AI Trajectory

null

{
  "EnableConfigs": [
    "IP_SCTP",
    "INET_SCTP_DIAG"
  ],
  "FocusSymbols": [
    "inet_diag_msg_sctpladdrs_fill",
    "inet_diag_msg_sctpaddrs_fill"
  ],
  "Reasoning": "The patch modifies the way SCTP addresses are copied to netlink messages in the SCTP diag module, fixing a potential info leak. This is functional code that can be reached via netlink sockets.",
  "WorthFuzzing": true
}

null

{
  "PatchDiff": "commit 7547582725025daba62035872aca35d4a5a74ac0\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate:   Wed Jul 15 09:45:13 2026 +0000\n\n    syz-cluster: applied patch under review\n\ndiff --git a/net/sctp/diag.c b/net/sctp/diag.c\nindex d758f5c3e06e56..12557e924cc2b6 100644\n--- a/net/sctp/diag.c\n+++ b/net/sctp/diag.c\n@@ -85,8 +85,12 @@ static int inet_diag_msg_sctpladdrs_fill(struct sk_buff *skb,\n \tinfo = nla_data(attr);\n \trcu_read_lock();\n \tlist_for_each_entry_rcu(laddr, address_list, list) {\n-\t\tmemcpy(info, \u0026laddr-\u003ea, sizeof(laddr-\u003ea));\n-\t\tmemset(info + sizeof(laddr-\u003ea), 0, addrlen - sizeof(laddr-\u003ea));\n+\t\tsize_t addr_len = laddr-\u003ea.sa.sa_family == AF_INET ?\n+\t\t\t\t  sizeof(struct sockaddr_in) :\n+\t\t\t\t  sizeof(struct sockaddr_in6);\n+\n+\t\tmemset(info, 0, addrlen);\n+\t\tmemcpy(info, \u0026laddr-\u003ea, addr_len);\n \t\tinfo += addrlen;\n \n \t\tif (!--addrcnt)\n@@ -113,9 +117,12 @@ static int inet_diag_msg_sctpaddrs_fill(struct sk_buff *skb,\n \tinfo = nla_data(attr);\n \tlist_for_each_entry(from, \u0026asoc-\u003epeer.transport_addr_list,\n \t\t\t    transports) {\n-\t\tmemcpy(info, \u0026from-\u003eipaddr, sizeof(from-\u003eipaddr));\n-\t\tmemset(info + sizeof(from-\u003eipaddr), 0,\n-\t\t       addrlen - sizeof(from-\u003eipaddr));\n+\t\tsize_t addr_len = from-\u003eipaddr.sa.sa_family == AF_INET ?\n+\t\t\t\t  sizeof(struct sockaddr_in) :\n+\t\t\t\t  sizeof(struct sockaddr_in6);\n+\n+\t\tmemset(info, 0, addrlen);\n+\t\tmemcpy(info, \u0026from-\u003eipaddr, addr_len);\n \t\tinfo += addrlen;\n \t}\n \n"
}

gemini-3.1-pro-preview

null

{
  "EnableConfigs": [
    "IP_SCTP",
    "INET_SCTP_DIAG"
  ],
  "FocusSymbols": [
    "inet_diag_msg_sctpladdrs_fill",
    "inet_diag_msg_sctpaddrs_fill"
  ],
  "Reasoning": "The patch modifies the way SCTP addresses are copied to netlink messages in the SCTP diag module, fixing a potential info leak. This is functional code that can be reached via netlink sockets.",
  "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 7547582725025daba62035872aca35d4a5a74ac0
Author: syz-cluster <triage@syzkaller.com>
Date:   Wed Jul 15 09:45:13 2026 +0000

    syz-cluster: applied patch under review

diff --git a/net/sctp/diag.c b/net/sctp/diag.c
index d758f5c3e06e56..12557e924cc2b6 100644
--- a/net/sctp/diag.c
+++ b/net/sctp/diag.c
@@ -85,8 +85,12 @@ static int inet_diag_msg_sctpladdrs_fill(struct sk_buff *skb,
 	info = nla_data(attr);
 	rcu_read_lock();
 	list_for_each_entry_rcu(laddr, address_list, list) {
-		memcpy(info, &laddr->a, sizeof(laddr->a));
-		memset(info + sizeof(laddr->a), 0, addrlen - sizeof(laddr->a));
+		size_t addr_len = laddr->a.sa.sa_family == AF_INET ?
+				  sizeof(struct sockaddr_in) :
+				  sizeof(struct sockaddr_in6);
+
+		memset(info, 0, addrlen);
+		memcpy(info, &laddr->a, addr_len);
 		info += addrlen;
 
 		if (!--addrcnt)
@@ -113,9 +117,12 @@ static int inet_diag_msg_sctpaddrs_fill(struct sk_buff *skb,
 	info = nla_data(attr);
 	list_for_each_entry(from, &asoc->peer.transport_addr_list,
 			    transports) {
-		memcpy(info, &from->ipaddr, sizeof(from->ipaddr));
-		memset(info + sizeof(from->ipaddr), 0,
-		       addrlen - sizeof(from->ipaddr));
+		size_t addr_len = from->ipaddr.sa.sa_family == AF_INET ?
+				  sizeof(struct sockaddr_in) :
+				  sizeof(struct sockaddr_in6);
+
+		memset(info, 0, addrlen);
+		memcpy(info, &from->ipaddr, addr_len);
 		info += addrlen;
 	}
 

