AI Trajectory

null

{
  "EnableConfigs": [
    "TLS",
    "INET"
  ],
  "FocusSymbols": [
    "tls_sw_splice_read",
    "tls_rx_rec_wait"
  ],
  "KMSANReasoning": "The patch modifies `tls_sw_splice_read()` in `net/tls/tls_sw.c` to account for `sock-\u003efile-\u003ef_flags \u0026 O_NONBLOCK` in addition to `SPLICE_F_NONBLOCK` when checking whether to perform non-blocking reader lock acquisition (`tls_rx_reader_lock()`) and record waiting (`tls_rx_rec_wait()`).\n\nThis change is purely control-flow and socket flag handling:\n1. The new local variable `nonblock` is immediately and unconditionally initialized with the result of boolean operations before being passed to helper functions.\n2. No new memory allocations or buffers are introduced.\n3. No data structures or padding are copied to user space, and no buffer bounds or length calculations are modified.\n4. There is no risk of reading uninitialized stack, heap, or page memory.\n\nPotential bugs arising from locking or socket state changes would be detected by standard debugging facilities (e.g., LOCKDEP, KASAN), so a dedicated KMSAN fuzzing session is not warranted.",
  "NeedsKMSAN": false,
  "Reasoning": "The patch modifies tls_sw_splice_read() in net/tls/tls_sw.c to honor the socket's O_NONBLOCK flag in addition to SPLICE_F_NONBLOCK when acquiring the reader lock and waiting for TLS records. kTLS is fully reachable in virtualized environments via standard socket syscalls and splice() without dedicated hardware. Fuzzing can verify concurrency, non-blocking semantics, and error handling on kTLS sockets.",
  "WorthFuzzing": true
}

null

{
  "PatchDiff": "commit aefef43701af3a52f6653ee0c4d8241e55aec1eb\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate:   Tue Oct 27 06:11:05 2026 +0000\n\n    syz-cluster: applied patch under review\n\ndiff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c\nindex 312e51270f293d..771e02bff51999 100644\n--- a/net/tls/tls_sw.c\n+++ b/net/tls/tls_sw.c\n@@ -2007,10 +2007,14 @@ ssize_t tls_sw_splice_read(struct socket *sock,  loff_t *ppos,\n \tstruct tls_msg *tlm;\n \tstruct sk_buff *skb;\n \tssize_t copied = 0;\n+\tbool nonblock;\n \tint chunk;\n \tint err;\n \n-\terr = tls_rx_reader_lock(sk, ctx, flags \u0026 SPLICE_F_NONBLOCK);\n+\tnonblock = flags \u0026 SPLICE_F_NONBLOCK ||\n+\t\t   sock-\u003efile-\u003ef_flags \u0026 O_NONBLOCK;\n+\n+\terr = tls_rx_reader_lock(sk, ctx, nonblock);\n \tif (err \u003c 0)\n \t\treturn err;\n \n@@ -2024,8 +2028,7 @@ ssize_t tls_sw_splice_read(struct socket *sock,  loff_t *ppos,\n \t} else {\n \t\tstruct tls_decrypt_arg darg;\n \n-\t\terr = tls_rx_rec_wait(sk, flags \u0026 SPLICE_F_NONBLOCK,\n-\t\t\t\t      true, false);\n+\t\terr = tls_rx_rec_wait(sk, nonblock, true, false);\n \t\tif (err \u003c= 0)\n \t\t\tgoto splice_read_end;\n \ndiff --git a/tools/testing/selftests/net/tls.c b/tools/testing/selftests/net/tls.c\nindex 9d3cd4fff062b5..c4203401c4bfc2 100644\n--- a/tools/testing/selftests/net/tls.c\n+++ b/tools/testing/selftests/net/tls.c\n@@ -889,6 +889,37 @@ TEST_F(tls, splice_to_pipe)\n \tEXPECT_EQ(memcmp(mem_send, mem_recv, send_len), 0);\n }\n \n+/* The socket's O_NONBLOCK governs the record wait, as on a plain TCP\n+ * socket, even without SPLICE_F_NONBLOCK.\n+ */\n+TEST_F(tls, splice_nonblock_socket)\n+{\n+\tstruct pollfd pfd = { .fd = self-\u003ecfd, .events = POLLIN };\n+\tint send_len = TLS_PAYLOAD_MAX_LEN;\n+\tchar mem_send[TLS_PAYLOAD_MAX_LEN];\n+\tchar mem_recv[TLS_PAYLOAD_MAX_LEN];\n+\tint flags, p[2];\n+\n+\tflags = fcntl(self-\u003ecfd, F_GETFL, 0);\n+\tASSERT_GE(flags, 0);\n+\tASSERT_EQ(fcntl(self-\u003ecfd, F_SETFL, flags | O_NONBLOCK), 0);\n+\n+\tmemrnd(mem_send, sizeof(mem_send));\n+\n+\tASSERT_GE(pipe(p), 0);\n+\tEXPECT_EQ(splice(self-\u003ecfd, NULL, p[1], NULL, send_len, 0), -1);\n+\tEXPECT_EQ(errno, EAGAIN);\n+\n+\t/* The record may still be in flight, wait for it. A failed splice()\n+\t * would leave the read() below blocking until the harness timeout.\n+\t */\n+\tEXPECT_EQ(send(self-\u003efd, mem_send, send_len, 0), send_len);\n+\tASSERT_EQ(poll(\u0026pfd, 1, 5000), 1);\n+\tASSERT_EQ(splice(self-\u003ecfd, NULL, p[1], NULL, send_len, 0), send_len);\n+\tEXPECT_EQ(read(p[0], mem_recv, send_len), send_len);\n+\tEXPECT_EQ(memcmp(mem_send, mem_recv, send_len), 0);\n+}\n+\n TEST_F(tls, splice_cmsg_to_pipe)\n {\n \tchar *test_str = \"test_read\";\n"
}

core

null

{
  "EnableConfigs": [
    "TLS",
    "INET"
  ],
  "FocusSymbols": [
    "tls_sw_splice_read",
    "tls_rx_rec_wait"
  ],
  "Reasoning": "The patch modifies tls_sw_splice_read() in net/tls/tls_sw.c to honor the socket's O_NONBLOCK flag in addition to SPLICE_F_NONBLOCK when acquiring the reader lock and waiting for TLS records. kTLS is fully reachable in virtualized environments via standard socket syscalls and splice() without dedicated hardware. Fuzzing can verify concurrency, non-blocking semantics, and error handling on kTLS sockets.",
  "WorthFuzzing": true
}

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.

