* [syzbot] [fs?] UBSAN: shift-out-of-bounds in befs_check_sb
@ 2023-07-12 13:47 syzbot
2024-03-03 8:30 ` syzbot
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: syzbot @ 2023-07-12 13:47 UTC (permalink / raw)
To: linux-fsdevel, linux-kernel, luisbg, salah.triki, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: 3f01e9fed845 Merge tag 'linux-watchdog-6.5-rc2' of git://w..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1310fc5ca80000
kernel config: https://syzkaller.appspot.com/x/.config?x=e6c2f785de9e303f
dashboard link: https://syzkaller.appspot.com/bug?extid=fc26c366038b54261e53
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=107f12e8a80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=174014a2a80000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/896ca272ae74/disk-3f01e9fe.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/deff7fbe3b2c/vmlinux-3f01e9fe.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ca3863031cc5/bzImage-3f01e9fe.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/9c7c5305480d/mount_0.gz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fc26c366038b54261e53@syzkaller.appspotmail.com
memfd_create() without MFD_EXEC nor MFD_NOEXEC_SEAL, pid=5019 'syz-executor590'
loop0: detected capacity change from 0 to 128
================================================================================
UBSAN: shift-out-of-bounds in fs/befs/super.c:96:9
shift exponent 3229888891 is too large for 32-bit type 'int'
CPU: 0 PID: 5019 Comm: syz-executor590 Not tainted 6.5.0-rc1-syzkaller-00006-g3f01e9fed845 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/03/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x136/0x150 lib/dump_stack.c:106
ubsan_epilogue lib/ubsan.c:217 [inline]
__ubsan_handle_shift_out_of_bounds+0x221/0x5a0 lib/ubsan.c:387
befs_check_sb.cold+0x19/0x6f fs/befs/super.c:96
befs_fill_super+0x9b5/0x1110 fs/befs/linuxvfs.c:873
mount_bdev+0x315/0x3e0 fs/super.c:1391
legacy_get_tree+0x109/0x220 fs/fs_context.c:611
vfs_get_tree+0x8d/0x350 fs/super.c:1519
do_new_mount fs/namespace.c:3335 [inline]
path_mount+0x136e/0x1e70 fs/namespace.c:3662
do_mount fs/namespace.c:3675 [inline]
__do_sys_mount fs/namespace.c:3884 [inline]
__se_sys_mount fs/namespace.c:3861 [inline]
__x64_sys_mount+0x283/0x300 fs/namespace.c:3861
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fe1b84908ba
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 5e 04 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd994dbc28 EFLAGS: 00000282 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffd994dbc30 RCX: 00007fe1b84908ba
RDX: 0000000020000100 RSI: 0000000020009e40 RDI: 00007ffd994dbc30
RBP: 0000000000000004 R08: 00007ffd994dbc70 R09: 0000000000009e1f
R10: 0000000003008001 R11: 0000000000000282 R12: 00007ffd994dbc70
R13: 0000000000000003 R14: 0000000000010000 R15: 0000000000000001
</TASK>
================================================================================
---
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@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the bug is already fixed, 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 change bug's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the bug is a duplicate of another bug, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [syzbot] [fs?] UBSAN: shift-out-of-bounds in befs_check_sb
2023-07-12 13:47 [syzbot] [fs?] UBSAN: shift-out-of-bounds in befs_check_sb syzbot
@ 2024-03-03 8:30 ` syzbot
2025-09-28 19:16 ` Forwarded: " syzbot
2025-09-28 20:17 ` syzbot
2 siblings, 0 replies; 6+ messages in thread
From: syzbot @ 2024-03-03 8:30 UTC (permalink / raw)
To: 20230801155823.206985-1-ghandatmanas,
88c258bd-3d0c-de79-b411-6552841eb8d0, axboe, brauner,
ghandatmanas, gregkh, jack, linux-fsdevel, linux-kernel-mentees,
linux-kernel, luisbg, salah.triki, syzkaller-bugs, syzkaller, w
syzbot suspects this issue was fixed by commit:
commit 6f861765464f43a71462d52026fbddfc858239a5
Author: Jan Kara <jack@suse.cz>
Date: Wed Nov 1 17:43:10 2023 +0000
fs: Block writes to mounted block devices
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=14b5e754180000
start commit: 8689f4f2ea56 Merge tag 'mmc-v6.5-2' of git://git.kernel.or..
