KASAN: use-after-free Read in lock_sock

KASAN: use-after-free Read in lock_sock_nested
Status: upstream: reported C repro on 2019/01/02 10:41
Reported-by: syzbot+500c69d1e21d970e461b@syzkaller.appspotmail.com
First crash: 386d, last: 84d

Cause bisection: the bug happens on the oldest tested release
Crash: inconsistent lock state in nr_find_socket (log)
Repro: syz .config

Fix bisection: fixed by (bisect log):

commit a07e3324538a989b7cdbf2c679be6a7f9df2544f
Author: Thomas Bogendoerfer <tbogendoerfer@suse.de>
Date: Mon May 13 11:47:25 2019 +0000

MIPS: kernel: only use i8253 clocksource with periodic clockevent

similar bugs (4):
Kernel	Title	Repro	Count	Last	Reported	Patched	Status
linux-4.19	KASAN: use-after-free Read in lock_sock_nested	syz	1	8d03h	180d	0/1	upstream: reported syz repro on 2019/07/26 21:27
linux-4.14	KASAN: use-after-free Read in lock_sock_nested	syz	47	23d	274d	0/1	upstream: reported syz repro on 2019/04/24 06:28
android-44	KASAN: use-after-free Read in lock_sock_nested	C	40	516d	287d	0/2	public: reported C repro on 2019/04/11 08:44
android-49	KASAN: use-after-free Read in lock_sock_nested	C	39	518d	711d	0/3	closed as invalid on 2019/03/07 05:41

Sample crash report:

==================================================================
BUG: KASAN: use-after-free in debug_spin_lock_before kernel/locking/spinlock_debug.c:83 [inline]
BUG: KASAN: use-after-free in do_raw_spin_lock+0x295/0x3a0 kernel/locking/spinlock_debug.c:112
Read of size 4 at addr ffff88809f0acf0c by task syz-executor847/10804

CPU: 0 PID: 10804 Comm: syz-executor847 Not tainted 5.3.0-rc1+ #51
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+0x1d8/0x2f8 lib/dump_stack.c:113
 print_address_description+0x75/0x5b0 mm/kasan/report.c:351
 __kasan_report+0x14b/0x1c0 mm/kasan/report.c:482
 kasan_report+0x26/0x50 mm/kasan/common.c:612
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:131
 debug_spin_lock_before kernel/locking/spinlock_debug.c:83 [inline]
 do_raw_spin_lock+0x295/0x3a0 kernel/locking/spinlock_debug.c:112
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:136 [inline]
 _raw_spin_lock_bh+0x40/0x50 kernel/locking/spinlock.c:175
 spin_lock_bh include/linux/spinlock.h:343 [inline]
 lock_sock_nested+0x45/0x120 net/core/sock.c:2917
 lock_sock include/net/sock.h:1522 [inline]
 nr_getname+0x5b/0x220 net/netrom/af_netrom.c:838
 __sys_accept4+0x63a/0x9a0 net/socket.c:1759
 __do_sys_accept4 net/socket.c:1789 [inline]
 __se_sys_accept4 net/socket.c:1786 [inline]
 __x64_sys_accept4+0x9a/0xb0 net/socket.c:1786
 do_syscall_64+0xfe/0x140 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4480e9
Code: e8 ac e7 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 4b 06 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f43bf6ced88 EFLAGS: 00000246 ORIG_RAX: 0000000000000120
RAX: ffffffffffffffda RBX: 00000000006ddc38 RCX: 00000000004480e9
RDX: 0000000000000000 RSI: 0000000020000b00 RDI: 0000000000000004
RBP: 00000000006ddc30 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006ddc3c
R13: 00007ffd18de174f R14: 00007f43bf6cf9c0 R15: 00000000006ddc3c

Allocated by task 0:
 save_stack mm/kasan/common.c:69 [inline]
 set_track mm/kasan/common.c:77 [inline]
 __kasan_kmalloc+0x11c/0x1b0 mm/kasan/common.c:487
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:501
 __do_kmalloc mm/slab.c:3655 [inline]
 __kmalloc+0x254/0x340 mm/slab.c:3664
 kmalloc include/linux/slab.h:557 [inline]
 sk_prot_alloc+0xb0/0x290 net/core/sock.c:1603
 sk_alloc+0x38/0x950 net/core/sock.c:1657
 nr_make_new net/netrom/af_netrom.c:476 [inline]
 nr_rx_frame+0xabc/0x1e40 net/netrom/af_netrom.c:959
 nr_loopback_timer+0x6a/0x140 net/netrom/nr_loopback.c:59
 call_timer_fn+0xec/0x200 kernel/time/timer.c:1322
 expire_timers kernel/time/timer.c:1366 [inline]
 __run_timers+0x7cd/0x9c0 kernel/time/timer.c:1685
 run_timer_softirq+0x4a/0x90 kernel/time/timer.c:1698
 __do_softirq+0x333/0x7c4 arch/x86/include/asm/paravirt.h:778

