syzbot
KASAN: slab-out-of-bounds Write in pipe_write
Status:
fixed on 2020/01/08 01:06
Reported-by: syzbot+838eb0878ffd51f27c41@syzkaller.appspotmail.com
Fix commit:
8f868d68d335
pipe: Fix missing mask update after pipe_wait()
First crash: 2447d, last: 2441d
Sample crash report:
==================================================================
BUG: KASAN: slab-out-of-bounds in pipe_write+0xe30/0x1000 fs/pipe.c:488
Write of size 8 at addr ffff88809ae61aa8 by task syz-executor462/9998
CPU: 0 PID: 9998 Comm: syz-executor462 Not tainted 5.4.0-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+0x197/0x210 lib/dump_stack.c:118
print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
__kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506
kasan_report+0x12/0x20 mm/kasan/common.c:638
__asan_report_store8_noabort+0x17/0x20 mm/kasan/generic_report.c:140
pipe_write+0xe30/0x1000 fs/pipe.c:488
call_write_iter include/linux/fs.h:1902 [inline]
new_sync_write+0x4d3/0x770 fs/read_write.c:483
__vfs_write+0xe1/0x110 fs/read_write.c:496
vfs_write+0x268/0x5d0 fs/read_write.c:558
ksys_write+0x220/0x290 fs/read_write.c:611
__do_sys_write fs/read_write.c:623 [inline]
__se_sys_write fs/read_write.c:620 [inline]
__x64_sys_write+0x73/0xb0 fs/read_write.c:620
do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x445879
Code: e8 ec bc 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 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 0f 83 cb 11 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f1adc8a8db8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00000000006dac28 RCX: 0000000000445879
RDX: 00000000fffffef3 RSI: 00000000200001c0 RDI: 0000000000000004
RBP: 00000000006dac20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dac2c
R13: 00007fff303618ef R14: 00007f1adc8a99c0 R15: 0000000000000000
Allocated by task 10000:
save_stack+0x23/0x90 mm/kasan/common.c:71
set_track mm/kasan/common.c:79 [inline]
__kasan_kmalloc mm/kasan/common.c:512 [inline]
__kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:485
kasan_kmalloc+0x9/0x10 mm/kasan/common.c:526
__do_kmalloc mm/slab.c:3656 [inline]
__kmalloc+0x163/0x770 mm/slab.c:3665
kmalloc_array include/linux/slab.h:598 [inline]
kcalloc include/linux/slab.h:609 [inline]
pipe_set_size fs/pipe.c:1143 [inline]
pipe_fcntl+0x3f7/0x8e0 fs/pipe.c:1209
do_fcntl+0x255/0x1030 fs/fcntl.c:417
__do_sys_fcntl fs/fcntl.c:463 [inline]
__se_sys_fcntl fs/fcntl.c:448 [inline]
__x64_sys_fcntl+0x16d/0x1e0 fs/fcntl.c:448
do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Freed by task 0:
(stack is not available)
The buggy address belongs to the object at ffff88809ae61a80
which belongs to the cache kmalloc-64 of size 64
The buggy address is located 40 bytes inside of
64-byte region [ffff88809ae61a80, ffff88809ae61ac0)
The buggy address belongs to the page:
page:ffffea00026b9840 refcount:1 mapcount:0 mapping:ffff8880aa400380 index:0x0
raw: 00fffe0000000200 ffffea00029f2fc8 ffff8880aa401348 ffff8880aa400380
raw: 0000000000000000 ffff88809ae61000 0000000100000020 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88809ae61980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88809ae61a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88809ae61a80: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc
^
ffff88809ae61b00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff88809ae61b80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================
* Struck through repros no longer work on HEAD.