Re: [syzbot] [audit?] BUG: unable to handle kernel paging request in integrity_audit_message
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From: syzbot <hidden>
Date: 2026-08-29 18:27:39
Also in:
linux-integrity, lkml, stable
On 29 August 2026 19:12:29 BST, syzbot [off-list ref] wrote:quoted
syzbot has found a reproducer for the following issue on:#syz test: dentry_path() returns ERR_PTR(-ENAMETOOLONG) when the path
I've failed to parse your command. Did you perhaps forget to provide the branch name, or added an extra ':'? Please use one of the two supported formats: 1. #syz test 2. #syz test: repo branch-or-commit-hash Note the lack of ':' in option 1.
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exceeds the buffer. validate_hash_algo() passes the result straight to integrity_audit_msg() without checking. ERR_PTR is not NULL, so integrity_audit_message() sees a valid pointer and calls strlen() on it, which faults: BUG: unable to handle page fault for address: ffffffffffffffdc RIP: 0010:strlen+0x30/0xa0 Call Trace: audit_log_untrustedstring+0x19/0x30 integrity_audit_message+0x366/0x4f0 ima_inode_setxattr+0x512/0x5f0 Check for IS_ERR() and use NULL instead, which makes the audit message skip the name= field instead of crashing. Fixes: 4f2946aa0c45 ("IMA: introduce a new policy option func=SETXATTR_CHECK") Cc: stable@vger.kernel.org Reported-by: syzbot+5ebeb3089ea6439c37be@syzkaller.appspotmail.com Link: https://lore.kernel.org/all/6a8f89e5.1d9ded08.62e62.00bf.GAE@google.com/ (local) Signed-off-by: Bradley Morgan <redacted> security/integrity/ima/ima_appraise.c | 2 ++ 1 file changed, 2 insertions(+)diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c index ced2e131b061..b280488e15fc 100644 --- a/security/integrity/ima/ima_appraise.c +++ b/security/integrity/ima/ima_appraise.c@@ -748,6 +748,8 @@ static int validate_hash_algo(struct dentry *dentry, return -EACCES; path = dentry_path(dentry, pathbuf, PATH_MAX); + if (IS_ERR(path)) + path = NULL; integrity_audit_msg(AUDIT_INTEGRITY_DATA, d_inode(dentry), path, "set_data", errmsg, -EACCES, 0);-- 2.47.3 >HEAD commit: cf72cbb39da8 Merge tag 'io_uring-7.3-20260828' of >git://gi.. >git tree: upstream >console output: https://syzkaller.appspot.com/x/log.txt?x=16e7cc15580000 >kernel config: https://syzkaller.appspot.com/x/.config?x=85bc5cc2fc7394d9 >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 >userspace arch: i386 >syz repro: https://syzkaller.appspot.com/x/repro.syz?x=159ebd79580000 >C reproducer: https://syzkaller.appspot.com/x/repro.c?x=123d1d79580000 > >Downloadable assets: >disk image (non-bootable): >https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-cf72cbb3.raw.xz >vmlinux: https://storage.googleapis.com/syzbot-assets/755d053ff703/vmlinux-cf72cbb3.xz >kernel image: >https://storage.googleapis.com/syzbot-assets/0837738ba281/bzImage-cf72cbb3.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 eb99067 P4D eb99067 PUD eb9b067 PMD 0 >Oops: Oops: 0000 [#1] SMP KASAN NOPTI >CPU: 0 UID: 0 PID: 5921 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) >Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS >1.16.3-debian-1.16.3-2 04/01/2014 >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:ffffc90002eb7920 EFLAGS: 00010246 >RAX: 0000000000000000 RBX: ffffffffffffffdc RCX: 0000000000000000 >RDX: 0000000000000004 RSI: ffffffff82081bc1 RDI: ffffffffffffffdc >RBP: ffffffffffffffdc R08: 0000000000000004 R09: 00000000000000a9 >R10: 00000000000006c0 R11: 0000000000000001 R12: ffff888027be0e40 >R13: 0000000000000007 R14: 00000000fffffff3 R15: ffffffffffffffdc >FS: 0000000000000000(0000) GS:ffff888096967000(0063) knlGS:000000005783f480 >CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 >CR2: ffffffffffffffdc CR3: 0000000055e55000 CR4: 0000000000352ef0 >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+0x299/0x560 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] > __ia32_sys_fsetxattr+0xc4/0x140 fs/xattr.c:779 > do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:79 [inline] > __do_fast_syscall_32+0x13a/0x8b0 arch/x86/entry/syscall_32.c:291 > do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:316 > entry_SYSENTER_compat_after_hwframe+0x84/0x8e >RIP: 0023:0xf7fb7fec >Code: Unable to access opcode bytes at 0xf7fb7fc2. >RSP: 002b:00000000fffd97bc EFLAGS: 00000296 ORIG_RAX: 00000000000000e4 >RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000080000080 >RDX: 0000000080001080 RSI: 0000000000000002 RDI: 0000000000000000 >RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 >R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 >R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 > </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:ffffc90002eb7920 EFLAGS: 00010246 >RAX: 0000000000000000 RBX: ffffffffffffffdc RCX: 0000000000000000 >RDX: 0000000000000004 RSI: ffffffff82081bc1 RDI: ffffffffffffffdc >RBP: ffffffffffffffdc R08: 0000000000000004 R09: 00000000000000a9 >R10: 00000000000006c0 R11: 0000000000000001 R12: ffff888027be0e40 >R13: 0000000000000007 R14: 00000000fffffff3 R15: ffffffffffffffdc >FS: 0000000000000000(0000) GS:ffff888096967000(0063) knlGS:000000005783f480 >CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 >CR2: 00000000f7fb8000 CR3: 0000000055e55000 CR4: 0000000000352ef0 >---------------- >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 > > >--- >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. > --- Thanks! https://lore.kernel.org/all/EE579805-42F2-4C58-B752-F28779EEB717@grrlz.net/