Re: [syzbot] [audit?] BUG: unable to handle kernel paging request in integrity_audit_message

From: Bradley Morgan

Date: Wed Aug 26 2026 - 21:06:58 EST

On 27 August 2026 01:50:45 BST, syzbot
<syzbot+5ebeb3089ea6439c37be@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>Hello,
>
>syzbot found the following issue on:

#syz set subsystems security:

Note: here's my suggested fix, in security/ima_appraise.c

path = dentry_path(dentry, pathbuf, PATH_MAX);
+if (IS_ERR(path))
path = NULL;

apparmor and tomoyo both IS_ERR check their dentry_path calls, ima
is the only one that doesnt. NULL fname is already handled by the audit
side

>
>HEAD commit: 66fb95a52111 Merge tag 'caps-pr-20260820' of
>git://git.ker..
>git tree: upstream
>console output: https://syzkaller.appspot.com/x/log.txt?x=1560d549580000
>kernel config: https://syzkaller.appspot.com/x/.config?x=b0978f5ed2905b98
>dashboard link:
>https://syzkaller.appspot.com/bug?extid=5ebeb3089ea6439c37be
>compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
>syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16fb4625580000
>
>Downloadable assets:
>disk image:
>https://storage.googleapis.com/syzbot-assets/e7d9049723b0/disk-66fb95a5.raw.xz
>vmlinux: https://storage.googleapis.com/syzbot-assets/a04d6efe59a0/vmlinux-66fb95a5.xz
>kernel image:
>https://storage.googleapis.com/syzbot-assets/81e3f2b9c049/bzImage-66fb95a5.xz
>
>IMPORTANT: if you fix the issue, please add the following tag to the commit:
>Reported-by: syzbot+5ebeb3089ea6439c37be@xxxxxxxxxxxxxxxxxxxxxxxxx
>
>BUG: unable to handle page fault for address: ffffffffffffffdc
>#PF: supervisor read access in kernel mode
>#PF: error_code(0x0000) - not-present page
>PGD eb97067 P4D eb97067 PUD eb99067 PMD 0
>Oops: Oops: 0000 [#1] SMP KASAN NOPTI
>CPU: 0 UID: 0 PID: 5818 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
>Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
>Google 07/16/2026
>RIP: 0010:strlen+0x30/0xa0 lib/string.c:402
>Code: 00 00 00 00 00 fc ff df 55 48 89 fa 48 89 fd 53 48 c1 ea 03 48 83 ec 08 0f b6 04 02 48 89 fa 83 e2 07 38 d0 7f 04 84 c0 75 50 <80> 7d 00 00 74 3d 48 bb 00 00 00 00 00 fc ff df 48 89 e8 48 83 c0
>RSP: 0018:ffffc90003d77940 EFLAGS: 00010246
>RAX: 0000000000000000 RBX: ffffffffffffffdc RCX: 0000000000000000
>RDX: 0000000000000004 RSI: ffffffff8207fb91 RDI: ffffffffffffffdc
>RBP: ffffffffffffffdc R08: 0000000000000004 R09: 00000000000000b7
>R10: 00000000000006c0 R11: ffffffff8bc921d3 R12: ffff8880785a84c0
>R13: 0000000000000007 R14: 00000000fffffff3 R15: ffffffffffffffdc
>FS: 000055555ec16500(0000) GS:ffff888123b86000(0000) knlGS:0000000000000000
>CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>CR2: ffffffffffffffdc CR3: 0000000075fb6000 CR4: 00000000003526f0
>Call Trace:
> <TASK>
> __fortify_strlen include/linux/fortify-string.h:218 [inline]
> audit_log_untrustedstring+0x19/0x30 kernel/audit.c:2203
> integrity_audit_message+0x366/0x4f0
> security/integrity/integrity_audit.c:60
> integrity_audit_msg+0x41/0x60 security/integrity/integrity_audit.c:32
> validate_hash_algo security/integrity/ima/ima_appraise.c:752 [inline]
> ima_inode_setxattr+0x512/0x5f0 security/integrity/ima/ima_appraise.c:775
> security_inode_setxattr+0x2d0/0x560 security/security.c:1940
> __vfs_setxattr_locked+0xad/0x2b0 fs/xattr.c:309
> vfs_setxattr+0x14a/0x390 fs/xattr.c:344
> do_setxattr+0x145/0x180 fs/xattr.c:662
> file_setxattr fs/xattr.c:672 [inline]
