| Seq | Timestamp | Type | Name | Duration |
|---|---|---|---|---|
| 0/0 | 2026/09/10 00:05 | flow | patch-triage |
1mArgs:null Results: {
"EnableConfigs": [
"NET",
"SYSCTL"
],
"FocusSymbols": [
"neightbl_dump_info",
"neightbl_set",
"neigh_proc_dointvec_ms_jiffies_positive"
],
"KMSANReasoning": "The patch adds validation range checks (min/max) for the neighbor table interval_probe_time_ms parameter via netlink policy and sysctl, and fixes netlink dump resumption state tracking in neightbl_dump_info() using cb-\u003eargs[2] (which is zero-initialized by the netlink dump subsystem). All local variables (min, max, default_skip, nidx) are explicitly initialized before use, and no new data structures, uninitialized memory reads, or info-leaks to userspace are introduced. Any potential bugs related to netlink dump iteration (such as list traversal or bounds errors) are within the scope of KASAN rather than KMSAN. Therefore, a dedicated KMSAN fuzzing session is not warranted.",
"NeedsKMSAN": false,
"Reasoning": "The patch modifies reachable networking code in net/core/neighbour.c: it updates the netlink attribute policy and proc sysctl handler to enforce upper bounds on interval_probe_time_ms, and refactors/fixes the neighbor table dump pagination logic in neightbl_dump_info. These paths are directly reachable from userspace via rtnetlink (RTM_GETNEIGHTBL / RTM_SETNEIGHTBL) and procfs sysctl.",
"WorthFuzzing": true
} |
| 1/1 | 2026/09/10 00:05 | action | read-patch-diff |
0mArgs:null Results: {
"PatchDiff": "commit 2cb3115a4f8063023231ca7f6dda9d8b8c49fea6\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate: Thu Sep 10 00:05:49 2026 +0000\n\n syz-cluster: applied patch under review\n\ndiff --git a/Documentation/netlink/specs/rt-neigh.yaml b/Documentation/netlink/specs/rt-neigh.yaml\nindex 0f46ef3135905..c8e55c98d5649 100644\n--- a/Documentation/netlink/specs/rt-neigh.yaml\n+++ b/Documentation/netlink/specs/rt-neigh.yaml\n@@ -341,6 +341,9 @@ attribute-sets:\n -\n name: interval-probe-time-ms\n type: u64\n+ checks:\n+ min: 1\n+ max: 86400000\n \n operations:\n enum-model: directional\ndiff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst\nindex 208f46967ee59..b05829e44d8fc 100644\n--- a/Documentation/networking/ip-sysctl.rst\n+++ b/Documentation/networking/ip-sysctl.rst\n@@ -248,7 +248,7 @@ neigh/default/unres_qlen - INTEGER\n \n neigh/default/interval_probe_time_ms - INTEGER\n \tThe probe interval for neighbor entries with NTF_MANAGED flag,\n-\tthe min value is 1.\n+\tthe min value is 1, and the max value is 86400000 (1 day).\n \n \tDefault: 5000\n \ndiff --git a/net/core/neighbour.c b/net/core/neighbour.c\nindex 1349c0eedb642..7448320f7ad52 100644\n--- a/net/core/neighbour.c\n+++ b/net/core/neighbour.c\n@@ -2359,6 +2359,13 @@ static const struct nla_policy nl_neightbl_policy[NDTA_MAX+1] = {\n \t[NDTA_PARMS]\t\t= { .type = NLA_NESTED },\n };\n \n+#define NTBL_PARM_MS_MAX\t(24 * 60 * 60 * MSEC_PER_SEC)\n+\n+static const struct netlink_range_validation nl_ntbl_parm_ms_range = {\n+\t.min = 1,\n+\t.max = NTBL_PARM_MS_MAX,\n+};\n+\n static const struct nla_policy nl_ntbl_parm_policy[NDTPA_MAX+1] = {\n \t[NDTPA_IFINDEX]\t\t\t= { .type = NLA_U32 },\n \t[NDTPA_QUEUE_LEN]\t\t= { .type = NLA_U32 },\n@@ -2375,7 +2382,8 @@ static const struct nla_policy nl_ntbl_parm_policy[NDTPA_MAX+1] = {\n \t[NDTPA_ANYCAST_DELAY]\t\t= { .type = NLA_U64 },\n \t[NDTPA_PROXY_DELAY]\t\t= { .type = NLA_U64 },\n \t[NDTPA_LOCKTIME]\t\t= { .type = NLA_U64 },\n-\t[NDTPA_INTERVAL_PROBE_TIME_MS]\t= { .type = NLA_U64, .min = 1 },\n+\t[NDTPA_INTERVAL_PROBE_TIME_MS]\t= NLA_POLICY_FULL_RANGE(NLA_U64,\n+\t\t\t\t\t\t\t\t\u0026nl_ntbl_parm_ms_range),\n };\n \n static int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh,\n@@ -2579,9 +2587,10 @@ static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb)\n {\n \tconst struct nlmsghdr *nlh = cb-\u003enlh;\n \tstruct net *net = sock_net(skb-\u003esk);\n+\tint default_skip = cb-\u003eargs[2];\n+\tint neigh_skip = cb-\u003eargs[1];\n \tint family, tidx, nidx = 0;\n \tint tbl_skip = cb-\u003eargs[0];\n-\tint neigh_skip = cb-\u003eargs[1];\n \tstruct neigh_table *tbl;\n \n \tif (cb-\u003estrict_check) {\n@@ -2605,17 +2614,21 @@ static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb)\n \t\tif (tidx \u003c tbl_skip || (family \u0026\u0026 tbl-\u003efamily != family))\n \t\t\tcontinue;\n \n-\t\tif (neightbl_fill_info(skb, tbl, NETLINK_CB(cb-\u003eskb).portid,\n+\t\tif (!default_skip \u0026\u0026\n+\t\t neightbl_fill_info(skb, tbl, NETLINK_CB(cb-\u003eskb).portid,\n \t\t\t\t nlh-\u003enlmsg_seq, RTM_NEWNEIGHTBL,\n \t\t\t\t NLM_F_MULTI) \u003c 0)\n \t\t\tbreak;\n \n-\t\tnidx = 0;\n-\t\tp = list_next_entry(\u0026tbl-\u003eparms, list);\n-\t\tlist_for_each_entry_from_rcu(p, \u0026tbl-\u003eparms_list, list) {\n+\t\tdefault_skip = 1;\n+\n+\t\tlist_for_each_entry_rcu(p, \u0026tbl-\u003eparms_list, list) {\n \t\t\tif (!net_eq(neigh_parms_net(p), net))\n \t\t\t\tcontinue;\n \n+\t\t\tif (!p-\u003edev || p-\u003edev == blackhole_netdev)\n+\t\t\t\tcontinue;\n+\n \t\t\tif (nidx \u003c neigh_skip)\n \t\t\t\tgoto next;\n \n@@ -2630,12 +2643,15 @@ static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb)\n \t\t}\n \n \t\tneigh_skip = 0;\n+\t\tnidx = 0;\n+\t\tdefault_skip = 0;\n \t}\n out:\n \trcu_read_unlock();\n \n \tcb-\u003eargs[0] = tidx;\n \tcb-\u003eargs[1] = nidx;\n+\tcb-\u003eargs[2] = default_skip;\n \n \treturn skb-\u003elen;\n }\n@@ -3669,12 +3685,13 @@ static int neigh_proc_dointvec_ms_jiffies_positive(const struct ctl_table *ctl,\n \t\t\t\t\t\t void *buffer, size_t *lenp, loff_t *ppos)\n {\n \tstruct ctl_table tmp = *ctl;\n-\tint ret;\n+\tint ret, min, max;\n \n-\tint min = msecs_to_jiffies(1);\n+\tmin = msecs_to_jiffies(1);\n+\tmax = msecs_to_jiffies(NTBL_PARM_MS_MAX);\n \n \ttmp.extra1 = \u0026min;\n-\ttmp.extra2 = NULL;\n+\ttmp.extra2 = \u0026max;\n \n \tret = proc_dointvec_ms_jiffies_minmax(\u0026tmp, write, buffer, lenp, ppos);\n \tneigh_proc_update(ctl, write);\n"
} |
| 2/1 | 2026/09/10 00:05 | agent | patch-evaluator |
0mModel:core Args: null Results: {
"EnableConfigs": [
"NET",
"SYSCTL"
],
"FocusSymbols": [
"neightbl_dump_info",
"neightbl_set",
"neigh_proc_dointvec_ms_jiffies_positive"
],
"Reasoning": "The patch modifies reachable networking code in net/core/neighbour.c: it updates the netlink attribute policy and proc sysctl handler to enforce upper bounds on interval_probe_time_ms, and refactors/fixes the neighbor table dump pagination logic in neightbl_dump_info. These paths are directly reachable from userspace via rtnetlink (RTM_GETNEIGHTBL / RTM_SETNEIGHTBL) and procfs sysctl.",
"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 2cb3115a4f8063023231ca7f6dda9d8b8c49fea6
Author: syz-cluster <triage@syzkaller.com>
Date: Thu Sep 10 00:05:49 2026 +0000
syz-cluster: applied patch under review
diff --git a/Documentation/netlink/specs/rt-neigh.yaml b/Documentation/netlink/specs/rt-neigh.yaml
index 0f46ef3135905..c8e55c98d5649 100644
--- a/Documentation/netlink/specs/rt-neigh.yaml
+++ b/Documentation/netlink/specs/rt-neigh.yaml
@@ -341,6 +341,9 @@ attribute-sets:
-
name: interval-probe-time-ms
type: u64
+ checks:
+ min: 1
+ max: 86400000
operations:
enum-model: directional
diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
index 208f46967ee59..b05829e44d8fc 100644
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
@@ -248,7 +248,7 @@ neigh/default/unres_qlen - INTEGER
neigh/default/interval_probe_time_ms - INTEGER
The probe interval for neighbor entries with NTF_MANAGED flag,
- the min value is 1.
