KASAN: use-after-free Read in vlan_dev_get

KASAN: use-after-free Read in vlan_dev_get_iflink
Status: upstream: reported C repro on 2020/04/25 21:56
Reported-by: syzbot+4e67765f93c038b2789a@syzkaller.appspotmail.com
First crash: 582d, last: 21d

similar bugs (2):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
linux-4.19	KASAN: use-after-free Read in vlan_dev_get_iflink	C		error	14	45d	595d	0/1	upstream: reported C repro on 2020/04/13 08:02
upstream	KASAN: use-after-free Read in vlan_dev_get_iflink	C	error	error	13	324d	494d	0/22	upstream: reported C repro on 2020/07/23 18:12

Sample crash report:

==================================================================
BUG: KASAN: use-after-free in vlan_dev_get_iflink+0x5f/0x70 net/8021q/vlan_dev.c:769
Read of size 4 at addr ffff8880905e0488 by task syz-executor582/6951

CPU: 0 PID: 6951 Comm: syz-executor582 Not tainted 4.14.192-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x283 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
 kasan_report_error.cold+0x8a/0x194 mm/kasan/report.c:351
 kasan_report mm/kasan/report.c:409 [inline]
 __asan_report_load4_noabort+0x68/0x70 mm/kasan/report.c:429
 vlan_dev_get_iflink+0x5f/0x70 net/8021q/vlan_dev.c:769
 dev_get_iflink+0x73/0xe0 net/core/dev.c:691
 rfc2863_policy+0x163/0x1b0 net/core/link_watch.c:43
 linkwatch_do_dev+0x1b/0xf0 net/core/link_watch.c:157
 linkwatch_forget_dev+0x15c/0x1f0 net/core/link_watch.c:223
 netdev_wait_allrefs net/core/dev.c:7837 [inline]
 netdev_run_todo+0x284/0xad0 net/core/dev.c:7938
 rtnl_unlock net/core/rtnetlink.c:106 [inline]
 rtnetlink_rcv_msg+0x3cb/0xb10 net/core/rtnetlink.c:4318
 netlink_rcv_skb+0x125/0x390 net/netlink/af_netlink.c:2433
 netlink_unicast_kernel net/netlink/af_netlink.c:1287 [inline]
 netlink_unicast+0x437/0x610 net/netlink/af_netlink.c:1313
 netlink_sendmsg+0x62e/0xb80 net/netlink/af_netlink.c:1878
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xb5/0x100 net/socket.c:656
 ___sys_sendmsg+0x6c8/0x800 net/socket.c:2062
 __sys_sendmsg+0xa3/0x120 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x27/0x40 net/socket.c:2103
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x446d79
RSP: 002b:00007efc89777d98 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000006dbc78 RCX: 0000000000446d79
RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000003
RBP: 00000000006dbc70 R08: 0000000000000018 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000246 R12: 00000000006dbc7c
R13: 0000000000040000 R14: 0000000000000000 R15: 0705001000000048

Allocated by task 6917:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551
 __do_kmalloc_node mm/slab.c:3682 [inline]
 __kmalloc_node+0x4c/0x70 mm/slab.c:3689
 kmalloc_node include/linux/slab.h:530 [inline]
 kvmalloc_node+0x46/0xd0 mm/util.c:397
 kvmalloc include/linux/mm.h:531 [inline]
 kvzalloc include/linux/mm.h:539 [inline]
 alloc_netdev_mqs+0x76/0xb70 net/core/dev.c:8103
 rtnl_create_link+0x1ab/0x890 net/core/rtnetlink.c:2460
 rtnl_newlink+0xe86/0x1830 net/core/rtnetlink.c:2718
 rtnetlink_rcv_msg+0x3be/0xb10 net/core/rtnetlink.c:4316
 netlink_rcv_skb+0x125/0x390 net/netlink/af_netlink.c:2433
 netlink_unicast_kernel net/netlink/af_netlink.c:1287 [inline]
 netlink_unicast+0x437/0x610 net/netlink/af_netlink.c:1313
 netlink_sendmsg+0x62e/0xb80 net/netlink/af_netlink.c:1878
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xb5/0x100 net/socket.c:656
 ___sys_sendmsg+0x6c8/0x800 net/socket.c:2062
 __sys_sendmsg+0xa3/0x120 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x27/0x40 net/socket.c:2103
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 6917:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xc3/0x1a0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xc9/0x250 mm/slab.c:3815
 kvfree+0x45/0x50 mm/util.c:416
 device_release+0x15f/0x1a0 drivers/base/core.c:833
 kobject_cleanup lib/kobject.c:646 [inline]
 kobject_release lib/kobject.c:675 [inline]
 kref_put include/linux/kref.h:70 [inline]
 kobject_put+0x1f3/0x2d0 lib/kobject.c:692
 netdev_run_todo+0x747/0xad0 net/core/dev.c:7960
 rtnl_unlock net/core/rtnetlink.c:106 [inline]
 rtnetlink_rcv_msg+0x3cb/0xb10 net/core/rtnetlink.c:4318
 netlink_rcv_skb+0x125/0x390 net/netlink/af_netlink.c:2433
 netlink_unicast_kernel net/netlink/af_netlink.c:1287 [inline]
 netlink_unicast+0x437/0x610 net/netlink/af_netlink.c:1313
 netlink_sendmsg+0x62e/0xb80 net/netlink/af_netlink.c:1878
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xb5/0x100 net/socket.c:656
 ___sys_sendmsg+0x6c8/0x800 net/socket.c:2062
 __sys_sendmsg+0xa3/0x120 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x27/0x40 net/socket.c:2103
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

