KASAN: use-after-free Read in l2cap_sock_close_cb

Status: upstream: reported C repro on 2020/08/01 21:47
Reported-by: syzbot+0fe4efc137563eac3894@syzkaller.appspotmail.com
First crash: 2211d, last: 2165d
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.14 KASAN: use-after-free Read in l2cap_sock_close_cb 19 syz unreliable 226 2131d 2213d 0/1 upstream: reported syz repro on 2020/07/31 05:53

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in constant_test_bit arch/x86/include/asm/bitops.h:317 [inline]
BUG: KASAN: use-after-free in sock_flag include/net/sock.h:839 [inline]
BUG: KASAN: use-after-free in l2cap_sock_kill net/bluetooth/l2cap_sock.c:1046 [inline]
BUG: KASAN: use-after-free in l2cap_sock_close_cb+0xbd/0xd0 net/bluetooth/l2cap_sock.c:1311
Read of size 8 at addr ffff88809e9182a0 by task syz-executor979/26954

CPU: 0 PID: 26954 Comm: syz-executor979 Not tainted 4.19.136-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+0x1fc/0x2fe lib/dump_stack.c:118
 print_address_description.cold+0x54/0x219 mm/kasan/report.c:256
 kasan_report_error.cold+0x8a/0x1c7 mm/kasan/report.c:354
 kasan_report mm/kasan/report.c:412 [inline]
 __asan_report_load8_noabort+0x88/0x90 mm/kasan/report.c:433
 constant_test_bit arch/x86/include/asm/bitops.h:317 [inline]
 sock_flag include/net/sock.h:839 [inline]
 l2cap_sock_kill net/bluetooth/l2cap_sock.c:1046 [inline]
 l2cap_sock_close_cb+0xbd/0xd0 net/bluetooth/l2cap_sock.c:1311
 l2cap_conn_del+0x3db/0x6b0 net/bluetooth/l2cap_core.c:1730
 l2cap_disconn_cfm net/bluetooth/l2cap_core.c:7435 [inline]
 l2cap_disconn_cfm+0x85/0xa0 net/bluetooth/l2cap_core.c:7428
 hci_disconn_cfm include/net/bluetooth/hci_core.h:1261 [inline]
 hci_conn_hash_flush+0x114/0x220 net/bluetooth/hci_conn.c:1495
 hci_dev_do_close+0x624/0xe70 net/bluetooth/hci_core.c:1666
 hci_unregister_dev+0x17c/0x7f0 net/bluetooth/hci_core.c:3271
 vhci_release+0x70/0xe0 drivers/bluetooth/hci_vhci.c:354
 __fput+0x2ce/0x890 fs/file_table.c:278
 task_work_run+0x148/0x1c0 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0xbb2/0x2b70 kernel/exit.c:887
 do_group_exit+0x125/0x310 kernel/exit.c:990
 get_signal+0x3f2/0x1f70 kernel/signal.c:2588
 do_signal+0x8f/0x1670 arch/x86/kernel/signal.c:821
 exit_to_usermode_loop+0x204/0x2a0 arch/x86/entry/common.c:163
 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
 do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x447169
Code: e8 4c 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 3b 07 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fa8bff16db8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00000000006dcc28 RCX: 0000000000447169
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00000000006dcc28
RBP: 00000000006dcc20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dcc2c
R13: 00007ffd57ed7e7f R14: 00007fa8bff179c0 R15: 0000000000000064

