lkml.org 
[lkml]   [2018]   [Sep]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectKASAN: use-after-free Read in fuse_dev_do_read
From
Hello,

syzbot found the following crash on:

HEAD commit: 54eda9df17f3 Merge tag 'pci-v4.19-fixes-1' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=109a3d9e400000
kernel config: https://syzkaller.appspot.com/x/.config?x=b8f349d23d3c4835
dashboard link: https://syzkaller.appspot.com/bug?extid=4e975615ca01f2277bdd
compiler: gcc (GCC) 8.0.1 20180413 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+4e975615ca01f2277bdd@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in constant_test_bit
arch/x86/include/asm/bitops.h:328 [inline]
BUG: KASAN: use-after-free in fuse_dev_do_read.isra.27+0x1659/0x1920
fs/fuse/dev.c:1318
Read of size 8 at addr ffff8801cbd4ea30 by task syz-executor0/28821

CPU: 1 PID: 28821 Comm: syz-executor0 Not tainted 4.19.0-rc3+ #11
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+0x1c4/0x2b4 lib/dump_stack.c:113
print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256
kasan_report_error mm/kasan/report.c:354 [inline]
kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
constant_test_bit arch/x86/include/asm/bitops.h:328 [inline]
fuse_dev_do_read.isra.27+0x1659/0x1920 fs/fuse/dev.c:1318
fuse_dev_read+0x1a9/0x250 fs/fuse/dev.c:1360
call_read_iter include/linux/fs.h:1801 [inline]
new_sync_read fs/read_write.c:406 [inline]
__vfs_read+0x6ac/0x9b0 fs/read_write.c:418
vfs_read+0x17f/0x3c0 fs/read_write.c:452
ksys_read+0x101/0x260 fs/read_write.c:578
__do_sys_read fs/read_write.c:588 [inline]
__se_sys_read fs/read_write.c:586 [inline]
__x64_sys_read+0x73/0xb0 fs/read_write.c:586
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4572d9
Code: fd b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007faaeefe4c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007faaeefe56d4 RCX: 00000000004572d9
RDX: 0000000000001000 RSI: 00000000200040c0 RDI: 0000000000000003
RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004d4508 R14: 00000000004c8d44 R15: 0000000000000000

Allocated by task 28825:
save_stack+0x43/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490
kmem_cache_alloc+0x12e/0x730 mm/slab.c:3554
__fuse_request_alloc+0x27/0xf0 fs/fuse/dev.c:58
fuse_request_alloc fs/fuse/dev.c:89 [inline]
__fuse_get_req+0x1f7/0x9e0 fs/fuse/dev.c:164
fuse_get_req fs/fuse/dev.c:194 [inline]
fuse_simple_request+0x28/0x730 fs/fuse/dev.c:549
fuse_statfs+0x368/0x8a0 fs/fuse/inode.c:442
statfs_by_dentry+0x136/0x210 fs/statfs.c:64
vfs_statfs+0x47/0x2e0 fs/statfs.c:74
user_statfs+0xbd/0x150 fs/statfs.c:89
__do_sys_statfs+0x7f/0xf0 fs/statfs.c:179
__se_sys_statfs fs/statfs.c:176 [inline]
__x64_sys_statfs+0x54/0x80 fs/statfs.c:176
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 28825:
save_stack+0x43/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
__kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
__cache_free mm/slab.c:3498 [inline]
kmem_cache_free+0x83/0x290 mm/slab.c:3756
fuse_request_free+0x8b/0xa0 fs/fuse/dev.c:104
fuse_put_request+0x2a6/0x350 fs/fuse/dev.c:304
fuse_simple_request+0x453/0x730 fs/fuse/dev.c:571
fuse_statfs+0x368/0x8a0 fs/fuse/inode.c:442
statfs_by_dentry+0x136/0x210 fs/statfs.c:64
vfs_statfs+0x47/0x2e0 fs/statfs.c:74
user_statfs+0xbd/0x150 fs/statfs.c:89
__do_sys_statfs+0x7f/0xf0 fs/statfs.c:179
__se_sys_statfs fs/statfs.c:176 [inline]
__x64_sys_statfs+0x54/0x80 fs/statfs.c:176
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8801cbd4ea00
which belongs to the cache fuse_request of size 448
The buggy address is located 48 bytes inside of
448-byte region [ffff8801cbd4ea00, ffff8801cbd4ebc0)
The buggy address belongs to the page:
page:ffffea00072f5380 count:1 mapcount:0 mapping:ffff8801d4ad4840 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffffea000717eb48 ffff8801d4ad5c48 ffff8801d4ad4840
raw: 0000000000000000 ffff8801cbd4e000 0000000100000008 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8801cbd4e900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8801cbd4e980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ffff8801cbd4ea00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8801cbd4ea80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8801cbd4eb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
This bug 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 bug report. See:
https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with
syzbot.

\
 
 \ /
  Last update: 2018-09-13 10:00    [W:0.075 / U:0.056 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site