Target architecture: amd64

For your convenience, here is the diff of the changes:
commit aefef43701af3a52f6653ee0c4d8241e55aec1eb
Author: syz-cluster <triage@syzkaller.com>
Date:   Tue Oct 27 06:11:05 2026 +0000

    syz-cluster: applied patch under review

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 312e51270f293d..771e02bff51999 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -2007,10 +2007,14 @@ ssize_t tls_sw_splice_read(struct socket *sock,  loff_t *ppos,
 	struct tls_msg *tlm;
 	struct sk_buff *skb;
 	ssize_t copied = 0;
+	bool nonblock;
 	int chunk;
 	int err;
 
-	err = tls_rx_reader_lock(sk, ctx, flags & SPLICE_F_NONBLOCK);
+	nonblock = flags & SPLICE_F_NONBLOCK ||
+		   sock->file->f_flags & O_NONBLOCK;
+
+	err = tls_rx_reader_lock(sk, ctx, nonblock);
 	if (err < 0)
 		return err;
 
@@ -2024,8 +2028,7 @@ ssize_t tls_sw_splice_read(struct socket *sock,  loff_t *ppos,
 	} else {
 		struct tls_decrypt_arg darg;
 
-		err = tls_rx_rec_wait(sk, flags & SPLICE_F_NONBLOCK,
-				      true, false);
+		err = tls_rx_rec_wait(sk, nonblock, true, false);
 		if (err <= 0)
 			goto splice_read_end;
 
diff --git a/tools/testing/selftests/net/tls.c b/tools/testing/selftests/net/tls.c
index 9d3cd4fff062b5..c4203401c4bfc2 100644
--- a/tools/testing/selftests/net/tls.c
+++ b/tools/testing/selftests/net/tls.c
@@ -889,6 +889,37 @@ TEST_F(tls, splice_to_pipe)
 	EXPECT_EQ(memcmp(mem_send, mem_recv, send_len), 0);
 }
 
+/* The socket's O_NONBLOCK governs the record wait, as on a plain TCP
+ * socket, even without SPLICE_F_NONBLOCK.
+ */
+TEST_F(tls, splice_nonblock_socket)
+{
+	struct pollfd pfd = { .fd = self->cfd, .events = POLLIN };
+	int send_len = TLS_PAYLOAD_MAX_LEN;
+	char mem_send[TLS_PAYLOAD_MAX_LEN];
+	char mem_recv[TLS_PAYLOAD_MAX_LEN];
+	int flags, p[2];
+
+	flags = fcntl(self->cfd, F_GETFL, 0);
+	ASSERT_GE(flags, 0);
+	ASSERT_EQ(fcntl(self->cfd, F_SETFL, flags | O_NONBLOCK), 0);
+
+	memrnd(mem_send, sizeof(mem_send));
+
+	ASSERT_GE(pipe(p), 0);
+	EXPECT_EQ(splice(self->cfd, NULL, p[1], NULL, send_len, 0), -1);
+	EXPECT_EQ(errno, EAGAIN);
+
+	/* The record may still be in flight, wait for it. A failed splice()
+	 * would leave the read() below blocking until the harness timeout.
+	 */
+	EXPECT_EQ(send(self->fd, mem_send, send_len, 0), send_len);
+	ASSERT_EQ(poll(&pfd, 1, 5000), 1);
+	ASSERT_EQ(splice(self->cfd, NULL, p[1], NULL, send_len, 0), send_len);
+	EXPECT_EQ(read(p[0], mem_recv, send_len), send_len);
+	EXPECT_EQ(memcmp(mem_send, mem_recv, send_len), 0);
+}
+
 TEST_F(tls, splice_cmsg_to_pipe)
 {
 	char *test_str = "test_read";

gemini-3.8-flash

null

null

							input: 3877
							output: 32
							thoughts: 459
						

**Analyzing a Linux Kernel Patch for TLS Software Offload**

Okay, so I'm presented with a patch series aimed at the Linux kernel, and my task is to evaluate it. The patch modifies two files: `net/tls/tls_sw.c` and `tools/testing/selftests/net/tls.c`. Let's dive into the core change, which seems to be in `net/tls/tls_sw.c` within the `tls_sw_splice_read` function.

My initial impression is that they're modifying the non-blocking behavior of the read operation. Specifically, it looks like they're consolidating the logic for determining if a read should be non-blocking. Before, the non-blocking flag was checked against the `SPLICE_F_NONBLOCK` flag. Now, they're explicitly checking for that flag *or* the `O_NONBLOCK` file flag of the socket itself. This makes sense; it ensures that the splice read respects *both* explicit splice non-blocking requests *and* any non-blocking socket option set by the application.

Further, I see that this non-blocking state is passed to `tls_rx_reader_lock` and `tls_rx_rec_wait` functions. This consistent propagation of the non-blocking state throughout the TLS receive path is crucial. It ensures the whole pipeline correctly handles situations where a read may need to return immediately rather than waiting for data. I need to understand what those functions are doing and whether this change properly handles all the potential edge cases. I'll need to double check the surrounding code to grasp how these functions work within this context. I will use `read-file` or `grepper` to find more about the context. The `tools/testing/selftests/net/tls.c` file should be useful, too, as it should include tests that may show this logic in action.

{
  "Expression": "tls_sw_splice_read",
  "PathPrefixes": [
    "net/tls/"
  ]
}

{
  "Output": "net/tls/tls.h=165=bool tls_sw_sock_is_readable(struct sock *sk);\nnet/tls/tls.h:166:ssize_t tls_sw_splice_read(struct socket *sock, loff_t *ppos,\nnet/tls/tls.h-167-\t\t\t   struct pipe_inode_info *pipe,\n--\nnet/tls/tls_main.c=952=static void build_proto_ops(struct proto_ops ops[TLS_NUM_CONFIG][TLS_NUM_CONFIG],\n--\nnet/tls/tls_main.c-960-\tops[TLS_BASE][TLS_SW  ] = ops[TLS_BASE][TLS_BASE];\nnet/tls/tls_main.c:961:\tops[TLS_BASE][TLS_SW  ].splice_read\t= tls_sw_splice_read;\nnet/tls/tls_main.c-962-\tops[TLS_BASE][TLS_SW  ].poll\t\t= tls_sk_poll;\n--\nnet/tls/tls_main.c-965-\tops[TLS_SW  ][TLS_SW  ] = ops[TLS_SW  ][TLS_BASE];\nnet/tls/tls_main.c:966:\tops[TLS_SW  ][TLS_SW  ].splice_read\t= tls_sw_splice_read;\nnet/tls/tls_main.c-967-\tops[TLS_SW  ][TLS_SW  ].poll\t\t= tls_sk_poll;\n--\nnet/tls/tls_sw.c=1806=int tls_sw_recvmsg(struct sock *sk,\n--\nnet/tls/tls_sw.c-1998-\nnet/tls/tls_sw.c:1999:ssize_t tls_sw_splice_read(struct socket *sock,  loff_t *ppos,\nnet/tls/tls_sw.c-2000-\t\t\t   struct pipe_inode_info *pipe,\n"
}

gemini-3.8-flash

null

null

							input: 5273
							output: 27
							thoughts: 74
						

Here's my summary, as I see it:

