AI Trajectory

null

{
  "EnableConfigs": [
    "CEPH_FS",
    "FS_ENCRYPTION"
  ],
  "FocusSymbols": [
    "__get_snap_name",
    "ceph_get_name"
  ],
  "Reasoning": "The patch fixes a potential buffer overflow in CephFS export operations by adding a length check against NAME_MAX when copying directory names. This modifies reachable filesystem logic used by file handle syscalls (e.g. open_by_handle_at), so it should be fuzzed.",
  "WorthFuzzing": true
}

null

{
  "PatchDiff": "commit d694e32f32fa55ac07643ba6d9caf364e9b9e5c5\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate:   Sun Jul 12 07:04:43 2026 +0000\n\n    syz-cluster: applied patch under review\n\ndiff --git a/fs/ceph/export.c b/fs/ceph/export.c\nindex b2f2af1046791d..debb9634b9e3d9 100644\n--- a/fs/ceph/export.c\n+++ b/fs/ceph/export.c\n@@ -442,6 +442,16 @@ static struct dentry *ceph_fh_to_parent(struct super_block *sb,\n \treturn dentry;\n }\n \n+static int ceph_export_copy_name(char *name, const char *src, u32 len)\n+{\n+\tif (len \u003e NAME_MAX)\n+\t\treturn -ENAMETOOLONG;\n+\n+\tmemcpy(name, src, len);\n+\tname[len] = '\\0';\n+\treturn 0;\n+}\n+\n static int __get_snap_name(struct dentry *parent, char *name,\n \t\t\t   struct dentry *child)\n {\n@@ -513,9 +523,8 @@ static int __get_snap_name(struct dentry *parent, char *name,\n \t\t\tBUG_ON(!rde-\u003einode.in);\n \t\t\tif (ceph_snap(inode) ==\n \t\t\t    le64_to_cpu(rde-\u003einode.in-\u003esnapid)) {\n-\t\t\t\tmemcpy(name, rde-\u003ename, rde-\u003ename_len);\n-\t\t\t\tname[rde-\u003ename_len] = '\\0';\n-\t\t\t\terr = 0;\n+\t\t\t\terr = ceph_export_copy_name(name, rde-\u003ename,\n+\t\t\t\t\t\t\t    rde-\u003ename_len);\n \t\t\t\tgoto out;\n \t\t\t}\n \t\t}\n@@ -580,8 +589,8 @@ static int ceph_get_name(struct dentry *parent, char *name,\n \n \trinfo = \u0026req-\u003er_reply_info;\n \tif (!IS_ENCRYPTED(dir)) {\n-\t\tmemcpy(name, rinfo-\u003edname, rinfo-\u003edname_len);\n-\t\tname[rinfo-\u003edname_len] = 0;\n+\t\terr = ceph_export_copy_name(name, rinfo-\u003edname,\n+\t\t\t\t\t    rinfo-\u003edname_len);\n \t} else {\n \t\tstruct fscrypt_str oname = FSTR_INIT(NULL, 0);\n \t\tstruct ceph_fname fname = { .dir\t= dir,\n@@ -595,10 +604,9 @@ static int ceph_get_name(struct dentry *parent, char *name,\n \t\t\tgoto out;\n \n \t\terr = ceph_fname_to_usr(\u0026fname, NULL, \u0026oname, NULL);\n-\t\tif (!err) {\n-\t\t\tmemcpy(name, oname.name, oname.len);\n-\t\t\tname[oname.len] = 0;\n-\t\t}\n+\t\tif (!err)\n+\t\t\terr = ceph_export_copy_name(name, oname.name,\n+\t\t\t\t\t\t    oname.len);\n \t\tceph_fname_free_buffer(dir, \u0026oname);\n \t}\n out:\n"
}

