AI Trajectory

null

{
  "EnableConfigs": [
    "NFT_CT"
  ],
  "FocusSymbols": [
    "nft_ct_expect_obj_init",
    "nft_ct_expect_obj_eval",
    "nft_ct_expect_obj_dump",
    "nft_ct_expect_timeout_get"
  ],
  "Reasoning": "The patch modifies the timeout parsing and evaluation logic for nft_ct_expect_obj in netfilter, fixing a potential overflow and incorrect timeout handling. This is a functional change in reachable core kernel logic.",
  "WorthFuzzing": true
}

null

{
  "PatchDiff": "commit d78910860a5cc3c26ffcef33c48a9c8cac71c85c\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate:   Tue Jun 23 05:59:53 2026 +0000\n\n    syz-cluster: applied patch under review\n\ndiff --git a/net/netfilter/nft_ct.c b/net/netfilter/nft_ct.c\nindex 958054dd2e2ecc..03a88c77e0f028 100644\n--- a/net/netfilter/nft_ct.c\n+++ b/net/netfilter/nft_ct.c\n@@ -1215,11 +1215,23 @@ struct nft_ct_expect_obj {\n \tu32\t\ttimeout;\n };\n \n+static int nft_ct_expect_timeout_get(const struct nlattr *attr, u32 *val)\n+{\n+\tunsigned long jiffies_val = msecs_to_jiffies(nla_get_u32(attr));\n+\n+\tif (jiffies_val \u003e UINT_MAX)\n+\t\treturn -ERANGE;\n+\n+\t*val = jiffies_val;\n+\treturn 0;\n+}\n+\n static int nft_ct_expect_obj_init(const struct nft_ctx *ctx,\n \t\t\t\t  const struct nlattr * const tb[],\n \t\t\t\t  struct nft_object *obj)\n {\n \tstruct nft_ct_expect_obj *priv = nft_obj_data(obj);\n+\tint err;\n \n \tif (!tb[NFTA_CT_EXPECT_L4PROTO] ||\n \t    !tb[NFTA_CT_EXPECT_DPORT] ||\n@@ -1254,8 +1266,11 @@ static int nft_ct_expect_obj_init(const struct nft_ctx *ctx,\n \t\treturn -EOPNOTSUPP;\n \t}\n \n+\terr = nft_ct_expect_timeout_get(tb[NFTA_CT_EXPECT_TIMEOUT], \u0026priv-\u003etimeout);\n+\tif (err)\n+\t\treturn err;\n+\n \tpriv-\u003edport = nla_get_be16(tb[NFTA_CT_EXPECT_DPORT]);\n-\tpriv-\u003etimeout = nla_get_u32(tb[NFTA_CT_EXPECT_TIMEOUT]);\n \tpriv-\u003esize = nla_get_u8(tb[NFTA_CT_EXPECT_SIZE]);\n \n \treturn nf_ct_netns_get(ctx-\u003enet, ctx-\u003efamily);\n@@ -1275,7 +1290,7 @@ static int nft_ct_expect_obj_dump(struct sk_buff *skb,\n \tif (nla_put_be16(skb, NFTA_CT_EXPECT_L3PROTO, htons(priv-\u003el3num)) ||\n \t    nla_put_u8(skb, NFTA_CT_EXPECT_L4PROTO, priv-\u003el4proto) ||\n \t    nla_put_be16(skb, NFTA_CT_EXPECT_DPORT, priv-\u003edport) ||\n-\t    nla_put_u32(skb, NFTA_CT_EXPECT_TIMEOUT, priv-\u003etimeout) ||\n+\t    nla_put_u32(skb, NFTA_CT_EXPECT_TIMEOUT, jiffies_to_msecs(priv-\u003etimeout)) ||\n \t    nla_put_u8(skb, NFTA_CT_EXPECT_SIZE, priv-\u003esize))\n \t\treturn -1;\n \n@@ -1325,7 +1340,7 @@ static void nft_ct_expect_obj_eval(struct nft_object *obj,\n \t\t          \u0026ct-\u003etuplehash[!dir].tuple.src.u3,\n \t\t          \u0026ct-\u003etuplehash[!dir].tuple.dst.u3,\n \t\t          priv-\u003el4proto, NULL, \u0026priv-\u003edport);\n-\texp-\u003etimeout += priv-\u003etimeout * HZ;\n+\texp-\u003etimeout += priv-\u003etimeout;\n \n \tif (nf_ct_expect_related(exp, 0) != 0)\n \t\tregs-\u003everdict.code = NF_DROP;\n"
}

