syzbot


UBSAN: undefined-behaviour in erofs_fill_super

Status: upstream: reported C repro on 2020/09/20 17:10
Reported-by: syzbot+fb7f8baf6114ca56065e@syzkaller.appspotmail.com
First crash: 1538d, last: 1508d
Fix bisection: failed (error log, bisect log)
  

Sample crash report:
audit: type=1400 audit(1601776257.602:8): avc:  denied  { execmem } for  pid=6511 comm="syz-executor967" scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=process permissive=1
erofs: read_super, device -> /dev/loop0
erofs: options -> 
================================================================================
UBSAN: Undefined behaviour in drivers/staging/erofs/super.c:122:3
shift exponent 55 is too large for 32-bit type 'int'
CPU: 1 PID: 6511 Comm: syz-executor967 Not tainted 4.19.149-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x22c/0x33e lib/dump_stack.c:118
 ubsan_epilogue+0xe/0x3a lib/ubsan.c:161
 __ubsan_handle_shift_out_of_bounds.cold+0x1c4/0x250 lib/ubsan.c:422
 superblock_read drivers/staging/erofs/super.c:122 [inline]
 erofs_read_super drivers/staging/erofs/super.c:356 [inline]
 erofs_fill_super+0x397/0x12fc drivers/staging/erofs/super.c:499
 mount_bdev+0x2fc/0x3b0 fs/super.c:1158
 erofs_mount+0x8c/0xc0 drivers/staging/erofs/super.c:512
 mount_fs+0xa3/0x318 fs/super.c:1261
 vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961
 vfs_kern_mount fs/namespace.c:951 [inline]
 do_new_mount fs/namespace.c:2469 [inline]
 do_mount+0x51c/0x2f10 fs/namespace.c:2799
 ksys_mount+0xcf/0x130 fs/namespace.c:3015
 __do_sys_mount fs/namespace.c:3029 [inline]
 __se_sys_mount fs/namespace.c:3026 [inline]
 __x64_sys_mount+0xba/0x150 fs/namespace.c:3026
 do_syscall_64+0xf9/0x670 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x446d4a
Code: b8 08 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 fd ad fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 da ad fb ff c3 66 0f 1f 84 00 00 00 00 00
RSP: 002b:00007fff86bca7c8 EFLAGS: 00000297 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fff86bca820 RCX: 0000000000446d4a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007fff86bca7e0
RBP: 00007fff86bca7e0 R08: 00007fff86bca820 R09: 00007fff00000015
R10: 0000000000000000 R11: 0000000000000297 R12: 0000000000000002
R13: 0000000000000004 R14: 0000000000000003 R15: 0000000000000003
================================================================================
erofs: blksize 8388608 isn't supported on this platform

Crashes (20):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/10/04 01:52 linux-4.19.y b09c34517e1a 1a3f9408 .config console log report syz C ci2-linux-4-19
2020/09/20 17:24 linux-4.19.y 015e94d0e37b 9564d2e9 .config console log report syz C ci2-linux-4-19
2020/10/20 19:24 linux-4.19.y ad326970d25c ff4a3345 .config console log report info ci2-linux-4-19
2020/10/18 03:39 linux-4.19.y ad326970d25c fea47c01 .config console log report info ci2-linux-4-19
2020/10/18 02:59 linux-4.19.y ad326970d25c fea47c01 .config console log report info ci2-linux-4-19
2020/10/15 20:48 linux-4.19.y a1b977b49b66 6e262c73 .config console log report info ci2-linux-4-19
2020/10/13 08:18 linux-4.19.y a1b977b49b66 bd69ee0d .config console log report info ci2-linux-4-19
2020/10/13 04:35 linux-4.19.y a1b977b49b66 d32b0bbf .config console log report info ci2-linux-4-19
2020/10/12 05:29 linux-4.19.y a1b977b49b66 4a77ae0b .config console log report info ci2-linux-4-19
2020/10/12 02:34 linux-4.19.y a1b977b49b66 4a77ae0b .config console log report info ci2-linux-4-19
2020/10/09 09:50 linux-4.19.y a1b977b49b66 fa79ed2a .config console log report info ci2-linux-4-19
2020/10/08 11:06 linux-4.19.y a1b977b49b66 92390980 .config console log report info ci2-linux-4-19
2020/10/08 08:49 linux-4.19.y a1b977b49b66 1880b4a9 .config console log report info ci2-linux-4-19
2020/10/01 03:48 linux-4.19.y 10ad6cfd5736 a9767fb2 .config console log report info ci2-linux-4-19
2020/09/29 13:36 linux-4.19.y 10ad6cfd5736 1b88c6d5 .config console log report info ci2-linux-4-19
2020/09/25 09:32 linux-4.19.y d09b80172c22 54289b08 .config console log report info ci2-linux-4-19
2020/09/24 14:06 linux-4.19.y d09b80172c22 54289b08 .config console log report info ci2-linux-4-19
2020/09/23 11:43 linux-4.19.y d09b80172c22 287cd75a .config console log report info ci2-linux-4-19
2020/09/22 19:45 linux-4.19.y 015e94d0e37b 3e8f6c27 .config console log report info ci2-linux-4-19
2020/09/20 17:09 linux-4.19.y 015e94d0e37b 9564d2e9 .config console log report info ci2-linux-4-19
* Struck through repros no longer work on HEAD.