gemini-3.1-pro-preview

null

{
  "EnableConfigs": [
    "CEPH_FS",
    "FS_ENCRYPTION"
  ],
  "FocusSymbols": [
    "__get_snap_name",
    "ceph_get_name"
  ],
  "Reasoning": "The patch fixes a potential buffer overflow in CephFS export operations by adding a length check against NAME_MAX when copying directory names. This modifies reachable filesystem logic used by file handle syscalls (e.g. open_by_handle_at), so it should be fuzzed.",
  "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 d694e32f32fa55ac07643ba6d9caf364e9b9e5c5
Author: syz-cluster <triage@syzkaller.com>
Date:   Sun Jul 12 07:04:43 2026 +0000

    syz-cluster: applied patch under review

diff --git a/fs/ceph/export.c b/fs/ceph/export.c
index b2f2af1046791d..debb9634b9e3d9 100644
--- a/fs/ceph/export.c
+++ b/fs/ceph/export.c
@@ -442,6 +442,16 @@ static struct dentry *ceph_fh_to_parent(struct super_block *sb,
 	return dentry;
 }
 
+static int ceph_export_copy_name(char *name, const char *src, u32 len)
+{
+	if (len > NAME_MAX)
+		return -ENAMETOOLONG;
+
+	memcpy(name, src, len);
+	name[len] = '\0';
+	return 0;
+}
+
 static int __get_snap_name(struct dentry *parent, char *name,
 			   struct dentry *child)
 {
@@ -513,9 +523,8 @@ static int __get_snap_name(struct dentry *parent, char *name,
 			BUG_ON(!rde->inode.in);
 			if (ceph_snap(inode) ==
 			    le64_to_cpu(rde->inode.in->snapid)) {
-				memcpy(name, rde->name, rde->name_len);
-				name[rde->name_len] = '\0';
-				err = 0;
+				err = ceph_export_copy_name(name, rde->name,
+							    rde->name_len);
 				goto out;
 			}
 		}
@@ -580,8 +589,8 @@ static int ceph_get_name(struct dentry *parent, char *name,
 
 	rinfo = &req->r_reply_info;
 	if (!IS_ENCRYPTED(dir)) {
-		memcpy(name, rinfo->dname, rinfo->dname_len);
-		name[rinfo->dname_len] = 0;
+		err = ceph_export_copy_name(name, rinfo->dname,
+					    rinfo->dname_len);
 	} else {
 		struct fscrypt_str oname = FSTR_INIT(NULL, 0);
 		struct ceph_fname fname = { .dir	= dir,
@@ -595,10 +604,9 @@ static int ceph_get_name(struct dentry *parent, char *name,
 			goto out;
 
 		err = ceph_fname_to_usr(&fname, NULL, &oname, NULL);
-		if (!err) {
-			memcpy(name, oname.name, oname.len);
-			name[oname.len] = 0;
-		}
+		if (!err)
+			err = ceph_export_copy_name(name, oname.name,
+						    oname.len);
 		ceph_fname_free_buffer(dir, &oname);
 	}
 out:

gemini-3.1-pro-preview

null

null

							input: 2391
							output: 31
							thoughts: 188
						

**Analyzing the Ceph Filesystem Patch**

Okay, so I've got this patch here that's making a change to `fs/ceph/export.c`. Looks like they're addressing a potential buffer overflow vulnerability. They've introduced a new helper function, `ceph_export_copy_name`. My initial thought is, "good, proactive approach." It's checking if the length of the name exceeds `NAME_MAX` before actually copying it. If it does, it returns `-ENAMETOOLONG`, preventing the `memcpy` and the subsequent buffer overrun. Replacing that direct `memcpy` with a call to this new helper is the core of the fix. Smart.

The affected functions are `__get_snap_name` and `ceph_get_name`, so those are the key areas to focus on. I need to dig into `fs/ceph/export.c` itself now. I'm wondering if this change necessitates any specific configuration options within the Ceph filesystem. Just to be thorough, I'm going to quickly check the `fs/ceph/Kconfig` file with a grep for `CEPH_FS` to see if there are any related config directives that might need adjustment or are affected by this patch. Always good to rule out any subtle side effects or required configurations.