gemini-3.1-pro-preview

null

{
  "EnableConfigs": [
    "NFT_CT"
  ],
  "FocusSymbols": [
    "nft_ct_expect_obj_init",
    "nft_ct_expect_obj_eval",
    "nft_ct_expect_obj_dump",
    "nft_ct_expect_timeout_get"
  ],
  "Reasoning": "The patch modifies the timeout parsing and evaluation logic for nft_ct_expect_obj in netfilter, fixing a potential overflow and incorrect timeout handling. This is a functional change in reachable core kernel logic.",
  "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 d78910860a5cc3c26ffcef33c48a9c8cac71c85c
Author: syz-cluster <triage@syzkaller.com>
Date:   Tue Jun 23 05:59:53 2026 +0000

    syz-cluster: applied patch under review

diff --git a/net/netfilter/nft_ct.c b/net/netfilter/nft_ct.c
index 958054dd2e2ecc..03a88c77e0f028 100644
--- a/net/netfilter/nft_ct.c
+++ b/net/netfilter/nft_ct.c
@@ -1215,11 +1215,23 @@ struct nft_ct_expect_obj {
 	u32		timeout;
 };
 
+static int nft_ct_expect_timeout_get(const struct nlattr *attr, u32 *val)
+{
+	unsigned long jiffies_val = msecs_to_jiffies(nla_get_u32(attr));
+
+	if (jiffies_val > UINT_MAX)
+		return -ERANGE;
+
+	*val = jiffies_val;
+	return 0;
+}
+
 static int nft_ct_expect_obj_init(const struct nft_ctx *ctx,
 				  const struct nlattr * const tb[],
 				  struct nft_object *obj)
 {
 	struct nft_ct_expect_obj *priv = nft_obj_data(obj);
+	int err;
 
 	if (!tb[NFTA_CT_EXPECT_L4PROTO] ||
 	    !tb[NFTA_CT_EXPECT_DPORT] ||
@@ -1254,8 +1266,11 @@ static int nft_ct_expect_obj_init(const struct nft_ctx *ctx,
 		return -EOPNOTSUPP;
 	}
 
+	err = nft_ct_expect_timeout_get(tb[NFTA_CT_EXPECT_TIMEOUT], &priv->timeout);
+	if (err)
+		return err;
+
 	priv->dport = nla_get_be16(tb[NFTA_CT_EXPECT_DPORT]);
-	priv->timeout = nla_get_u32(tb[NFTA_CT_EXPECT_TIMEOUT]);
 	priv->size = nla_get_u8(tb[NFTA_CT_EXPECT_SIZE]);
 
 	return nf_ct_netns_get(ctx->net, ctx->family);
@@ -1275,7 +1290,7 @@ static int nft_ct_expect_obj_dump(struct sk_buff *skb,
 	if (nla_put_be16(skb, NFTA_CT_EXPECT_L3PROTO, htons(priv->l3num)) ||
 	    nla_put_u8(skb, NFTA_CT_EXPECT_L4PROTO, priv->l4proto) ||
 	    nla_put_be16(skb, NFTA_CT_EXPECT_DPORT, priv->dport) ||
-	    nla_put_u32(skb, NFTA_CT_EXPECT_TIMEOUT, priv->timeout) ||
+	    nla_put_u32(skb, NFTA_CT_EXPECT_TIMEOUT, jiffies_to_msecs(priv->timeout)) ||
 	    nla_put_u8(skb, NFTA_CT_EXPECT_SIZE, priv->size))
 		return -1;
 
