KASAN: use-after-free Read in macvlan_dev_get

KASAN: use-after-free Read in macvlan_dev_get_iflink
Status: upstream: reported C repro on 2020/06/28 02:47
Reported-by: syzbot+95eec132c4bd9b1d8430@syzkaller.appspotmail.com
First crash: 18d, last: 2d05h

similar bugs (2):
Kernel	Title	Repro	Bisected	Count	Last	Reported	Patched	Status
linux-4.14	KASAN: use-after-free Read in macvlan_dev_get_iflink	C		30	1d16h	120d	0/1	upstream: reported C repro on 2020/03/06 01:40
linux-4.19	KASAN: use-after-free Read in macvlan_dev_get_iflink	C		28	1d07h	120d	0/1	upstream: reported C repro on 2020/03/06 01:52

Sample crash report:

==================================================================
BUG: KASAN: use-after-free in macvlan_dev_get_iflink+0x6a/0x70 drivers/net/macvlan.c:1137
Read of size 4 at addr ffff88808b62a100 by task syz-executor984/7033

CPU: 0 PID: 7033 Comm: syz-executor984 Not tainted 5.8.0-rc2-syzkaller #0
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+0x1f0/0x31e lib/dump_stack.c:118
 print_address_description+0x66/0x5a0 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report+0x132/0x1d0 mm/kasan/report.c:530
 macvlan_dev_get_iflink+0x6a/0x70 drivers/net/macvlan.c:1137
 default_operstate net/core/link_watch.c:41 [inline]
 rfc2863_policy+0x11f/0x2a0 net/core/link_watch.c:53
 linkwatch_do_dev+0x3a/0x160 net/core/link_watch.c:160
 netdev_wait_allrefs net/core/dev.c:9678 [inline]
 netdev_run_todo+0x2c8/0xc90 net/core/dev.c:9774
 rtnl_unlock net/core/rtnetlink.c:112 [inline]
 rtnetlink_rcv_msg+0x890/0xd40 net/core/rtnetlink.c:5461
 netlink_rcv_skb+0x190/0x3a0 net/netlink/af_netlink.c:2469
 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
 netlink_unicast+0x786/0x940 net/netlink/af_netlink.c:1329
 netlink_sendmsg+0xa57/0xd70 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg net/socket.c:672 [inline]
 ____sys_sendmsg+0x519/0x800 net/socket.c:2352
 ___sys_sendmsg net/socket.c:2406 [inline]
 __sys_sendmsg+0x2b1/0x360 net/socket.c:2439
 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x446e69
Code: Bad RIP value.
RSP: 002b:00007f7fa3a46d98 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000006dbc98 RCX: 0000000000446e69
RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000006
RBP: 00000000006dbc90 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000000a R11: 0000000000000246 R12: 00000000006dbc9c
R13: 0000000000000000 R14: 0000000000000000 R15: 0705001000000048

Allocated by task 7001:
 save_stack mm/kasan/common.c:48 [inline]
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc+0x103/0x140 mm/kasan/common.c:494
 kmalloc_node include/linux/slab.h:578 [inline]
 kvmalloc_node+0x81/0x110 mm/util.c:574
 kvmalloc include/linux/mm.h:753 [inline]
 kvzalloc include/linux/mm.h:761 [inline]
 alloc_netdev_mqs+0x86/0xf90 net/core/dev.c:9938
 rtnl_create_link+0x242/0x9c0 net/core/rtnetlink.c:3067
 __rtnl_newlink net/core/rtnetlink.c:3329 [inline]
 rtnl_newlink+0x12a2/0x1bf0 net/core/rtnetlink.c:3397
 rtnetlink_rcv_msg+0x889/0xd40 net/core/rtnetlink.c:5460
 netlink_rcv_skb+0x190/0x3a0 net/netlink/af_netlink.c:2469
 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
 netlink_unicast+0x786/0x940 net/netlink/af_netlink.c:1329
 netlink_sendmsg+0xa57/0xd70 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg net/socket.c:672 [inline]
 ____sys_sendmsg+0x519/0x800 net/socket.c:2352
 ___sys_sendmsg net/socket.c:2406 [inline]
 __sys_sendmsg+0x2b1/0x360 net/socket.c:2439
 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 7001:
 save_stack mm/kasan/common.c:48 [inline]
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0x114/0x170 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x10a/0x220 mm/slab.c:3757
 device_release+0x70/0x1a0 drivers/base/core.c:1555
 kobject_cleanup lib/kobject.c:693 [inline]
 kobject_release lib/kobject.c:722 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x15b/0x220 lib/kobject.c:739
 netdev_run_todo+0xb17/0xc90 net/core/dev.c:9797
 rtnl_unlock net/core/rtnetlink.c:112 [inline]
 rtnetlink_rcv_msg+0x890/0xd40 net/core/rtnetlink.c:5461
 netlink_rcv_skb+0x190/0x3a0 net/netlink/af_netlink.c:2469
 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
 netlink_unicast+0x786/0x940 net/netlink/af_netlink.c:1329
 netlink_sendmsg+0xa57/0xd70 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg net/socket.c:672 [inline]
 ____sys_sendmsg+0x519/0x800 net/socket.c:2352
 ___sys_sendmsg net/socket.c:2406 [inline]
 __sys_sendmsg+0x2b1/0x360 net/socket.c:2439
 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff88808b62a000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 256 bytes inside of
 4096-byte region [ffff88808b62a000, ffff88808b62b000)
The buggy address belongs to the page:
page:ffffea00022d8a80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 head:ffffea00022d8a80 order:1 compound_mapcount:0
flags: 0xfffe0000010200(slab|head)
raw: 00fffe0000010200 ffffea0002a12288 ffffea0002462c08 ffff8880aa402000
raw: 0000000000000000 ffff88808b62a000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88808b62a000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88808b62a080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88808b62a100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff88808b62a180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88808b62a200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (8):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	Maintainers
ci-upstream-kasan-gce-smack-root	2020/06/28 02:46	upstream	1590a2e1	ffec44b5	.config	log	report	syz	C	davem@davemloft.net, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org
ci-upstream-kasan-gce	2020/07/01 16:57	upstream	7c30b859	39acb39d	.config	log	report			davem@davemloft.net, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org
ci-upstream-kasan-gce-selinux-root	2020/06/30 00:14	upstream	4e99b321	a2cdad9d	.config	log	report			davem@davemloft.net, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org
ci-upstream-kasan-gce-smack-root	2020/06/28 16:24	upstream	4e99b321	a2cdad9d	.config	log	report			davem@davemloft.net, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org
ci-upstream-kasan-gce-smack-root	2020/06/28 01:32	upstream	1590a2e1	ffec44b5	.config	log	report			davem@davemloft.net, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org
ci-upstream-kasan-gce-smack-root	2020/06/16 13:32	upstream	7ae77150	baca2611	.config	log	report			davem@davemloft.net, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2020/07/02 16:13	linux-next	aab20039	bed10395	.config	log	report			davem@davemloft.net, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org
ci-upstream-linux-next-kasan-gce-root	2020/07/02 05:02	linux-next	aab20039	bed10395	.config	log	report			davem@davemloft.net, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org