KASAN: use-after-free Write in __sco_sock

KASAN: use-after-free Write in __sco_sock_close
Status: fixed on 2021/03/10 01:48
Reported-by: syzbot+077eca30d3cb7c02b273@syzkaller.appspotmail.com
Fix commit: 6dfccd13 Bluetooth: Fix null pointer dereference in hci_event_packet()
First crash: 251d, last: 154d

Cause bisection: introduced by (bisect log) :
commit 43ea43b9d8b27b7acd443ec59319faa3cdb8a616
Author: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Date: Wed Oct 12 11:21:43 2016 +0000

[media] radio-bcm2048: don't ignore errors

Crash: WARNING in nf_unregister_net_hook (log)
Repro: C syz .config

Fix bisection: fixed by (bisect log) :
commit 6dfccd13db2ff2b709ef60a50163925d477549aa
Author: Anmol Karn <anmol.karan123@gmail.com>
Date: Wed Sep 30 14:18:13 2020 +0000

Bluetooth: Fix null pointer dereference in hci_event_packet()

duplicates (1):
Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
KASAN: use-after-free Write in sco_chan_del	C	done		29	243d	251d	0/22	closed as dup on 2020/08/18 06:37

Patch testing requests:
Created	Duration	User	Patch	Repo	Result
2020/08/14 11:59	16m	foxhlchen@gmail.com	patch	git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 47ec5303	OK
2020/08/12 05:59	10m	foxhlchen@gmail.com		upstream	report log

Sample crash report:

==================================================================
BUG: KASAN: use-after-free in instrument_atomic_write include/linux/instrumented.h:71 [inline]
BUG: KASAN: use-after-free in atomic_dec_and_test include/asm-generic/atomic-instrumented.h:748 [inline]
BUG: KASAN: use-after-free in hci_conn_drop include/net/bluetooth/hci_core.h:1116 [inline]
BUG: KASAN: use-after-free in sco_chan_del net/bluetooth/sco.c:149 [inline]
BUG: KASAN: use-after-free in __sco_sock_close+0x47c/0xed0 net/bluetooth/sco.c:434
Write of size 4 at addr ffff8880a6ff8010 by task syz-executor236/7006