git tree: upstream
kernel config: https://syzkaller.appspot.com/x/.config?x=15873d91ff37a949
dashboard link: https://syzkaller.appspot.com/bug?extid=fc26c366038b54261e53
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14237dc2a80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13e34d22a80000
If the result looks correct, please mark the issue as fixed by replying with:
#syz fix: fs: Block writes to mounted block devices
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
^ permalink raw reply [flat|nested] 6+ messages in thread
* Forwarded: Re: [syzbot] [fs?] UBSAN: shift-out-of-bounds in befs_check_sb
2023-07-12 13:47 [syzbot] [fs?] UBSAN: shift-out-of-bounds in befs_check_sb syzbot
2024-03-03 8:30 ` syzbot
@ 2025-09-28 19:16 ` syzbot
2025-09-28 20:17 ` syzbot
2 siblings, 0 replies; 6+ messages in thread
From: syzbot @ 2025-09-28 19:16 UTC (permalink / raw)
To: linux-kernel, syzkaller-bugs
For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.
***
Subject: Re: [syzbot] [fs?] UBSAN: shift-out-of-bounds in befs_check_sb
Author: xandfury@gmail.com
syzbot <syzbot+fc26c366038b54261e53@syzkaller.appspotmail.com> writes:
> syzbot suspects this issue was fixed by commit:
>
> commit 6f861765464f43a71462d52026fbddfc858239a5
> Author: Jan Kara <jack@suse.cz>
> Date: Wed Nov 1 17:43:10 2023 +0000
>
> fs: Block writes to mounted block devices
>
> bisection log: <https://syzkaller.appspot.com/x/bisect.txt?x=14b5e754180000>
> start commit: 8689f4f2ea56 Merge tag ’mmc-v6.5-2’ of git://git.kernel.or..
> git tree: upstream
> kernel config: <https://syzkaller.appspot.com/x/.config?x=15873d91ff37a949>
> dashboard link: <https://syzkaller.appspot.com/bug?extid=fc26c366038b54261e53>
> syz repro: <https://syzkaller.appspot.com/x/repro.syz?x=14237dc2a80000>
> C reproducer: <https://syzkaller.appspot.com/x/repro.c?x=13e34d22a80000>
>
> If the result looks correct, please mark the issue as fixed by replying with:
>
> #syz fix: fs: Block writes to mounted block devices
>
> For information about bisection process see: <https://goo.gl/tpsmEJ#bisection>
#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 6f861765464f43a71462d52026fbddfc858239a5
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [syzbot] [fs?] UBSAN: shift-out-of-bounds in befs_check_sb
[not found] <87ecrq2xr2.fsf@gmail.com>
@ 2025-09-28 19:53 ` syzbot
0 siblings, 0 replies; 6+ messages in thread
From: syzbot @ 2025-09-28 19:53 UTC (permalink / raw)
To: linux-kernel, syzkaller-bugs, xandfury
Hello,
syzbot tried to test the proposed patch but the build/boot failed:
./include/linux/thread_info.h:244:4: error: call to '__bad_copy_from' declared with 'error' attribute: copy source size is too small
drivers/nvme/target/fc.c:150:2: warning: 'counted_by' should not be applied to an array with element of unknown size because 'struct nvmet_fc_fcp_iod' is a struct type with a flexible array member. This will be an error in a future compiler version [-Wbounds-safety-counted-by-elt-type-unknown-size]
Tested on:
commit: 6f861765 fs: Block writes to mounted block devices
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel config: https://syzkaller.appspot.com/x/.config?x=f5b21423ca3f0a96
dashboard link: https://syzkaller.appspot.com/bug?extid=fc26c366038b54261e53
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
Note: no patches were applied.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Forwarded: Re: [syzbot] [fs?] UBSAN: shift-out-of-bounds in befs_check_sb
2023-07-12 13:47 [syzbot] [fs?] UBSAN: shift-out-of-bounds in befs_check_sb syzbot
2024-03-03 8:30 ` syzbot
2025-09-28 19:16 ` Forwarded: " syzbot
@ 2025-09-28 20:17 ` syzbot
2 siblings, 0 replies; 6+ messages in thread
From: syzbot @ 2025-09-28 20:17 UTC (permalink / raw)
To: linux-kernel, syzkaller-bugs
For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.