@@ -1325,7 +1340,7 @@ static void nft_ct_expect_obj_eval(struct nft_object *obj,
 		          &ct->tuplehash[!dir].tuple.src.u3,
 		          &ct->tuplehash[!dir].tuple.dst.u3,
 		          priv->l4proto, NULL, &priv->dport);
-	exp->timeout += priv->timeout * HZ;
+	exp->timeout += priv->timeout;
 
 	if (nf_ct_expect_related(exp, 0) != 0)
 		regs->verdict.code = NF_DROP;

gemini-3.1-pro-preview

null

null

							input: 2580
							output: 31
							thoughts: 211
						

**Analyzing the Connection Tracking Expectation Timeout Patch**

Okay, so I'm looking at this patch that tweaks the connection tracking expectation timeout handling within the Netfilter subsystem, specifically in `net/netfilter/nft_ct.c`. It seems they're making some important changes to how the `timeout` value is handled for `nft_ct_expect_obj`.

Essentially, it looks like they're addressing a potential bug or vulnerability related to timeouts. The changes involve introducing a new function, `nft_ct_expect_timeout_get`, which is crucial. It converts the timeout value from milliseconds to jiffies *and* crucially, includes overflow checks.  This is smart; integer overflows with time calculations are notoriously tricky to debug. They're updating the initialization of the `nft_ct_expect_obj` with `nft_ct_expect_timeout_get`, which is the logical place. The dumping function (`nft_ct_expect_obj_dump`) gets updated to convert the stored jiffies back to milliseconds for output. Lastly, I see `nft_ct_expect_obj_eval` is being changed to directly use `priv->timeout` instead of multiplying by `HZ`—which is because we now have the timeout in jiffies.

Overall, this patch seems like a solid, functional improvement. It aims to eliminate a potential overflow condition or ensure correct timeout values are used. That sounds good, and based on this, I'm thinking it definitely warrants some serious fuzzing to make sure this is solid. No corner cases slipped through.

Now, I need to figure out the relevant configuration options. Time to use `grepper` to find the Makefile entry for `nft_ct.c` and figure out what kernel config options control this part of the Netfilter code.

{
  "Expression": "nft_ct\\.o",
  "PathPrefix": "net/netfilter/Makefile"
}

{
  "Output": "net/netfilter/Makefile=111=obj-$(CONFIG_NFT_NUMGEN)\t+= nft_numgen.o\nnet/netfilter/Makefile:112:obj-$(CONFIG_NFT_CT)\t\t+= nft_ct.o\nnet/netfilter/Makefile-113-obj-$(CONFIG_NFT_FLOW_OFFLOAD)\t+= nft_flow_offload.o\n"
}

gemini-3.1-pro-preview

null

null

							input: 3304
							output: 31
							thoughts: 61
						

**Analyzing the `NFT_CT` Configuration**

Okay, so the current configuration item is `NFT_CT`. My immediate thought is, are there any dependent configurations I need to be aware of? Let's quickly trace those dependencies. Looking, it looks like `NFT_CT` is built upon `NF_TABLES` and `NF_CONNTRACK`. Good, that's what I expected. Now, I should probably double-check that by examining `net/netfilter/Kconfig`, just to be certain. I want to make sure I haven't missed anything crucial in terms of build options or related dependencies.

{
  "Expression": "config NFT_CT",
  "PathPrefix": "net/netfilter/Kconfig"
}

{
  "Output": "net/netfilter/Kconfig=484=config NFT_NUMGEN\n--\nnet/netfilter/Kconfig-489-\nnet/netfilter/Kconfig:490:config NFT_CT\nnet/netfilter/Kconfig-491-\tdepends on NF_CONNTRACK\n"
}

gemini-3.1-pro-preview

null

null

							input: 3609
							output: 35
							thoughts: 13
						

Here's my attempt at summarizing the thought process, tailored for an expert audience:

**Analyzing the `NFT_CT` Definition**

Okay, so the prompt directs me to fully define `NFT_CT`. Right, that's the starting point. I need to treat this as if I’m building a knowledge graph of sorts. Let's see... what are the layers here? I'm not going to give some definition; instead, the prompt is about determining *what is the definition*. I should check for edge cases.

