KASAN: slab-out-of-bounds Read in hci_inquiry_result_with_rssi_evt

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: e5a54aa2 Linux 4.14.190
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=166a08d0900000
kernel config: https://syzkaller.appspot.com/x/.config?x=dbb53fc7192d83c3
dashboard link: https://syzkaller.appspot.com/bug?extid=8761bb11d98585d2546c
compiler: gcc (GCC) 10.1.0-syz 20200507

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8761bb...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:372 [inline]
BUG: KASAN: slab-out-of-bounds in bacpy include/net/bluetooth/bluetooth.h:233 [inline]
BUG: KASAN: slab-out-of-bounds in hci_inquiry_result_with_rssi_evt+0x1df/0x640 net/bluetooth/hci_event.c:3629
Read of size 6 at addr ffff88808beb3ebb by task kworker/u5:4/7969

CPU: 0 PID: 7969 Comm: kworker/u5:4 Not tainted 4.14.190-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: hci1 hci_rx_work
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x1b2/0x283 lib/dump_stack.c:58
print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
kasan_report_error.cold+0x8a/0x194 mm/kasan/report.c:351
kasan_report+0x6f/0x7b mm/kasan/report.c:409
memcpy+0x20/0x50 mm/kasan/kasan.c:302
memcpy include/linux/string.h:372 [inline]
bacpy include/net/bluetooth/bluetooth.h:233 [inline]
hci_inquiry_result_with_rssi_evt+0x1df/0x640 net/bluetooth/hci_event.c:3629
hci_event_packet+0x19cd/0x7c7a net/bluetooth/hci_event.c:5364
hci_rx_work+0x3e6/0x970 net/bluetooth/hci_core.c:4244
process_one_work+0x793/0x14a0 kernel/workqueue.c:2116
worker_thread+0x5cc/0xff0 kernel/workqueue.c:2250
kthread+0x30d/0x420 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404

Allocated by task 9332:
save_stack mm/kasan/kasan.c:447 [inline]
set_track mm/kasan/kasan.c:459 [inline]
kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551
__do_kmalloc_node mm/slab.c:3682 [inline]
__kmalloc_node_track_caller+0x4c/0x70 mm/slab.c:3696
__kmalloc_reserve net/core/skbuff.c:137 [inline]
__alloc_skb+0x96/0x510 net/core/skbuff.c:205
alloc_skb include/linux/skbuff.h:980 [inline]
bt_skb_alloc include/net/bluetooth/bluetooth.h:336 [inline]
vhci_get_user drivers/bluetooth/hci_vhci.c:180 [inline]
vhci_write+0xb1/0x420 drivers/bluetooth/hci_vhci.c:299
call_write_iter include/linux/fs.h:1778 [inline]
new_sync_write fs/read_write.c:469 [inline]
__vfs_write+0x44c/0x630 fs/read_write.c:482
vfs_write+0x17f/0x4d0 fs/read_write.c:544
SYSC_write fs/read_write.c:590 [inline]
SyS_write+0xf2/0x210 fs/read_write.c:582
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 3658:
save_stack mm/kasan/kasan.c:447 [inline]
set_track mm/kasan/kasan.c:459 [inline]
kasan_slab_free+0xc3/0x1a0 mm/kasan/kasan.c:524
__cache_free mm/slab.c:3496 [inline]
kfree+0xc9/0x250 mm/slab.c:3815
kernfs_fop_release+0x10e/0x180 fs/kernfs/file.c:783
__fput+0x25f/0x7a0 fs/file_table.c:210
task_work_run+0x11f/0x190 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:191 [inline]
exit_to_usermode_loop+0x1ad/0x200 arch/x86/entry/common.c:164
prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
entry_SYSCALL_64_after_hwframe+0x46/0xbb

The buggy address belongs to the object at ffff88808beb3cc0
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 507 bytes inside of
512-byte region [ffff88808beb3cc0, ffff88808beb3ec0)
The buggy address belongs to the page:
page:ffffea00022facc0 count:1 mapcount:0 mapping:ffff88808beb3040 index:0x0
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffff88808beb3040 0000000000000000 0000000100000006
raw: ffffea00022777e0 ffffea00015eeaa0 ffff88812fe52940 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff88808beb3d80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88808beb3e00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88808beb3e80: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
^
ffff88808beb3f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88808beb3f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: e5a54aa2 Linux 4.14.190
git tree: linux-4.14.y

console output: https://syzkaller.appspot.com/x/log.txt?x=1632f56c900000

kernel config: https://syzkaller.appspot.com/x/.config?x=dbb53fc7192d83c3
dashboard link: https://syzkaller.appspot.com/bug?extid=8761bb11d98585d2546c
compiler: gcc (GCC) 10.1.0-syz 20200507

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=168ebff4900000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13311ff4900000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8761bb...@syzkaller.appspotmail.com

audit: type=1400 audit(1596204830.010:8): avc: denied { execmem } for pid=6375 comm="syz-executor128" scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=process permissive=1
IPVS: ftp: loaded support on port[0] = 21