+ the min value is 1, and the max value is 86400000 (1 day).
Default: 5000
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 1349c0eedb642..7448320f7ad52 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -2359,6 +2359,13 @@ static const struct nla_policy nl_neightbl_policy[NDTA_MAX+1] = {
[NDTA_PARMS] = { .type = NLA_NESTED },
};
+#define NTBL_PARM_MS_MAX (24 * 60 * 60 * MSEC_PER_SEC)
+
+static const struct netlink_range_validation nl_ntbl_parm_ms_range = {
+ .min = 1,
+ .max = NTBL_PARM_MS_MAX,
+};
+
static const struct nla_policy nl_ntbl_parm_policy[NDTPA_MAX+1] = {
[NDTPA_IFINDEX] = { .type = NLA_U32 },
[NDTPA_QUEUE_LEN] = { .type = NLA_U32 },
@@ -2375,7 +2382,8 @@ static const struct nla_policy nl_ntbl_parm_policy[NDTPA_MAX+1] = {
[NDTPA_ANYCAST_DELAY] = { .type = NLA_U64 },
[NDTPA_PROXY_DELAY] = { .type = NLA_U64 },
[NDTPA_LOCKTIME] = { .type = NLA_U64 },
- [NDTPA_INTERVAL_PROBE_TIME_MS] = { .type = NLA_U64, .min = 1 },
+ [NDTPA_INTERVAL_PROBE_TIME_MS] = NLA_POLICY_FULL_RANGE(NLA_U64,
+ &nl_ntbl_parm_ms_range),
};
static int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh,
@@ -2579,9 +2587,10 @@ static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
{
const struct nlmsghdr *nlh = cb->nlh;
struct net *net = sock_net(skb->sk);
+ int default_skip = cb->args[2];
+ int neigh_skip = cb->args[1];
int family, tidx, nidx = 0;
int tbl_skip = cb->args[0];
- int neigh_skip = cb->args[1];
struct neigh_table *tbl;
if (cb->strict_check) {
@@ -2605,17 +2614,21 @@ static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
if (tidx < tbl_skip || (family && tbl->family != family))
continue;
- if (neightbl_fill_info(skb, tbl, NETLINK_CB(cb->skb).portid,
+ if (!default_skip &&
+ neightbl_fill_info(skb, tbl, NETLINK_CB(cb->skb).portid,
nlh->nlmsg_seq, RTM_NEWNEIGHTBL,
NLM_F_MULTI) < 0)
break;
- nidx = 0;
- p = list_next_entry(&tbl->parms, list);
- list_for_each_entry_from_rcu(p, &tbl->parms_list, list) {
+ default_skip = 1;
+
+ list_for_each_entry_rcu(p, &tbl->parms_list, list) {
if (!net_eq(neigh_parms_net(p), net))
continue;
+ if (!p->dev || p->dev == blackhole_netdev)
+ continue;
+
if (nidx < neigh_skip)
goto next;
@@ -2630,12 +2643,15 @@ static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
}
neigh_skip = 0;
+ nidx = 0;
+ default_skip = 0;
}
out:
rcu_read_unlock();
cb->args[0] = tidx;
cb->args[1] = nidx;
+ cb->args[2] = default_skip;
return skb->len;
}
@@ -3669,12 +3685,13 @@ static int neigh_proc_dointvec_ms_jiffies_positive(const struct ctl_table *ctl,
void *buffer, size_t *lenp, loff_t *ppos)
{
struct ctl_table tmp = *ctl;
- int ret;
+ int ret, min, max;
- int min = msecs_to_jiffies(1);
+ min = msecs_to_jiffies(1);
+ max = msecs_to_jiffies(NTBL_PARM_MS_MAX);
tmp.extra1 = &min;
- tmp.extra2 = NULL;
+ tmp.extra2 = &max;
ret = proc_dointvec_ms_jiffies_minmax(&tmp, write, buffer, lenp, ppos);
neigh_proc_update(ctl, write);
|
| 3/2 | 2026/09/10 00:05 | llm | patch-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 4508 output: 31 thoughts: 499 Thoughts: **Fuzzing Triage Assessment of a Network Neighbor Patch Series** Okay, so I need to decide if this patch series is worth throwing at syzkaller. Let's break this down. First, the core task: evaluating a Linux kernel patch for fuzzing potential, specifically for the purpose of syzkaller triage. That's pretty standard, right? This is straight-up kernel development, QA, and defensive engineering territory. Alright, risk analysis first. It seems pretty benign from the get-go, classic QA analysis. Let's see what we are dealing with. Okay, I've got the modified files: `Documentation/netlink/specs/rt-neigh.yaml`, `Documentation/networking/ip-sysctl.rst`, and the critical one, `net/core/neighbour.c`. That's where the action is, so let's dig into `net/core/neighbour.c`. It looks like we have: 1. Updates to `nl_ntbl_parm_policy` with input validation, specifically a max range for `NTBL_PARM_MS_MAX`, which is good. That's a good defensive programming practice, mitigating potential integer overflows or other unexpected input. 2. Significant changes to `neightbl_dump_info`. It looks like there's some fixing in how it handles `default_skip` within `cb->args[2]`, a change from `list_for_each_entry_from_rcu` to `list_for_each_entry_rcu`, which is important for RCU-safe traversal. Additionally, there are checks on `p->dev`, specifically `if (!p->dev || p->dev == blackhole_netdev) continue;`, which may be for null pointer handling or handling of the blackhole device. Finally, there is a refactor of dumping logic, likely fixing a state machine for dumping neighbor table parameters through netlink. 3. Changes to `neigh_proc_dointvec_ms_jiffies_positive` with max bounds checks for sysctl, another defensive change. Crucially, this is all in `net/core/neighbour.c`. That's *core* networking code, so this should get some attention. The question is, is this reachable? And the answer is yes, absolutely! We're talking about reaching this through rtnetlink (`RTM_GETNEIGHTBL` / `RTM_SETNEIGHTBL`) and sysctl calls (`/proc/sys/net/ipv4/neigh/...` or `/proc/sys/net/ipv6/neigh/...`). This also covers netlink table dump and set functions (`neightbl_dump_info` and `neightbl_set`) and the sysctl handler. My next step is to grep around `net/core/neighbour.c` and functions nearby to get a better feel. |
| 4/2 | 2026/09/10 00:06 | tool | grepper |
0mArgs:{
"Expression": "neightbl_dump_info",
"PathPrefix": "net/core/"
}Results: {
"Output": "net/core/neighbour.c=2562=static int neightbl_valid_dump_info(const struct nlmsghdr *nlh,\n--\nnet/core/neighbour.c-2585-\nnet/core/neighbour.c:2586:static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb)\nnet/core/neighbour.c-2587-{\n--\nnet/core/neighbour.c=3961=static const struct rtnl_msg_handler neigh_rtnl_msg_handlers[] __initconst = {\n--\nnet/core/neighbour.c-3965-\t .flags = RTNL_FLAG_DOIT_UNLOCKED | RTNL_FLAG_DUMP_UNLOCKED},\nnet/core/neighbour.c:3966:\t{.msgtype = RTM_GETNEIGHTBL, .dumpit = neightbl_dump_info,\nnet/core/neighbour.c-3967-\t .flags = RTNL_FLAG_DUMP_UNLOCKED},\n"
} |
| 5/2 | 2026/09/10 00:06 | llm | patch-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 5929 output: 37 thoughts: 32 Thoughts: Okay, here's my interpretation of those thoughts, summarized from my perspective as a highly knowledgeable professional in the field: **Digging Deeper into the Network Neighbor Discovery Process** Alright, I'm thinking we need to broaden our scope a bit here. While we've focused on [assumed previous topic, not in the provided text], the core of this seems to be about the nuances of network neighbor discovery, specifically around time-sensitive processes. So, to ensure we haven't overlooked any critical factors, I need to take a look at `neigh_proc_dointvec_ms_jiffies_positive` and `neightbl_set`. I suspect that these might contain key timing parameters, or critical network table management. Let's see if either of them is subtly affecting, or could be affecting, performance in a way we hadn't considered. It’s always best to be thorough, especially when timing and table management are involved. These functions are likely central to neighbor discovery’s accurate operation. |