Allocated by task 21624:
 __do_kmalloc mm/slab.c:3727 [inline]
 __kmalloc+0x15a/0x3c0 mm/slab.c:3736
 kmalloc include/linux/slab.h:520 [inline]
 sk_prot_alloc+0x1e2/0x2d0 net/core/sock.c:1466
 sk_alloc+0x36/0xec0 net/core/sock.c:1520
 l2cap_sock_alloc.constprop.0+0x31/0x210 net/bluetooth/l2cap_sock.c:1590
 l2cap_sock_create+0x110/0x1b0 net/bluetooth/l2cap_sock.c:1636
 bt_sock_create+0x154/0x2a0 net/bluetooth/af_bluetooth.c:130
 __sock_create+0x3d8/0x740 net/socket.c:1276
 sock_create net/socket.c:1316 [inline]
 __sys_socket+0xef/0x200 net/socket.c:1346
 __do_sys_socket net/socket.c:1355 [inline]
 __se_sys_socket net/socket.c:1353 [inline]
 __x64_sys_socket+0x6f/0xb0 net/socket.c:1353
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 21626:
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xcc/0x210 mm/slab.c:3822
 sk_prot_free net/core/sock.c:1503 [inline]
 __sk_destruct+0x5ff/0x810 net/core/sock.c:1584
 sk_destruct net/core/sock.c:1599 [inline]
 __sk_free+0x165/0x3b0 net/core/sock.c:1610
 sk_free+0x3b/0x50 net/core/sock.c:1621
 sock_put include/net/sock.h:1707 [inline]
 l2cap_sock_kill.part.0+0x6b/0x80 net/bluetooth/l2cap_sock.c:1055
 l2cap_sock_kill net/bluetooth/l2cap_sock.c:1206 [inline]
 l2cap_sock_release+0x158/0x190 net/bluetooth/l2cap_sock.c:1204
 __sock_release+0xcd/0x2a0 net/socket.c:579
 sock_close+0x15/0x20 net/socket.c:1140
 __fput+0x2ce/0x890 fs/file_table.c:278
 task_work_run+0x148/0x1c0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:193 [inline]
 exit_to_usermode_loop+0x251/0x2a0 arch/x86/entry/common.c:167
 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
 do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88809e918240
 which belongs to the cache kmalloc-2048 of size 2048
The buggy address is located 96 bytes inside of
 2048-byte region [ffff88809e918240, ffff88809e918a40)
The buggy address belongs to the page:
page:ffffea00027a4600 count:1 mapcount:0 mapping:ffff88812c39cc40 index:0x0 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffffea00021ea508 ffffea0002792888 ffff88812c39cc40
raw: 0000000000000000 ffff88809e918240 0000000100000003 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809e918180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88809e918200: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
>ffff88809e918280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff88809e918300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88809e918380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (157):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/08/02 16:24 linux-4.19.y 13af6c74b14a 96dd3623 .config console log report syz C ci2-linux-4-19
2020/09/10 04:00 linux-4.19.y 67957f12548c ac7ca78e .config console log report syz ci2-linux-4-19
2020/08/23 20:02 linux-4.19.y d18b78abc0c6 a6d5f3ad .config console log report syz ci2-linux-4-19
2020/09/16 20:39 linux-4.19.y a87f96283793 77507d02 .config console log report info ci2-linux-4-19
2020/09/16 11:39 linux-4.19.y a87f96283793 18d7d030 .config console log report info ci2-linux-4-19
2020/09/15 22:08 linux-4.19.y a87f96283793 18d7d030 .config console log report info ci2-linux-4-19
2020/09/15 16:38 linux-4.19.y a87f96283793 9e681632 .config console log report info ci2-linux-4-19
2020/09/12 00:49 linux-4.19.y 67957f12548c 79fb24e2 .config console log report ci2-linux-4-19
2020/09/11 09:43 linux-4.19.y 67957f12548c ac7ca78e .config console log report ci2-linux-4-19
2020/09/11 04:30 linux-4.19.y 67957f12548c ac7ca78e .config console log report ci2-linux-4-19
2020/09/11 01:31 linux-4.19.y 67957f12548c ac7ca78e .config console log report ci2-linux-4-19
2020/09/10 22:32 linux-4.19.y 67957f12548c ac7ca78e .config console log report ci2-linux-4-19
2020/09/10 17:49 linux-4.19.y 67957f12548c ac7ca78e .config console log report ci2-linux-4-19
2020/09/10 16:39 linux-4.19.y 67957f12548c ac7ca78e .config console log report ci2-linux-4-19
2020/09/10 10:27 linux-4.19.y 67957f12548c ac7ca78e .config console log report ci2-linux-4-19
2020/09/10 07:40 linux-4.19.y 67957f12548c ac7ca78e .config console log report ci2-linux-4-19
2020/09/10 06:19 linux-4.19.y 67957f12548c ac7ca78e .config console log report ci2-linux-4-19
2020/09/10 05:09 linux-4.19.y 67957f12548c ac7ca78e .config console log report ci2-linux-4-19
2020/09/09 23:15 linux-4.19.y 67957f12548c ac7ca78e .config console log report ci2-linux-4-19
2020/09/09 18:51 linux-4.19.y 67957f12548c ac7ca78e .config console log report ci2-linux-4-19
2020/09/09 17:46 linux-4.19.y 67957f12548c ac7ca78e .config console log report ci2-linux-4-19
2020/09/09 16:36 linux-4.19.y c37da90efff5 0ea7a887 .config console log report ci2-linux-4-19
2020/09/09 12:17 linux-4.19.y c37da90efff5 0ea7a887 .config console log report ci2-linux-4-19
2020/09/09 09:32 linux-4.19.y c37da90efff5 0ea7a887 .config console log report ci2-linux-4-19
2020/09/09 05:17 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/09 04:13 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/09 02:16 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/09 01:04 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/08 21:03 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/08 18:16 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/08 17:11 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/08 12:38 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/08 10:14 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/08 09:05 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/08 05:20 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/08 03:55 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/08 02:00 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/08 00:46 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/07 19:51 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/07 17:06 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/07 15:45 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/07 13:03 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/07 11:10 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/07 09:49 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/07 06:06 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/07 04:09 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/06 15:35 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/06 14:25 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/06 13:22 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/06 06:28 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/06 01:39 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/05 23:59 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/05 20:38 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/05 10:51 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/09/05 05:04 linux-4.19.y c37da90efff5 abf9ba4f .config console log report ci2-linux-4-19
2020/08/01 21:46 linux-4.19.y 13af6c74b14a 8df85ed9 .config console log report ci2-linux-4-19
* Struck through repros no longer work on HEAD.