KASAN: stack-out-of-bounds Read in xfrm_selector

KASAN: stack-out-of-bounds Read in xfrm_selector_match
Status: public: reported C repro on 2019/04/11 08:44
Reported-by: syzbot+c8463c5b3015c191734e@syzkaller.appspotmail.com
First crash: 812d, last: 581d

similar bugs (4):
Kernel	Title	Repro	Count	Last	Reported	Patched	Status
android-49	KASAN: stack-out-of-bounds Read in xfrm_selector_match	C	672	571d	1038d	0/3	closed as invalid on 2018/11/08 02:37
upstream	KASAN: stack-out-of-bounds Read in xfrm_selector_match		368	868d	875d	4/17	fixed on 2018/02/13 04:59
android-414	KASAN: stack-out-of-bounds Read in xfrm_selector_match		1	219d	219d	0/1	auto-closed as invalid on 2020/02/19 14:26
android-49	KASAN: stack-out-of-bounds Read in xfrm_selector_match (2)	C	13	217d	412d	0/3	public: reported C repro on 2019/04/13 00:00

Sample crash report:

random: sshd: uninitialized urandom read (32 bytes read, 34 bits of entropy available)
random: sshd: uninitialized urandom read (32 bytes read, 34 bits of entropy available)
random: nonblocking pool is initialized
A link change request failed with some changes committed already. Interface teql0 may have been left with an inconsistent configuration, please check.
==================================================================
BUG: KASAN: stack-out-of-bounds in memcmp+0x126/0x160 lib/string.c:742
Read of size 1 at addr ffff8800b92078e0 by task syz-executor471/3708

CPU: 0 PID: 3708 Comm: syz-executor471 Not tainted 4.4.140-ged9bdc8 #68
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 c082ff154dcd4715 ffff8800b9207410 ffffffff81e0e08d
 ffffea0002e481c0 ffff8800b92078e0 0000000000000000 ffff8800b92078e0
 0000000000000000 ffff8800b9207448 ffffffff81515a56 ffff8800b92078e0
Call Trace:
 [<ffffffff81e0e08d>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81e0e08d>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
 [<ffffffff81515a56>] print_address_description+0x6c/0x216 mm/kasan/report.c:252
 [<ffffffff81515d75>] kasan_report_error mm/kasan/report.c:351 [inline]
 [<ffffffff81515d75>] kasan_report.cold.7+0x175/0x2f7 mm/kasan/report.c:408
 [<ffffffff814f9804>] __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:426
 [<ffffffff81e2a516>] memcmp+0x126/0x160 lib/string.c:742
 [<ffffffff833ce84d>] addr_match include/net/xfrm.h:837 [inline]
 [<ffffffff833ce84d>] __xfrm6_selector_match net/xfrm/xfrm_policy.c:81 [inline]
 [<ffffffff833ce84d>] xfrm_selector_match+0x12d/0xe50 net/xfrm/xfrm_policy.c:95
 [<ffffffff833cf6c1>] xfrm_sk_policy_lookup+0x151/0x350 net/xfrm/xfrm_policy.c:1241
 [<ffffffff833d2455>] xfrm_lookup+0x1b5/0xb70 net/xfrm/xfrm_policy.c:2189
 [<ffffffff833d3d29>] xfrm_lookup_route+0x39/0x1b0 net/xfrm/xfrm_policy.c:2323
 [<ffffffff83428b77>] ip6_dst_lookup_flow+0x1b7/0x2f0 net/ipv6/ip6_output.c:1072
 [<ffffffff834cd5f8>] tcp_v6_connect+0xd58/0x1b70 net/ipv6/tcp_ipv6.c:249
 [<ffffffff832f9a79>] __inet_stream_connect+0x2a9/0xc30 net/ipv4/af_inet.c:615
 [<ffffffff83249740>] tcp_sendmsg_fastopen net/ipv4/tcp.c:1092 [inline]
 [<ffffffff83249740>] tcp_sendmsg+0x1600/0x2b00 net/ipv4/tcp.c:1112
 [<ffffffff83300cc3>] inet_sendmsg+0x203/0x4d0 net/ipv4/af_inet.c:755
 [<ffffffff82f1deac>] sock_sendmsg_nosec net/socket.c:625 [inline]
 [<ffffffff82f1deac>] sock_sendmsg+0xcc/0x110 net/socket.c:635
 [<ffffffff82f1eb8c>] SYSC_sendto+0x21c/0x370 net/socket.c:1665
 [<ffffffff82f21210>] SyS_sendto+0x40/0x50 net/socket.c:1633
 [<ffffffff838c27a5>] entry_SYSCALL_64_fastpath+0x22/0x9e

The buggy address belongs to the page:
page:ffffea0002e481c0 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x4000000000000000()
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8800b9207780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8800b9207800: 00 00 00 00 00 00 f1 f1 f1 f1 00 00 f2 f2 f2 f2
>ffff8800b9207880: f2 f2 00 00 00 00 00 00 00 00 00 00 f2 f2 00 00
                                                       ^
 ffff8800b9207900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8800b9207980: 00 00 00 f1 f1 f1 f1 00 00 00 00 00 f2 f2 f2 00
==================================================================