| 6/2 | 2026/09/10 00:06 | tool | grepper |
0mArgs:{
"Expression": "neigh_proc_dointvec_ms_jiffies_positive",
"PathPrefix": "net/"
}Results: {
"Output": "net/core/neighbour.c=3669=static int neigh_proc_dointvec_zero_intmax(const struct ctl_table *ctl, int write,\n--\nnet/core/neighbour.c-3683-\nnet/core/neighbour.c:3684:static int neigh_proc_dointvec_ms_jiffies_positive(const struct ctl_table *ctl, int write,\nnet/core/neighbour.c-3685-\t\t\t\t\t\t void *buffer, size_t *lenp, loff_t *ppos)\n--\nnet/core/neighbour.c=3751=static int neigh_proc_base_reachable_time(const struct ctl_table *ctl, int write,\n--\nnet/core/neighbour.c-3796-#define NEIGH_SYSCTL_MS_JIFFIES_POSITIVE_ENTRY(attr, name) \\\nnet/core/neighbour.c:3797:\tNEIGH_SYSCTL_ENTRY(attr, attr, name, 0644, neigh_proc_dointvec_ms_jiffies_positive)\nnet/core/neighbour.c-3798-\n"
} |
| 7/2 | 2026/09/10 00:06 | llm | patch-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 6503 output: 31 thoughts: 23 Thoughts: Here's my take on those thoughts, tailored for an expert audience: **Analyzing Network Table Parameter Policies** Okay, so I'm looking at `nl_ntbl_parm_policy` and `neightbl_set`. Immediately, my brain is going to cross-reference these with my existing mental models for network table configurations and neighbor table management. I'm likely checking for any potential conflicts or inconsistencies between the two. Specifically, I'm thinking: is the policy enforced by `nl_ntbl_parm_policy` reflected accurately (and predictably) in the settings managed by `neightbl_set`? Are there any overrides happening? Or, are there any situations where one influences the other in an unexpected way? My immediate concern is that I'm able to predict behaviour, and that there are not any unintended consequences. The interplay between these two is critical for network performance and stability, and a misconfiguration here can lead to all sorts of headaches. I need to understand if these are independent settings or tightly coupled, and, if coupled, what's the interaction matrix like? |
| 8/2 | 2026/09/10 00:06 | tool | grepper |
0mArgs:{
"Expression": "nl_ntbl_parm_policy",
"PathPrefix": "net/"
}Results: {
"Output": "net/core/neighbour.c=2364=static const struct netlink_range_validation nl_ntbl_parm_ms_range = {\n--\nnet/core/neighbour.c-2368-\nnet/core/neighbour.c:2369:static const struct nla_policy nl_ntbl_parm_policy[NDTPA_MAX+1] = {\nnet/core/neighbour.c-2370-\t[NDTPA_IFINDEX]\t\t\t= { .type = NLA_U32 },\n--\nnet/core/neighbour.c=2389=static int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh,\n--\nnet/core/neighbour.c-2445-\t\t\t\t\t\t tb[NDTA_PARMS],\nnet/core/neighbour.c:2446:\t\t\t\t\t\t nl_ntbl_parm_policy, extack);\nnet/core/neighbour.c-2447-\t\tif (err \u003c 0)\n"
} |
| 9/2 | 2026/09/10 00:06 | llm | patch-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 7046 output: 36 thoughts: 75 Thoughts: Here's my analysis of those code changes, taking on the persona of an expert: **Deep Dive into Neighbor Table Modifications** Alright, let's get down to brass tacks. I need to fully grasp what's going on within these changes. The critical areas I'm zoning in on are precisely how `neightbl_dump_info`, `neigh_proc_dointvec_ms_jiffies_positive`, and `neightbl_set` have been altered. These functions are key to managing and interacting with the neighbor table, so understanding their modifications is paramount. To build a thorough understanding I'm going to pull up `net/core/neighbour.c` and focus on lines 2580 through 2660. The `read-file` command should give me the detailed context I need, letting me see how these functions are implemented and interact with the broader neighbor table functionality. I'm looking for the nitty-gritty: How are the data structures changing? What are the new parameters or behaviors? Are there any new locking mechanisms involved? Any changes to error handling? I need the full picture to be confident in my understanding. |
| 10/2 | 2026/09/10 00:06 | tool | read-file |
0mArgs:{
"File": "net/core/neighbour.c",
"FirstLine": 2580,
"LineCount": 80
}Results: {
"Contents": "2580:\t\t\treturn -EINVAL;\n2581:\t\t}\n2582:\t\n2583:\t\treturn 0;\n2584:\t}\n2585:\t\n2586:\tstatic int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb)\n2587:\t{\n2588:\t\tconst struct nlmsghdr *nlh = cb-\u003enlh;\n2589:\t\tstruct net *net = sock_net(skb-\u003esk);\n2590:\t\tint default_skip = cb-\u003eargs[2];\n2591:\t\tint neigh_skip = cb-\u003eargs[1];\n2592:\t\tint family, tidx, nidx = 0;\n2593:\t\tint tbl_skip = cb-\u003eargs[0];\n2594:\t\tstruct neigh_table *tbl;\n2595:\t\n2596:\t\tif (cb-\u003estrict_check) {\n2597:\t\t\tint err = neightbl_valid_dump_info(nlh, cb-\u003eextack);\n2598:\t\n2599:\t\t\tif (err \u003c 0)\n2600:\t\t\t\treturn err;\n2601:\t\t}\n2602:\t\n2603:\t\tfamily = ((struct rtgenmsg *)nlmsg_data(nlh))-\u003ertgen_family;\n2604:\t\n2605:\t\trcu_read_lock();\n2606:\t\n2607:\t\tfor (tidx = 0; tidx \u003c NEIGH_NR_TABLES; tidx++) {\n2608:\t\t\tstruct neigh_parms *p;\n2609:\t\n2610:\t\t\ttbl = rcu_dereference(neigh_tables[tidx]);\n2611:\t\t\tif (!tbl)\n2612:\t\t\t\tcontinue;\n2613:\t\n2614:\t\t\tif (tidx \u003c tbl_skip || (family \u0026\u0026 tbl-\u003efamily != family))\n2615:\t\t\t\tcontinue;\n2616:\t\n2617:\t\t\tif (!default_skip \u0026\u0026\n2618:\t\t\t neightbl_fill_info(skb, tbl, NETLINK_CB(cb-\u003eskb).portid,\n2619:\t\t\t\t\t nlh-\u003enlmsg_seq, RTM_NEWNEIGHTBL,\n2620:\t\t\t\t\t NLM_F_MULTI) \u003c 0)\n2621:\t\t\t\tbreak;\n2622:\t\n2623:\t\t\tdefault_skip = 1;\n2624:\t\n2625:\t\t\tlist_for_each_entry_rcu(p, \u0026tbl-\u003eparms_list, list) {\n2626:\t\t\t\tif (!net_eq(neigh_parms_net(p), net))\n2627:\t\t\t\t\tcontinue;\n2628:\t\n2629:\t\t\t\tif (!p-\u003edev || p-\u003edev == blackhole_netdev)\n2630:\t\t\t\t\tcontinue;\n2631:\t\n2632:\t\t\t\tif (nidx \u003c neigh_skip)\n2633:\t\t\t\t\tgoto next;\n2634:\t\n2635:\t\t\t\tif (neightbl_fill_param_info(skb, tbl, p,\n2636:\t\t\t\t\t\t\t NETLINK_CB(cb-\u003eskb).portid,\n2637:\t\t\t\t\t\t\t nlh-\u003enlmsg_seq,\n2638:\t\t\t\t\t\t\t RTM_NEWNEIGHTBL,\n2639:\t\t\t\t\t\t\t NLM_F_MULTI) \u003c 0)\n2640:\t\t\t\t\tgoto out;\n2641:\t\t\tnext:\n2642:\t\t\t\tnidx++;\n2643:\t\t\t}\n2644:\t\n2645:\t\t\tneigh_skip = 0;\n2646:\t\t\tnidx = 0;\n2647:\t\t\tdefault_skip = 0;\n2648:\t\t}\n2649:\tout:\n2650:\t\trcu_read_unlock();\n2651:\t\n2652:\t\tcb-\u003eargs[0] = tidx;\n2653:\t\tcb-\u003eargs[1] = nidx;\n2654:\t\tcb-\u003eargs[2] = default_skip;\n2655:\t\n2656:\t\treturn skb-\u003elen;\n2657:\t}\n2658:\t\n2659:\tstatic int __neigh_fill_info(struct sk_buff *skb, struct neighbour *neigh,\n"
