syzbot


UBSAN: shift-out-of-bounds in exfat_fill_super

Status: fixed on 2021/04/09 19:46
Subsystems: exfat
[Documentation on labels]
Reported-by: syzbot+da4fe66aaadd3c2e2d1c@syzkaller.appspotmail.com
Fix commit: 78c276f5495a exfat: fix shift-out-of-bounds in exfat_fill_super()
First crash: 1238d, last: 1217d
Cause bisection: failed (error log, bisect log)
  
Discussions (6)
Title Replies (including bot) Last reply
[PATCH 5.10 000/663] 5.10.20-rc1 review 673 (673) 2021/03/05 18:03
[PATCH 5.11 000/775] 5.11.3-rc1 review 776 (776) 2021/03/01 16:15
[PATCH v2] exfat: fix shift-out-of-bounds in exfat_fill_super() 3 (3) 2021/02/01 04:24
[PATCH] exfat: fix shift-out-of-bounds in exfat_fill_super() 2 (2) 2021/01/29 21:10
UBSAN: shift-out-of-bounds in exfat_fill_super 4 (5) 2021/01/26 05:14
RE: UBSAN: shift-out-of-bounds in exfat_fill_super 1 (1) 2021/01/26 05:08
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream UBSAN: shift-out-of-bounds in exfat_fill_super (2) exfat 1 212d 208d 0/28 auto-obsoleted due to no activity on 2024/02/22 05:01
Last patch testing requests (1)
Created Duration User Patch Repo Result
2021/04/01 15:44 22m phil@philpotter.co.uk https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master OK

Sample crash report:
loop0: detected capacity change from 16383 to 0
================================================================================
UBSAN: shift-out-of-bounds in fs/exfat/super.c:471:28
shift exponent 4294967294 is too large for 32-bit type 'int'
CPU: 0 PID: 8443 Comm: syz-executor876 Not tainted 5.11.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x183/0x22e lib/dump_stack.c:120
 ubsan_epilogue lib/ubsan.c:148 [inline]
 __ubsan_handle_shift_out_of_bounds+0x432/0x4d0 lib/ubsan.c:395
 exfat_read_boot_sector fs/exfat/super.c:471 [inline]
 __exfat_fill_super fs/exfat/super.c:556 [inline]
 exfat_fill_super+0x2acb/0x2d00 fs/exfat/super.c:624
 get_tree_bdev+0x406/0x630 fs/super.c:1291
 vfs_get_tree+0x86/0x270 fs/super.c:1496
 do_new_mount fs/namespace.c:2881 [inline]
 path_mount+0x1937/0x2c50 fs/namespace.c:3211
 do_mount fs/namespace.c:3224 [inline]
 __do_sys_mount fs/namespace.c:3432 [inline]
 __se_sys_mount+0x2f9/0x3b0 fs/namespace.c:3409
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x446f8a
Code: b8 08 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 fd ad fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 da ad fb ff c3 66 0f 1f 84 00 00 00 00 00
RSP: 002b:00007fff97c1b978 EFLAGS: 00000297 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fff97c1b9d0 RCX: 0000000000446f8a
RDX: 0000000020000000 RSI: 0000000020000340 RDI: 00007fff97c1b990
RBP: 00007fff97c1b990 R08: 00007fff97c1b9d0 R09: 00007fff00000015
R10: 0000000000000000 R11: 0000000000000297 R12: 000000000000000c
R13: 0000000000000004 R14: 0000000000000003 R15: 0000000000000003
================================================================================

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2021/01/21 17:42 upstream 9791581c049c d4f4eca5 .config console log report syz C ci-upstream-kasan-gce-smack-root UBSAN: shift-out-of-bounds in exfat_fill_super
2021/02/11 23:31 upstream 291009f656e8 a5f86b15 .config console log report info ci-upstream-kasan-gce-smack-root UBSAN: shift-out-of-bounds in exfat_fill_super
2021/01/21 17:22 upstream 9791581c049c d4f4eca5 .config console log report info ci-upstream-kasan-gce-smack-root UBSAN: shift-out-of-bounds in exfat_fill_super
* Struck through repros no longer work on HEAD.