**kTLS Socket Vulnerability Analysis**

Okay, so I'm looking at this `tls_sw_splice_read` function and I realize it's reachable from userspace, specifically through the `splice` system call on a kTLS socket. That's immediately interesting. I know kTLS, Kernel TLS, is that software-based TLS implementation in the kernel, and it's accessed via standard socket interfaces – the `TLS_SW` stuff in `net/tls`. The fact that `splice` can trigger this… well, that’s a direct conduit. I need to understand this better and see if there are any obvious implications. First step? Let's go straight to the Kconfig and review the configuration options related to `net/tls`. I want to understand the dependencies and build options for this feature and see what other things might be enabled with it. This `splice` connection is a potential attack vector, and I need to assess the attack surface as quickly as possible.

{
  "Expression": "config TLS",
  "PathPrefixes": [
    "net/tls/"
  ]
}

{
  "Output": "net/tls/Kconfig-4-#\nnet/tls/Kconfig:5:config TLS\nnet/tls/Kconfig-6-\ttristate \"Transport Layer Security support\"\n--\nnet/tls/Kconfig-18-\nnet/tls/Kconfig:19:config TLS_DEVICE\nnet/tls/Kconfig-20-\tbool \"Transport Layer Security HW offload\"\n"
}

gemini-3.8-flash

null

null

							input: 5696
							output: 32
							thoughts: 15
						

Okay, here's my take on those thoughts, tailored for an expert audience:

**Diving into `net/tls/Kconfig`**

Alright, let's get down to brass tacks. My initial thought process is to immediately zero in on the `net/tls/Kconfig` file. Given my expertise, I already know this likely houses the kernel configuration options related to TLS (Transport Layer Security) within the networking subsystem. That's the logical starting point. I'm going to be looking for the fundamental building blocks – the configuration knobs that control things like enabling or disabling TLS support, selecting specific TLS versions, cipher suites, and any hardware acceleration options if available. My aim is to quickly understand the current landscape of TLS configuration within this kernel context. I'll be anticipating dependencies on other Kconfig files, and I'll be looking for hints about the overall architecture and how these options relate to different network protocols or devices. I'm expecting to find a clear hierarchy, possibly grouped by feature or protocol. This Kconfig file will essentially be the Rosetta Stone, guiding me through the kernel's TLS implementation and allowing me to tailor it for a specific environment or debug a particular TLS issue.

{
  "File": "net/tls/Kconfig",
  "FirstLine": 1,
  "LineCount": 40
}

{
  "Contents": "   1:\t# SPDX-License-Identifier: GPL-2.0-only\n   2:\t#\n   3:\t# TLS configuration\n   4:\t#\n   5:\tconfig TLS\n   6:\t\ttristate \"Transport Layer Security support\"\n   7:\t\tdepends on INET\n   8:\t\tselect CRYPTO\n   9:\t\tselect CRYPTO_AES\n  10:\t\tselect CRYPTO_GCM\n  11:\t\tselect NET_SOCK_MSG\n  12:\t\tdefault n\n  13:\t\thelp\n  14:\t\tEnable kernel support for TLS protocol. This allows symmetric\n  15:\t\tencryption handling of the TLS protocol to be done in-kernel.\n  16:\t\n  17:\t\tIf unsure, say N.\n  18:\t\n  19:\tconfig TLS_DEVICE\n  20:\t\tbool \"Transport Layer Security HW offload\"\n  21:\t\tdepends on TLS\n  22:\t\tselect SKB_DECRYPTED\n  23:\t\tselect SOCK_VALIDATE_XMIT\n  24:\t\tselect SOCK_RX_QUEUE_MAPPING\n  25:\t\tdefault n\n  26:\t\thelp\n  27:\t\tEnable kernel support for HW offload of the TLS protocol.\n  28:\t\n  29:\t\tIf unsure, say N.\n"
}

gemini-3.8-flash

null

null

							input: 6318
							output: 38
							thoughts: 29
						

Okay, let's dive into this. Here's my take on those lines of code in `net/tls/tls_sw.c`:

**Deep Dive into `net/tls/tls_sw.c` - Line 2000**

Alright, time to crack open `net/tls/tls_sw.c` and zero in on the vicinity of line 2000. My immediate thought is, "What exactly are we doing in this section?" Given the file and the general area, I'm expecting something related to the TLS software implementation - most likely around key exchange, record handling, or potentially some security policy enforcement. I need to understand the specifics of whatever change occurred there. Is this a bug fix? An optimization? A new feature? Perhaps we are modifying the cipher suite negotiation or implementing a new security standard. I need to contextualize this. I'm going to start by reading the surrounding code and seeing what changed. I'll be looking for clues about the goals of the developers and what specific aspects of the TLS connection are impacted. Let's see what we've got.

{
  "File": "net/tls/tls_sw.c",
  "FirstLine": 2000,
  "LineCount": 50
}

{
  "Contents": "2000:\t\t\t\t   struct pipe_inode_info *pipe,\n2001:\t\t\t\t   size_t len, unsigned int flags)\n2002:\t{\n2003:\t\tstruct tls_context *tls_ctx = tls_get_ctx(sock-\u003esk);\n2004:\t\tstruct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);\n2005:\t\tstruct strp_msg *rxm = NULL;\n2006:\t\tstruct sock *sk = sock-\u003esk;\n2007:\t\tstruct tls_msg *tlm;\n2008:\t\tstruct sk_buff *skb;\n2009:\t\tssize_t copied = 0;\n2010:\t\tbool nonblock;\n2011:\t\tint chunk;\n2012:\t\tint err;\n2013:\t\n2014:\t\tnonblock = flags \u0026 SPLICE_F_NONBLOCK ||\n2015:\t\t\t   sock-\u003efile-\u003ef_flags \u0026 O_NONBLOCK;\n2016:\t\n2017:\t\terr = tls_rx_reader_lock(sk, ctx, nonblock);\n2018:\t\tif (err \u003c 0)\n2019:\t\t\treturn err;\n2020:\t\n2021:\t\t/* If crypto failed the connection is broken */\n2022:\t\terr = ctx-\u003easync_wait.err;\n2023:\t\tif (err)\n2024:\t\t\tgoto splice_read_end;\n2025:\t\n2026:\t\tif (!skb_queue_empty(\u0026ctx-\u003erx_list)) {\n2027:\t\t\tskb = __skb_dequeue(\u0026ctx-\u003erx_list);\n2028:\t\t} else {\n2029:\t\t\tstruct tls_decrypt_arg darg;\n2030:\t\n2031:\t\t\terr = tls_rx_rec_wait(sk, nonblock, true, false);\n2032:\t\t\tif (err \u003c= 0)\n2033:\t\t\t\tgoto splice_read_end;\n2034:\t\n2035:\t\t\tmemset(\u0026darg.inargs, 0, sizeof(darg.inargs));\n2036:\t\n2037:\t\t\terr = tls_rx_one_record(sk, NULL, \u0026darg);\n2038:\t\t\tif (err \u003c 0)\n2039:\t\t\t\tgoto splice_read_end;\n2040:\t\n2041:\t\t\ttls_rx_rec_done(ctx);\n2042:\t\t\tskb = darg.skb;\n2043:\t\t}\n2044:\t\n2045:\t\trxm = strp_msg(skb);\n2046:\t\ttlm = tls_msg(skb);\n2047:\t\n2048:\t\t/* splice does not support reading control messages */\n2049:\t\tif (tlm-\u003econtrol != TLS_RECORD_TYPE_DATA) {\n"
}

