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KASAN: use-after-free Read in seccomp_notify_release

Status: fixed on 2019/03/06 07:43
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+981c26489b2d1c6316ba@syzkaller.appspotmail.com
Fix commit: a811dc61559e seccomp: fix UAF in user-trap code
First crash: 1931d, last: 1882d
▶ ▼ Discussions (2)
Title Replies (including bot) Last reply
[PATCH] seccomp: fix UAF in user-trap code 3 (3) 2019/01/15 17:42
KASAN: use-after-free Read in seccomp_notify_release 1 (2) 2019/01/12 16:34
▶ ▼ 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 (2) kernel C done 9 1857d 1858d 12/26 fixed on 2019/05/27 12:48

Sample crash report:
audit: type=1326 audit(1547242557.061:2115): auid=4294967295 uid=0 gid=0 ses=4294967295 subj==unconfined pid=9988 comm="syz-executor667" exe="/root/syz-executor667976370" sig=31 arch=c000003e syscall=202 compat=0 ip=0x447c09 code=0x0
audit: type=1326 audit(1547242557.061:2116): auid=4294967295 uid=0 gid=0 ses=4294967295 subj==unconfined pid=9980 comm="syz-executor667" exe="/root/syz-executor667976370" sig=31 arch=c000003e syscall=3 compat=0 ip=0x4069e1 code=0x0
==================================================================
BUG: KASAN: use-after-free in __lock_acquire+0x3556/0x4a30 kernel/locking/lockdep.c:3215
Read of size 8 at addr ffff88808c5c8a80 by task syz-executor667/9991

CPU: 0 PID: 9991 Comm: syz-executor667 Not tainted 5.0.0-rc1+ #20
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+0x1db/0x2d0 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:135
 __lock_acquire+0x3556/0x4a30 kernel/locking/lockdep.c:3215
 lock_acquire+0x1db/0x570 kernel/locking/lockdep.c:3841
 __mutex_lock_common kernel/locking/mutex.c:925 [inline]
 __mutex_lock+0x12f/0x1670 kernel/locking/mutex.c:1072
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087
 seccomp_notify_release+0x54/0x270 kernel/seccomp.c:979
 __fput+0x3c5/0xb10 fs/file_table.c:278
 ____fput+0x16/0x20 fs/file_table.c:309
 task_work_run+0x1f4/0x2b0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x32a/0x3b0 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+0x696/0x800 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4069e1
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 d4 18 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007ffe443110b0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00000000004069e1
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 0000000000000003
RBP: 0000000000000002 R08: 0000000000000001 R09: 00000000bb1414ac
R10: 00007ffe443110d0 R11: 0000000000000293 R12: 00000000006e39fc
R13: 00000000006e39f0 R14: 00000000000003e8 R15: 000000000000002d

