syzbot


KASAN: use-after-free Read in seccomp_notify_release (2)

Status: fixed on 2019/05/27 12:48
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+b562969adb2e04af3442@syzkaller.appspotmail.com
Fix commit: 7a0df7fbc145 seccomp: Make NEW_LISTENER and TSYNC flags exclusive
First crash: 1914d, last: 1913d
Cause bisection: introduced by (bisect log) :
commit a799aea0988ea0d1b1f263e996fdad2f6133c680
Author: wenxu <wenxu@ucloud.cn>
Date: Wed Jan 9 02:40:11 2019 +0000

  netfilter: nft_flow_offload: Fix reverse route lookup

Crash: KASAN: use-after-free Read in seccomp_notify_release (log)
Repro: C syz .config
  
Discussions (5)
Title Replies (including bot) Last reply
[PATCH 5.0 000/122] 5.0.14-stable review 134 (134) 2019/05/08 06:36
[GIT PULL] seccomp fixes for v5.1-rc8 2 (2) 2019/04/29 22:10
[PATCH 0/2] seccomp: Make NEW_LISTENER and TSYNC flags exclusive 6 (6) 2019/04/25 05:30
[PATCH 1/2] seccomp: fix up grammar in comment 13 (13) 2019/04/24 01:02
KASAN: use-after-free Read in seccomp_notify_release (2) 3 (4) 2019/04/23 22:06
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: use-after-free Read in seccomp_notify_release kernel C 27 1938d 1986d 11/27 fixed on 2019/03/06 07:43

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in __lock_acquire+0x2d5e/0x3fb0 kernel/locking/lockdep.c:3573
Read of size 8 at addr ffff8880a8514280 by task syz-executor164/7581

CPU: 0 PID: 7581 Comm: syz-executor164 Not tainted 5.1.0-rc1+ #35
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+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132
 __lock_acquire+0x2d5e/0x3fb0 kernel/locking/lockdep.c:3573
 lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211
 __mutex_lock_common kernel/locking/mutex.c:925 [inline]
 __mutex_lock+0xf7/0x1310 kernel/locking/mutex.c:1072
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087
 seccomp_notify_release+0x62/0x280 kernel/seccomp.c:984
 __fput+0x2e5/0x8d0 fs/file_table.c:278
 ____fput+0x16/0x20 fs/file_table.c:309
 task_work_run+0x14a/0x1c0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:166
 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
 do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x405621
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 04 19 00 00 c3 48 83 ec 08 e8 6a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 b3 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007ffc73460950 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000405621
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000064 R08: 00007fef2c407700 R09: 0000000000000000
R10: 00007ffc73460960 R11: 0000000000000293 R12: 00000000006dbc30
R13: 0000000000000002 R14: 00000000006dbc3c R15: 000000000000002d

Allocated by task 7588:
 save_stack+0x45/0xd0 mm/kasan/common.c:75
 set_track mm/kasan/common.c:87 [inline]
 __kasan_kmalloc mm/kasan/common.c:497 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:470
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:511
 kmem_cache_alloc_trace+0x151/0x760 mm/slab.c:3621
 kmalloc include/linux/slab.h:545 [inline]
 kzalloc include/linux/slab.h:740 [inline]
 seccomp_prepare_filter kernel/seccomp.c:453 [inline]
 seccomp_prepare_user_filter kernel/seccomp.c:493 [inline]
 seccomp_set_mode_filter kernel/seccomp.c:1262 [inline]
 do_seccomp+0x743/0x2250 kernel/seccomp.c:1376
 __do_sys_seccomp kernel/seccomp.c:1395 [inline]
 __se_sys_seccomp kernel/seccomp.c:1392 [inline]
 __x64_sys_seccomp+0x73/0xb0 kernel/seccomp.c:1392
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 7588:
 save_stack+0x45/0xd0 mm/kasan/common.c:75
 set_track mm/kasan/common.c:87 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:459
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:467
 __cache_free mm/slab.c:3498 [inline]
 kfree+0xcf/0x230 mm/slab.c:3821
 seccomp_filter_free kernel/seccomp.c:567 [inline]
 seccomp_filter_free kernel/seccomp.c:563 [inline]
 seccomp_set_mode_filter kernel/seccomp.c:1317 [inline]
 do_seccomp+0xb00/0x2250 kernel/seccomp.c:1376
 __do_sys_seccomp kernel/seccomp.c:1395 [inline]
 __se_sys_seccomp kernel/seccomp.c:1392 [inline]
 __x64_sys_seccomp+0x73/0xb0 kernel/seccomp.c:1392
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8880a8514200
 which belongs to the cache kmalloc-192 of size 192
The buggy address is located 128 bytes inside of
 192-byte region [ffff8880a8514200, ffff8880a85142c0)
The buggy address belongs to the page:
page:ffffea0002a14500 count:1 mapcount:0 mapping:ffff88812c3f0040 index:0x0
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea00026bf2c8 ffffea0002a2dd48 ffff88812c3f0040
raw: 0000000000000000 ffff8880a8514000 0000000100000010 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a8514180: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff8880a8514200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880a8514280: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                   ^
 ffff8880a8514300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880a8514380: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (9):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/03/24 21:02 upstream 1bdd3dbfff7a acbc5b7d .config console log report syz C ci-upstream-kasan-gce-root
2019/03/24 20:58 upstream 1bdd3dbfff7a acbc5b7d .config console log report syz C ci-upstream-kasan-gce
2019/03/24 20:56 upstream 1bdd3dbfff7a acbc5b7d .config console log report syz C ci-upstream-kasan-gce-smack-root
2019/03/24 19:50 upstream 1bdd3dbfff7a acbc5b7d .config console log report syz C ci-upstream-kasan-gce-selinux-root
2019/03/24 21:05 upstream 1bdd3dbfff7a acbc5b7d .config console log report syz C ci-upstream-kasan-gce-386
2019/03/24 20:55 linux-next e382d91f5f80 acbc5b7d .config console log report syz C ci-upstream-linux-next-kasan-gce-root
2019/03/24 19:32 upstream 1bdd3dbfff7a acbc5b7d .config console log report ci-upstream-kasan-gce-selinux-root
2019/03/25 20:44 linux-next e382d91f5f80 2c86e0a5 .config console log report ci-upstream-linux-next-kasan-gce-root
2019/03/25 04:38 linux-next e382d91f5f80 2c86e0a5 .config console log report ci-upstream-linux-next-kasan-gce-root
* Struck through repros no longer work on HEAD.