gemini-3.8-flash

null

null

							input: 7377
							output: 40
							thoughts: 688
						

**Analyzing the kTLS Splice Read Patch**

Okay, so I'm looking at this patch for `tls_sw_splice_read`. Essentially, the change replaces the direct use of `flags & SPLICE_F_NONBLOCK` with a new `nonblock` variable, defined as `flags & SPLICE_F_NONBLOCK || sock->file->f_flags & O_NONBLOCK;`. My initial thought is that this is intended to correctly handle the `O_NONBLOCK` flag set on the socket itself, even when `splice()` isn't explicitly given `SPLICE_F_NONBLOCK`. This definitely makes sense; it's a common oversight.

This means the patch affects the locking and waiting behavior within kTLS during splice reads. Specifically, it touches the functions `tls_rx_reader_lock` and `tls_rx_rec_wait`, along with `tls_sw_splice_read`.

Now, is this reachable code? Absolutely. kTLS is the standard in-kernel software crypto solution on TCP sockets, enabled via `CONFIG_TLS`. A user would create a TCP socket, attach TLS via `setsockopt` calls (for `TCP_ULP` and `TLS_RX/TX`), potentially set `O_NONBLOCK` on the socket, and then call `splice()` to read from the socket into a pipe. And, importantly, I can confirm that this is reachable in syzkaller. I've got descriptors for kTLS and splice: `syz_init_net_socket`, `setsockopt$inet_tcp_TCP_ULP`, `setsockopt$inet_tls_rx`, `splice`, etc. Excellent, that's a huge positive.

Is this worth fuzzing? Yes, without a doubt. It dives into core networking and kTLS logic, specifically in `net/tls/tls_sw.c`. The instructions say that since `WorthFuzzing=true`, I need to extract specific kernel functions into `FocusSymbols` to guide the fuzzer. It's best to target specific feature logic and entry points.

So, `tls_sw_splice_read` is the primary target as it's the function being directly modified. I should also investigate `tls_rx_reader_lock` and `tls_rx_rec_wait`. They're being used by the main function that's being modified. I should verify where they are defined and how they are used to ensure the fuzzing covers the core functions affected by the change.

{
  "Expression": "tls_rx_reader_lock|tls_rx_rec_wait",
  "PathPrefixes": [
    "net/tls/"
  ]
}

{
  "Output": "net/tls/tls_sw.c=1094=static int\nnet/tls/tls_sw.c:1095:tls_rx_rec_wait(struct sock *sk, bool nonblock, bool released, bool has_copied)\nnet/tls/tls_sw.c-1096-{\n--\nnet/tls/tls_sw.c-1162-\tif (unlikely(!tls_strp_msg_load(\u0026ctx-\u003estrp, released)))\nnet/tls/tls_sw.c:1163:\t\treturn tls_rx_rec_wait(sk, nonblock, false, has_copied);\nnet/tls/tls_sw.c-1164-\n--\nnet/tls/tls_sw.c=1737=static int tls_rx_reader_acquire(struct sock *sk, struct tls_sw_context_rx *ctx,\n--\nnet/tls/tls_sw.c-1767-\nnet/tls/tls_sw.c:1768:static int tls_rx_reader_lock(struct sock *sk, struct tls_sw_context_rx *ctx,\nnet/tls/tls_sw.c-1769-\t\t\t      bool nonblock)\n--\nnet/tls/tls_sw.c=1806=int tls_sw_recvmsg(struct sock *sk,\n--\nnet/tls/tls_sw.c-1831-\nnet/tls/tls_sw.c:1832:\terr = tls_rx_reader_lock(sk, ctx, flags \u0026 MSG_DONTWAIT);\nnet/tls/tls_sw.c-1833-\tif (err \u003c 0)\n--\nnet/tls/tls_sw.c-1860-\nnet/tls/tls_sw.c:1861:\t\terr = tls_rx_rec_wait(sk, flags \u0026 MSG_DONTWAIT,\nnet/tls/tls_sw.c-1862-\t\t\t\t      released, !!(decrypted + copied));\n--\nnet/tls/tls_sw.c=1999=ssize_t tls_sw_splice_read(struct socket *sock,  loff_t *ppos,\n--\nnet/tls/tls_sw.c-2016-\nnet/tls/tls_sw.c:2017:\terr = tls_rx_reader_lock(sk, ctx, nonblock);\nnet/tls/tls_sw.c-2018-\tif (err \u003c 0)\n--\nnet/tls/tls_sw.c-2030-\nnet/tls/tls_sw.c:2031:\t\terr = tls_rx_rec_wait(sk, nonblock, true, false);\nnet/tls/tls_sw.c-2032-\t\tif (err \u003c= 0)\n--\nnet/tls/tls_sw.c=2076=int tls_sw_read_sock(struct sock *sk, read_descriptor_t *desc,\n--\nnet/tls/tls_sw.c-2114-\nnet/tls/tls_sw.c:2115:\t\t\terr = tls_rx_rec_wait(sk, true, released, !!copied);\nnet/tls/tls_sw.c-2116-\t\t\tif (err \u003c= 0)\n"
}

gemini-3.8-flash

null

null

							input: 9455
							output: 38
							thoughts: 396
						

**Analyzing the Core Functions in the TLS Software Splice Read Path**

Okay, so I'm looking at `tls_sw_splice_read` – it's definitely *not* static, defined as `ssize_t tls_sw_splice_read(...)`. Now, are `tls_rx_reader_lock` and `tls_rx_rec_wait` static? Yes, both are. Hmm, the question then becomes, are static functions viable as focus symbols, since `tls_sw_splice_read` is *the* direct entrypoint for this operation (`ops->splice_read`) and non-static? Static functions *do* have symbols in vmlinux unless inlined, but `tls_sw_splice_read` feels like the most obvious starting point.

