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

Status: fixed on 2020/09/16 13:17
Fix commit: 68bb9eddbf5d Bluetooth: Prevent out-of-bounds read in hci_inquiry_result_with_rssi_evt()
First crash: 912d, last: 895d

Fix bisection: fixed by (bisect log) :
commit 68bb9eddbf5da767131079325b2097341ab05dca
Author: Peilin Ye <>
Date: Fri Jul 10 21:45:26 2020 +0000

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

similar bugs (2):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-out-of-bounds Read in hci_inquiry_result_with_rssi_evt C error 9 910d 930d 17/24 fixed on 2020/09/16 22:51
linux-4.19 KASAN: slab-out-of-bounds Read in hci_inquiry_result_with_rssi_evt C done 4 905d 934d 1/1 fixed on 2020/09/09 05:22

Sample crash report:
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

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

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

Crashes (6):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets Title
ci2-linux-4-14 2020/07/31 14:15 linux-4.14.y e5a54aa2d312 8df85ed9 .config console log report syz C
ci2-linux-4-14 2020/08/17 10:07 linux-4.14.y 14b58326976d 5ce13532 .config console log report
ci2-linux-4-14 2020/08/08 01:32 linux-4.14.y 14b58326976d ff51e522 .config console log report
ci2-linux-4-14 2020/08/06 06:25 linux-4.14.y ca4f2c56d416 0487ea6f .config console log report
ci2-linux-4-14 2020/08/02 09:36 linux-4.14.y 7f2c5eb458b8 96dd3623 .config console log report
ci2-linux-4-14 2020/07/31 13:56 linux-4.14.y e5a54aa2d312 8df85ed9 .config console log report
* Struck through repros no longer work on HEAD.