Freed by task 10804:
 save_stack mm/kasan/common.c:69 [inline]
 set_track mm/kasan/common.c:77 [inline]
 __kasan_slab_free+0x12a/0x1e0 mm/kasan/common.c:449
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:457
 __cache_free mm/slab.c:3425 [inline]
 kfree+0x115/0x200 mm/slab.c:3756
 sk_prot_free net/core/sock.c:1640 [inline]
 __sk_destruct+0x567/0x660 net/core/sock.c:1726
 sk_destruct net/core/sock.c:1734 [inline]
 __sk_free+0x317/0x3e0 net/core/sock.c:1745
 sk_free net/core/sock.c:1756 [inline]
 sock_put include/net/sock.h:1725 [inline]
 sock_efree+0x60/0x80 net/core/sock.c:2042
 skb_release_head_state+0x100/0x220 net/core/skbuff.c:652
 skb_release_all net/core/skbuff.c:663 [inline]
 __kfree_skb+0x25/0x170 net/core/skbuff.c:679
 kfree_skb+0x6f/0xb0 net/core/skbuff.c:697
 nr_accept+0x4ef/0x650 net/netrom/af_netrom.c:819
 __sys_accept4+0x5bc/0x9a0 net/socket.c:1754
 __do_sys_accept4 net/socket.c:1789 [inline]
 __se_sys_accept4 net/socket.c:1786 [inline]
 __x64_sys_accept4+0x9a/0xb0 net/socket.c:1786
 do_syscall_64+0xfe/0x140 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88809f0ace80
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 140 bytes inside of
 2048-byte region [ffff88809f0ace80, ffff88809f0ad680)
The buggy address belongs to the page:
page:ffffea00027c2b00 refcount:1 mapcount:0 mapping:ffff8880aa400e00 index:0x0 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea0002704708 ffffea0002695508 ffff8880aa400e00
raw: 0000000000000000 ffff88809f0ac600 0000000100000003 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809f0ace00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88809f0ace80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88809f0acf00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff88809f0acf80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88809f0ad000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
------------[ cut here ]------------
ODEBUG: activate not available (active state 0) object type: timer_list hint: nr_t1timer_expiry+0x0/0x400 net/netrom/nr_timer.c:46
WARNING: CPU: 0 PID: 10804 at lib/debugobjects.c:484 debug_print_object lib/debugobjects.c:481 [inline]
WARNING: CPU: 0 PID: 10804 at lib/debugobjects.c:484 debug_object_activate+0x33d/0x6f0 lib/debugobjects.c:680
Modules linked in:
CPU: 0 PID: 10804 Comm: syz-executor847 Tainted: G    B             5.3.0-rc1+ #51
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:debug_print_object lib/debugobjects.c:481 [inline]
RIP: 0010:debug_object_activate+0x33d/0x6f0 lib/debugobjects.c:680
Code: f7 e8 f7 01 4a fe 4d 8b 06 48 c7 c7 ca 56 88 88 48 c7 c6 f0 2d a1 88 48 c7 c2 e3 69 81 88 31 c9 49 89 d9 31 c0 e8 63 6d e0 fd <0f> 0b 48 ba 00 00 00 00 00 fc ff df ff 05 65 92 95 05 49 83 c6 20
RSP: 0018:ffff88809633faa8 EFLAGS: 00010046
RAX: a65408733c6cb800 RBX: ffffffff86dc84e0 RCX: ffff8880a8b08440
RDX: 0000000000000000 RSI: 0000000080000001 RDI: 0000000000000000
RBP: ffff88809633faf0 R08: ffffffff816063f4 R09: ffffed1015d440c2
R10: ffffed1015d440c2 R11: 0000000000000000 R12: ffff8880a10bfd70
R13: 1ffff11014217fae R14: ffffffff88cd9fc0 R15: ffff88809f0ad358
FS:  00007f43bf6cf700(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000008c7b1000 CR4: 00000000001406f0
Call Trace:
 debug_timer_activate kernel/time/timer.c:710 [inline]
 __mod_timer+0x960/0x16e0 kernel/time/timer.c:1035
 mod_timer+0x1f/0x30 kernel/time/timer.c:1096
 sk_reset_timer+0x22/0x50 net/core/sock.c:2821
 nr_start_t1timer+0x78/0x90 net/netrom/nr_timer.c:52
 nr_release+0x238/0x390 net/netrom/af_netrom.c:537
 __sock_release net/socket.c:590 [inline]
 sock_close+0xe1/0x260 net/socket.c:1268
 __fput+0x2e4/0x740 fs/file_table.c:280
 ____fput+0x15/0x20 fs/file_table.c:313
 task_work_run+0x17e/0x1b0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop arch/x86/entry/common.c:163 [inline]
 prepare_exit_to_usermode+0x459/0x580 arch/x86/entry/common.c:194
 syscall_return_slowpath+0x113/0x4a0 arch/x86/entry/common.c:274
 do_syscall_64+0x126/0x140 arch/x86/entry/common.c:299
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4480e9
Code: e8 ac e7 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 4b 06 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f43bf6ced88 EFLAGS: 00000246 ORIG_RAX: 0000000000000120
RAX: fffffffffffffff2 RBX: 00000000006ddc38 RCX: 00000000004480e9
RDX: 0000000000000000 RSI: 0000000020000b00 RDI: 0000000000000004
RBP: 00000000006ddc30 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006ddc3c
R13: 00007ffd18de174f R14: 00007f43bf6cf9c0 R15: 00000000006ddc3c
irq event stamp: 0
hardirqs last  enabled at (0): [<0000000000000000>] 0x0
hardirqs last disabled at (0): [<ffffffff81484c09>] copy_process+0x1589/0x5bc0 kernel/fork.c:1960
softirqs last  enabled at (0): [<ffffffff81484c7f>] copy_process+0x15ff/0x5bc0 kernel/fork.c:1963
softirqs last disabled at (0): [<0000000000000000>] 0x0
---[ end trace 41aab9a9be4009d5 ]---