I should verify whether `tls_rx_rec_wait` and `tls_rx_reader_lock` are getting inlined. Maybe `tls_sw_splice_read` is the *best* single entry point to examine the logic. Let's refer to Section 4 in the document, which calls out functions implementing the added/altered logic or direct API entrypoints. That points squarely to `tls_sw_splice_read` being *the* function where the changes are implemented! But, could we also include the static functions?

Let's check for inlining, starting with `tls_rx_rec_wait`. It's pretty substantial, spanning roughly 70 lines (1095-1164), with loops and string parser logic, and it's *not* marked inline. That strongly suggests it's not being inlined. Then, `tls_rx_reader_lock` (lines 1768-1804): it's shorter but important, too.

I'll read `tls_rx_reader_lock`.

{
  "File": "net/tls/tls_sw.c",
  "FirstLine": 1765,
  "LineCount": 45
}

{
  "Contents": "1765:\t\treturn 0;\n1766:\t}\n1767:\t\n1768:\tstatic int tls_rx_reader_lock(struct sock *sk, struct tls_sw_context_rx *ctx,\n1769:\t\t\t\t      bool nonblock)\n1770:\t{\n1771:\t\tint err;\n1772:\t\n1773:\t\tlock_sock(sk);\n1774:\t\terr = tls_rx_reader_acquire(sk, ctx, nonblock);\n1775:\t\tif (err)\n1776:\t\t\trelease_sock(sk);\n1777:\t\treturn err;\n1778:\t}\n1779:\t\n1780:\tstatic void tls_rx_reader_release(struct sock *sk, struct tls_sw_context_rx *ctx)\n1781:\t{\n1782:\t\t/* Fire any deferred announce once per reader so that a record\n1783:\t\t * parsed but not yet announced becomes visible to the next\n1784:\t\t * reader. The call is idempotent through msg_announced.\n1785:\t\t */\n1786:\t\ttls_rx_msg_maybe_announce(\u0026ctx-\u003estrp);\n1787:\t\n1788:\t\tif (unlikely(ctx-\u003ereader_contended)) {\n1789:\t\t\tif (wq_has_sleeper(\u0026ctx-\u003ewq))\n1790:\t\t\t\twake_up(\u0026ctx-\u003ewq);\n1791:\t\t\telse\n1792:\t\t\t\tctx-\u003ereader_contended = 0;\n1793:\t\n1794:\t\t\tWARN_ON_ONCE(!ctx-\u003ereader_present);\n1795:\t\t}\n1796:\t\n1797:\t\tWRITE_ONCE(ctx-\u003ereader_present, 0);\n1798:\t}\n1799:\t\n1800:\tstatic void tls_rx_reader_unlock(struct sock *sk, struct tls_sw_context_rx *ctx)\n1801:\t{\n1802:\t\ttls_rx_reader_release(sk, ctx);\n1803:\t\trelease_sock(sk);\n1804:\t}\n1805:\t\n1806:\tint tls_sw_recvmsg(struct sock *sk,\n1807:\t\t\t   struct msghdr *msg,\n1808:\t\t\t   size_t len,\n1809:\t\t\t   int flags)\n"
}

gemini-3.8-flash

null

null

							input: 10923
							output: 31
							thoughts: 93
						

Here's my analysis of what I'm looking at, from a low-level perspective:

**Deep Dive into `tls_sw_splice_read` and Related Functions**

Okay, so I'm zeroing in on `tls_sw_splice_read`. It's standing out as the key function here. Now, I need to understand its relationship to `tls_sw_recvmsg`. My immediate focus is on how `tls_sw_splice_read` itself is being directly modified. I have a hunch it is doing something the other function isn't, or doing it differently.

To get a broader picture, I should check the kernel configuration. I'll navigate to `net/tls/Kconfig`. I'm looking for the `TLS` config option, and it's dependency on `INET`. That makes sense; TLS is inherently network-dependent.

Next, I'll examine the `Makefile` in `net/tls/`. This will tell me how everything is being compiled and linked. That should illuminate any build-time dependencies or compilation flags I need to consider.

{
  "File": "net/tls/Makefile",
  "FirstLine": 1,
  "LineCount": 20
}

{
  "Contents": "   1:\t# SPDX-License-Identifier: GPL-2.0-only\n   2:\t#\n   3:\t# Makefile for the TLS subsystem.\n   4:\t#\n   5:\t\n   6:\tCFLAGS_trace.o := -I$(src)\n   7:\t\n   8:\tobj-$(CONFIG_TLS) += tls.o\n   9:\t\n  10:\ttls-y := tls_main.o tls_sw.o tls_proc.o trace.o tls_strp.o\n  11:\t\n  12:\ttls-$(CONFIG_TLS_DEVICE) += tls_device.o tls_device_fallback.o\n"
}

gemini-3.8-flash

null

null

							input: 11451
							output: 151
							thoughts: 744
						

**Fuzzing Verdict: TLS/Splice Code Path**

Okay, let's break this down. My analysis indicates that fuzzing a specific code path related to TLS and the `splice()` syscall is highly valuable. The primary driver for this is a modification to `net/tls/tls_sw.c`. This patch alters the behavior of `tls_sw_splice_read`, specifically regarding non-blocking operations on TLS sockets.

My initial examination of the build system reveals that enabling `CONFIG_TLS` is key, and it depends on `CONFIG_INET`. I can confirm through dependency checks that only `INET` and `TLS` are explicitly required to build the module, although `TLS` selects several crypto-related configurations. Importantly, I've confirmed that the patch modifies `net/tls/tls_sw.c` and a user-space selftest, but only the kernel code is relevant for our purposes.

The change in `tls_sw_splice_read` hinges on checking the `O_NONBLOCK` flag of a socket's file descriptor in addition to the `SPLICE_F_NONBLOCK` flag passed to `splice()`. This impacts the behavior of the `tls_rx_reader_lock` and, more importantly, `tls_rx_rec_wait` functions. Essentially, this modifies how blocking/non-blocking mode is determined within `splice()` when operating on a TLS socket. This code path is easily reachable within a standard QEMU environment.