Crashes (36):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro
ci-android-44-kasan-gce	2018/07/17 02:33	https://android.googlesource.com/kernel/common android-4.4	ed9bdc8a	40cb0c9a	.config	log	report	syz	C
ci-android-44-kasan-gce	2018/04/10 13:37	https://android.googlesource.com/kernel/common android-4.4	38f41ec1	8e873e9d	.config	log	report	syz	C
ci-android-44-kasan-gce-386	2018/04/10 13:24	https://android.googlesource.com/kernel/common android-4.4	38f41ec1	8e873e9d	.config	log	report	syz
ci-android-44-kasan-gce	2018/10/25 21:29	https://android.googlesource.com/kernel/common android-4.4	c4b00eb7	a8292de9	.config	log	report
ci-android-44-kasan-gce	2018/10/22 08:57	https://android.googlesource.com/kernel/common android-4.4	3eb8e735	ecb386fe	.config	log	report
ci-android-44-kasan-gce	2018/10/10 09:45	https://android.googlesource.com/kernel/common android-4.4	ea3a6005	8b311eaf	.config	log	report
ci-android-44-kasan-gce	2018/10/06 15:02	https://android.googlesource.com/kernel/common android-4.4	ea3a6005	8b311eaf	.config	log	report
ci-android-44-kasan-gce	2018/08/26 14:03	https://android.googlesource.com/kernel/common android-4.4	e5c5f1fa	758cd203	.config	log	report
ci-android-44-kasan-gce	2018/08/18 12:18	https://android.googlesource.com/kernel/common android-4.4	f76bdbdd	db1858f6	.config	log	report
ci-android-44-kasan-gce	2018/08/11 05:20	https://android.googlesource.com/kernel/common android-4.4	a5fc6659	7a88b141	.config	log	report
ci-android-44-kasan-gce	2018/08/03 08:18	https://android.googlesource.com/kernel/common android-4.4	2241aa98	5b7e23bb	.config	log	report
ci-android-44-kasan-gce	2018/07/31 06:42	https://android.googlesource.com/kernel/common android-4.4	8ddb600e	1a381291	.config	log	report
ci-android-44-kasan-gce	2018/07/23 22:09	https://android.googlesource.com/kernel/common android-4.4	1b37d68f	912c93d7	.config	log	report
ci-android-44-kasan-gce	2018/07/15 13:40	https://android.googlesource.com/kernel/common android-4.4	ed9bdc8a	92a49505	.config	log	report
ci-android-44-kasan-gce	2018/06/30 19:59	https://android.googlesource.com/kernel/common android-4.4	cf21a9ac	dba0b50e	.config	log	report
ci-android-44-kasan-gce	2018/06/29 00:28	https://android.googlesource.com/kernel/common android-4.4	cf21a9ac	dba0b50e	.config	log	report
ci-android-44-kasan-gce	2018/06/28 15:21	https://android.googlesource.com/kernel/common android-4.4	cf21a9ac	dba0b50e	.config	log	report
ci-android-44-kasan-gce	2018/06/24 07:24	https://android.googlesource.com/kernel/common android-4.4	226f96b0	2064fc5c	.config	log	report
ci-android-44-kasan-gce	2018/06/24 01:05	https://android.googlesource.com/kernel/common android-4.4	226f96b0	2064fc5c	.config	log	report
ci-android-44-kasan-gce	2018/06/19 18:33	https://android.googlesource.com/kernel/common android-4.4	226f96b0	732e4256	.config	log	report
ci-android-44-kasan-gce	2018/06/19 16:42	https://android.googlesource.com/kernel/common android-4.4	226f96b0	732e4256	.config	log	report
ci-android-44-kasan-gce	2018/06/08 09:11	https://android.googlesource.com/kernel/common android-4.4	fb7e3196	f7b27b7a	.config	log	report
ci-android-44-kasan-gce	2018/06/06 11:30	https://android.googlesource.com/kernel/common android-4.4	7e3a6fc4	41f9540d	.config	log	report
ci-android-44-kasan-gce	2018/05/29 15:49	https://android.googlesource.com/kernel/common android-4.4	3f51ea2d	e276de77	.config	log	report
ci-android-44-kasan-gce	2018/05/18 19:43	https://android.googlesource.com/kernel/common android-4.4	46155cc7	849705db	.config	log	report
ci-android-44-kasan-gce	2018/05/17 09:36	https://android.googlesource.com/kernel/common android-4.4	46155cc7	a367c1d7	.config	log	report
ci-android-44-kasan-gce	2018/05/17 08:08	https://android.googlesource.com/kernel/common android-4.4	46155cc7	a367c1d7	.config	log	report
ci-android-44-kasan-gce	2018/05/13 11:59	https://android.googlesource.com/kernel/common android-4.4	aa3863d2	c05b619d	.config	log	report
ci-android-44-kasan-gce	2018/05/10 21:36	https://android.googlesource.com/kernel/common android-4.4	3702e76f	12c7428a	.config	log	report
ci-android-44-kasan-gce	2018/05/10 03:15	https://android.googlesource.com/kernel/common android-4.4	033c952f	12c7428a	.config	log	report
ci-android-44-kasan-gce	2018/05/08 00:43	https://android.googlesource.com/kernel/common android-4.4	fcce5711	9e0846e8	.config	log	report
ci-android-44-kasan-gce	2018/05/04 07:39	https://android.googlesource.com/kernel/common android-4.4	1fe7e920	9ce14f4b	.config	log	report
ci-android-44-kasan-gce	2018/03/08 22:32	https://android.googlesource.com/kernel/common android-4.4	d63fdf61	acd0caa5	.config	log	report
ci-android-44-kasan-gce-386	2018/04/19 07:23	https://android.googlesource.com/kernel/common android-4.4	38f41ec1	829f0234	.config	log	report
ci-android-44-kasan-gce-386	2018/04/18 12:20	https://android.googlesource.com/kernel/common android-4.4	38f41ec1	52643b44	.config	log	report
ci-android-44-kasan-gce-386	2018/04/10 12:36	https://android.googlesource.com/kernel/common android-4.4	38f41ec1	8e873e9d	.config	log	report