KASAN: use-after-free Read in hci_get_auth

KASAN: use-after-free Read in hci_get_auth_info
Status: upstream: reported syz repro on 2020/08/08 06:56
Reported-by: syzbot+13010b6a10bbd82cc79c@syzkaller.appspotmail.com
First crash: 406d, last: 406d

Cause bisection: failed (bisect log)

Fix bisection: failed (bisect log)

similar bugs (1):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
linux-4.14	KASAN: use-after-free Read in hci_get_auth_info	syz		error	1	315d	405d	0/1	upstream: reported syz repro on 2020/08/09 04:54

Patch testing requests:
Created	Duration	User	Patch	Repo	Result
2020/09/07 01:39	15m	dragonjetli@gmail.com	patch	https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master	OK
2020/09/07 01:38	16m	dragonjetli@gmail.com		https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master	OK
2020/09/07 00:53	16m	anant.thazhemadam@gmail.com	patch	https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master	OK

Sample crash report:

==================================================================
BUG: KASAN: use-after-free in __mutex_waiter_is_first kernel/locking/mutex.c:200 [inline]
BUG: KASAN: use-after-free in __mutex_lock_common+0x12cd/0x2fc0 kernel/locking/mutex.c:1040
Read of size 8 at addr ffff88808e668060 by task syz-executor.4/19584

CPU: 0 PID: 19584 Comm: syz-executor.4 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
 __mutex_waiter_is_first kernel/locking/mutex.c:200 [inline]
 __mutex_lock_common+0x12cd/0x2fc0 kernel/locking/mutex.c:1040
 __mutex_lock kernel/locking/mutex.c:1103 [inline]
 mutex_lock_nested+0x1a/0x20 kernel/locking/mutex.c:1118
 hci_get_auth_info+0x69/0x3a0 net/bluetooth/hci_conn.c:1689
 hci_sock_bound_ioctl net/bluetooth/hci_sock.c:957 [inline]
 hci_sock_ioctl+0x5ae/0x750 net/bluetooth/hci_sock.c:1060
 sock_do_ioctl+0x7b/0x260 net/socket.c:1047
 sock_ioctl+0x4aa/0x690 net/socket.c:1198
 vfs_ioctl fs/ioctl.c:48 [inline]
 ksys_ioctl fs/ioctl.c:753 [inline]
 __do_sys_ioctl fs/ioctl.c:762 [inline]
 __se_sys_ioctl+0xf9/0x160 fs/ioctl.c:760
 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45ccd9
Code: 2d b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 fb b5 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f113a564c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000001d300 RCX: 000000000045ccd9
RDX: 0000000020000000 RSI: 00000000800448d7 RDI: 0000000000000005
RBP: 000000000078bf40 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c
R13: 00007ffd62ea93af R14: 00007f113a5659c0 R15: 000000000078bf0c

Allocated by task 6822:
 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_alloc_dev+0x4c/0x1aa0 net/bluetooth/hci_core.c:3543
 __vhci_create_device drivers/bluetooth/hci_vhci.c:99 [inline]
 vhci_create_device+0x113/0x520 drivers/bluetooth/hci_vhci.c:148
 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

Freed by task 9965:
 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
 bt_host_release+0x18/0x20 net/bluetooth/hci_sysfs.c:86
 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
 vhci_release+0x7b/0xc0 drivers/bluetooth/hci_vhci.c:341
 __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
 __do_sys_exit_group+0x13/0x20 kernel/exit.c:914
 __ia32_sys_exit_group+0x0/0x40 kernel/exit.c:912
 __x64_sys_exit_group+0x37/0x40 kernel/exit.c:912
 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff88808e668000
 which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 96 bytes inside of
 8192-byte region [ffff88808e668000, ffff88808e66a000)
The buggy address belongs to the page:
page:ffffea0002399a00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 head:ffffea0002399a00 order:2 compound_mapcount:0 compound_pincount:0
flags: 0xfffe0000010200(slab|head)
raw: 00fffe0000010200 ffffea000217a208 ffffea0001e6c008 ffff8880aa4021c0
raw: 0000000000000000 ffff88808e668000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88808e667f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88808e667f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88808e668000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                       ^
 ffff88808e668080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88808e668100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (1):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci-upstream-kasan-gce-smack-root	2020/08/07 19:34	upstream	d6efb3ac3e6c	cb436c69	.config	log	report	syz