gemini-3.1-pro-preview

null

null

							input: 2175
							output: 32
							thoughts: 191
						

**Analyzing the SCTP Diagnostic Patch**

Okay, so I'm looking at this patch for `net/sctp/diag.c`. It seems they've touched `inet_diag_msg_sctpladdrs_fill` and `inet_diag_msg_sctpaddrs_fill`. Right, it's about how the addresses are being copied into the netlink message. The old way, apparently, was just copying the entire `sizeof(laddr->a)`. Knowing SCTP, that `laddr->a` is likely a union, probably holding either a `sockaddr_in`, `sockaddr_in6`, or something similar like a `union sctp_addr`. That union could have uninitialized parts, and this patch addresses precisely that.

Instead of the brute-force copy, the patch now checks the address family. Smart. It's only copying the actual size of the address based on that family and then zeroing out the remaining memory in the union. This is definitely the right way to do it. Prevents the leak of any potentially sensitive data that might be sitting uninitialized in that union. We definitely don't want junk from kernel memory making it to userspace!

Now, I should quickly check `net/sctp/diag.c` directly to see what configuration options might be needed to enable SCTP diagnostics in the first place. I'll just use `grepper` to hunt down the relevant Kconfig options. It'll be quicker that way, hopefully.

{
  "Expression": "SCTP_DIAG",
  "PathPrefix": "net/sctp/"
}

{
  "Output": "net/sctp/Kconfig=68=endchoice\nnet/sctp/Kconfig-69-\nnet/sctp/Kconfig:70:config INET_SCTP_DIAG\nnet/sctp/Kconfig-71-\tdepends on INET_DIAG\n--\nnet/sctp/Makefile=6=obj-$(CONFIG_IP_SCTP) += sctp.o\nnet/sctp/Makefile:7:obj-$(CONFIG_INET_SCTP_DIAG) += sctp_diag.o\nnet/sctp/Makefile-8-\n"
}

gemini-3.1-pro-preview

null

null

							input: 2880
							output: 38
							thoughts: 181
						

**SCTP Diagnostic Analysis**

Okay, so I'm looking at this potential vulnerability, and it seems to hinge around the SCTP netlink interface, specifically when dumping socket information. The key config options here are `INET_SCTP_DIAG` and, crucially, `IP_SCTP`. Without these, this isn't even relevant.

My focus has narrowed to those `inet_diag_msg_sctpladdrs_fill` and `inet_diag_msg_sctpaddrs_fill` functions. That’s where the netlink interaction populates the data. This appears to be functional code, which is good – it's something that actually *does* something. And this is interesting because if it’s fixing an info leak or an out-of-bounds read, it has value. I’m thinking this is absolutely worth a deep fuzzing campaign. Those functions are the attack surface.

Let’s quickly double-check that those are the only relevant configs, just to be thorough. I don't want to miss anything.

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

{
  "Output": "net/sctp/Kconfig=68=endchoice\nnet/sctp/Kconfig-69-\nnet/sctp/Kconfig:70:config INET_SCTP_DIAG\nnet/sctp/Kconfig-71-\tdepends on INET_DIAG\n"
}

gemini-3.1-pro-preview

null

null

							input: 3412
							output: 120
							thoughts: 93
						

Here's my analysis of the situation:

**Investigating SCTP Diagnostic Message Filling**

Okay, so we're dealing with configurations related to SCTP: specifically, `IP_SCTP` and `INET_SCTP_DIAG`. My immediate concern is the function responsible for filling SCTP address diagnostics, `inet_diag_msg_sctpladdrs_fill`. I need to ensure its scope is well-defined. I've confirmed that `inet_diag_msg_sctpladdrs_fill` is indeed declared as static. This is important for understanding how changes impact the broader system.

The patch itself appears to be touching both `inet_diag_msg_sctpladdrs_fill` and `inet_diag_msg_sctpaddrs_fill`. Now, I'll need to carefully examine the modifications within those functions and their impact, but for now, I've established the key pieces of the puzzle. I will use these results for further assessment.

{
  "EnableConfigs": [
    "IP_SCTP",
    "INET_SCTP_DIAG"
  ],
  "FocusSymbols": [
    "inet_diag_msg_sctpladdrs_fill",
    "inet_diag_msg_sctpaddrs_fill"
  ],
  "Reasoning": "The patch modifies the way SCTP addresses are copied to netlink messages in the SCTP diag module, fixing a potential info leak. This is functional code that can be reached via netlink sockets.",
  "WorthFuzzing": true
}

{
  "EnableConfigs": [
    "IP_SCTP",
    "INET_SCTP_DIAG"
  ],
  "FocusSymbols": [
    "inet_diag_msg_sctpladdrs_fill",
    "inet_diag_msg_sctpaddrs_fill"
  ],
  "Reasoning": "The patch modifies the way SCTP addresses are copied to netlink messages in the SCTP diag module, fixing a potential info leak. This is functional code that can be reached via netlink sockets.",
  "WorthFuzzing": true
}