syzbot
WARNING in format_decode
Status:
fixed on 2025/08/14 13:18
Reported-by: syzbot+3ab28ab664e34a0158c1@syzkaller.appspotmail.com
Fix commit:
f8242745871f
bpf: Reject %p% format string in bprintf-like helpers
First crash: 409d, last: 391d
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Bug presence (1)
| Date |
Name |
Commit |
Repro |
Result |
| 2025/08/10 |
upstream (ToT) |
2b38afce25c4 |
C
|
Didn't crash |
Sample crash report:
ntfs3: loop1: Mark volume as dirty due to NTFS errors
------------[ cut here ]------------
Please remove unsupported %� in format string
WARNING: CPU: 1 PID: 7096 at lib/vsprintf.c:2679 format_decode+0xcfd/0x13d0 lib/vsprintf.c:2679
Modules linked in:
CPU: 1 PID: 7096 Comm: syz.1.289 Not tainted 6.6.97-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:format_decode+0xcfd/0x13d0 lib/vsprintf.c:2679
Code: ff e8 27 3a 26 f7 c6 05 29 e3 d5 03 01 41 0f b6 04 1c 84 c0 0f 85 be 06 00 00 41 0f b6 36 48 c7 c7 a0 4f c9 8b e8 63 9e f0 f6 <0f> 0b e9 79 fe ff ff 48 8b 0c 24 80 e1 07 38 c1 0f 8c 46 f3 ff ff
RSP: 0018:ffffc90004d47888 EFLAGS: 00010246
RAX: 0a8440948c644100 RBX: dffffc0000000000 RCX: 0000000000080000
RDX: ffffc9000c8ea000 RSI: 000000000000340d RDI: 000000000000340e
RBP: ffff0000ffffff00 R08: ffffc90004d47487 R09: 1ffff920009a8e90
R10: dffffc0000000000 R11: fffff520009a8e91 R12: 1ffff920009a8f55
R13: 0000000000000000 R14: ffffc90004d47aac R15: ffff0a00ffffff00
FS: 00007f35962296c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001000 CR3: 0000000078481000 CR4: 00000000003526e0
Call Trace:
<TASK>
bstr_printf+0xc4/0xf90 lib/vsprintf.c:3252
____bpf_trace_printk kernel/trace/bpf_trace.c:386 [inline]
bpf_trace_printk+0x10f/0x190 kernel/trace/bpf_trace.c:371
bpf_prog_12183cdb1cd51dab+0x36/0x3a
bpf_dispatcher_nop_func include/linux/bpf.h:1213 [inline]
__bpf_prog_run include/linux/filter.h:612 [inline]
bpf_prog_run include/linux/filter.h:619 [inline]
bpf_test_run+0x340/0x8a0 net/bpf/test_run.c:424
bpf_prog_test_run_skb+0xa67/0x11c0 net/bpf/test_run.c:1050
bpf_prog_test_run+0x321/0x390 kernel/bpf/syscall.c:4123
__sys_bpf+0x440/0x800 kernel/bpf/syscall.c:5485
__do_sys_bpf kernel/bpf/syscall.c:5571 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5569 [inline]
__x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5569
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f359538e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f3596229038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f35955b5fa0 RCX: 00007f359538e929
RDX: 0000000000000028 RSI: 0000200000000080 RDI: 000000000000000a
RBP: 00007f3595410b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f35955b5fa0 R15: 00007fff4d2efcc8
</TASK>
* Struck through repros no longer work on HEAD.