linux-kernel - [syzbot] [bcachefs?] UBSAN: shift-out-of-bounds in read_one

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Message-ID: <00000000000067ff3c0617c603c2@google.com>
Date: Mon, 06 May 2024 02:51:28 -0700
From: syzbot <syzbot+a8b0fb419355c91dda7f@...kaller.appspotmail.com>
To: bfoster@...hat.com, kent.overstreet@...ux.dev, 
	linux-bcachefs@...r.kernel.org, linux-fsdevel@...r.kernel.org, 
	linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [bcachefs?] UBSAN: shift-out-of-bounds in read_one_super

Hello,

syzbot found the following issue on:

HEAD commit:    78186bd77b47 Merge branch 'for-next/mm-ryan-staging' into ..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=177bab54980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=5ee4da92608aba71
dashboard link: https://syzkaller.appspot.com/bug?extid=a8b0fb419355c91dda7f
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=154d0d1f180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12119450980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6645ec7d501b/disk-78186bd7.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0d272001bc0f/vmlinux-78186bd7.xz
kernel image: https://storage.googleapis.com/syzbot-assets/95e2c70cba6e/Image-78186bd7.gz.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/6679d36fb016/mount_1.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a8b0fb419355c91dda7f@...kaller.appspotmail.com

loop3: detected capacity change from 0 to 32799
------------[ cut here ]------------
UBSAN: shift-out-of-bounds in fs/bcachefs/super-io.c:652:18
shift exponent 32 is too large for 32-bit type 'int'
CPU: 1 PID: 7180 Comm: syz-executor245 Not tainted 6.9.0-rc6-syzkaller-g78186bd77b47 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call trace:
 dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:317
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:324
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xe4/0x150 lib/dump_stack.c:114
 dump_stack+0x1c/0x28 lib/dump_stack.c:123
 ubsan_epilogue lib/ubsan.c:231 [inline]
 __ubsan_handle_shift_out_of_bounds+0x2f4/0x36c lib/ubsan.c:468
 read_one_super+0xab8/0x2614 fs/bcachefs/super-io.c:652
 __bch2_read_super+0x714/0x10a8 fs/bcachefs/super-io.c:750
 bch2_read_super+0x38/0x4c fs/bcachefs/super-io.c:842
 bch2_fs_open+0x1e0/0xb64 fs/bcachefs/super.c:2049
 bch2_mount+0x558/0xe10 fs/bcachefs/fs.c:1903
 legacy_get_tree+0xd4/0x16c fs/fs_context.c:662
 vfs_get_tree+0x90/0x288 fs/super.c:1779
 do_new_mount+0x278/0x900 fs/namespace.c:3352
 path_mount+0x590/0xe04 fs/namespace.c:3679
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount fs/namespace.c:3875 [inline]
 __arm64_sys_mount+0x45c/0x594 fs/namespace.c:3875
 __invoke_syscall arch/arm64/kernel/syscall.c:34 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:48
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:133
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:152
 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712
 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598
---[ end trace ]---
bcachefs (/dev/loop3): error reading default superblock: Invalid superblock: too big (got 4696 bytes, layout max 2199023255552)
bcachefs (/dev/loop3): error reading superblock: Not a bcachefs superblock (got magic 00000000-0000-0000-0000-000000000000)Not a bcachefs superblock (got magic 00000000-0000-0000-0000-000000000000)


---
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