{
  "Expression": "config CEPH_FS",
  "PathPrefix": "fs/ceph/Kconfig"
}

{
  "Output": "fs/ceph/Kconfig-1-# SPDX-License-Identifier: GPL-2.0-only\nfs/ceph/Kconfig:2:config CEPH_FS\nfs/ceph/Kconfig-3-\ttristate \"Ceph distributed file system\"\n--\nfs/ceph/Kconfig=19=if CEPH_FS\nfs/ceph/Kconfig:20:config CEPH_FSCACHE\nfs/ceph/Kconfig-21-\tbool \"Enable Ceph client caching support\"\n--\nfs/ceph/Kconfig=27=endif\nfs/ceph/Kconfig-28-\nfs/ceph/Kconfig:29:config CEPH_FS_POSIX_ACL\nfs/ceph/Kconfig-30-\tbool \"Ceph POSIX Access Control Lists\"\n--\nfs/ceph/Kconfig-38-\nfs/ceph/Kconfig:39:config CEPH_FS_SECURITY_LABEL\nfs/ceph/Kconfig-40-\tbool \"CephFS Security Labels\"\n"
}

gemini-3.1-pro-preview

null

null

							input: 3133
							output: 30
							thoughts: 82
						

**Analyzing CephFS Export Operations**

Okay, so the configuration is definitely targeting `CEPH_FS`. That narrows down the scope quite a bit. It looks like the changes are focused on the `__get_snap_name` and `ceph_get_name` functions. These functions are clearly tied to CephFS export operations. That tells me these are likely used by something like the NFS server, or other mechanisms that are exporting the CephFS filesystem. Now, to get a clear picture of how these fit into the larger process, I need to consult the `export.c` file within the `fs/ceph` directory. That's where the critical `export operations` struct should be defined. From there I should be able to see how these functions interact within the export workflow for CephFS.

{
  "Expression": "export_operations",
  "PathPrefix": "fs/ceph/export.c"
}

{
  "Output": "fs/ceph/export.c=455=static int __get_snap_name(struct dentry *parent, char *name,\n--\nfs/ceph/export.c-470-\t\t\t/*\nfs/ceph/export.c:471:\t\t\t * .get_name() from struct export_operations\nfs/ceph/export.c-472-\t\t\t * assumes that its 'name' parameter is pointing\n--\nfs/ceph/export.c=557=static int ceph_get_name(struct dentry *parent, char *name,\n--\nfs/ceph/export.c-619-\nfs/ceph/export.c:620:const struct export_operations ceph_export_ops = {\nfs/ceph/export.c-621-\t.encode_fh = ceph_encode_fh,\n"
}

gemini-3.1-pro-preview

null

null

							input: 3626
							output: 32
							thoughts: 163
						

**Analyzing the Ceph Name Retrieval Patch**

Okay, so I've got this patch in front of me that addresses a buffer overflow vulnerability. The core of it seems to be in these two functions: `__get_snap_name` and `ceph_get_name`. The fix itself is straightforward – a check to make sure the length doesn't exceed `NAME_MAX` before the problematic operation happens. Functionally, this looks sound, and I'd say it's definitely a good candidate for fuzzing to verify robustness. I'll make a mental note to focus my attention on those two symbols, `__get_snap_name` and `ceph_get_name`, when setting up the fuzzing environment.

The relevant config is `CEPH_FS`, which makes sense. I should quickly check if any other configs come into play. Ah, here's something – `IS_ENCRYPTED(dir)` is used within `ceph_get_name`. That *might* indicate a dependency on `FS_ENCRYPTION` or something similar. Although, `CEPH_FS` is still the primary config of concern. To confirm, I'll take a quick look at `fs/ceph/Kconfig` to see if there are any encryption-related configurations that are also important here.