***
Subject: Re: [syzbot] [fs?] UBSAN: shift-out-of-bounds in befs_check_sb
Author: xandfury@gmail.com
syzbot <syzbot+fc26c366038b54261e53@syzkaller.appspotmail.com> writes:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 3f01e9fed845 Merge tag ’linux-watchdog-6.5-rc2’ of git://w..
> git tree: upstream
> console+strace: <https://syzkaller.appspot.com/x/log.txt?x=1310fc5ca80000>
> kernel config: <https://syzkaller.appspot.com/x/.config?x=e6c2f785de9e303f>
> dashboard link: <https://syzkaller.appspot.com/bug?extid=fc26c366038b54261e53>
> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro: <https://syzkaller.appspot.com/x/repro.syz?x=107f12e8a80000>
> C reproducer: <https://syzkaller.appspot.com/x/repro.c?x=174014a2a80000>
>
> Downloadable assets:
> disk image: <https://storage.googleapis.com/syzbot-assets/896ca272ae74/disk-3f01e9fe.raw.xz>
> vmlinux: <https://storage.googleapis.com/syzbot-assets/deff7fbe3b2c/vmlinux-3f01e9fe.xz>
> kernel image: <https://storage.googleapis.com/syzbot-assets/ca3863031cc5/bzImage-3f01e9fe.xz>
> mounted in repro: <https://storage.googleapis.com/syzbot-assets/9c7c5305480d/mount_0.gz>
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+fc26c366038b54261e53@syzkaller.appspotmail.com
>
> memfd_create() without MFD_EXEC nor MFD_NOEXEC_SEAL, pid=5019 ’syz-executor590’
> loop0: detected capacity change from 0 to 128
> `=============================================================================='
> UBSAN: shift-out-of-bounds in fs/befs/super.c:96:9
> shift exponent 3229888891 is too large for 32-bit type ’int’
> CPU: 0 PID: 5019 Comm: syz-executor590 Not tainted 6.5.0-rc1-syzkaller-00006-g3f01e9fed845 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/03/2023
> Call Trace:
> <TASK>
> __dump_stack lib/dump_stack.c:88 [inline]
> dump_stack_lvl+0x136/0x150 lib/dump_stack.c:106
> ubsan_epilogue lib/ubsan.c:217 [inline]
> __ubsan_handle_shift_out_of_bounds+0x221/0x5a0 lib/ubsan.c:387
> befs_check_sb.cold+0x19/0x6f fs/befs/super.c:96
> befs_fill_super+0x9b5/0x1110 fs/befs/linuxvfs.c:873
> mount_bdev+0x315/0x3e0 fs/super.c:1391
> legacy_get_tree+0x109/0x220 fs/fs_context.c:611
> vfs_get_tree+0x8d/0x350 fs/super.c:1519
> do_new_mount fs/namespace.c:3335 [inline]
> path_mount+0x136e/0x1e70 fs/namespace.c:3662
> do_mount fs/namespace.c:3675 [inline]
> __do_sys_mount fs/namespace.c:3884 [inline]
> __se_sys_mount fs/namespace.c:3861 [inline]
> __x64_sys_mount+0x283/0x300 fs/namespace.c:3861
> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
> RIP: 0033:0x7fe1b84908ba
> Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 5e 04 00 00 66 2e 0f 1f
> 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01
> f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007ffd994dbc28 EFLAGS: 00000282 ORIG_RAX: 00000000000000a5
> RAX: ffffffffffffffda RBX: 00007ffd994dbc30 RCX: 00007fe1b84908ba
> RDX: 0000000020000100 RSI: 0000000020009e40 RDI: 00007ffd994dbc30
> RBP: 0000000000000004 R08: 00007ffd994dbc70 R09: 0000000000009e1f
> R10: 0000000003008001 R11: 0000000000000282 R12: 00007ffd994dbc70
> R13: 0000000000000003 R14: 0000000000010000 R15: 0000000000000001
> </TASK>
> `=============================================================================='
>
>
> —
> 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@googlegroups.com.
