to_iter` to write data to user space. The key is to verify that any data being copied is always initialized before `copy_to_iter` is called, and also to verify that the `iter_out` is updated accordingly. The initial `memset` calls on `mtuinfo` or the similar structure that follows are a good sign. But, I must verify this happens for all cases. I checked the `IP_OPTIONS` code in `net/ipv4/ip_sockglue.c` carefully, confirming that only the expected number of bytes is copied from the kernel, based on `opt->optlen`. This prevents an accidental read beyond what's supposed to be returned. I'm checking `IP_PKTOPTIONS` and the related code flow. I noticed the use of `iov_iter_is_kvec` and the potential for a `sopt->iter_out` iterator that might have been advanced previously. However, the code initializes `sopt->iter_out` at the beginning. The concern here is the safety of the `sopt->iter_out.ubuf` pointer, which is derived from `optval`. Fortunately, the iterator is always initialized correctly using `iov_iter_ubuf`. This means the user's buffer is properly managed. The same applies for the `IPV6_2292PKTOPTIONS` case. I examined `sockopt_expand_out`. The added bounds check (`size > MAX_RW_COUNT`) is clearly a security enhancement. It's designed to prevent excessively large re-allocations and potential overflows within the iterator structure. This is critical for preventing uninitialized memory reads on `iov_iter_revert` later and fixes a potential issue on revert length! Then, I looked at multicast filtering (`ip_mc_gsfget` and `ip6_mc_msfget`). The key here is the use of `iov_iter_advance` and `iov_iter_revert`. I verified that `iov_iter_advance` only advances the iterator without writing anything and that the subsequent `copy_to_iter` calls write only initialized data. I traced the flow in detail, noting how `num` and `copycount` are set and ensured that `iov_iter_revert` rewinds the iterator by exactly the amount that was advanced, and that data is written as the iterator is rewound. The compat version `compat_ip_get_mcast_msfilter`, `compat_ipv6_get_msfilter` function and the non-compat versions such as `ipv6_get_msfilter` are essentially the same logic. This avoids uninitialized reads. Crucially, I ensured that any `copy_to_iter` failure (e.g., `-EFAULT`) results in an early return without any memory leaks or uninitialized memory being exposed. I then focused on the `copyval` case in `do_ip_getsockopt`. The use of a stack-allocated, always-initialized `int val` ensures that the data being copied is always valid. I considered the `unsigned char` optimization when `len < sizeof(int)`, but again, `val` is properly initialized. Checking `ipv6_getsockopt`, in the case of `SOL_IP`, I saw it delegates to `ip_getsockopt`, making it a non-issue. I then verified that `sopt.optlen` is always initialized by either `sockopt_set_user`, or `sockopt_init_user`, before `put_user` is called. It's initialized before the call to `do_ipv6_getsockopt`. Finally, the `sockptr_to_sockopt` path appears safe, initializing `opt.optlen` and leaving `opt` fully initialized. I then cross-referenced all other calls to the `do_ip_getsockopt` and `do_ipv6_getsockopt` functions in the kernel. This provides confidence that no critical paths were missed. Overall, the code looks well-structured and handles the complexities of iterator advancement and reversion carefully. The precautions in place, especially the bounds checks and the initialization practices, give me confidence that there are
