Forwarded: Re: [syzbot] UBSAN: shift-out-of-bounds in minix_statfs

[syzbot <syzbot+5ad0824204c7bf9b67f2@syzkaller.appspotmail.com>]

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Subject: Re: [syzbot] UBSAN: shift-out-of-bounds in minix_statfs
Author: xandfury@gmail.com

syzbot <syzbot+5ad0824204c7bf9b67f2@syzkaller.appspotmail.com> writes:

> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    b8a98b6bf66a Merge tag ’pci-v5.16-fixes-2’ of git://git.ke..
> git tree:       upstream
> console output: <https://syzkaller.appspot.com/x/log.txt?x=1342c069b00000>
> kernel config:  <https://syzkaller.appspot.com/x/.config?x=221ffc09e39ebbd1>
> dashboard link: <https://syzkaller.appspot.com/bug?extid=5ad0824204c7bf9b67f2>
> 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=15e8a551b00000>
> C reproducer:   <https://syzkaller.appspot.com/x/repro.c?x=176da9b9b00000>
>
> Bisection is inconclusive: the issue happens on the oldest tested release.
>
> bisection log:  <https://syzkaller.appspot.com/x/bisect.txt?x=17e8a7bdb00000>
> final oops:     <https://syzkaller.appspot.com/x/report.txt?x=1418a7bdb00000>
> console output: <https://syzkaller.appspot.com/x/log.txt?x=1018a7bdb00000>
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+5ad0824204c7bf9b67f2@syzkaller.appspotmail.com
>
> loop0: detected capacity change from 0 to 272
> `=============================================================================='
> UBSAN: shift-out-of-bounds in fs/minix/inode.c:380:57
> shift exponent 65510 is too large for 64-bit type ’long unsigned int’
> CPU: 0 PID: 3601 Comm: syz-executor657 Not tainted 5.16.0-rc4-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> Call Trace:
>  <TASK>
>  __dump_stack lib/dump_stack.c:88 [inline]
>  dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
>  ubsan_epilogue+0xb/0x5a lib/ubsan.c:151
>  __ubsan_handle_shift_out_of_bounds.cold+0xb1/0x181 lib/ubsan.c:330
>  minix_statfs.cold+0x17/0x1c fs/minix/inode.c:380
>  statfs_by_dentry+0x133/0x210 fs/statfs.c:66
>  vfs_statfs fs/statfs.c:90 [inline]
>  fd_statfs+0x66/0x100 fs/statfs.c:120
>  __do_sys_fstatfs+0x7a/0xf0 fs/statfs.c:216
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x44/0xae
> RIP: 0033:0x7f33e4f00e09
> 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 c0 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007ffeedacabd8 EFLAGS: 00000246 ORIG_RAX: 000000000000008a
> RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f33e4f00e09
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
> RBP: 00007f33e4ec06a0 R08: 0000000000000000 R09: 0000000000000000
> R10: 00007ffeedacaa90 R11: 0000000000000246 R12: 00007f33e4ec0730
> R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
>  </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.
> For information about bisection process see: <https://goo.gl/tpsmEJ#bisection>
> syzbot can test patches for this issue, for details see:
> <https://goo.gl/tpsmEJ#testing-patches>

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master