KASAN: use-after-free Read in nr

KASAN: use-after-free Read in nr_release (2)
Status: upstream: reported syz repro on 2019/08/29 11:28
Reported-by: syzbot+fd05016a0b263a41eb33@syzkaller.appspotmail.com
First crash: 556d, last: 465d

Cause bisection: failed (bisect log)

Fix bisection: failed (bisect log)

similar bugs (3):
Kernel	Title	Repro	Cause bisect	Count	Last	Reported	Patched	Status
linux-4.19	KASAN: use-after-free Read in nr_release	C		106	12d	575d	0/1	upstream: reported C repro on 2019/08/10 01:07
upstream	KASAN: use-after-free Read in nr_release	C	done	25	558d	637d	13/21	fixed on 2019/08/27 17:15
linux-4.14	KASAN: use-after-free Read in nr_release	syz		82	3d23h	571d	0/1	upstream: reported syz repro on 2019/08/13 12:20

Sample crash report:

==================================================================
BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:26 [inline]
BUG: KASAN: use-after-free in refcount_inc_not_zero_checked+0x81/0x200 lib/refcount.c:123
Read of size 4 at addr ffff8880a9ba4500 by task syz-executor.4/10058

CPU: 0 PID: 10058 Comm: syz-executor.4 Not tainted 5.3.0+ #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+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
 __kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506
 kasan_report+0x12/0x20 mm/kasan/common.c:634
 check_memory_region_inline mm/kasan/generic.c:185 [inline]
 check_memory_region+0x134/0x1a0 mm/kasan/generic.c:192
 __kasan_check_read+0x11/0x20 mm/kasan/common.c:92
 atomic_read include/asm-generic/atomic-instrumented.h:26 [inline]
 refcount_inc_not_zero_checked+0x81/0x200 lib/refcount.c:123
 refcount_inc_checked+0x17/0x70 lib/refcount.c:156
 sock_hold include/net/sock.h:649 [inline]
 nr_release+0x62/0x3e0 net/netrom/af_netrom.c:520
 __sock_release+0xce/0x280 net/socket.c:590
 sock_close+0x1e/0x30 net/socket.c:1268
 __fput+0x2ff/0x890 fs/file_table.c:280
 ____fput+0x16/0x20 fs/file_table.c:313
 task_work_run+0x145/0x1c0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x316/0x380 arch/x86/entry/common.c:163
 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
 do_syscall_64+0x65f/0x760 arch/x86/entry/common.c:300
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x413711
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 04 1b 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:00007fff0a69fe80 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000413711
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 0000000000000001 R08: ffffffffffffffff R09: ffffffffffffffff
R10: 00007fff0a69ff60 R11: 0000000000000293 R12: 000000000075c9a0
R13: 000000000075c9a0 R14: 0000000000760c38 R15: 000000000075c124