86/3	2026/10/15 13:06	tool	grepper	0m Args: { "Expression": "do_ip(v6)?_getsockopt" } Results: { "Output": "include/net/ip.h=834=int ip_setsockopt(struct sock sk, int level, int optname, sockptr_t optval,\ninclude/net/ip.h-835-\t\t unsigned int optlen);\ninclude/net/ip.h:836:int do_ip_getsockopt(struct sock sk, int level, int optname, sockopt_t sopt);\ninclude/net/ip.h-837-int ip_getsockopt(struct sock sk, int level, int optname, char __user optval,\n--\ninclude/net/ipv6.h=1142=int ipv6_setsockopt(struct sock sk, int level, int optname, sockptr_t optval,\ninclude/net/ipv6.h-1143-\t\t unsigned int optlen);\ninclude/net/ipv6.h:1144:int do_ipv6_getsockopt(struct sock sk, int level, int optname,\ninclude/net/ipv6.h-1145-\t\t sockopt_t sopt);\n--\nnet/core/filter.c=5723=static int sol_ip_sockopt(struct sock sk, int optname,\n--\nnet/core/filter.c-5749-\nnet/core/filter.c:5750:\t\terr = do_ip_getsockopt(sk, SOL_IP, optname, \u0026opt);\nnet/core/filter.c-5751-\t\toptlen = opt.optlen;\n--\nnet/core/filter.c=5759=static int sol_ipv6_sockopt(struct sock sk, int optname,\n--\nnet/core/filter.c-5786-\nnet/core/filter.c:5787:\t\terr = do_ipv6_getsockopt(sk, SOL_IPV6, optname, \u0026opt);\nnet/core/filter.c-5788-\t\toptlen = opt.optlen;\n--\nnet/ipv4/ip_sockglue.c=1474=static int compat_ip_get_mcast_msfilter(struct sock sk, sockopt_t opt)\n--\nnet/ipv4/ip_sockglue.c-1511-\nnet/ipv4/ip_sockglue.c:1512:int do_ip_getsockopt(struct sock sk, int level, int optname, sockopt_t sopt)\nnet/ipv4/ip_sockglue.c-1513-{\n--\nnet/ipv4/ip_sockglue.c=1759=int ip_getsockopt(struct sock sk, int level,\n--\nnet/ipv4/ip_sockglue.c-1768-\nnet/ipv4/ip_sockglue.c:1769:\terr = do_ip_getsockopt(sk, level, optname, \u0026opt);\nnet/ipv4/ip_sockglue.c-1770-\tif (put_user(opt.optlen, optlen))\n--\nnet/ipv6/ipv6_sockglue.c=959=static int compat_ipv6_get_msfilter(struct sock sk, sockopt_t opt)\n--\nnet/ipv6/ipv6_sockglue.c-1000-\nnet/ipv6/ipv6_sockglue.c:1001:int do_ipv6_getsockopt(struct sock sk, int level, int optname, sockopt_t sopt)\nnet/ipv6/ipv6_sockglue.c-1002-{\n--\nnet/ipv6/ipv6_sockglue.c=1355=int ipv6_getsockopt(struct sock sk, int level, int optname,\n--\nnet/ipv6/ipv6_sockglue.c-1378-\nnet/ipv6/ipv6_sockglue.c:1379:\terr = do_ipv6_getsockopt(sk, level, optname, \u0026sopt);\nnet/ipv6/ipv6_sockglue.c-1380-\tif (put_user(sopt.optlen, optlen))\n" }
87/3	2026/10/15 13:06	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 74525 output: 25 thoughts: 65 Thoughts: Okay, here's my take on those thoughts, tailored for an expert audience: Refactoring `getsockopt` Calls: A Quick Review and a Potentially Missed Detail Right, so this patch aims to refactor all the callers of `do_ip_getsockopt` and `do_ipv6_getsockopt`. That makes sense; consolidating and modernizing those calls likely helps with maintainability and, potentially, security. But, my immediate thought is... wait a minute, aren't there a couple of related functions in the IP multicast space? Specifically, what about `ip_mroute_getsockopt` and `ip6_mroute_getsockopt`? Those are also related to `getsockopt` operations, and if we're doing a comprehensive cleanup, we can't leave them behind. Okay, let's just do a quick grep search to be absolutely sure. Gotta be thorough. We don't want any regressions or overlooked areas in a patch like this. Always best to double-check these things.