} |
| 11/2 | 2026/09/10 00:06 | llm | patch-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 8545 output: 25 thoughts: 337 Thoughts: **My Assessment of the `net/core/neighbour.c` Changes** Okay, let's break this down systematically. My initial assessment is that these changes, residing within `net/core/neighbour.c`, are definitely worth a closer look, given their potential impact on core networking functionality. I see three key functions that have been modified: `nl_ntbl_parm_policy` (associated with `neightbl_set`), `neightbl_dump_info`, and `neigh_proc_dointvec_ms_jiffies_positive`. The context suggests this is code handling Neighbor Discovery and related table management. Reachable? Absolutely. The `neightbl_dump_info` function is accessible through `RTM_GETNEIGHTBL` rtnetlink messages, and `neightbl_set` is reachable via `RTM_SETNEIGHTBL` rtnetlink messages. This means these are exposed interfaces. Then, `neigh_proc_dointvec_ms_jiffies_positive` is hooked up as a sysctl handler for the `neigh/*/interval_probe_time_ms` setting. No exotic configurations are needed to reach these, and this is pretty standard networking code. Worth fuzzing? Given this reachability and potential for impacting table management, I'd say this is definitely worth fuzzing; TRUE. This is core functionality. The focus should be on these symbols: `neightbl_dump_info`, `neightbl_set`, and `neigh_proc_dointvec_ms_jiffies_positive`. Finally, before I dig deeper, I need to check the Kconfig and Makefile to make sure this code is built under `CONFIG_NET`. It's essential to understand if this functionality is part of the standard kernel configuration. I'll need to check the build configuration and the Makefile to make sure, but, given the path, I expect it's a safe bet to assume this is enabled in standard kernel configurations. |
| 12/2 | 2026/09/10 00:06 | tool | grepper |
0mArgs:{
"Expression": "neighbour.o",
"PathPrefix": "net/"
}Results: {
"Output": "net/batman-adv/bat_iv_ogm.c=1944=static int batadv_iv_ogm_receive(struct sk_buff *skb,\n--\nnet/batman-adv/bat_iv_ogm.c-1994-/**\nnet/batman-adv/bat_iv_ogm.c:1995: * batadv_iv_ogm_neigh_get_tq_avg() - Get the TQ average for a neighbour on a\nnet/batman-adv/bat_iv_ogm.c-1996- * given outgoing interface.\n--\nnet/core/Makefile=12=obj-y\t\t += dev.o dev_api.o dev_addr_lists.o dst.o netevent.o \\\nnet/core/Makefile:13:\t\t\tneighbour.o rtnetlink.o utils.o link_watch.o filter.o \\\nnet/core/Makefile-14-\t\t\tsock_diag.o dev_ioctl.o tso.o sock_reuseport.o \\\n--\nnet/ipv4/ip_gre.c-79- only Linux complies to rfc1812 now (yes, guys, Linux is the only\nnet/ipv4/ip_gre.c:80: true router now :-)), all routers (at least, in neighbourhood of mine)\nnet/ipv4/ip_gre.c-81- return only 8 bytes of payload. It is the end.\n"
} |
| 13/2 | 2026/09/10 00:06 | llm | patch-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 9692 output: 29 thoughts: 118 Thoughts: **Investigating the `neighbour.o` Module and Configuration Dependencies** Okay, so I see that `neighbour.o` is built as part of `obj-y` in `net/core/Makefile`, and that's contingent on `CONFIG_NET`. My initial thought is to quickly verify if there are any sysctl configurations specifically for `neigh_proc_dointvec_ms_jiffies_positive`. I need to figure out if there's a dependency on `CONFIG_SYSCTL`, `CONFIG_NET`, or even potentially `CONFIG_INET`. I suspect there might be conditional compilation involved. Now, let's dive into `net/core/neighbour.c`. I need to look for any preprocessor ifdefs surrounding `neigh_proc_dointvec_ms_jiffies_positive`. That'll confirm if the inclusion of this variable or the relevant functionality depends on any of those configuration options I just mentioned. This should give me a solid understanding of its compile-time behavior. |
| 14/2 | 2026/09/10 00:06 | tool | grepper |
0mArgs:{
"Expression": "CONFIG_",
"PathPrefix": "net/core/neighbour.c"
}Results: {
"Output": "net/core/neighbour.c-22-#include \u003clinux/proc_fs.h\u003e\nnet/core/neighbour.c:23:#ifdef CONFIG_SYSCTL\nnet/core/neighbour.c-24-#include \u003clinux/sysctl.h\u003e\n--\nnet/core/neighbour.c=56=static void pneigh_ifdown(struct neigh_table *tbl, struct net_device *dev,\n--\nnet/core/neighbour.c-58-\nnet/core/neighbour.c:59:#ifdef CONFIG_PROC_FS\nnet/core/neighbour.c-60-static const struct seq_operations neigh_stat_seq_ops;\n--\nnet/core/neighbour.c=1821=void neigh_table_init(int index, struct neigh_table *tbl)\n--\nnet/core/neighbour.c-1839-\nnet/core/neighbour.c:1840:#ifdef CONFIG_PROC_FS\nnet/core/neighbour.c-1841-\tif (!proc_create_seq_data(tbl-\u003eid, 0, init_net.proc_net_stat,\n--\nnet/core/neighbour.c=3255=EXPORT_SYMBOL(neigh_xmit);\nnet/core/neighbour.c-3256-\nnet/core/neighbour.c:3257:#ifdef CONFIG_PROC_FS\nnet/core/neighbour.c-3258-\n--\nnet/core/neighbour.c=3565=static const struct seq_operations neigh_stat_seq_ops = {\n--\nnet/core/neighbour.c-3570-};\nnet/core/neighbour.c:3571:#endif /* CONFIG_PROC_FS */\nnet/core/neighbour.c-3572-\n--\nnet/core/neighbour.c=3612=EXPORT_SYMBOL(neigh_app_ns);\nnet/core/neighbour.c-3613-\nnet/core/neighbour.c:3614:#ifdef CONFIG_SYSCTL\nnet/core/neighbour.c-3615-static int unres_qlen_max = INT_MAX / SKB_TRUESIZE(ETH_FRAME_LEN);\n--\nnet/core/neighbour.c=3957=EXPORT_SYMBOL(neigh_sysctl_unregister);\nnet/core/neighbour.c-3958-\nnet/core/neighbour.c:3959:#endif\t/* CONFIG_SYSCTL */\nnet/core/neighbour.c-3960-\n"
} |
| 15/2 | 2026/09/10 00:06 | llm | patch-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 10663 output: 169 thoughts: 392 Thoughts: **My Analysis of this Network Neighbor Table Patch** Okay, so I'm looking at this patch and my initial thought is, of course, that `CONFIG_SYSCTL` is *required* for the sysctl bits in `net/core/neighbour.c`, and `CONFIG_NET` is the absolute base config. It's almost automatic, but let's just confirm that `CONFIG_INET` is also a good idea to have enabled, given that we're dealing with neighbor tables, ARP, and IPv6 ND, which generally live under the umbrella of `CONFIG_INET` or `CONFIG_IPV6`. But yes, `CONFIG_NET` and `CONFIG_SYSCTL` are the core essentials here. Now, let's drill down into the details. I see some key symbols flagged as 'focused': `neightbl_dump_info`, `neightbl_set`, and `neigh_proc_dointvec_ms_jiffies_positive`. I need to ensure these aren't some universally used things, because if it *is* used universally, that's important to keep in mind, and that it may affect other parts of the system. But no, they are specific to rtnetlink neighbor table operations and proc