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

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

failed to create VM pool: failed to create GCE image: create image operation failed: &{Code:PERMISSIONS_ERROR Location: Message:Required 'read' permission for 'disks/ci-upstream-kasan-gce-root-test-job-test-job-image.tar.gz' ForceSendFields:[] NullFields:[]}.


Tested on:

commit: 8013d1d3 Merge tag 'soc-fixes-5.18-3' of git://git.ker..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/ master
kernel config: https://syzkaller.appspot.com/x/.config?x=86cb1decc7a278ba
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

Note: no patches were applied.

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
UBSAN: shift-out-of-bounds in minix_statfs

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: 1 PID: 4072 Comm: syz-executor.0 Not tainted 5.18.0-rc6-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/0x50 lib/ubsan.c:151
__ubsan_handle_shift_out_of_bounds.cold+0xb1/0x187 lib/ubsan.c:322
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: 0033:0x7f4cdb689049
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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4cdc800168 EFLAGS: 00000246 ORIG_RAX: 000000000000008a
RAX: ffffffffffffffda RBX: 00007f4cdb79bf60 RCX: 00007f4cdb689049
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007f4cdb6e308d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc2a4de68f R14: 00007f4cdc800300 R15: 0000000000022000
</TASK>
================================================================================


Tested on:

commit: c5eb0a61 Linux 5.18-rc6

git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/ master

console output: https://syzkaller.appspot.com/x/log.txt?x=123c9202f00000
kernel config: https://syzkaller.appspot.com/x/.config?x=4119a2ddffeb4b9c

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
UBSAN: shift-out-of-bounds in minix_statfs

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: 4072 Comm: syz-executor.0 Not tainted 5.18.0-rc6-syzkaller-00007-g9be9ed2612b5 #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
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: 0033:0x7fd947889049

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 b8 ff ff ff f7 d8 64 89 01 48

RSP: 002b:00007fd948953168 EFLAGS: 00000246 ORIG_RAX: 000000000000008a
RAX: ffffffffffffffda RBX: 00007fd94799bf60 RCX: 00007fd947889049

RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005

RBP: 00007fd9478e308d R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 00007ffcd9f4c98f R14: 00007fd948953300 R15: 0000000000022000
</TASK>
================================================================================


Tested on:

commit: 9be9ed26 Merge tag 'platform-drivers-x86-v5.18-4' of g..

git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/ master

console output: https://syzkaller.appspot.com/x/log.txt?x=12d55e7af00000