Given these findings, I conclude:

*   **WorthFuzzing: True**. The changes directly touch a reachable code path that can be exploited in standard environments.
*   **EnableConfigs: \["TLS", "INET"\]**. These are the critical kernel configurations needed to activate the target code.
*   **FocusSymbols: \["tls\_sw\_splice\_read", "tls\_rx\_rec\_wait"\]**. `tls_sw_splice_read` is the exact function modified. Adding `tls_rx_rec_wait` makes sense because it implements the actual waiting/non-blocking record reception logic. Though `tls_rx_rec_wait` is static, `tls_sw_splice_read` is an exported function, so it's a good target.

I've reviewed the fuzzing guidelines and confirmed that this analysis aligns with the specified criteria. It's now time to call `set-results`.

{
  "EnableConfigs": [
    "TLS",
    "INET"
  ],
  "FocusSymbols": [
    "tls_sw_splice_read",
    "tls_rx_rec_wait"
  ],
  "Reasoning": "The patch modifies tls_sw_splice_read() in net/tls/tls_sw.c to honor the socket's O_NONBLOCK flag in addition to SPLICE_F_NONBLOCK when acquiring the reader lock and waiting for TLS records. kTLS is fully reachable in virtualized environments via standard socket syscalls and splice() without dedicated hardware. Fuzzing can verify concurrency, non-blocking semantics, and error handling on kTLS sockets.",
  "WorthFuzzing": true
}

{
  "EnableConfigs": [
    "TLS",
    "INET"
  ],
  "FocusSymbols": [
    "tls_sw_splice_read",
    "tls_rx_rec_wait"
  ],
  "Reasoning": "The patch modifies tls_sw_splice_read() in net/tls/tls_sw.c to honor the socket's O_NONBLOCK flag in addition to SPLICE_F_NONBLOCK when acquiring the reader lock and waiting for TLS records. kTLS is fully reachable in virtualized environments via standard socket syscalls and splice() without dedicated hardware. Fuzzing can verify concurrency, non-blocking semantics, and error handling on kTLS sockets.",
  "WorthFuzzing": true
}

{
  "WorthFuzzing": true
}

null

core

null

{
  "KMSANReasoning": "The patch modifies `tls_sw_splice_read()` in `net/tls/tls_sw.c` to account for `sock-\u003efile-\u003ef_flags \u0026 O_NONBLOCK` in addition to `SPLICE_F_NONBLOCK` when checking whether to perform non-blocking reader lock acquisition (`tls_rx_reader_lock()`) and record waiting (`tls_rx_rec_wait()`).\n\nThis change is purely control-flow and socket flag handling:\n1. The new local variable `nonblock` is immediately and unconditionally initialized with the result of boolean operations before being passed to helper functions.\n2. No new memory allocations or buffers are introduced.\n3. No data structures or padding are copied to user space, and no buffer bounds or length calculations are modified.\n4. There is no risk of reading uninitialized stack, heap, or page memory.\n\nPotential bugs arising from locking or socket state changes would be detected by standard debugging facilities (e.g., LOCKDEP, KASAN), so a dedicated KMSAN fuzzing session is not warranted.",
  "NeedsKMSAN": false
}

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.

Target architecture: amd64

For your convenience, here is the diff of the changes:
commit aefef43701af3a52f6653ee0c4d8241e55aec1eb
Author: syz-cluster <triage@syzkaller.com>
Date:   Tue Oct 27 06:11:05 2026 +0000

    syz-cluster: applied patch under review

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 312e51270f293d..771e02bff51999 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -2007,10 +2007,14 @@ ssize_t tls_sw_splice_read(struct socket *sock,  loff_t *ppos,
 	struct tls_msg *tlm;
 	struct sk_buff *skb;
 	ssize_t copied = 0;
+	bool nonblock;
 	int chunk;
 	int err;
 
-	err = tls_rx_reader_lock(sk, ctx, flags & SPLICE_F_NONBLOCK);
+	nonblock = flags & SPLICE_F_NONBLOCK ||
+		   sock->file->f_flags & O_NONBLOCK;
+
+	err = tls_rx_reader_lock(sk, ctx, nonblock);
 	if (err < 0)
 		return err;
 
@@ -2024,8 +2028,7 @@ ssize_t tls_sw_splice_read(struct socket *sock,  loff_t *ppos,
 	} else {
 		struct tls_decrypt_arg darg;
 
-		err = tls_rx_rec_wait(sk, flags & SPLICE_F_NONBLOCK,
-				      true, false);
+		err = tls_rx_rec_wait(sk, nonblock, true, false);
 		if (err <= 0)
 			goto splice_read_end;
 
diff --git a/tools/testing/selftests/net/tls.c b/tools/testing/selftests/net/tls.c
index 9d3cd4fff062b5..c4203401c4bfc2 100644
--- a/tools/testing/selftests/net/tls.c
+++ b/tools/testing/selftests/net/tls.c
@@ -889,6 +889,37 @@ TEST_F(tls, splice_to_pipe)
 	EXPECT_EQ(memcmp(mem_send, mem_recv, send_len), 0);
 }
 
+/* The socket's O_NONBLOCK governs the record wait, as on a plain TCP
+ * socket, even without SPLICE_F_NONBLOCK.
+ */
+TEST_F(tls, splice_nonblock_socket)
+{
+	struct pollfd pfd = { .fd = self->cfd, .events = POLLIN };
+	int send_len = TLS_PAYLOAD_MAX_LEN;
+	char mem_send[TLS_PAYLOAD_MAX_LEN];
+	char mem_recv[TLS_PAYLOAD_MAX_LEN];
+	int flags, p[2];
+
+	flags = fcntl(self->cfd, F_GETFL, 0);
+	ASSERT_GE(flags, 0);
+	ASSERT_EQ(fcntl(self->cfd, F_SETFL, flags | O_NONBLOCK), 0);
+
+	memrnd(mem_send, sizeof(mem_send));
+
+	ASSERT_GE(pipe(p), 0);
+	EXPECT_EQ(splice(self->cfd, NULL, p[1], NULL, send_len, 0), -1);
+	EXPECT_EQ(errno, EAGAIN);
+
+	/* The record may still be in flight, wait for it. A failed splice()
+	 * would leave the read() below blocking until the harness timeout.
+	 */
+	EXPECT_EQ(send(self->fd, mem_send, send_len, 0), send_len);
+	ASSERT_EQ(poll(&pfd, 1, 5000), 1);
+	ASSERT_EQ(splice(self->cfd, NULL, p[1], NULL, send_len, 0), send_len);
+	EXPECT_EQ(read(p[0], mem_recv, send_len), send_len);
+	EXPECT_EQ(memcmp(mem_send, mem_recv, send_len), 0);
+}
+
 TEST_F(tls, splice_cmsg_to_pipe)
 {
 	char *test_str = "test_read";

gemini-3.8-flash

null

null

							input: 3089
							output: 38
							thoughts: 439
						

**KMSAN Fuzzing Session Assessment**

Okay, so I need to decide if this patch series warrants a dedicated KMSAN fuzzing session. Let's break it down. Looking at the diff, it seems the change is in `net/tls/tls_sw.c`, specifically around the `tls_sw_splice_read` function. I see the addition of a `nonblock` variable and a replacement of existing logic with the `nonblock` variable. It looks like the original code was passing `SPLICE_F_NONBLOCK` directly, but now they're checking it and also the file flags. Further down, there's a corresponding change in the call to `tls_rx_rec_wait`. The new code is passing the `nonblock` variable to both calls.

