AI Trajectory

null

{
  "EnableConfigs": [
    "IP_SCTP"
  ],
  "FocusSymbols": [
    "sctp_setsockopt_reset_streams"
  ],
  "Reasoning": "The patch fixes a bug in the calculation of the maximum option length for SCTP_RESET_STREAMS, allowing it to process up to USHRT_MAX streams instead of being incorrectly capped. This is a functional change in SCTP socket options.",
  "WorthFuzzing": true
}

null

{
  "PatchDiff": "commit be46b5df1a1493f91991959a5d8a1d535560007e\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate:   Thu Jun 25 14:40:22 2026 +0000\n\n    syz-cluster: applied patch under review\n\ndiff --git a/net/sctp/socket.c b/net/sctp/socket.c\nindex 66e12fb0c646ad..b8f13044a21915 100644\n--- a/net/sctp/socket.c\n+++ b/net/sctp/socket.c\n@@ -4111,8 +4111,9 @@ static int sctp_setsockopt_reset_streams(struct sock *sk,\n \tif (optlen \u003c sizeof(*params))\n \t\treturn -EINVAL;\n \t/* srs_number_streams is u16, so optlen can't be bigger than this. */\n-\toptlen = min_t(unsigned int, optlen, USHRT_MAX +\n-\t\t\t\t\t     sizeof(__u16) * sizeof(*params));\n+\toptlen = min_t(unsigned int, optlen,\n+\t\t       struct_size_t(struct sctp_reset_streams, srs_stream_list,\n+\t\t\t\t     USHRT_MAX));\n \n \tif (params-\u003esrs_number_streams * sizeof(__u16) \u003e\n \t    optlen - sizeof(*params))\n@@ -4598,8 +4599,8 @@ static int sctp_setsockopt(struct sock *sk, int level, int optname,\n \tif (optlen \u003e 0) {\n \t\t/* Trim it to the biggest size sctp sockopt may need if necessary */\n \t\toptlen = min_t(unsigned int, optlen,\n-\t\t\t       PAGE_ALIGN(USHRT_MAX +\n-\t\t\t\t\t  sizeof(__u16) * sizeof(struct sctp_reset_streams)));\n+\t\t\t       PAGE_ALIGN(struct_size_t(struct sctp_reset_streams,\n+\t\t\t\t\t\t\tsrs_stream_list, USHRT_MAX)));\n \t\tkopt = memdup_sockptr(optval, optlen);\n \t\tif (IS_ERR(kopt))\n \t\t\treturn PTR_ERR(kopt);\n"
}

gemini-3.1-pro-preview

null

{
  "EnableConfigs": [
    "IP_SCTP"
  ],
  "FocusSymbols": [
    "sctp_setsockopt_reset_streams"
  ],
  "Reasoning": "The patch fixes a bug in the calculation of the maximum option length for SCTP_RESET_STREAMS, allowing it to process up to USHRT_MAX streams instead of being incorrectly capped. This is a functional change in SCTP socket options.",
  "WorthFuzzing": true
}

You are an expert Linux kernel maintainer.
Your job is to review a provided patch series and determine
if it makes functional changes to the kernel that should be fuzzed.

IMPORTANT: The changes have ALREADY been applied and committed as the HEAD commit in
your workspace. Do NOT rely on your internal knowledge of the kernel. You must actively
use your code access tools to examine the actual source code and confirm any assumptions.

Return WorthFuzzing=false if the patch only contains:
- Modifications to Documentation/, Kconfig files, or code comments.
- Purely decorative changes, such as logging (e.g., pr_err, printk) or tracepoints.
- Changes to numeric constants or macros that do not functionally alter execution flow.
- Code paths that are impossible to reach in virtualized environments like GCE or QEMU,
even when utilizing software-emulated hardware (e.g., usb gadget, mac80211_hwsim).

If it modifies reachable core kernel logic, drivers, or architectures, use your code search
tools to verify the code can be executed, then return WorthFuzzing=true.

When returning WorthFuzzing=true, you MUST ALSO:
1. Extract any specific kernel functions that should be heavily fuzzed into FocusSymbols.
   Avoid listing generic hot-path functions to prevent skewed test distributions.
2. Identify any specific CONFIG_ options required to properly test this new/modified feature.
   Go and look into the Kconfig files and check for ifdefs around the code, do not make assumptions.
   Do not list too generic configs (we already have them enabled). Only list those that
   specifically cover the modified code. List them in the EnableConfigs output array,
   and DO NOT add a '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.