>
> syzbot will keep track of this issue. See:
> <https://goo.gl/tpsmEJ#status> for how to communicate with syzbot.
>
> If the bug is already fixed, 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 change bug’s subsystems, reply with:
> #syz set subsystems: new-subsystem
> (See the list of subsystem names on the web dashboard)
>
> If the bug is a duplicate of another bug, reply with:
> #syz dup: exact-subject-of-another-report
>
> If you want to undo deduplication, reply with:
> #syz undup
#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [syzbot] [fs?] UBSAN: shift-out-of-bounds in befs_check_sb
[not found] <87a52e2uxz.fsf@gmail.com>
@ 2025-09-28 20:43 ` syzbot
0 siblings, 0 replies; 6+ messages in thread
From: syzbot @ 2025-09-28 20:43 UTC (permalink / raw)
To: linux-kernel, syzkaller-bugs, xandfury
Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
UBSAN: shift-out-of-bounds in befs_check_sb
loop0: detected capacity change from 0 to 128
------------[ cut here ]------------
UBSAN: shift-out-of-bounds in fs/befs/super.c:96:9
shift exponent 2066842816 is too large for 32-bit type 'int'
CPU: 0 UID: 0 PID: 6637 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
<TASK>
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
ubsan_epilogue+0xa/0x40 lib/ubsan.c:233
__ubsan_handle_shift_out_of_bounds+0x386/0x410 lib/ubsan.c:494
befs_check_sb+0x421/0x4c0 fs/befs/super.c:96
befs_fill_super+0x49b/0xa70 fs/befs/linuxvfs.c:841
get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1692
vfs_get_tree+0x8f/0x2b0 fs/super.c:1815
do_new_mount+0x2a2/0x9e0 fs/namespace.c:3808
do_mount fs/namespace.c:4136 [inline]
__do_sys_mount fs/namespace.c:4347 [inline]
__se_sys_mount+0x317/0x410 fs/namespace.c:4324
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc8d5fb066a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007fc8d5615e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fc8d5615ef0 RCX: 00007fc8d5fb066a
RDX: 0000200000000040 RSI: 0000200000000000 RDI: 00007fc8d5615eb0
RBP: 0000200000000040 R08: 00007fc8d5615ef0 R09: 0000000000800001
R10: 0000000000800001 R11: 0000000000000246 R12: 0000200000000000
R13: 00007fc8d5615eb0 R14: 0000000000009e17 R15: 0000200000000080
</TASK>
---[ end trace ]---
Tested on:
commit: 8f973663 Merge tag 'trace-v6.17-rc7' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17f7f142580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f5b21423ca3f0a96
dashboard link: https://syzkaller.appspot.com/bug?extid=fc26c366038b54261e53
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
Note: no patches were applied.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2025-09-28 20:43 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2023-07-12 13:47 [syzbot] [fs?] UBSAN: shift-out-of-bounds in befs_check_sb syzbot
2024-03-03 8:30 ` syzbot
2025-09-28 19:16 ` Forwarded: " syzbot
2025-09-28 20:17 ` syzbot
[not found] <87ecrq2xr2.fsf@gmail.com>
2025-09-28 19:53 ` syzbot
[not found] <87a52e2uxz.fsf@gmail.com>
2025-09-28 20:43 ` syzbot
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