Crashes (22):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	Maintainers
ci-upstream-kasan-gce-smack-root	2019/07/27 09:44	upstream	3ea54d9b	c85e1c5b	.config	log	report	syz	C	davem@davemloft.net, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, ralf@linux-mips.org
ci-upstream-linux-next-kasan-gce-root	2019/02/15 05:24	linux-next	b3418f8b	76dd003f	.config	log	report	syz		davem@davemloft.net, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, ralf@linux-mips.org
ci-upstream-kasan-gce-root	2019/08/03 18:12	upstream	dcb8cfbd	6affd8e8	.config	log	report			davem@davemloft.net, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, ralf@linux-mips.org
ci-upstream-kasan-gce-selinux-root	2019/08/01 10:34	upstream	5c620753	c692b5bd	.config	log	report			davem@davemloft.net, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, ralf@linux-mips.org
ci-upstream-kasan-gce-root	2019/07/28 10:47	upstream	5168afe6	c85e1c5b	.config	log	report			davem@davemloft.net, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, ralf@linux-mips.org
ci-upstream-kasan-gce-root	2019/07/27 06:40	upstream	3ea54d9b	c85e1c5b	.config	log	report			davem@davemloft.net, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, ralf@linux-mips.org
ci-upstream-kasan-gce-smack-root	2019/07/27 06:39	upstream	3ea54d9b	c85e1c5b	.config	log	report			davem@davemloft.net, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, ralf@linux-mips.org
ci-upstream-kasan-gce-root	2019/07/27 06:36	upstream	3ea54d9b	c85e1c5b	.config	log	report			davem@davemloft.net, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, ralf@linux-mips.org
ci-upstream-kasan-gce-smack-root	2019/07/25 00:08	upstream	bed38c3e	32329ceb	.config	log	report			davem@davemloft.net, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, ralf@linux-mips.org
ci-upstream-kasan-gce-smack-root	2019/04/24 05:04	upstream	7142eaa5	4d3d6a50	.config	log	report			davem@davemloft.net, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, ralf@linux-mips.org
ci-upstream-kasan-gce-selinux-root	2019/02/15 08:35	upstream	cb5b020a	76dd003f	.config	log	report			davem@davemloft.net, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, ralf@linux-mips.org
ci-upstream-kasan-gce-selinux-root	2019/01/01 20:21	upstream	e1ef035d	3d85f48c	.config	log	report			davem@davemloft.net, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, ralf@linux-mips.org
ci-upstream-net-this-kasan-gce	2019/07/30 23:36	net	107e47cc	7c7ded69	.config	log	report			davem@davemloft.net, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, ralf@linux-mips.org
ci-upstream-net-this-kasan-gce	2019/07/27 16:32	net	107e47cc	c85e1c5b	.config	log	report			davem@davemloft.net, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, ralf@linux-mips.org
ci-upstream-net-this-kasan-gce	2019/07/26 19:01	net	107e47cc	3e5d1beb	.config	log	report			davem@davemloft.net, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, ralf@linux-mips.org
ci-upstream-net-this-kasan-gce	2019/07/20 06:35	net	31cc088a	1656845f	.config	log	report
ci-upstream-net-this-kasan-gce	2019/06/02 06:42	net	e8d67fa5	53c81ea5	.config	log	report			davem@davemloft.net, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, ralf@linux-mips.org
ci-upstream-net-kasan-gce	2019/10/30 18:26	net-next	74923441	5ea87a66	.config	log	report			davem@davemloft.net, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, ralf@linux-mips.org
ci-upstream-net-kasan-gce	2019/07/31 01:54	net-next	31cc088a	7c7ded69	.config	log	report			davem@davemloft.net, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, ralf@linux-mips.org
ci-upstream-net-kasan-gce	2019/07/24 23:02	net-next	31cc088a	32329ceb	.config	log	report			davem@davemloft.net, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, ralf@linux-mips.org
ci-upstream-net-kasan-gce	2019/03/16 10:18	net-next	3b319ee2	bab43553	.config	log	report			davem@davemloft.net, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, ralf@linux-mips.org
ci-upstream-linux-next-kasan-gce-root	2019/07/25 22:57	linux-next	13bf6d6a	732bc5a0	.config	log	report			davem@davemloft.net, linux-hams@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, ralf@linux-mips.org