CPU: 0 PID: 7006 Comm: syz-executor236 Not tainted 5.8.0-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
 check_memory_region_inline mm/kasan/generic.c:183 [inline]
 check_memory_region+0x2b5/0x2f0 mm/kasan/generic.c:192
 instrument_atomic_write include/linux/instrumented.h:71 [inline]
 atomic_dec_and_test include/asm-generic/atomic-instrumented.h:748 [inline]
 hci_conn_drop include/net/bluetooth/hci_core.h:1116 [inline]
 sco_chan_del net/bluetooth/sco.c:149 [inline]
 __sco_sock_close+0x47c/0xed0 net/bluetooth/sco.c:434
 sco_sock_close net/bluetooth/sco.c:448 [inline]
 sco_sock_release+0x63/0x4f0 net/bluetooth/sco.c:1053
 __sock_release net/socket.c:596 [inline]
 sock_close+0xd8/0x260 net/socket.c:1277
 __fput+0x2f0/0x750 fs/file_table.c:281
 task_work_run+0x137/0x1c0 kernel/task_work.c:135
 exit_task_work include/linux/task_work.h:25 [inline]
 do_exit+0x5f3/0x1f20 kernel/exit.c:806
 do_group_exit+0x161/0x2d0 kernel/exit.c:903
 get_signal+0x139b/0x1d30 kernel/signal.c:2743
 arch_do_signal+0x33/0x610 arch/x86/kernel/signal.c:811
 exit_to_user_mode_loop kernel/entry/common.c:135 [inline]
 exit_to_user_mode_prepare+0x8d/0x1c0 kernel/entry/common.c:166
 syscall_exit_to_user_mode+0x5e/0x1a0 kernel/entry/common.c:241
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x446eb9
Code: Bad RIP value.
RSP: 002b:00007ffe6f094b58 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: fffffffffffffffc RBX: 0000000000000003 RCX: 0000000000446eb9
RDX: 0000000000000008 RSI: 00000000200000c0 RDI: 0000000000000004
RBP: 0000000000000004 R08: 0000000000000002 R09: 00000000000300ff
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000407b10 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 7006:
 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
 kmem_cache_alloc_trace+0x234/0x300 mm/slab.c:3551
 kmalloc include/linux/slab.h:555 [inline]
 kzalloc include/linux/slab.h:669 [inline]
 hci_conn_add+0x5d/0x1040 net/bluetooth/hci_conn.c:525
 hci_connect_sco+0x2aa/0xa20 net/bluetooth/hci_conn.c:1283
 sco_connect net/bluetooth/sco.c:241 [inline]
 sco_sock_connect+0x2de/0xaa0 net/bluetooth/sco.c:588
 __sys_connect_file net/socket.c:1853 [inline]
 __sys_connect+0x2da/0x360 net/socket.c:1870
 __do_sys_connect net/socket.c:1881 [inline]
 __se_sys_connect net/socket.c:1878 [inline]
 __x64_sys_connect+0x76/0x80 net/socket.c:1878
 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 7005:
 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:1796
 kobject_cleanup lib/kobject.c:704 [inline]
 kobject_release lib/kobject.c:735 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x1a0/0x2c0 lib/kobject.c:752
 hci_conn_del+0x2c2/0x550 net/bluetooth/hci_conn.c:645
 hci_phy_link_complete_evt net/bluetooth/hci_event.c:4940 [inline]
 hci_event_packet+0x82c8/0x17e10 net/bluetooth/hci_event.c:6205
 hci_rx_work+0x246/0xa20 net/bluetooth/hci_core.c:4889
 process_one_work+0x789/0xfc0 kernel/workqueue.c:2269
 worker_thread+0xaa4/0x1460 kernel/workqueue.c:2415
 kthread+0x37e/0x3a0 drivers/block/aoe/aoecmd.c:1234
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

The buggy address belongs to the object at ffff8880a6ff8000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 16 bytes inside of
 4096-byte region [ffff8880a6ff8000, ffff8880a6ff9000)
The buggy address belongs to the page:
page:ffffea00029bfe00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 head:ffffea00029bfe00 order:1 compound_mapcount:0
flags: 0xfffe0000010200(slab|head)
raw: 00fffe0000010200 ffffea00024f5608 ffffea00029bf888 ffff8880aa402000
raw: 0000000000000000 ffff8880a6ff8000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a6ff7f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880a6ff7f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880a6ff8000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff8880a6ff8080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a6ff8100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (10):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro
ci-upstream-kasan-gce-smack-root	2020/08/06 22:04	upstream	47ec5303	1f122f88	.config	log	report	syz	C
ci-upstream-kasan-gce-smack-root	2020/08/06 20:44	upstream	47ec5303	1f122f88	.config	log	report	syz	C
ci-upstream-kasan-gce-smack-root	2020/08/05 19:14	upstream	442489c2	b7129355	.config	log	report	syz	C
ci-upstream-kasan-gce-smack-root	2020/08/05 18:44	upstream	442489c2	b7129355	.config	log	report	syz	C
ci-upstream-kasan-gce-smack-root	2020/08/04 23:35	upstream	c0842fbc	80a06902	.config	log	report	syz	C
ci-upstream-kasan-gce-smack-root	2020/08/04 20:44	upstream	c0842fbc	80a06902	.config	log	report	syz	C
ci-upstream-kasan-gce-smack-root	2020/08/04 06:00	upstream	bcf87687	196277c4	.config	log	report	syz	C
ci-upstream-kasan-gce-smack-root	2020/08/04 00:35	upstream	bcf87687	196277c4	.config	log	report	syz	C
ci-upstream-kasan-gce-smack-root	2020/08/03 21:41	upstream	bcf87687	196277c4	.config	log	report	syz	C
ci-upstream-kasan-gce-smack-root	2020/08/02 17:21	upstream	ac3a0c84	63a73341	.config	log	report	syz	C