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

[Bradley Morgan <brads@mainlining.org>]

On 27 August 2026 02:06:15 BST, syzbot
<syzbot+5ebeb3089ea6439c37be@syzkaller.appspotmail.com> wrote:
>> On 27 August 2026 01:50:45 BST, syzbot
>> <syzbot+5ebeb3089ea6439c37be@syzkaller.appspotmail.com> wrote:
>>>Hello,
>>>
>>>syzbot found the following issue on:
>>
>>
>> #syz set subsystems security:
>
>The specified label "security" is unknown.
>Please use one of the supported labels.
>
>The following labels are suported:
>actionable, missing-backport, no-reminders, prio: {low, normal, high},
>subsystems: {..
>see below ..}
>The list of subsystems:
>https://syzkaller.appspot.com/upstream/subsystems?all=true

AHH, there isn't a security/ subsystem on syzbot, oops!

yeah my fix stands

>
>>
>>
>> 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@syzkaller.appspotmail.com
>>>
>>>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@googlegroups.com.
>>>
>>>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@grrlz.net/
>

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