sysctl for neighbor parameters. Got it. Next, I need to do a quick sanity check on the patch's overall reasoning. Okay, so it looks like what the patch actually does is it validates the interval probe time range in the rtnetlink policy and the sysctl table. And it also refactors pagination and filtering in `neightbl_dump_info`, specifically with tracking `default_skip` and filtering out `blackhole_netdev` and missing devices. This makes sense. Reachability-wise, this is all modifying core netlink neighbor table dumping/configuration and sysctl interface, which is reachable from userspace via the standard network-focused RTNetlink calls like `RTM_GETNEIGHTBL` and `RTM_SETNEIGHTBL`, and also via `/proc/sys/net/*`. The implications of all of this are that it is **worth fuzzing**. We have interval-based configuration/dumping via RTNetlink. The required configs are `NET` and `SYSCTL`. The FocusSymbols are, again, `neightbl_dump_info`, `neightbl_set`, and `neigh_proc_dointvec_ms_jiffies_positive`. Okay, I'm confident in this analysis. Let's invoke `set-results`. |
| 16/2 | 2026/09/10 00:06 | tool | set-results |
0mArgs:{
"EnableConfigs": [
"NET",
"SYSCTL"
],
"FocusSymbols": [
"neightbl_dump_info",
"neightbl_set",
"neigh_proc_dointvec_ms_jiffies_positive"
],
"Reasoning": "The patch modifies reachable networking code in net/core/neighbour.c: it updates the netlink attribute policy and proc sysctl handler to enforce upper bounds on interval_probe_time_ms, and refactors/fixes the neighbor table dump pagination logic in neightbl_dump_info. These paths are directly reachable from userspace via rtnetlink (RTM_GETNEIGHTBL / RTM_SETNEIGHTBL) and procfs sysctl.",
"WorthFuzzing": true
}Results: {
"EnableConfigs": [
"NET",
"SYSCTL"
],
"FocusSymbols": [
"neightbl_dump_info",
"neightbl_set",
"neigh_proc_dointvec_ms_jiffies_positive"
],
"Reasoning": "The patch modifies reachable networking code in net/core/neighbour.c: it updates the netlink attribute policy and proc sysctl handler to enforce upper bounds on interval_probe_time_ms, and refactors/fixes the neighbor table dump pagination logic in neightbl_dump_info. These paths are directly reachable from userspace via rtnetlink (RTM_GETNEIGHTBL / RTM_SETNEIGHTBL) and procfs sysctl.",
"WorthFuzzing": true
} |
| 17/1 | 2026/09/10 00:06 | action | If |
0mArgs:{
"WorthFuzzing": true
}Results: null |
| 18/2 | 2026/09/10 00:06 | agent | kmsan-evaluator |
0mModel:core Args: null Results: {
"KMSANReasoning": "The patch adds validation range checks (min/max) for the neighbor table interval_probe_time_ms parameter via netlink policy and sysctl, and fixes netlink dump resumption state tracking in neightbl_dump_info() using cb-\u003eargs[2] (which is zero-initialized by the netlink dump subsystem). All local variables (min, max, default_skip, nidx) are explicitly initialized before use, and no new data structures, uninitialized memory reads, or info-leaks to userspace are introduced. Any potential bugs related to netlink dump iteration (such as list traversal or bounds errors) are within the scope of KASAN rather than KMSAN. Therefore, a dedicated KMSAN fuzzing session is not warranted.",
"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 2cb3115a4f8063023231ca7f6dda9d8b8c49fea6
Author: syz-cluster <triage@syzkaller.com>
Date: Thu Sep 10 00:05:49 2026 +0000
syz-cluster: applied patch under review
diff --git a/Documentation/netlink/specs/rt-neigh.yaml b/Documentation/netlink/specs/rt-neigh.yaml
index 0f46ef3135905..c8e55c98d5649 100644
--- a/Documentation/netlink/specs/rt-neigh.yaml
+++ b/Documentation/netlink/specs/rt-neigh.yaml
@@ -341,6 +341,9 @@ attribute-sets:
-
name: interval-probe-time-ms
type: u64
+ checks:
+ min: 1
+ max: 86400000
operations:
enum-model: directional
diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
index 208f46967ee59..b05829e44d8fc 100644
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
@@ -248,7 +248,7 @@ neigh/default/unres_qlen - INTEGER
neigh/default/interval_probe_time_ms - INTEGER
The probe interval for neighbor entries with NTF_MANAGED flag,
- the min value is 1.
+ the min value is 1, and the max value is 86400000 (1 day).
Default: 5000
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 1349c0eedb642..7448320f7ad52 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -2359,6 +2359,13 @@ static const struct nla_policy nl_neightbl_policy[NDTA_MAX+1] = {
[NDTA_PARMS] = { .type = NLA_NESTED },
};
+#define NTBL_PARM_MS_MAX (24 * 60 * 60 * MSEC_PER_SEC)
+
+static const struct netlink_range_validation nl_ntbl_parm_ms_range = {
+ .min = 1,
+ .max = NTBL_PARM_MS_MAX,
+};
+
static const struct nla_policy nl_ntbl_parm_policy[NDTPA_MAX+1] = {
[NDTPA_IFINDEX] = { .type = NLA_U32 },
[NDTPA_QUEUE_LEN] = { .type = NLA_U32 },
@@ -2375,7 +2382,8 @@ static const struct nla_policy nl_ntbl_parm_policy[NDTPA_MAX+1] = {
[NDTPA_ANYCAST_DELAY] = { .type = NLA_U64 },
[NDTPA_PROXY_DELAY] = { .type = NLA_U64 },
[NDTPA_LOCKTIME] = { .type = NLA_U64 },
- [NDTPA_INTERVAL_PROBE_TIME_MS] = { .type = NLA_U64, .min = 1 },
+ [NDTPA_INTERVAL_PROBE_TIME_MS] = NLA_POLICY_FULL_RANGE(NLA_U64,
+ &nl_ntbl_parm_ms_range),
};
static int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh,
@@ -2579,9 +2587,10 @@ static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
{
const struct nlmsghdr *nlh = cb->nlh;
struct net *net = sock_net(skb->sk);
+ int default_skip = cb->args[2];
+ int neigh_skip = cb->args[1];
int family, tidx, nidx = 0;
int tbl_skip = cb->args[0];
- int neigh_skip = cb->args[1];
struct neigh_table *tbl;
if (cb->strict_check) {
@@ -2605,17 +2614,21 @@ static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
if (tidx < tbl_skip || (family && tbl->family != family))
continue;
- if (neightbl_fill_info(skb, tbl, NETLINK_CB(cb->skb).portid,
+ if (!default_skip &&
+ neightbl_fill_info(skb, tbl, NETLINK_CB(cb->skb).portid,
nlh->nlmsg_seq, RTM_NEWNEIGHTBL,
NLM_F_MULTI) < 0)
break;
- nidx = 0;
- p = list_next_entry(&tbl->parms, list);
- list_for_each_entry_from_rcu(p, &tbl->parms_list, list) {
+ default_skip = 1;
+
+ list_for_each_entry_rcu(p, &tbl->parms_list, list) {
if (!net_eq(neigh_parms_net(p), net))
continue;
+ if (!p->dev || p->dev == blackhole_netdev)
+ continue;
+
if (nidx < neigh_skip)
goto next;
@@ -2630,12 +2643,15 @@ static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
}
neigh_skip = 0;
+ nidx = 0;
+ default_skip = 0;
}
out:
rcu_read_unlock();
cb->args[0] = tidx;
cb->args[1] = nidx;
+ cb->args[2] = default_skip;
return skb->len;
}
@@ -3669,12 +3685,13 @@ static int neigh_proc_dointvec_ms_jiffies_positive(const struct ctl_table *ctl,
void *buffer, size_t *lenp, loff_t *ppos)
{
struct ctl_table tmp = *ctl;
- int ret;
+ int ret, min, max;
- int min = msecs_to_jiffies(1);
+ min = msecs_to_jiffies(1);