88/3	2026/10/15 13:06	tool	grepper	0m Args: { "Expression": "ip(6)?_mroute_getsockopt" } Results: { "Output": "include/linux/mroute.h=19=int ip_mroute_setsockopt(struct sock , int, sockptr_t, unsigned int);\ninclude/linux/mroute.h:20:int ip_mroute_getsockopt(struct sock sk, int optname, sockopt_t opt);\ninclude/linux/mroute.h-21-int ipmr_ioctl(struct sock sk, int cmd, void arg);\n--\ninclude/linux/mroute.h=27=static inline int ip_mroute_setsockopt(struct sock sock, int optname,\n--\ninclude/linux/mroute.h-32-\ninclude/linux/mroute.h:33:static inline int ip_mroute_getsockopt(struct sock sk, int optname,\ninclude/linux/mroute.h-34-\t\t\t\t sockopt_t opt)\n--\ninclude/linux/mroute6.h=29=extern int ip6_mroute_setsockopt(struct sock , int, sockptr_t, unsigned int);\ninclude/linux/mroute6.h:30:int ip6_mroute_getsockopt(struct sock sk, int optname, sockopt_t sopt);\ninclude/linux/mroute6.h-31-extern int ip6_mr_input(struct sk_buff skb);\n--\ninclude/linux/mroute6.h=44=static inline\ninclude/linux/mroute6.h:45:int ip6_mroute_getsockopt(struct sock sock, int optname, sockopt_t sopt)\ninclude/linux/mroute6.h-46-{\n--\nnet/ipv4/ip_sockglue.c=1512=int do_ip_getsockopt(struct sock sk, int level, int optname, sockopt_t sopt)\n--\nnet/ipv4/ip_sockglue.c-1522-\tif (ip_mroute_opt(optname))\nnet/ipv4/ip_sockglue.c:1523:\t\treturn ip_mroute_getsockopt(sk, optname, sopt);\nnet/ipv4/ip_sockglue.c-1524-\n--\nnet/ipv4/ipmr.c=1619=int ipmr_sk_ioctl(struct sock sk, unsigned int cmd, void __user arg)\n--\nnet/ipv4/ipmr.c-1640-/* Getsock opt support for the multicast routing system. /\nnet/ipv4/ipmr.c:1641:int ip_mroute_getsockopt(struct sock sk, int optname, sockopt_t opt)\nnet/ipv4/ipmr.c-1642-{\n--\nnet/ipv6/ip6mr.c=1713=int ip6_mroute_setsockopt(struct sock sk, int optname, sockptr_t optval,\n--\nnet/ipv6/ip6mr.c-1895-\nnet/ipv6/ip6mr.c:1896:int ip6_mroute_getsockopt(struct sock sk, int optname, sockopt_t sopt)\nnet/ipv6/ip6mr.c-1897-{\n--\nnet/ipv6/ipv6_sockglue.c=1001=int do_ipv6_getsockopt(struct sock sk, int level, int optname, sockopt_t sopt)\n--\nnet/ipv6/ipv6_sockglue.c-1007-\tif (ip6_mroute_opt(optname))\nnet/ipv6/ipv6_sockglue.c:1008:\t\treturn ip6_mroute_getsockopt(sk, optname, sopt);\nnet/ipv6/ipv6_sockglue.c-1009-\n" }
89/3	2026/10/15 13:06	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 75789 output: 469 thoughts: 3872 Thoughts: Analysis of NeedsKMSAN for Socket Option Refactoring Alright, let's break this down. We're refactoring `do_ip_getsockopt`, `do_ipv6_getsockopt`, and related multicast functions, shifting from `sockptr_t` to `sockopt_t` and using `iov_iter` for data transfer. My primary concern is whether this change introduces or exposes uninitialized memory risks that only KMSAN would catch. Let's methodically go through this. First, I need to rigorously analyze what is copied to userspace. Every single structure that's sent out. I see zeroing with `memset(&ss, 0, sizeof(ss))` before copies for `struct sockaddr_storage ss`, `struct ip6_mtuinfo mtuinfo`, and `struct in6_flowlabel_req freq`. Good. No worries about padding. The `group_filter gsf` and `compat_group_filter gf32` structures are initialized via `copy_from_iter` before being modified and written back. So, user provided data read, written back, no padding or uninitialized memory sent to user. Scalar values like `val`, `ucval`, and `opt.optlen` are explicitly initialized before they're copied. Got it. Next, I have to ensure the length calculations, bounds checks, and iterator management are perfect. The code uses `iov_iter_advance`, `iov_iter_revert`, and `sockopt_expand_out` for offsetting. If there's an issue there, such as buffer overruns or invalid iterator state, it would likely be caught by KASAN or standard assertions, not KMSAN. The logic ensures that `copy_to_iter` checks the bounds and that the caller's and callee's views of the iterators are in sync. Based on this analysis, I'm confident there are no new uninitialized memory vulnerabilities in the data paths between kernel and userspace. Everything sent out is explicitly initialized. There are only changes to the data path using iterators, not the data itself. KASAN and the standard debuggers will flag bounds errors or iterator issues, and there's no way to leak uninitialized data. Hence, this doesn't necessitate a KMSAN session. The logic errors would show up fast with the standard bug detectors. Therefore, `NeedsKMSAN = false`. Done.