Allocated by task 10059:
 save_stack+0x23/0x90 mm/kasan/common.c:69
 set_track mm/kasan/common.c:77 [inline]
 __kasan_kmalloc mm/kasan/common.c:510 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:483
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:524
 __do_kmalloc mm/slab.c:3655 [inline]
 __kmalloc+0x163/0x770 mm/slab.c:3664
 kmalloc include/linux/slab.h:557 [inline]
 sk_prot_alloc+0x23a/0x310 net/core/sock.c:1603
 sk_alloc+0x39/0xf70 net/core/sock.c:1657
 nr_create+0xb9/0x5e0 net/netrom/af_netrom.c:433
 __sock_create+0x3d8/0x730 net/socket.c:1418
 sock_create net/socket.c:1469 [inline]
 __sys_socket+0x103/0x220 net/socket.c:1511
 __do_sys_socket net/socket.c:1520 [inline]
 __se_sys_socket net/socket.c:1518 [inline]
 __x64_sys_socket+0x73/0xb0 net/socket.c:1518
 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 10058:
 save_stack+0x23/0x90 mm/kasan/common.c:69
 set_track mm/kasan/common.c:77 [inline]
 kasan_set_free_info mm/kasan/common.c:332 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:471
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:480
 __cache_free mm/slab.c:3425 [inline]
 kfree+0x10a/0x2c0 mm/slab.c:3756
 sk_prot_free net/core/sock.c:1640 [inline]
 __sk_destruct+0x4f7/0x6e0 net/core/sock.c:1726
 sk_destruct+0x86/0xa0 net/core/sock.c:1734
 __sk_free+0xfb/0x360 net/core/sock.c:1745
 sk_free+0x42/0x50 net/core/sock.c:1756
 sock_put include/net/sock.h:1725 [inline]
 nr_release+0x356/0x3e0 net/netrom/af_netrom.c:554
 __sock_release+0xce/0x280 net/socket.c:590
 sock_close+0x1e/0x30 net/socket.c:1268
 __fput+0x2ff/0x890 fs/file_table.c:280
 ____fput+0x16/0x20 fs/file_table.c:313
 task_work_run+0x145/0x1c0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x316/0x380 arch/x86/entry/common.c:163
 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
 do_syscall_64+0x65f/0x760 arch/x86/entry/common.c:300
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8880a9ba4480
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 128 bytes inside of
 2048-byte region [ffff8880a9ba4480, ffff8880a9ba4c80)
The buggy address belongs to the page:
page:ffffea0002a6e900 refcount:1 mapcount:0 mapping:ffff8880aa400e00 index:0x0 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea000239d608 ffffea000238c408 ffff8880aa400e00
raw: 0000000000000000 ffff8880a9ba4480 0000000100000003 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a9ba4400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a9ba4480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880a9ba4500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff8880a9ba4580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a9ba4600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (59):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro
ci-upstream-kasan-gce-root	2019/09/27 04:57	upstream	cbafe18c	2f1548bc	.config	log	report	syz
ci-upstream-kasan-gce-root	2019/09/27 01:52	upstream	cbafe18c	2f1548bc	.config	log	report	syz
ci-upstream-kasan-gce-root	2019/08/28 21:23	upstream	6525771f	fd37b39e	.config	log	report	syz
ci-upstream-linux-next-kasan-gce-root	2019/09/30 19:13	linux-next	8b0eed9f	c7a4fb99	.config	log	report	syz
ci-upstream-linux-next-kasan-gce-root	2019/09/18 15:35	linux-next	a4b5b2e0	c2dcd700	.config	log	report	syz
ci-upstream-linux-next-kasan-gce-root	2019/08/29 01:05	linux-next	ed2393ca	fd37b39e	.config	log	report	syz
ci-upstream-kasan-gce-root	2019/11/27 04:22	upstream	be2eca94	1048481f	.config	log	report
ci-upstream-kasan-gce-selinux-root	2019/11/24 05:39	upstream	6b8a7946	598ca6c8	.config	log	report
ci-upstream-kasan-gce-selinux-root	2019/11/23 05:29	upstream	a6b0373f	598ca6c8	.config	log	report
ci-upstream-kasan-gce-selinux-root	2019/11/19 11:51	upstream	af42d346	5bc70212	.config	log	report
ci-upstream-kasan-gce-selinux-root	2019/11/19 06:22	upstream	af42d346	5bc70212	.config	log	report
ci-upstream-kasan-gce-root	2019/11/16 14:29	upstream	6c9594bd	d5696d51	.config	log	report
ci-upstream-kasan-gce-smack-root	2019/11/12 07:30	upstream	de620fb9	048f2d49	.config	log	report