+ max = msecs_to_jiffies(NTBL_PARM_MS_MAX);
tmp.extra1 = &min;
- tmp.extra2 = NULL;
+ tmp.extra2 = &max;
ret = proc_dointvec_ms_jiffies_minmax(&tmp, write, buffer, lenp, ppos);
neigh_proc_update(ctl, write);
|
| 19/3 | 2026/09/10 00:06 | llm | kmsan-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 3720 output: 36 thoughts: 567 Thoughts: **Analyzing the Patch for KMSAN Fuzzing Needs** Okay, let's break this down. My initial thought is to figure out whether this patch necessitates a focused KMSAN fuzzing session. The changes are primarily around validating and handling the `interval-probe-time-ms` parameter for neighbor tables via Netlink. First, the patch introduces input validation with min/max values for `interval-probe-time-ms` in both the documentation and the kernel code (`net/core/neighbour.c`). The maximum value seems to be capped at 24 hours (86400000 milliseconds, or `NTBL_PARM_MS_MAX`). This is good; explicit bounds are always a win. The use of `NLA_POLICY_FULL_RANGE` with the `nl_ntbl_parm_ms_range` suggests that Netlink message parsing is being made more robust. That makes me feel better about general security. The core of the change lies within `neightbl_dump_info()`. I see that the patch updates the dumping logic to manage dump continuation and restart states more explicitly with `default_skip`. This is interesting; dumps can often expose vulnerabilities. I also see that there's a refinement in the iteration logic, using `list_for_each_entry_rcu` instead of `list_for_each_entry_from_rcu`, and that blackhole/null devices are now being explicitly skipped. Finally, the code also uses `neigh_proc_dointvec_ms_jiffies_positive()` to set a maximum value in jiffies format. Now, this is where I need to dig deeper. While the changes appear to improve code clarity and potentially fix a subtle bug or two, dump routines are a prime target for fuzzing. I need to be *absolutely* certain that these changes haven't introduced any memory leaks or uninitialized variable reads within the `neightbl_dump_info` function or related Netlink processing. A Netlink dump might be a great vector for a security issue, so I'll need to use `read-file` or `grepper` to see how the netlink dump works. I'm going to look at how this logic is used and how the Netlink messages are built and parsed. Specifically, I'll be looking for where data is being read and written in `neightbl_dump_info()` and other relevant functions. I need to understand the full context of these changes to make a sound judgment about the fuzzing strategy. |
| 20/3 | 2026/09/10 00:06 | tool | read-file |
0mArgs:{
"File": "net/core/neighbour.c",
"FirstLine": 2575,
"LineCount": 80
}Results: {
"Contents": "2575:\t\t\treturn -EINVAL;\n2576:\t\t}\n2577:\t\n2578:\t\tif (nlmsg_attrlen(nlh, sizeof(*ndtm))) {\n2579:\t\t\tNL_SET_ERR_MSG(extack, \"Invalid data after header in neighbor table dump request\");\n2580:\t\t\treturn -EINVAL;\n2581:\t\t}\n2582:\t\n2583:\t\treturn 0;\n2584:\t}\n2585:\t\n2586:\tstatic int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb)\n2587:\t{\n2588:\t\tconst struct nlmsghdr *nlh = cb-\u003enlh;\n2589:\t\tstruct net *net = sock_net(skb-\u003esk);\n2590:\t\tint default_skip = cb-\u003eargs[2];\n2591:\t\tint neigh_skip = cb-\u003eargs[1];\n2592:\t\tint family, tidx, nidx = 0;\n2593:\t\tint tbl_skip = cb-\u003eargs[0];\n2594:\t\tstruct neigh_table *tbl;\n2595:\t\n2596:\t\tif (cb-\u003estrict_check) {\n2597:\t\t\tint err = neightbl_valid_dump_info(nlh, cb-\u003eextack);\n2598:\t\n2599:\t\t\tif (err \u003c 0)\n2600:\t\t\t\treturn err;\n2601:\t\t}\n2602:\t\n2603:\t\tfamily = ((struct rtgenmsg *)nlmsg_data(nlh))-\u003ertgen_family;\n2604:\t\n2605:\t\trcu_read_lock();\n2606:\t\n2607:\t\tfor (tidx = 0; tidx \u003c NEIGH_NR_TABLES; tidx++) {\n2608:\t\t\tstruct neigh_parms *p;\n2609:\t\n2610:\t\t\ttbl = rcu_dereference(neigh_tables[tidx]);\n2611:\t\t\tif (!tbl)\n2612:\t\t\t\tcontinue;\n2613:\t\n2614:\t\t\tif (tidx \u003c tbl_skip || (family \u0026\u0026 tbl-\u003efamily != family))\n2615:\t\t\t\tcontinue;\n2616:\t\n2617:\t\t\tif (!default_skip \u0026\u0026\n2618:\t\t\t neightbl_fill_info(skb, tbl, NETLINK_CB(cb-\u003eskb).portid,\n2619:\t\t\t\t\t nlh-\u003enlmsg_seq, RTM_NEWNEIGHTBL,\n2620:\t\t\t\t\t NLM_F_MULTI) \u003c 0)\n2621:\t\t\t\tbreak;\n2622:\t\n2623:\t\t\tdefault_skip = 1;\n2624:\t\n2625:\t\t\tlist_for_each_entry_rcu(p, \u0026tbl-\u003eparms_list, list) {\n2626:\t\t\t\tif (!net_eq(neigh_parms_net(p), net))\n2627:\t\t\t\t\tcontinue;\n2628:\t\n2629:\t\t\t\tif (!p-\u003edev || p-\u003edev == blackhole_netdev)\n2630:\t\t\t\t\tcontinue;\n2631:\t\n2632:\t\t\t\tif (nidx \u003c neigh_skip)\n2633:\t\t\t\t\tgoto next;\n2634:\t\n2635:\t\t\t\tif (neightbl_fill_param_info(skb, tbl, p,\n2636:\t\t\t\t\t\t\t NETLINK_CB(cb-\u003eskb).portid,\n2637:\t\t\t\t\t\t\t nlh-\u003enlmsg_seq,\n2638:\t\t\t\t\t\t\t RTM_NEWNEIGHTBL,\n2639:\t\t\t\t\t\t\t NLM_F_MULTI) \u003c 0)\n2640:\t\t\t\t\tgoto out;\n2641:\t\t\tnext:\n2642:\t\t\t\tnidx++;\n2643:\t\t\t}\n2644:\t\n2645:\t\t\tneigh_skip = 0;\n2646:\t\t\tnidx = 0;\n2647:\t\t\tdefault_skip = 0;\n2648:\t\t}\n2649:\tout:\n2650:\t\trcu_read_unlock();\n2651:\t\n2652:\t\tcb-\u003eargs[0] = tidx;\n2653:\t\tcb-\u003eargs[1] = nidx;\n2654:\t\tcb-\u003eargs[2] = default_skip;\n"
} |
| 21/3 | 2026/09/10 00:06 | llm | kmsan-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 6017 output: 36 thoughts: 28 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: **Investigating Neighbor Table Filling** Okay, so I'm digging into this neighbor table population logic. I need to make sure I'm covering all the bases. Before I go too deep, I should probably double-check the `neightbl_fill_info` and `neightbl_fill_param_info` structures and associated functions. I've got a feeling there's something relevant in either those structures or associated processing. It's a key spot and there are likely parameters that influence the behavior. Going over the parameters related to the filling process will give more information about the filling process. Better to confirm everything related to them before moving to other things. It's a good approach for making sure all of the different options are covered. |
| 22/3 | 2026/09/10 00:06 | tool | read-file |
0mArgs:{
"File": "net/core/neighbour.c",
"FirstLine": 2485,
"LineCount": 85
}Results: {