First, I need to make certain it's about the technical definition. If it's a domain specific term, for example, is it the *Crypto Token*, or is it *Not For This* as an acronym or initialism. This is the stage I'm at. Let's find out.

{
  "File": "net/netfilter/Kconfig",
  "FirstLine": 485,
  "LineCount": 20
}

{
  "Contents": " 485:\t\ttristate \"Netfilter nf_tables number generator module\"\n 486:\t\thelp\n 487:\t\t  This option adds the number generator expression used to perform\n 488:\t\t  incremental counting and random numbers bound to a upper limit.\n 489:\t\n 490:\tconfig NFT_CT\n 491:\t\tdepends on NF_CONNTRACK\n 492:\t\ttristate \"Netfilter nf_tables conntrack module\"\n 493:\t\thelp\n 494:\t\t  This option adds the \"ct\" expression that you can use to match\n 495:\t\t  connection tracking information such as the flow state.\n 496:\t\n 497:\tconfig NFT_EXTHDR_DCCP\n 498:\t\tbool \"Netfilter nf_tables exthdr DCCP support (DEPRECATED)\"\n 499:\t\tdefault n\n 500:\t\thelp\n 501:\t\t  This option adds support for matching on DCCP extension headers.\n 502:\t\n 503:\tconfig NFT_FLOW_OFFLOAD\n 504:\t\tdepends on NF_CONNTRACK \u0026\u0026 NF_FLOW_TABLE\n"
}

gemini-3.1-pro-preview

null

null

							input: 4135
							output: 124
							thoughts: 323
						

**Analyzing the Netfilter Connection Tracking Patch**

Okay, so I'm looking at this patch and the core of it revolves around `NFT_CT`, that's the primary configuration parameter I need to be concerned with here. My focus should be on the connection tracking expectations objects, particularly these functions: `nft_ct_expect_obj_init`, `nft_ct_expect_obj_eval`, `nft_ct_expect_obj_dump`, and the newly introduced `nft_ct_expect_timeout_get`. Those are my critical focus symbols. I'll need to scrutinize how these are being altered.

Let's see... the patch list those four functions specifically. Good, confirming my initial assessment. Now, regarding configurations, it mentions `NFT_CT`, `NF_CONNTRACK`, and `NF_TABLES`. I need to be sure I'm capturing the dependencies correctly. Since `NFT_CT` implicitly depends on `NF_CONNTRACK` (and that's nested within an `if NF_TABLES` conditional), just stating `NFT_CT` should be sufficient. That should cover both `NF_CONNTRACK` and `NF_TABLES` being present, right? Let me just double-check that. Yes, by its very nature, `NFT_CT` necessitates both of those underlying components.

Right, so the crux of the change seems to be a bug fix related to the `nft_ct_expect_obj_init` function. It's about how the timeout is being handled - potential overflow with jiffies conversion, or incorrect parsing/evaluation. This is a functional change deep within the netfilter subsystem, so it's a critical area to focus on. Okay, I've got a good handle on it now; time to set the results.

{
  "EnableConfigs": [
    "NFT_CT"
  ],
  "FocusSymbols": [
    "nft_ct_expect_obj_init",
    "nft_ct_expect_obj_eval",
    "nft_ct_expect_obj_dump",
    "nft_ct_expect_timeout_get"
  ],
  "Reasoning": "The patch modifies the timeout parsing and evaluation logic for nft_ct_expect_obj in netfilter, fixing a potential overflow and incorrect timeout handling. This is a functional change in reachable core kernel logic.",
  "WorthFuzzing": true
}

{
  "EnableConfigs": [
    "NFT_CT"
  ],
  "FocusSymbols": [
    "nft_ct_expect_obj_init",
    "nft_ct_expect_obj_eval",
    "nft_ct_expect_obj_dump",
    "nft_ct_expect_timeout_get"
  ],
  "Reasoning": "The patch modifies the timeout parsing and evaluation logic for nft_ct_expect_obj in netfilter, fixing a potential overflow and incorrect timeout handling. This is a functional change in reachable core kernel logic.",
  "WorthFuzzing": true
}