For your convenience, here is the diff of the changes:
commit be46b5df1a1493f91991959a5d8a1d535560007e
Author: syz-cluster <triage@syzkaller.com>
Date:   Thu Jun 25 14:40:22 2026 +0000

    syz-cluster: applied patch under review

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 66e12fb0c646ad..b8f13044a21915 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -4111,8 +4111,9 @@ static int sctp_setsockopt_reset_streams(struct sock *sk,
 	if (optlen < sizeof(*params))
 		return -EINVAL;
 	/* srs_number_streams is u16, so optlen can't be bigger than this. */
-	optlen = min_t(unsigned int, optlen, USHRT_MAX +
-					     sizeof(__u16) * sizeof(*params));
+	optlen = min_t(unsigned int, optlen,
+		       struct_size_t(struct sctp_reset_streams, srs_stream_list,
+				     USHRT_MAX));
 
 	if (params->srs_number_streams * sizeof(__u16) >
 	    optlen - sizeof(*params))
@@ -4598,8 +4599,8 @@ static int sctp_setsockopt(struct sock *sk, int level, int optname,
 	if (optlen > 0) {
 		/* Trim it to the biggest size sctp sockopt may need if necessary */
 		optlen = min_t(unsigned int, optlen,
-			       PAGE_ALIGN(USHRT_MAX +
-					  sizeof(__u16) * sizeof(struct sctp_reset_streams)));
+			       PAGE_ALIGN(struct_size_t(struct sctp_reset_streams,
+							srs_stream_list, USHRT_MAX)));
 		kopt = memdup_sockptr(optval, optlen);
 		if (IS_ERR(kopt))
 			return PTR_ERR(kopt);

gemini-3.1-pro-preview

null

null

							input: 2123
							output: 40
							thoughts: 345
						

**Analyzing the SCTP Socket Option Patch**

Okay, so this patch is touching `net/sctp/socket.c`, specifically how we're handling option length calculations within `sctp_setsockopt_reset_streams` and `sctp_setsockopt`. It looks like it's addressing a subtle but significant bug. The existing code was using a flawed calculation for `optlen`, specifically where it was computing the size of the stream reset option.

Let me break this down. They were doing `USHRT_MAX + sizeof(__u16) * sizeof(*params)`.  Hold on a second... `sizeof(*params)` is actually the size of the `struct sctp_reset_streams`, which is 12 bytes. So they were essentially multiplying the size of a `__u16` (which is 2 bytes) by 12, resulting in a product of 24. That's clearly wrong. The correct way to calculate the total size should be `sizeof(struct sctp_reset_streams) + USHRT_MAX * sizeof(__u16)`.  The patch is smart, it is replacing that flawed calculation with a much more appropriate call to `struct_size_t`, which directly addresses this issue.

This is a functional change, not a new feature, which is good. It's fixing a bug that potentially affects the correct handling of `sctp_setsockopt` and `sctp_setsockopt_reset_streams`.  It's always good to see these types of fixes. Before I sign off on this, I'll need to double check `net/sctp/socket.c` to see if there are any specific kernel configurations (`CONFIG_IP_SCTP` specifically) that might affect this. That should be a straightforward check to verify that SCTP is enabled in the current configuration. I'll need to review the specific implementations of `sctp_setsockopt_reset_streams` as well.

{
  "Expression": "sctp_setsockopt_reset_streams",
  "PathPrefix": "net/sctp/socket.c"
}

{
  "Output": "net/sctp/socket.c=4063=static int sctp_setsockopt_enable_strreset(struct sock *sk,\n--\nnet/sctp/socket.c-4104-\nnet/sctp/socket.c:4105:static int sctp_setsockopt_reset_streams(struct sock *sk,\nnet/sctp/socket.c-4106-\t\t\t\t\t struct sctp_reset_streams *params,\n--\nnet/sctp/socket.c=4579=static int sctp_setsockopt(struct sock *sk, int level, int optname,\n--\nnet/sctp/socket.c-4746-\tcase SCTP_RESET_STREAMS:\nnet/sctp/socket.c:4747:\t\tretval = sctp_setsockopt_reset_streams(sk, kopt, optlen);\nnet/sctp/socket.c-4748-\t\tbreak;\n"
}

