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

syzbot
2022-04-21T08:37:25Z

syzbot has found a reproducer for the following issue on:

HEAD commit: b253435746d9 Merge tag 'xtensa-20220416' of https://github..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=177e30e8f00000
kernel config: https://syzkaller.appspot.com/x/.config?x=ff9f8140cbb3af7
dashboard link: https://syzkaller.appspot.com/bug?extid=1631f09646bc214d2e76
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=12e13cfcf00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=135e3008f00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1631f09646bc214d2e76@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 8189
================================================================================
UBSAN: shift-out-of-bounds in fs/ntfs3/super.c:673:16
shift exponent -192 is negative
CPU: 1 PID: 3587 Comm: syz-executor611 Not tainted 5.18.0-rc3-syzkaller-00016-gb253435746d9 #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/0x50 lib/ubsan.c:151
__ubsan_handle_shift_out_of_bounds.cold+0xb1/0x187 lib/ubsan.c:322
ntfs_fill_super.cold+0x2bf/0x549 fs/ntfs/bitmap.c:84
get_tree_bdev+0x440/0x760 fs/super.c:1292
vfs_get_tree+0x89/0x2f0 fs/super.c:1497
do_new_mount fs/namespace.c:3040 [inline]
path_mount+0x1320/0x1fa0 fs/namespace.c:3370
do_mount fs/namespace.c:3383 [inline]
__do_sys_mount fs/namespace.c:3591 [inline]
__se_sys_mount fs/namespace.c:3568 [inline]
__x64_sys_mount+0x27f/0x300 fs/namespace.c:3568
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: 0033:0x7fb8d7bcd7ea
Code: 83 c4 08 5b 5d c3 66 2e 0f 1f 84 00 00 00 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 00 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:00007ffdfb6d7948 EFLAGS: 00000286 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffdfb6d79a0 RCX: 00007fb8d7bcd7ea
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffdfb6d7960
RBP: 00007ffdfb6d7960 R08: 00007ffdfb6d79a0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000286 R12: 0000000020001b80
R13: 0000000000000003 R14: 0000000000000004 R15: 0000000000000110
</TASK>
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