{
  "Expression": "config CEPH_FS_",
  "PathPrefix": "fs/ceph/Kconfig"
}

{
  "Output": "fs/ceph/Kconfig=27=endif\nfs/ceph/Kconfig-28-\nfs/ceph/Kconfig:29:config CEPH_FS_POSIX_ACL\nfs/ceph/Kconfig-30-\tbool \"Ceph POSIX Access Control Lists\"\n--\nfs/ceph/Kconfig-38-\nfs/ceph/Kconfig:39:config CEPH_FS_SECURITY_LABEL\nfs/ceph/Kconfig-40-\tbool \"CephFS Security Labels\"\n"
}

gemini-3.1-pro-preview

null

null

							input: 4227
							output: 28
							thoughts: 30
						

Okay, here's my interpretation of that thought process, assuming I'm deep in the weeds of Ceph filesystem development:

**Investigating CEPH_FS_ENCRYPTION Availability**

Alright, I need to check something related to file system encryption within Ceph. The key is likely `CEPH_FS_ENCRYPTION`, or something related. My instinct is to quickly hunt for the relevant configuration option. The kernel configuration file (`Kconfig`) is the typical place for these sorts of feature flags within the Ceph file system code. Specifically, the place to look for that seems like `fs/ceph/Kconfig`. Let's use `grep` with `ENCRYPT` to search that file and see what turns up. It's the most expedient method to ascertain if the expected feature is defined in the project, and in what context.

{
  "Expression": "ENCRYPT",
  "PathPrefix": "fs/ceph/Kconfig"
}

{
  "Output": "fs/ceph/Kconfig=2=config CEPH_FS\n--\nfs/ceph/Kconfig-6-\tselect NETFS_SUPPORT\nfs/ceph/Kconfig:7:\tselect FS_ENCRYPTION_ALGS if FS_ENCRYPTION\nfs/ceph/Kconfig-8-\tdefault n\n"
}

gemini-3.1-pro-preview

null

null

							input: 4547
							output: 120
							thoughts: 255
						

**My Analysis of the CephFS Export Patch**

Okay, so this patch is related to CephFS encryption configuration, specifically around the `FS_ENCRYPTION` config option. I'll need to update `EnableConfigs` to include both `CEPH_FS` and `FS_ENCRYPTION`. That makes sense; we need to enable the filesystem and the encryption feature to truly test this.

My initial focus symbols are `__get_snap_name` and `ceph_get_name`. I was just considering if `ceph_export_copy_name` should also be included, since it's a static helper. My experience tells me it might be inlined, but even if it is, there is no harm in including it. In any case, its callers are `__get_snap_name` and `ceph_get_name`.

The reasoning is pretty clear: This patch is a fix for a potential buffer overflow vulnerability during CephFS export operations when directory names are copied. It adds a crucial length check against `NAME_MAX`. Since this is a functional change within reachable core kernel logic (specifically within CephFS export operations), it definitely needs to be fuzzed. It's a clear candidate for syzkaller.

I also need to verify that `ceph_get_name` is indeed reachable. Right, it's accessed through NFS export operations via `export_operations`. Syzkaller and similar fuzzers can reach these code paths through syscalls like `name_to_handle_at` and `open_by_handle_at`, which utilize those export operations. That's a solid path to test this.

Alright, I'm satisfied with the analysis, and I'll record the results now.

{
  "EnableConfigs": [
    "CEPH_FS",
    "FS_ENCRYPTION"
  ],
  "FocusSymbols": [
    "__get_snap_name",
    "ceph_get_name"
  ],
  "Reasoning": "The patch fixes a potential buffer overflow in CephFS export operations by adding a length check against NAME_MAX when copying directory names. This modifies reachable filesystem logic used by file handle syscalls (e.g. open_by_handle_at), so it should be fuzzed.",
  "WorthFuzzing": true
}

{
  "EnableConfigs": [
    "CEPH_FS",
    "FS_ENCRYPTION"
  ],
  "FocusSymbols": [
    "__get_snap_name",
    "ceph_get_name"
  ],
  "Reasoning": "The patch fixes a potential buffer overflow in CephFS export operations by adding a length check against NAME_MAX when copying directory names. This modifies reachable filesystem logic used by file handle syscalls (e.g. open_by_handle_at), so it should be fuzzed.",
  "WorthFuzzing": true
}