Allocated by task 10001:
 save_stack+0x45/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 __kasan_kmalloc mm/kasan/common.c:496 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:469
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:504
 kmem_cache_alloc_trace+0x151/0x760 mm/slab.c:3609
 kmalloc include/linux/slab.h:545 [inline]
 kzalloc include/linux/slab.h:740 [inline]
 seccomp_prepare_filter kernel/seccomp.c:451 [inline]
 seccomp_prepare_user_filter kernel/seccomp.c:491 [inline]
 seccomp_set_mode_filter kernel/seccomp.c:1257 [inline]
 do_seccomp+0x941/0x2cc0 kernel/seccomp.c:1370
 __do_sys_seccomp kernel/seccomp.c:1389 [inline]
 __se_sys_seccomp kernel/seccomp.c:1386 [inline]
 __x64_sys_seccomp+0x73/0xb0 kernel/seccomp.c:1386
 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 10001:
 save_stack+0x45/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:458
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:466
 __cache_free mm/slab.c:3487 [inline]
 kfree+0xcf/0x230 mm/slab.c:3806
 seccomp_filter_free kernel/seccomp.c:565 [inline]
 seccomp_filter_free kernel/seccomp.c:561 [inline]
 seccomp_set_mode_filter kernel/seccomp.c:1311 [inline]
 do_seccomp+0xda3/0x2cc0 kernel/seccomp.c:1370
 __do_sys_seccomp kernel/seccomp.c:1389 [inline]
 __se_sys_seccomp kernel/seccomp.c:1386 [inline]
 __x64_sys_seccomp+0x73/0xb0 kernel/seccomp.c:1386
 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88808c5c8a00
 which belongs to the cache kmalloc-192 of size 192
The buggy address is located 128 bytes inside of
 192-byte region [ffff88808c5c8a00, ffff88808c5c8ac0)
The buggy address belongs to the page:
page:ffffea0002317200 count:1 mapcount:0 mapping:ffff88812c3f0040 index:0x0
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea0002276e08 ffff88812c3f1148 ffff88812c3f0040
raw: 0000000000000000 ffff88808c5c8000 0000000100000010 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88808c5c8980: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88808c5c8a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88808c5c8a80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                   ^
 ffff88808c5c8b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88808c5c8b80: 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (27):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/01/11 21:38 upstream de6629eb262e c3f3344c .config console log report syz C ci-upstream-kasan-gce-root
2019/01/11 16:24 upstream 1bdbe2274920 c3f3344c .config console log report syz C ci-upstream-kasan-gce
2019/01/11 13:13 upstream 1bdbe2274920 80dde172 .config console log report syz C ci-upstream-kasan-gce-selinux-root
2019/01/11 12:01 upstream 1bdbe2274920 80dde172 .config console log report syz C ci-upstream-kasan-gce-smack-root
2019/01/11 11:37 upstream 1bdbe2274920 80dde172 .config console log report syz C ci-upstream-kasan-gce-386
2019/01/11 11:56 linux-next b808822a75a3 80dde172 .config console log report syz C ci-upstream-linux-next-kasan-gce-root
2019/03/01 09:34 upstream 7d762d69145a 8a4b3a6b .config console log report ci-upstream-kasan-gce-smack-root
2019/02/20 01:13 upstream 40e196a906d9 4df543c9 .config console log report ci-upstream-kasan-gce
2019/02/19 23:45 upstream b5372fe5dc84 4df543c9 .config console log report ci-upstream-kasan-gce
2019/02/19 01:09 upstream a3b22b9f11d9 59f36113 .config console log report ci-upstream-kasan-gce
2019/02/17 18:08 upstream 8d33316d5205 3e98cc30 .config console log report ci-upstream-kasan-gce-root
2019/02/17 14:45 upstream 64c0133eb88a 3e98cc30 .config console log report ci-upstream-kasan-gce-smack-root
2019/02/16 21:56 upstream 5ded5871030e f42dee6d .config console log report ci-upstream-kasan-gce
2019/02/16 20:12 upstream 5ded5871030e f42dee6d .config console log report ci-upstream-kasan-gce
2019/02/15 22:41 upstream 5ded5871030e f42dee6d .config console log report ci-upstream-kasan-gce-smack-root
2019/02/15 19:09 upstream cb5b020a8d38 f6f233c0 .config console log report ci-upstream-kasan-gce
2019/02/15 18:14 upstream cb5b020a8d38 f6f233c0 .config console log report ci-upstream-kasan-gce-root
2019/02/12 15:53 upstream aa0c38cf39de 6ecc6d0f .config console log report ci-upstream-kasan-gce
2019/02/01 17:45 upstream 5b4746a03199 0c07abcf .config console log report ci-upstream-kasan-gce-root
2019/02/25 09:33 upstream 5908e6b738e3 a70141bf .config console log report ci-upstream-kasan-gce-386
2019/02/22 11:15 upstream 8a61716ff2ab 6a5fcca4 .config console log report ci-upstream-kasan-gce-386
2019/02/18 19:10 upstream 301e361072e5 59f36113 .config console log report ci-upstream-kasan-gce-386
2019/02/17 19:34 upstream 8d33316d5205 3e98cc30 .config console log report ci-upstream-kasan-gce-386
2019/02/14 12:53 upstream 1f947a7a011f 6a46f448 .config console log report ci-upstream-kasan-gce-386
2019/02/13 02:18 upstream 57902dc0670c 1eedba36 .config console log report ci-upstream-kasan-gce-386
2019/01/11 11:04 upstream 1bdbe2274920 80dde172 .config console log report ci-upstream-kasan-gce-386
2019/02/17 07:58 linux-next 7a92eb7cc1dc f42dee6d .config console log report ci-upstream-linux-next-kasan-gce-root
* Struck through repros no longer work on HEAD.