So, the key change is about non-blocking behavior within a TLS splice read. It seems we are more correctly checking for non-blocking operations. Interesting. I'll need to dig deeper into the code to understand the implications of this change. It looks like it could change how non-blocking operations behave within the context of a socket. I'll have to consider how this interacts with the `tls_rx_reader_lock` function. I think it is important to analyze how the patch changes the flow control. The fact that the changes affect the handling of non-blocking I/O is a bit of a red flag and could introduce some subtle race conditions or memory issues, so it warrants further investigation. I also see there's a test in `tools/testing/selftests/net/tls.c`. That's good, but does the test suite sufficiently cover this change in particular? That's what I need to determine.

{
  "File": "net/tls/tls_sw.c",
  "FirstLine": 2000,
  "LineCount": 60
}

{
  "Contents": "2000:\t\t\t\t   struct pipe_inode_info *pipe,\n2001:\t\t\t\t   size_t len, unsigned int flags)\n2002:\t{\n2003:\t\tstruct tls_context *tls_ctx = tls_get_ctx(sock-\u003esk);\n2004:\t\tstruct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);\n2005:\t\tstruct strp_msg *rxm = NULL;\n2006:\t\tstruct sock *sk = sock-\u003esk;\n2007:\t\tstruct tls_msg *tlm;\n2008:\t\tstruct sk_buff *skb;\n2009:\t\tssize_t copied = 0;\n2010:\t\tbool nonblock;\n2011:\t\tint chunk;\n2012:\t\tint err;\n2013:\t\n2014:\t\tnonblock = flags \u0026 SPLICE_F_NONBLOCK ||\n2015:\t\t\t   sock-\u003efile-\u003ef_flags \u0026 O_NONBLOCK;\n2016:\t\n2017:\t\terr = tls_rx_reader_lock(sk, ctx, nonblock);\n2018:\t\tif (err \u003c 0)\n2019:\t\t\treturn err;\n2020:\t\n2021:\t\t/* If crypto failed the connection is broken */\n2022:\t\terr = ctx-\u003easync_wait.err;\n2023:\t\tif (err)\n2024:\t\t\tgoto splice_read_end;\n2025:\t\n2026:\t\tif (!skb_queue_empty(\u0026ctx-\u003erx_list)) {\n2027:\t\t\tskb = __skb_dequeue(\u0026ctx-\u003erx_list);\n2028:\t\t} else {\n2029:\t\t\tstruct tls_decrypt_arg darg;\n2030:\t\n2031:\t\t\terr = tls_rx_rec_wait(sk, nonblock, true, false);\n2032:\t\t\tif (err \u003c= 0)\n2033:\t\t\t\tgoto splice_read_end;\n2034:\t\n2035:\t\t\tmemset(\u0026darg.inargs, 0, sizeof(darg.inargs));\n2036:\t\n2037:\t\t\terr = tls_rx_one_record(sk, NULL, \u0026darg);\n2038:\t\t\tif (err \u003c 0)\n2039:\t\t\t\tgoto splice_read_end;\n2040:\t\n2041:\t\t\ttls_rx_rec_done(ctx);\n2042:\t\t\tskb = darg.skb;\n2043:\t\t}\n2044:\t\n2045:\t\trxm = strp_msg(skb);\n2046:\t\ttlm = tls_msg(skb);\n2047:\t\n2048:\t\t/* splice does not support reading control messages */\n2049:\t\tif (tlm-\u003econtrol != TLS_RECORD_TYPE_DATA) {\n2050:\t\t\terr = -EINVAL;\n2051:\t\t\tgoto splice_requeue;\n2052:\t\t}\n2053:\t\n2054:\t\tchunk = min_t(unsigned int, rxm-\u003efull_len, len);\n2055:\t\tcopied = skb_splice_bits(skb, sk, rxm-\u003eoffset, pipe, chunk, flags);\n2056:\t\tif (copied \u003c 0)\n2057:\t\t\tgoto splice_requeue;\n2058:\t\n2059:\t\tif (copied \u003c rxm-\u003efull_len) {\n"
}

gemini-3.8-flash

null

null

							input: 4838
							output: 40
							thoughts: 706
						

**Analyzing a TLS Socket Patch for Uninitialized Memory**

Okay, let's break down this patch. My immediate thought is to determine if it introduces or exposes any uninitialized memory vulnerabilities. I see the core change is within the `tls_sw_splice_read` function. Previously, the code checked `flags & SPLICE_F_NONBLOCK` when dealing with locking and waiting within `tls_rx_reader_lock` and `tls_rx_rec_wait`. Now, it uses `nonblock = flags & SPLICE_F_NONBLOCK || sock->file->f_flags & O_NONBLOCK;`. This means if the socket file itself has `O_NONBLOCK` set, the `nonblock` flag becomes true, regardless of what `splice()` received. This `nonblock` value then feeds into `tls_rx_reader_lock` and `tls_rx_rec_wait`.

Now, I need to methodically apply the KMSAN criteria. Does this patch touch structures sent to userspace? No. Does it rely on potentially uninitialized variables or struct fields within conditional logic? Let's see... the `nonblock` variable is now conditionally set, but the conditions are simple. It is logically *OR*'d with *two* defined values. But first, let's assess. Does it allocate or initialize complex data structures where uninitialized fields could be read later? No apparent new allocations here. Does this change any bounds checks that may cause access to uninitialized data? Based on the code, No.

Looking at the code, `bool nonblock;` is set unconditionally on line 2014. It is then passed as an argument to `tls_rx_reader_lock` and `tls_rx_rec_wait`. No new memory is allocated. No `copy_to_user`, no info-leaks. The `nonblock` variable is assigned a *boolean* value based on existing flags, and is definitely initialized. I don't see anything here that alters buffer lengths or offsets or anything that directly accesses uninitialized memory. Also, if `nonblock` is true and there's no record, `tls_rx_rec_wait` returns an error (like `-EAGAIN`) and exits early. No uninitialized memory usage there.