"Contents": "2485:\t\t\t\tcase NDTPA_MCAST_PROBES:\n2486:\t\t\t\t\tNEIGH_VAR_SET(p, MCAST_PROBES,\n2487:\t\t\t\t\t\t nla_get_u32(tbp[i]));\n2488:\t\t\t\t\tbreak;\n2489:\t\t\t\tcase NDTPA_MCAST_REPROBES:\n2490:\t\t\t\t\tNEIGH_VAR_SET(p, MCAST_REPROBES,\n2491:\t\t\t\t\t\t nla_get_u32(tbp[i]));\n2492:\t\t\t\t\tbreak;\n2493:\t\t\t\tcase NDTPA_BASE_REACHABLE_TIME:\n2494:\t\t\t\t\tNEIGH_VAR_SET(p, BASE_REACHABLE_TIME,\n2495:\t\t\t\t\t\t nla_get_msecs(tbp[i]));\n2496:\t\t\t\t\t/* update reachable_time as well, otherwise, the change will\n2497:\t\t\t\t\t * only be effective after the next time neigh_periodic_work\n2498:\t\t\t\t\t * decides to recompute it (can be multiple minutes)\n2499:\t\t\t\t\t */\n2500:\t\t\t\t\tneigh_set_reach_time(p);\n2501:\t\t\t\t\tbreak;\n2502:\t\t\t\tcase NDTPA_GC_STALETIME:\n2503:\t\t\t\t\tNEIGH_VAR_SET(p, GC_STALETIME,\n2504:\t\t\t\t\t\t nla_get_msecs(tbp[i]));\n2505:\t\t\t\t\tbreak;\n2506:\t\t\t\tcase NDTPA_DELAY_PROBE_TIME:\n2507:\t\t\t\t\tNEIGH_VAR_SET(p, DELAY_PROBE_TIME,\n2508:\t\t\t\t\t\t nla_get_msecs(tbp[i]));\n2509:\t\t\t\t\tcall_netevent_notifiers(NETEVENT_DELAY_PROBE_TIME_UPDATE, p);\n2510:\t\t\t\t\tbreak;\n2511:\t\t\t\tcase NDTPA_INTERVAL_PROBE_TIME_MS:\n2512:\t\t\t\t\tNEIGH_VAR_SET(p, INTERVAL_PROBE_TIME_MS,\n2513:\t\t\t\t\t\t nla_get_msecs(tbp[i]));\n2514:\t\t\t\t\tbreak;\n2515:\t\t\t\tcase NDTPA_RETRANS_TIME:\n2516:\t\t\t\t\tNEIGH_VAR_SET(p, RETRANS_TIME,\n2517:\t\t\t\t\t\t nla_get_msecs(tbp[i]));\n2518:\t\t\t\t\tbreak;\n2519:\t\t\t\tcase NDTPA_ANYCAST_DELAY:\n2520:\t\t\t\t\tNEIGH_VAR_SET(p, ANYCAST_DELAY,\n2521:\t\t\t\t\t\t nla_get_msecs(tbp[i]));\n2522:\t\t\t\t\tbreak;\n2523:\t\t\t\tcase NDTPA_PROXY_DELAY:\n2524:\t\t\t\t\tNEIGH_VAR_SET(p, PROXY_DELAY,\n2525:\t\t\t\t\t\t nla_get_msecs(tbp[i]));\n2526:\t\t\t\t\tbreak;\n2527:\t\t\t\tcase NDTPA_LOCKTIME:\n2528:\t\t\t\t\tNEIGH_VAR_SET(p, LOCKTIME,\n2529:\t\t\t\t\t\t nla_get_msecs(tbp[i]));\n2530:\t\t\t\t\tbreak;\n2531:\t\t\t\t}\n2532:\t\t\t}\n2533:\t\t}\n2534:\t\n2535:\t\terr = -ENOENT;\n2536:\t\tif ((tb[NDTA_THRESH1] || tb[NDTA_THRESH2] ||\n2537:\t\t tb[NDTA_THRESH3] || tb[NDTA_GC_INTERVAL]) \u0026\u0026\n2538:\t\t !net_eq(net, \u0026init_net))\n2539:\t\t\tgoto errout_tbl_lock;\n2540:\t\n2541:\t\tif (tb[NDTA_THRESH1])\n2542:\t\t\tWRITE_ONCE(tbl-\u003egc_thresh1, nla_get_u32(tb[NDTA_THRESH1]));\n2543:\t\n2544:\t\tif (tb[NDTA_THRESH2])\n2545:\t\t\tWRITE_ONCE(tbl-\u003egc_thresh2, nla_get_u32(tb[NDTA_THRESH2]));\n2546:\t\n2547:\t\tif (tb[NDTA_THRESH3])\n2548:\t\t\tWRITE_ONCE(tbl-\u003egc_thresh3, nla_get_u32(tb[NDTA_THRESH3]));\n2549:\t\n2550:\t\tif (tb[NDTA_GC_INTERVAL])\n2551:\t\t\tWRITE_ONCE(tbl-\u003egc_interval, nla_get_msecs(tb[NDTA_GC_INTERVAL]));\n2552:\t\n2553:\t\terr = 0;\n2554:\t\n2555:\terrout_tbl_lock:\n2556:\t\tspin_unlock_bh(\u0026tbl-\u003elock);\n2557:\t\trcu_read_unlock();\n2558:\terrout:\n2559:\t\treturn err;\n2560:\t}\n2561:\t\n2562:\tstatic int neightbl_valid_dump_info(const struct nlmsghdr *nlh,\n2563:\t\t\t\t\t struct netlink_ext_ack *extack)\n2564:\t{\n2565:\t\tstruct ndtmsg *ndtm;\n2566:\t\n2567:\t\tndtm = nlmsg_payload(nlh, sizeof(*ndtm));\n2568:\t\tif (!ndtm) {\n2569:\t\t\tNL_SET_ERR_MSG(extack, \"Invalid header for neighbor table dump request\");\n"
} |
| 23/3 | 2026/09/10 00:06 | llm | kmsan-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 7708 output: 36 thoughts: 39 Thoughts: Okay, here's my take on those lines of code, presented as a personal thought process, assuming I'm already pretty familiar with the material: **Digging into `neightbl_fill_info` and `neightbl_fill_param_info`** Right, let's take a closer look at lines 2200-2360. I need to refresh my memory on the interactions and behaviors of `neightbl_fill_info` and `neightbl_fill_param_info` functions. My immediate thought is, what are the use cases of these functions? They are often used in similar contexts, but their differences are important to note. Is this code segment calling the functions in a way that suggests a subtle difference in their execution? I need to understand what 'fill' means in this context. Is it about populating a data structure, initializing it, or updating existing entries? This is critical for knowing how these functions contribute to the larger picture. I will be looking out for common patterns and arguments to get a solid grasp of how they work. I'll check the calls to understand the argument signatures. Are they taking similar arguments, or do they expect distinct parameters? And of course, I must know, are we handling cases with varying memory allocations? I will need to understand what parameters are being utilized so I know when to be concerned about overflow errors. This will help me to decide whether this is a place to focus on further optimization, refactoring, or simply confirming correct behavior. More than likely, I'm expecting `neightbl_fill_info` to do a more general data population, and `neightbl_fill_param_info` to focus on a particular set of parameters within the larger structure. That's my starting assumption, but the actual code will dictate if that's accurate. I'm going to make sure to check the surrounding context to see if it is used for something I haven't considered. I'm ready to dive into the code! |
| 24/3 | 2026/09/10 00:06 | tool | read-file |
0mArgs:{
"File": "net/core/neighbour.c",
"FirstLine": 2200,
"LineCount": 80
}Results: {
"Contents": "2200:\t\t nla_put_u32(skb, NDTPA_REFCNT, refcount_read(\u0026parms-\u003erefcnt)) ||\n2201:\t\t nla_put_u32(skb, NDTPA_QUEUE_LENBYTES,\n2202:\t\t\t\tNEIGH_VAR(parms, QUEUE_LEN_BYTES)) ||\n2203:\t\t /* approximative value for deprecated QUEUE_LEN (in packets) */\n2204:\t\t nla_put_u32(skb, NDTPA_QUEUE_LEN,\n2205:\t\t\t\tNEIGH_VAR(parms, QUEUE_LEN_BYTES) / SKB_TRUESIZE(ETH_FRAME_LEN)) ||\n2206:\t\t nla_put_u32(skb, NDTPA_PROXY_QLEN, NEIGH_VAR(parms, PROXY_QLEN)) ||\n2207:\t\t nla_put_u32(skb, NDTPA_APP_PROBES, NEIGH_VAR(parms, APP_PROBES)) ||\n2208:\t\t nla_put_u32(skb, NDTPA_UCAST_PROBES,\n2209:\t\t\t\tNEIGH_VAR(parms, UCAST_PROBES)) ||\n2210:\t\t nla_put_u32(skb, NDTPA_MCAST_PROBES,\n2211:\t\t\t\tNEIGH_VAR(parms, MCAST_PROBES)) ||\n2212:\t\t nla_put_u32(skb, NDTPA_MCAST_REPROBES,\n2213:\t\t\t\tNEIGH_VAR(parms, MCAST_REPROBES)) ||\n2214:\t\t nla_put_msecs(skb, NDTPA_REACHABLE_TIME, READ_ONCE(parms-\u003ereachable_time),\n2215:\t\t\t\t NDTPA_PAD) ||\n2216:\t\t nla_put_msecs(skb, NDTPA_BASE_REACHABLE_TIME,\n2217:\t\t\t\t NEIGH_VAR(parms, BASE_REACHABLE_TIME), NDTPA_PAD) ||\n2218:\t\t nla_put_msecs(skb, NDTPA_GC_STALETIME,\n2219:\t\t\t\t NEIGH_VAR(parms, GC_STALETIME), NDTPA_PAD) ||\n2220:\t\t nla_put_msecs(skb, NDTPA_DELAY_PROBE_TIME,\n2221:\t\t\t\t NEIGH_VAR(parms, DELAY_PROBE_TIME), NDTPA_PAD) ||\n2222:\t\t nla_put_msecs(skb, NDTPA_RETRANS_TIME,\n2223:\t\t\t\t NEIGH_VAR(parms, RETRANS_TIME), NDTPA_PAD) ||\n2224:\t\t nla_put_msecs(skb, NDTPA_ANYCAST_DELAY,\n2225:\t\t\t\t NEIGH_VAR(parms, ANYCAST_DELAY), NDTPA_PAD) ||\n2226:\t\t nla_put_msecs(skb, NDTPA_PROXY_DELAY,\n2227:\t\t\t\t NEIGH_VAR(parms, PROXY_DELAY), NDTPA_PAD) ||\n2228:\t\t nla_put_msecs(skb, NDTPA_LOCKTIME,\n2229:\t\t\t\t NEIGH_VAR(parms, LOCKTIME), NDTPA_PAD) ||\n2230:\t\t nla_put_msecs(skb, NDTPA_INTERVAL_PROBE_TIME_MS,\n2231:\t\t\t\t NEIGH_VAR(parms, INTERVAL_PROBE_TIME_MS), NDTPA_PAD))\n2232:\t\t\tgoto