The buggy address belongs to the object at ffff8880905e0380
 which belongs to the cache kmalloc-4096 of size 4096
The buggy address is located 264 bytes inside of
 4096-byte region [ffff8880905e0380, ffff8880905e1380)
The buggy address belongs to the page:
page:ffffea0002417800 count:1 mapcount:0 mapping:ffff8880905e0380 index:0x0 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffff8880905e0380 0000000000000000 0000000100000001
raw: ffffea000243ba20 ffffea000249a2a0 ffff88812fe52dc0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880905e0380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880905e0400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880905e0480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff8880905e0500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880905e0580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Fix bisection attempts:
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro
ci2-linux-4-14	2021/11/08 15:40	linux-4.14.y	0447aa205abe	0487ea6f	.config	log	report	syz	C
ci2-linux-4-14	2021/10/09 15:13	linux-4.14.y	ed99bf0e81b5	0487ea6f	.config	log	report	syz	C
ci2-linux-4-14	2021/09/09 14:47	linux-4.14.y	f96eb53cbd76	0487ea6f	.config	log	report	syz	C
ci2-linux-4-14	2021/08/10 14:11	linux-4.14.y	46914f96189b	0487ea6f	.config	log	report	syz	C
ci2-linux-4-14	2021/07/11 13:45	linux-4.14.y	4e68c9b0763f	0487ea6f	.config	log	report	syz	C
ci2-linux-4-14	2021/06/11 13:19	linux-4.14.y	3d3abdc8ebd3	0487ea6f	.config	log	report	syz	C
ci2-linux-4-14	2021/05/12 12:48	linux-4.14.y	7d7d1c0ab3eb	0487ea6f	.config	log	report	syz	C
ci2-linux-4-14	2021/04/12 12:20	linux-4.14.y	958e517f4e16	0487ea6f	.config	log	report	syz	C
ci2-linux-4-14	2021/02/27 23:44	linux-4.14.y	3242aa3a635c	0487ea6f	.config	log	report	syz	C
ci2-linux-4-14	2020/11/24 11:36	linux-4.14.y	0df445b0f0da	0487ea6f	.config	log	report	syz	C
ci2-linux-4-14	2020/10/25 11:11	linux-4.14.y	5b7a52cd2eef	0487ea6f	.config	log	report	syz	C
ci2-linux-4-14	2020/09/25 10:48	linux-4.14.y	ca87c8281190	0487ea6f	.config	log	report	syz	C

Crashes (12):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci2-linux-4-14	2020/08/06 07:01	linux-4.14.y	ca4f2c56d416	0487ea6f	.config	log	report	syz	C
ci2-linux-4-14	2021/03/13 11:49	linux-4.14.y	c7150cd2fa8c	4a003785	.config	log	report			info	KASAN: use-after-free Read in vlan_dev_get_iflink
ci2-linux-4-14	2021/01/28 22:26	linux-4.14.y	2d2791fce891	7df34f59	.config	log	report			info	KASAN: use-after-free Read in vlan_dev_get_iflink
ci2-linux-4-14	2021/01/28 13:41	linux-4.14.y	2d2791fce891	eefc07f2	.config	log	report			info	KASAN: use-after-free Read in vlan_dev_get_iflink
ci2-linux-4-14	2021/01/13 07:42	linux-4.14.y	f79dc86058bc	0cdd6185	.config	log	report			info
ci2-linux-4-14	2020/12/26 05:14	linux-4.14.y	3f2ecb86cb90	821e0b09	.config	log	report			info
ci2-linux-4-14	2020/12/03 20:50	linux-4.14.y	c196b3a9c83a	59ad4022	.config	log	report			info
ci2-linux-4-14	2020/12/02 19:42	linux-4.14.y	c196b3a9c83a	eff43e99	.config	log	report			info
ci2-linux-4-14	2020/08/26 10:23	linux-4.14.y	d7e78d08fa77	344da168	.config	log	report
ci2-linux-4-14	2020/08/06 05:56	linux-4.14.y	ca4f2c56d416	0487ea6f	.config	log	report
ci2-linux-4-14	2020/04/27 18:30	linux-4.14.y	050272a0423e	0ce7569e	.config	log	report
ci2-linux-4-14	2020/04/25 21:55	linux-4.14.y	050272a0423e	b8bb8e5f	.config	log	report