==================================================================
BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:372 [inline]
BUG: KASAN: slab-out-of-bounds in bacpy include/net/bluetooth/bluetooth.h:233 [inline]
BUG: KASAN: slab-out-of-bounds in hci_inquiry_result_with_rssi_evt+0x1df/0x640 net/bluetooth/hci_event.c:3629

Read of size 6 at addr ffff88809fe1d4fb by task kworker/u5:0/1202

CPU: 1 PID: 1202 Comm: kworker/u5:0 Not tainted 4.14.190-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

Workqueue: hci0 hci_rx_work

Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x1b2/0x283 lib/dump_stack.c:58
print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
kasan_report_error.cold+0x8a/0x194 mm/kasan/report.c:351
kasan_report+0x6f/0x7b mm/kasan/report.c:409
memcpy+0x20/0x50 mm/kasan/kasan.c:302
memcpy include/linux/string.h:372 [inline]
bacpy include/net/bluetooth/bluetooth.h:233 [inline]
hci_inquiry_result_with_rssi_evt+0x1df/0x640 net/bluetooth/hci_event.c:3629
hci_event_packet+0x19cd/0x7c7a net/bluetooth/hci_event.c:5364
hci_rx_work+0x3e6/0x970 net/bluetooth/hci_core.c:4244
process_one_work+0x793/0x14a0 kernel/workqueue.c:2116
worker_thread+0x5cc/0xff0 kernel/workqueue.c:2250
kthread+0x30d/0x420 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404

Allocated by task 6376:

save_stack mm/kasan/kasan.c:447 [inline]
set_track mm/kasan/kasan.c:459 [inline]
kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551
__do_kmalloc_node mm/slab.c:3682 [inline]
__kmalloc_node_track_caller+0x4c/0x70 mm/slab.c:3696
__kmalloc_reserve net/core/skbuff.c:137 [inline]
__alloc_skb+0x96/0x510 net/core/skbuff.c:205
alloc_skb include/linux/skbuff.h:980 [inline]
bt_skb_alloc include/net/bluetooth/bluetooth.h:336 [inline]
vhci_get_user drivers/bluetooth/hci_vhci.c:180 [inline]
vhci_write+0xb1/0x420 drivers/bluetooth/hci_vhci.c:299
call_write_iter include/linux/fs.h:1778 [inline]
new_sync_write fs/read_write.c:469 [inline]
__vfs_write+0x44c/0x630 fs/read_write.c:482
vfs_write+0x17f/0x4d0 fs/read_write.c:544
SYSC_write fs/read_write.c:590 [inline]
SyS_write+0xf2/0x210 fs/read_write.c:582
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 4435:

save_stack mm/kasan/kasan.c:447 [inline]
set_track mm/kasan/kasan.c:459 [inline]
kasan_slab_free+0xc3/0x1a0 mm/kasan/kasan.c:524
__cache_free mm/slab.c:3496 [inline]
kfree+0xc9/0x250 mm/slab.c:3815
kernfs_fop_release+0x10e/0x180 fs/kernfs/file.c:783
__fput+0x25f/0x7a0 fs/file_table.c:210
task_work_run+0x11f/0x190 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:191 [inline]
exit_to_usermode_loop+0x1ad/0x200 arch/x86/entry/common.c:164
prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
entry_SYSCALL_64_after_hwframe+0x46/0xbb

The buggy address belongs to the object at ffff88809fe1d300

which belongs to the cache kmalloc-512 of size 512
The buggy address is located 507 bytes inside of

512-byte region [ffff88809fe1d300, ffff88809fe1d500)

The buggy address belongs to the page:

page:ffffea00027f8740 count:1 mapcount:0 mapping:ffff88809fe1d080 index:0xffff88809fe1d080
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffff88809fe1d080 ffff88809fe1d080 0000000100000004
raw: ffffea00022e3120 ffffea000226efa0 ffff88812fe52940 0000000000000000

page dumped because: kasan: bad access detected

Memory state around the buggy address:

ffff88809fe1d400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88809fe1d480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88809fe1d500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff88809fe1d580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88809fe1d600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

[syzbot]

syzbot suspects this issue was fixed by commit:

commit 68bb9eddbf5da767131079325b2097341ab05dca
Author: Peilin Ye <yepei...@gmail.com>
Date: Fri Jul 10 21:45:26 2020 +0000

Bluetooth: Prevent out-of-bounds read in hci_inquiry_result_with_rssi_evt()

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=13d65b11900000
start commit: e5a54aa2 Linux 4.14.190
git tree: linux-4.14.y

kernel config: https://syzkaller.appspot.com/x/.config?x=dbb53fc7192d83c3
dashboard link: https://syzkaller.appspot.com/bug?extid=8761bb11d98585d2546c

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=168ebff4900000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13311ff4900000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: Bluetooth: Prevent out-of-bounds read in hci_inquiry_result_with_rssi_evt()

For information about bisection process see: https://goo.gl/tpsmEJ#bisection