> file_setxattr+0x139/0x1b0 fs/xattr.c:666
> path_setxattrat+0x335/0x3b0 fs/xattr.c:732
> __do_sys_fsetxattr fs/xattr.c:782 [inline]
> __se_sys_fsetxattr fs/xattr.c:779 [inline]
> __x64_sys_fsetxattr+0xc5/0x140 fs/xattr.c:779
> do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
> do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>RIP: 0033:0x7f506239e0d9
>Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
>RSP: 002b:00007fff3373f938 EFLAGS: 00000246 ORIG_RAX: 00000000000000be
>RAX: ffffffffffffffda RBX: 00007f5062625fa0 RCX: 00007f506239e0d9
>RDX: 0000200000000380 RSI: 0000200000000080 RDI: 0000000000000004
>RBP: 00007f5062435024 R08: 0000000000000000 R09: 0000000000000000
>R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
>R13: 00007f5062625fac R14: 00007f5062625fa0 R15: 00007f5062625fa0
> </TASK>
>Modules linked in:
>CR2: ffffffffffffffdc
>---[ end trace 0000000000000000 ]---
>RIP: 0010:strlen+0x30/0xa0 lib/string.c:402
>Code: 00 00 00 00 00 fc ff df 55 48 89 fa 48 89 fd 53 48 c1 ea 03 48 83 ec 08 0f b6 04 02 48 89 fa 83 e2 07 38 d0 7f 04 84 c0 75 50 <80> 7d 00 00 74 3d 48 bb 00 00 00 00 00 fc ff df 48 89 e8 48 83 c0
>RSP: 0018:ffffc90003d77940 EFLAGS: 00010246
>RAX: 0000000000000000 RBX: ffffffffffffffdc RCX: 0000000000000000
>RDX: 0000000000000004 RSI: ffffffff8207fb91 RDI: ffffffffffffffdc
>RBP: ffffffffffffffdc R08: 0000000000000004 R09: 00000000000000b7
>R10: 00000000000006c0 R11: ffffffff8bc921d3 R12: ffff8880785a84c0
>R13: 0000000000000007 R14: 00000000fffffff3 R15: ffffffffffffffdc
>FS: 000055555ec16500(0000) GS:ffff888123b86000(0000) knlGS:0000000000000000
>CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>CR2: ffffffffffffffdc CR3: 0000000075fb6000 CR4: 00000000003526f0
>----------------
>Code disassembly (best guess):
> 0: 00 00 add %al,(%rax)
> 2: 00 00 add %al,(%rax)
> 4: 00 fc add %bh,%ah
> 6: ff lcall (bad)
> 7: df 55 48 fists 0x48(%rbp)
> a: 89 fa mov %edi,%edx
> c: 48 89 fd mov %rdi,%rbp
> f: 53 push %rbx
> 10: 48 c1 ea 03 shr $0x3,%rdx
> 14: 48 83 ec 08 sub $0x8,%rsp
> 18: 0f b6 04 02 movzbl (%rdx,%rax,1),%eax
> 1c: 48 89 fa mov %rdi,%rdx
> 1f: 83 e2 07 and $0x7,%edx
> 22: 38 d0 cmp %dl,%al
> 24: 7f 04 jg 0x2a
> 26: 84 c0 test %al,%al
> 28: 75 50 jne 0x7a
>* 2a: 80 7d 00 00 cmpb $0x0,0x0(%rbp) <-- trapping instruction
> 2e: 74 3d je 0x6d
> 30: 48 bb 00 00 00 00 00 movabs $0xdffffc0000000000,%rbx
> 37: fc ff df
> 3a: 48 89 e8 mov %rbp,%rax
> 3d: 48 rex.W
> 3e: 83 .byte 0x83
> 3f: c0 .byte 0xc0
>
>
>---
>This report is generated by a bot. It may contain errors.
>See https://goo.gl/tpsmEJ for more information about syzbot.
>syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx.
>
>syzbot will keep track of this issue. See:
>https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
>
>If the report is already addressed, let syzbot know by replying with:
>#syz fix: exact-commit-title
>
>If you want syzbot to run the reproducer, reply with:
>#syz test: git://repo/address.git branch-or-commit-hash
>If you attach or paste a git patch, syzbot will apply it before testing.
>
>If you want to overwrite report's subsystems, reply with:
>#syz set subsystems: new-subsystem
>(See the list of subsystem names on the web dashboard)
>
>If the report is a duplicate of another one, reply with:
>#syz dup: exact-subject-of-another-report
>
>If you want to undo deduplication, reply with:
>#syz undup
>
>

--- Thanks!
https://lore.kernel.org/all/EE579805-42F2-4C58-B752-F28779EEB717@xxxxxxxxx/