gemini-3.1-pro-preview

null

null

							input: 3197
							output: 34
							thoughts: 88
						

**Analyzing the Socket Option Reset Stream Functionality**

Okay, so I'm looking at this patch and it appears to be focused on the `SCTP_RESET_STREAMS` socket option. I see that the function `sctp_setsockopt_reset_streams` is called directly from `sctp_setsockopt`. That makes sense - `sctp_setsockopt` is the main entry point for all the socket options, and this function handles a very specific one. The patch itself seems to be touching both `sctp_setsockopt` and `sctp_setsockopt_reset_streams`, which likely means they're changing the interaction between those two functions or the functionality of that particular socket option. I'll need to dig into the specifics of *how* it's changed, of course, to understand the implications. Given the config is `IP_SCTP` so SCTP is obviously enabled, but I should probably confirm that using Kconfig. Time to cross-reference with the kernel configuration to make sure I'm not missing anything obvious about the compile time options.

{
  "Expression": "config IP_SCTP",
  "PathPrefix": "net/sctp/Kconfig"
}

{
  "Output": "net/sctp/Kconfig-5-\nnet/sctp/Kconfig:6:menuconfig IP_SCTP\nnet/sctp/Kconfig-7-\ttristate \"The SCTP Protocol\"\n"
}

gemini-3.1-pro-preview

null

null

							input: 3624
							output: 103
							thoughts: 526
						

**My Assessment of the SCTP Stream Reset Patch**

Okay, so I've been looking at this patch related to SCTP stream reset, and here's my breakdown. It seems like the core configuration item to keep in mind is `IP_SCTP`. The key functions I need to focus on are `sctp_setsockopt_reset_streams` and, perhaps as a point of comparison, `sctp_setsockopt`. While `sctp_setsockopt` is a generally active area, this patch is directly targeted at `sctp_setsockopt_reset_streams`, so that's the main focus.

Essentially, this patch addresses a bug in how the maximum option length (`optlen`) was being calculated, which affected the `SCTP_RESET_STREAMS` socket option. The original calculation was flawed. Previously, the maximum number of streams that could be handled was limited due to an incorrect size calculation involving `USHRT_MAX` and the size of the stream list.

Looking into the details, the old code incorrectly calculated the maximum length as `65559` (`65535 + 24`). However, the size of the `struct sctp_reset_streams` plus the actual stream list, which is a flexible array of `__u16`, really comes out to `131082` when considering `USHRT_MAX` number of streams. This older calculation meant that `sctp_setsockopt_reset_streams` was only usable for up to 32773 streams, but now we're looking at a maximum of `65535` streams.

This is a clear functional change because the incorrect calculation limited the practical usage of `SCTP_RESET_STREAMS`, so this is definitely a functional change.

Therefore, my settings will reflect this:

*   **WorthFuzzing**: `true` (because this is a functional change fixing a boundary condition)
*   **FocusSymbols**: `["sctp_setsockopt_reset_streams"]` (as the bug is specific to this function)
*   **EnableConfigs**: `["IP_SCTP"]` (as this patch is related to SCTP)
*   **Reasoning**: "The patch fixes a bug in the calculation of the maximum option length for `SCTP_RESET_STREAMS`, allowing it to process up to `USHRT_MAX` streams instead of being incorrectly capped. This is a functional change in SCTP socket options."

{
  "EnableConfigs": [
    "IP_SCTP"
  ],
  "FocusSymbols": [
    "sctp_setsockopt_reset_streams"
  ],
  "Reasoning": "The patch fixes a bug in the calculation of the maximum option length for SCTP_RESET_STREAMS, allowing it to process up to USHRT_MAX streams instead of being incorrectly capped. This is a functional change in SCTP socket options.",
  "WorthFuzzing": true
}

{
  "EnableConfigs": [
    "IP_SCTP"
  ],
  "FocusSymbols": [
    "sctp_setsockopt_reset_streams"
  ],
  "Reasoning": "The patch fixes a bug in the calculation of the maximum option length for SCTP_RESET_STREAMS, allowing it to process up to USHRT_MAX streams instead of being incorrectly capped. This is a functional change in SCTP socket options.",
  "WorthFuzzing": true
}