To be absolutely certain, I'll quickly grep the codebase for `tls_rx_reader_lock` and `tls_rx_rec_wait` to confirm that the functions being called don't have any obvious uninitialized memory concerns themselves, though that's a scope issue outside the immediate patch. Based on this quick analysis, I'm confident that this patch doesn't introduce any uninitialized memory issues. We're good.

{
  "Expression": "tls_rx_rec_wait|tls_rx_reader_lock",
  "PathPrefixes": [
    "net/tls/"
  ]
}

{
  "Output": "net/tls/tls_sw.c=1094=static int\nnet/tls/tls_sw.c:1095:tls_rx_rec_wait(struct sock *sk, bool nonblock, bool released, bool has_copied)\nnet/tls/tls_sw.c-1096-{\n--\nnet/tls/tls_sw.c-1162-\tif (unlikely(!tls_strp_msg_load(\u0026ctx-\u003estrp, released)))\nnet/tls/tls_sw.c:1163:\t\treturn tls_rx_rec_wait(sk, nonblock, false, has_copied);\nnet/tls/tls_sw.c-1164-\n--\nnet/tls/tls_sw.c=1737=static int tls_rx_reader_acquire(struct sock *sk, struct tls_sw_context_rx *ctx,\n--\nnet/tls/tls_sw.c-1767-\nnet/tls/tls_sw.c:1768:static int tls_rx_reader_lock(struct sock *sk, struct tls_sw_context_rx *ctx,\nnet/tls/tls_sw.c-1769-\t\t\t      bool nonblock)\n--\nnet/tls/tls_sw.c=1806=int tls_sw_recvmsg(struct sock *sk,\n--\nnet/tls/tls_sw.c-1831-\nnet/tls/tls_sw.c:1832:\terr = tls_rx_reader_lock(sk, ctx, flags \u0026 MSG_DONTWAIT);\nnet/tls/tls_sw.c-1833-\tif (err \u003c 0)\n--\nnet/tls/tls_sw.c-1860-\nnet/tls/tls_sw.c:1861:\t\terr = tls_rx_rec_wait(sk, flags \u0026 MSG_DONTWAIT,\nnet/tls/tls_sw.c-1862-\t\t\t\t      released, !!(decrypted + copied));\n--\nnet/tls/tls_sw.c=1999=ssize_t tls_sw_splice_read(struct socket *sock,  loff_t *ppos,\n--\nnet/tls/tls_sw.c-2016-\nnet/tls/tls_sw.c:2017:\terr = tls_rx_reader_lock(sk, ctx, nonblock);\nnet/tls/tls_sw.c-2018-\tif (err \u003c 0)\n--\nnet/tls/tls_sw.c-2030-\nnet/tls/tls_sw.c:2031:\t\terr = tls_rx_rec_wait(sk, nonblock, true, false);\nnet/tls/tls_sw.c-2032-\t\tif (err \u003c= 0)\n--\nnet/tls/tls_sw.c=2076=int tls_sw_read_sock(struct sock *sk, read_descriptor_t *desc,\n--\nnet/tls/tls_sw.c-2114-\nnet/tls/tls_sw.c:2115:\t\t\terr = tls_rx_rec_wait(sk, true, released, !!copied);\nnet/tls/tls_sw.c-2116-\t\t\tif (err \u003c= 0)\n"
}

gemini-3.8-flash

null

null

							input: 6974
							output: 251
							thoughts: 367
						

**Analyzing the Non-Blocking Behavior of `tls_sw_splice_read`**

Okay, this is straightforward. The patch in `net/tls/tls_sw.c` is making sure that the `tls_sw_splice_read` function correctly respects the `O_NONBLOCK` flag from the socket's file structure, in addition to the standard `SPLICE_F_NONBLOCK` flag, when dealing with the RX reader lock and waiting for TLS records. This is critical for proper non-blocking socket behavior.

Now, the important question is: do we need KMSAN? No, we absolutely don't. Here's why I'm confident in saying that:

*   **No Uninitialized Memory Risks:** The `nonblock` variable is a locally-scoped boolean, initialized right before its use, eliminating any chance of uninitialized memory being exposed.
*   **No Kernel-to-User Leaks:** This patch doesn't allocate, free, or copy kernel memory to userspace.
*   **No Buffer Manipulation:** There are no manipulations of buffer lengths or struct padding that could lead to accidental exposure of uninitialized memory.
*   **Focus on Blocking Behavior:** The change is isolated to the blocking versus non-blocking synchronization and waiting logic within the socket splice read path.
*   **Robustness of Existing Tools:** Any potential issues related to locking or concurrency will be readily detected by LOCKDEP and other standard detectors. Memory corruption and lifetime issues are well-covered by KASAN.

Given these points, KMSAN is overkill here. We can confidently set `NeedsKMSAN` to `false`. Let's get that `set-results` invoked.

{
  "KMSANReasoning": "The patch modifies `tls_sw_splice_read()` in `net/tls/tls_sw.c` to account for `sock-\u003efile-\u003ef_flags \u0026 O_NONBLOCK` in addition to `SPLICE_F_NONBLOCK` when checking whether to perform non-blocking reader lock acquisition (`tls_rx_reader_lock()`) and record waiting (`tls_rx_rec_wait()`).\n\nThis change is purely control-flow and socket flag handling:\n1. The new local variable `nonblock` is immediately and unconditionally initialized with the result of boolean operations before being passed to helper functions.\n2. No new memory allocations or buffers are introduced.\n3. No data structures or padding are copied to user space, and no buffer bounds or length calculations are modified.\n4. There is no risk of reading uninitialized stack, heap, or page memory.\n\nPotential bugs arising from locking or socket state changes would be detected by standard debugging facilities (e.g., LOCKDEP, KASAN), so a dedicated KMSAN fuzzing session is not warranted.",
  "NeedsKMSAN": false
}

{
  "KMSANReasoning": "The patch modifies `tls_sw_splice_read()` in `net/tls/tls_sw.c` to account for `sock-\u003efile-\u003ef_flags \u0026 O_NONBLOCK` in addition to `SPLICE_F_NONBLOCK` when checking whether to perform non-blocking reader lock acquisition (`tls_rx_reader_lock()`) and record waiting (`tls_rx_rec_wait()`).\n\nThis change is purely control-flow and socket flag handling:\n1. The new local variable `nonblock` is immediately and unconditionally initialized with the result of boolean operations before being passed to helper functions.\n2. No new memory allocations or buffers are introduced.\n3. No data structures or padding are copied to user space, and no buffer bounds or length calculations are modified.\n4. There is no risk of reading uninitialized stack, heap, or page memory.\n\nPotential bugs arising from locking or socket state changes would be detected by standard debugging facilities (e.g., LOCKDEP, KASAN), so a dedicated KMSAN fuzzing session is not warranted.",
  "NeedsKMSAN": false
}