90/3	2026/10/15 13:07	tool	set-results	0m Args: { "KMSANReasoning": "The patch series refactors getsockopt handlers in IPv4 and IPv6 (including do_ip_getsockopt, do_ipv6_getsockopt, ip_mroute_getsockopt, ip6_mroute_getsockopt, and multicast filter helpers) to use the iterator-based `sockopt_t` abstraction instead of `sockptr_t`.\n\nEvaluation against KMSAN applicability criteria:\n1. Kernel-to-user copies: All kernel structures copied to user buffers (or iterators) are either completely zeroed beforehand (e.g., `memset(\u0026ss, 0, sizeof(ss))` in ip_mc_gsfget and ip6_mc_msfget, `memset(\u0026mtuinfo, 0, ...)` for IPV6_PATHMTU, `memset(\u0026freq, 0, ...)` for IPV6_FLOWLABEL_MGR), fully initialized from user input via copy_from_iter before write-back (e.g., `gsf` in ip_get_mcast_msfilter and ipv6_get_msfilter), or are fully initialized scalar types (`val`, `ucval`, `sopt.optlen`). No uninitialized stack or heap padding is exposed to userspace.\n2. Control flow / branching: Conditional branching does not depend on uninitialized variables or struct fields; `sockopt_t` structures are explicitly initialized by `sockopt_init_user`, `sockopt_set_user`, or `sockptr_to_sockopt`.\n3. Buffer lengths and bounds: Adjustments to lengths and iterator positioning (`iov_iter_advance`, `iov_iter_revert`, and bounds checking in `sockopt_expand_out`) affect user iterator offsets and buffer bounds. Any potential buffer miscalculations or memory safety issues here would be bounds/out-of-bounds errors detected by KASAN rather than uninitialized memory reads.\n\nBecause no uninitialized memory access or info-leak risks are introduced or exposed, dedicated KMSAN fuzzing is not required. Standard KASAN fuzzing is sufficient.", "NeedsKMSAN": false } Results: { "KMSANReasoning": "The patch series refactors getsockopt handlers in IPv4 and IPv6 (including do_ip_getsockopt, do_ipv6_getsockopt, ip_mroute_getsockopt, ip6_mroute_getsockopt, and multicast filter helpers) to use the iterator-based `sockopt_t` abstraction instead of `sockptr_t`.\n\nEvaluation against KMSAN applicability criteria:\n1. Kernel-to-user copies: All kernel structures copied to user buffers (or iterators) are either completely zeroed beforehand (e.g., `memset(\u0026ss, 0, sizeof(ss))` in ip_mc_gsfget and ip6_mc_msfget, `memset(\u0026mtuinfo, 0, ...)` for IPV6_PATHMTU, `memset(\u0026freq, 0, ...)` for IPV6_FLOWLABEL_MGR), fully initialized from user input via copy_from_iter before write-back (e.g., `gsf` in ip_get_mcast_msfilter and ipv6_get_msfilter), or are fully initialized scalar types (`val`, `ucval`, `sopt.optlen`). No uninitialized stack or heap padding is exposed to userspace.\n2. Control flow / branching: Conditional branching does not depend on uninitialized variables or struct fields; `sockopt_t` structures are explicitly initialized by `sockopt_init_user`, `sockopt_set_user`, or `sockptr_to_sockopt`.\n3. Buffer lengths and bounds: Adjustments to lengths and iterator positioning (`iov_iter_advance`, `iov_iter_revert`, and bounds checking in `sockopt_expand_out`) affect user iterator offsets and buffer bounds. Any potential buffer miscalculations or memory safety issues here would be bounds/out-of-bounds errors detected by KASAN rather than uninitialized memory reads.\n\nBecause no uninitialized memory access or info-leak risks are introduced or exposed, dedicated KMSAN fuzzing is not required. Standard KASAN fuzzing is sufficient.", "NeedsKMSAN": false }

LLM Calls Summary:
Total Calls	Total Tokens	Avg Tokens	Total Duration (Seconds)	Avg Duration (Seconds)

Tool Calls Summary:
Total Calls	Total Duration (Seconds)	Avg Duration (Seconds)