nla_put_failure;\n2233:\t\treturn nla_nest_end(skb, nest);\n2234:\t\n2235:\tnla_put_failure:\n2236:\t\tnla_nest_cancel(skb, nest);\n2237:\t\treturn -EMSGSIZE;\n2238:\t}\n2239:\t\n2240:\tstatic int neightbl_fill_info(struct sk_buff *skb, struct neigh_table *tbl,\n2241:\t\t\t\t u32 pid, u32 seq, int type, int flags)\n2242:\t{\n2243:\t\tstruct nlmsghdr *nlh;\n2244:\t\tstruct ndtmsg *ndtmsg;\n2245:\t\n2246:\t\tnlh = nlmsg_put(skb, pid, seq, type, sizeof(*ndtmsg), flags);\n2247:\t\tif (nlh == NULL)\n2248:\t\t\treturn -EMSGSIZE;\n2249:\t\n2250:\t\tndtmsg = nlmsg_data(nlh);\n2251:\t\tndtmsg-\u003endtm_family = tbl-\u003efamily;\n2252:\t\tndtmsg-\u003endtm_pad1 = 0;\n2253:\t\tndtmsg-\u003endtm_pad2 = 0;\n2254:\t\n2255:\t\tif (nla_put_string(skb, NDTA_NAME, tbl-\u003eid) ||\n2256:\t\t nla_put_msecs(skb, NDTA_GC_INTERVAL, READ_ONCE(tbl-\u003egc_interval),\n2257:\t\t\t\t NDTA_PAD) ||\n2258:\t\t nla_put_u32(skb, NDTA_THRESH1, READ_ONCE(tbl-\u003egc_thresh1)) ||\n2259:\t\t nla_put_u32(skb, NDTA_THRESH2, READ_ONCE(tbl-\u003egc_thresh2)) ||\n2260:\t\t nla_put_u32(skb, NDTA_THRESH3, READ_ONCE(tbl-\u003egc_thresh3)))\n2261:\t\t\tgoto nla_put_failure;\n2262:\t\t{\n2263:\t\t\tunsigned long now = jiffies;\n2264:\t\t\tlong flush_delta = now - READ_ONCE(tbl-\u003elast_flush);\n2265:\t\t\tlong rand_delta = now - READ_ONCE(tbl-\u003elast_rand);\n2266:\t\t\tstruct neigh_hash_table *nht;\n2267:\t\t\tstruct ndt_config ndc = {\n2268:\t\t\t\t.ndtc_key_len\t\t= tbl-\u003ekey_len,\n2269:\t\t\t\t.ndtc_entry_size\t= tbl-\u003eentry_size,\n2270:\t\t\t\t.ndtc_entries\t\t= atomic_read(\u0026tbl-\u003eentries),\n2271:\t\t\t\t.ndtc_last_flush\t= jiffies_to_msecs(flush_delta),\n2272:\t\t\t\t.ndtc_last_rand\t\t= jiffies_to_msecs(rand_delta),\n2273:\t\t\t\t.ndtc_proxy_qlen\t= READ_ONCE(tbl-\u003eproxy_queue.qlen),\n2274:\t\t\t};\n2275:\t\n2276:\t\t\tnht = rcu_dereference(tbl-\u003enht);\n2277:\t\t\tndc.ndtc_hash_rnd = nht-\u003ehash_rnd[0];\n2278:\t\t\tndc.ndtc_hash_mask = ((1 \u003c\u003c nht-\u003ehash_shift) - 1);\n2279:\t\n"
} |
| 25/3 | 2026/09/10 00:06 | llm | kmsan-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 10094 output: 181 thoughts: 783 Thoughts: **Patch Analysis: A Quick Look** Okay, let's break down this patch, I need to be sure everything is solid. First, it looks like there are a few key areas of focus: 1. **Netlink Policy Update**: This is a straightforward change. The `[NDTPA_INTERVAL_PROBE_TIME_MS]` parameter in `nl_ntbl_parm_policy` is getting a defined range (min=1, max=NTBL_PARM_MS_MAX) using `NLA_POLICY_FULL_RANGE`, which is good practice. 2. **Sysctl Update**: The `neigh_proc_dointvec_ms_jiffies_positive` function is correctly setting an upper bound on the sysctl value using `tmp.extra2 = &max;`. Makes sense. Ensuring controlled upper bounds is key for stability and security. 3. **Dump Continuation Bug Fix**: This is the most interesting part. It appears there was a bug in how `neightbl_dump_info` handled dumping the neighbor table, especially when dealing with continuation (e.g., when the buffer fills up). Previously, `cb->args[0]` tracked `tidx` and `cb->args[1]` tracked `neigh_skip`, but if the buffer ran out in the middle of parms_list, it would redump info if not properly skipped. The patch introduces `default_skip = cb->args[2];` to correctly track and skip the table default info, particularly after the buffer fills. It also ensures clean iteration of `parms_list` and skips special cases like `blackhole_netdev` or NULL devices. Now, let's get into the nitty-gritty and think about any potential issues: * **Uninitialized Memory Reads or Leaks**: Everything seems to be initialized properly. The variables in `neightbl_dump_info` are all initialized and the `cb->args` array is zero-initialized by the netlink dump subsystem, as it should be. The `min` and `max` variables in `neigh_proc_dointvec_ms_jiffies_positive` are initialized before use, and the `nl_ntbl_parm_ms_range` struct is statically initialized. Good, good, good. * **Buffer Overruns/Uninitialized Structures/Padding**: From what I can tell, this patch doesn't introduce any new fields or structs that are copied to userspace. The construction of netlink messages in `neightbl_fill_info` and `neightbl_fill_param_info` remain unchanged, except for the iteration and skip handling. No red flags here. Alright, so the next thing I need to check is whether this patch introduces any vulnerability in terms of the kernel sanitizers. So, does anything here need KMSAN or is it covered by KASAN? * **KASAN / LOCKDEP / UBSAN Coverage**: KASAN already covers RCU list traversals and out-of-bounds accesses. Since this patch doesn't introduce any new uninitialized memory vulnerabilities or uninitialized data access risks, KMSAN is not necessary here. This is a crucial distinction. **Therefore, NeedsKMSAN should be false.** Now, let's do a final check: * I'll be using `set-results tool` before the final reply. * `NeedsKMSAN`: False. * `KMSANReasoning`: Detailed above, contrasting KASAN vs KMSAN applicability. This all looks good to me. |
| 26/3 | 2026/09/10 00:06 | tool | set-results |
0mArgs:{
"KMSANReasoning": "The patch adds validation range checks (min/max) for the neighbor table interval_probe_time_ms parameter via netlink policy and sysctl, and fixes netlink dump resumption state tracking in neightbl_dump_info() using cb-\u003eargs[2] (which is zero-initialized by the netlink dump subsystem). All local variables (min, max, default_skip, nidx) are explicitly initialized before use, and no new data structures, uninitialized memory reads, or info-leaks to userspace are introduced. Any potential bugs related to netlink dump iteration (such as list traversal or bounds errors) are within the scope of KASAN rather than KMSAN. Therefore, a dedicated KMSAN fuzzing session is not warranted.",
"NeedsKMSAN": false
}Results: {
"KMSANReasoning": "The patch adds validation range checks (min/max) for the neighbor table interval_probe_time_ms parameter via netlink policy and sysctl, and fixes netlink dump resumption state tracking in neightbl_dump_info() using cb-\u003eargs[2] (which is zero-initialized by the netlink dump subsystem). All local variables (min, max, default_skip, nidx) are explicitly initialized before use, and no new data structures, uninitialized memory reads, or info-leaks to userspace are introduced. Any potential bugs related to netlink dump iteration (such as list traversal or bounds errors) are within the scope of KASAN rather than KMSAN. Therefore, a dedicated KMSAN fuzzing session is not warranted.",
"NeedsKMSAN": false
} |
| Total Calls | Total Tokens | Avg Tokens | Total Duration (Seconds) | Avg Duration (Seconds) |
|---|
| Total Calls | Total Duration (Seconds) | Avg Duration (Seconds) |
|---|