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

From: Paul Moore

Date: Wed Aug 26 2026 - 21:22:37 EST

On Wed, Aug 26, 2026 at 9:06 PM Bradley Morgan <brads@xxxxxxxxxxxxxx> wrote:
> 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

Thanks for taking a look Bradley. Adding Mimi, Roberto, and the
linux-integrity list as the security/integrity/ima/ima_appraise.c file
is their domain.

> >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/

--
paul-moore.com