ci-upstream-kasan-gce-root	2019/11/10 18:45	upstream	00aff683	dc438b91	.config	log	report
ci-upstream-kasan-gce-selinux-root	2019/11/10 10:01	upstream	00aff683	dc438b91	.config	log	report
ci-upstream-kasan-gce-root	2019/11/07 23:40	upstream	847120f8	f39aff9e	.config	log	report
ci-upstream-kasan-gce-root	2019/11/06 19:12	upstream	26bc6721	da505f84	.config	log	report
ci-upstream-kasan-gce-root	2019/11/06 16:48	upstream	26bc6721	da505f84	.config	log	report
ci-upstream-kasan-gce-root	2019/11/03 07:50	upstream	9d234505	a41ca8fa	.config	log	report
ci-upstream-kasan-gce-root	2019/10/30 13:59	upstream	23fdb198	5ea87a66	.config	log	report
ci-upstream-kasan-gce-root	2019/10/30 08:35	upstream	23fdb198	5ea87a66	.config	log	report
ci-upstream-kasan-gce-root	2019/10/30 02:49	upstream	23fdb198	5ea87a66	.config	log	report
ci-upstream-kasan-gce-root	2019/10/29 18:58	upstream	23fdb198	5ea87a66	.config	log	report
ci-upstream-kasan-gce-selinux-root	2019/10/29 17:13	upstream	8005803a	5ea87a66	.config	log	report
ci-upstream-kasan-gce-smack-root	2019/10/25 22:58	upstream	39a38bcb	c2e837da	.config	log	report
ci-upstream-kasan-gce-root	2019/10/14 00:18	upstream	da940012	2f661ec4	.config	log	report
ci-upstream-kasan-gce-selinux-root	2019/10/10 11:31	upstream	8a8c600d	a4efa8c0	.config	log	report
ci-upstream-kasan-gce-selinux-root	2019/10/09 04:40	upstream	d5001955	b1ebbfef	.config	log	report
ci-upstream-kasan-gce-root	2019/10/06 05:55	upstream	4ea65534	f3f7d9c8	.config	log	report
ci-upstream-kasan-gce-selinux-root	2019/10/05 00:29	upstream	b145b0eb	f3f7d9c8	.config	log	report
ci-upstream-kasan-gce-selinux-root	2019/10/04 01:31	upstream	cc3a7bfe	fc17ba49	.config	log	report
ci-upstream-kasan-gce-selinux-root	2019/10/03 15:52	upstream	0f1a7b3f	fc17ba49	.config	log	report
ci-upstream-kasan-gce-root	2019/10/02 12:39	upstream	54ecb8f7	2e29b534	.config	log	report
ci-upstream-kasan-gce-root	2019/10/01 07:26	upstream	54ecb8f7	c7a4fb99	.config	log	report
ci-upstream-kasan-gce-selinux-root	2019/09/28 11:49	upstream	8f744bde	d8074e0b	.config	log	report
ci-upstream-kasan-gce-root	2019/09/28 02:07	upstream	8f744bde	d8074e0b	.config	log	report
ci-upstream-kasan-gce-selinux-root	2019/09/22 04:11	upstream	227c3e9e	d96e88f3	.config	log	report
ci-upstream-kasan-gce-root	2019/09/06 02:23	upstream	3b47fd5c	040fda58	.config	log	report
ci-upstream-kasan-gce-root	2019/08/30 10:12	upstream	6525771f	fd37b39e	.config	log	report
ci-upstream-kasan-gce-root	2019/08/28 20:09	upstream	6525771f	fd37b39e	.config	log	report
ci-upstream-net-kasan-gce	2019/10/25 22:08	net-next	503a6463	c2e837da	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/11/25 17:16	linux-next	c165016b	371caf77	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/11/23 23:09	linux-next	b9d3d014	598ca6c8	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/11/14 05:19	linux-next	4e8f108c	048f2d49	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/11/07 02:38	linux-next	dcd34bd2	da505f84	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/10/21 02:02	linux-next	c4b9850b	8c88c9c1	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/10/20 11:57	linux-next	c4b9850b	8c88c9c1	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/10/18 01:57	linux-next	3ef845da	8c88c9c1	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/10/17 13:03	linux-next	3ef845da	8c88c9c1	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/10/15 10:03	linux-next	0e9d28bc	05ad7292	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/10/10 22:49	linux-next	4a9e93db	1a3bad90	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/10/04 16:43	linux-next	311ef88a	3e1e84d4	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/09/27 10:56	linux-next	bb2aee77	2f1548bc	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/09/19 16:54	linux-next	eb2f1273	eb940044	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/09/19 08:22	linux-next	288b9117	46c0be24	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/09/18 14:12	linux-next	a4b5b2e0	c2dcd700	.config	log	report