On 27 August 2026 01:50:45 BST, syzbot <[email protected]> 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: [email protected] > >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 [email protected]. > >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/[email protected]/
