[syzbot] [ocfs2?] UBSAN: shift-out-of-bounds in ocfs2_fill_super (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: c2ee9f594da8 KVM: selftests: Fix build on on non-x86 archi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14008c30580000
kernel config: https://syzkaller.appspot.com/x/.config?x=fc6f8ce8c5369043
dashboard link: https://syzkaller.appspot.com/bug?extid=56f7cd1abe4b8e475180
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16ced0a7980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12008c30580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-c2ee9f59.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8a3541902b13/vmlinux-c2ee9f59.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a00efacc2604/bzImage-c2ee9f59.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/4065d12afe1f/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+56f7cd...@syzkaller.appspotmail.com

WARNING: The mand mount option has been deprecated and
and is ignored by this kernel. Remove the mand
option from the mount to silence this warning.
=======================================================
------------[ cut here ]------------
UBSAN: shift-out-of-bounds in fs/ocfs2/super.c:2336:10
shift exponent 32768 is too large for 32-bit type 'int'
CPU: 0 UID: 0 PID: 5093 Comm: syz-executor204 Not tainted 6.12.0-rc4-syzkaller-00047-gc2ee9f594da8 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
ubsan_epilogue lib/ubsan.c:231 [inline]
__ubsan_handle_shift_out_of_bounds+0x3c8/0x420 lib/ubsan.c:468
ocfs2_verify_volume fs/ocfs2/super.c:2336 [inline]
ocfs2_sb_probe fs/ocfs2/super.c:792 [inline]
ocfs2_fill_super+0xf9c/0x5750 fs/ocfs2/super.c:988
mount_bdev+0x20a/0x2d0 fs/super.c:1679
legacy_get_tree+0xee/0x190 fs/fs_context.c:662
vfs_get_tree+0x90/0x2b0 fs/super.c:1800
do_new_mount+0x2be/0xb40 fs/namespace.c:3507
do_mount fs/namespace.c:3847 [inline]
__do_sys_mount fs/namespace.c:4057 [inline]
__se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4034
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8c48e89c7a
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:00007ffd10baf0f8 EFLAGS: 00000282 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffd10baf110 RCX: 00007f8c48e89c7a
RDX: 00000000200002c0 RSI: 0000000020000040 RDI: 00007ffd10baf110
RBP: 0000000000000004 R08: 00007ffd10baf150 R09: 0000000000004434
R10: 00000000000008c0 R11: 0000000000000282 R12: 00000000000008c0
R13: 00007ffd10baf150 R14: 0000000000000003 R15: 0000000001000000
</TASK>
---[ end trace ]---


---
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***

Subject: Re: UBSAN: shift-out-of-bounds in ocfs2_fill_super
Author: dman...@yandex.ru

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 2e1b3cc9d7f790145a80cb705b168f05dab65df2

diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index 3d404624bb96..9852067570e3 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -2319,6 +2319,7 @@ static int ocfs2_verify_volume(struct ocfs2_dinode *di,
struct ocfs2_blockcheck_stats *stats)
{
int status = -EAGAIN;
+ u32 blkszbit;

if (memcmp(di->i_signature, OCFS2_SUPER_BLOCK_SIGNATURE,
strlen(OCFS2_SUPER_BLOCK_SIGNATURE)) == 0) {
@@ -2333,11 +2334,15 @@ static int ocfs2_verify_volume(struct ocfs2_dinode *di,
goto out;
}
status = -EINVAL;
- if ((1 << le32_to_cpu(di->id2.i_super.s_blocksize_bits)) != blksz) {
+ /* Acceptable block sizes are 512 bytes, 1K, 2K and 4K. */
+ blkszbit = le32_to_cpu(di->id2.i_super.s_blocksize_bits);
+ if (blkszbit < 9 || blkszbit > 12) {
mlog(ML_ERROR, "found superblock with incorrect block "
- "size: found %u, should be %u\n",
- 1 << le32_to_cpu(di->id2.i_super.s_blocksize_bits),
- blksz);
+ "size bit: found %u, should be 9, 10, 11, or 12\n",
+ blkszbit);
+ } else if ((1 << le32_to_cpu(blkszbit)) != blksz) {
+ mlog(ML_ERROR, "found superblock with incorrect block "
+ "size: found %u, should be %u\n", 1 << blkszbit, blksz);
} else if (le16_to_cpu(di->id2.i_super.s_major_rev_level) !=
OCFS2_MAJOR_REV_LEVEL ||
le16_to_cpu(di->id2.i_super.s_minor_rev_level) !=

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+56f7cd...@syzkaller.appspotmail.com
Tested-by: syzbot+56f7cd...@syzkaller.appspotmail.com

Tested on:

commit: 2e1b3cc9 Merge tag 'arm-fixes-6.12-2' of git://git.ker..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=10301d5f980000
kernel config: https://syzkaller.appspot.com/x/.config?x=31194b6116728121

dashboard link: https://syzkaller.appspot.com/bug?extid=56f7cd1abe4b8e475180
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=15c456a7980000

Note: testing is done by a robot and is best-effort only.