syzbot


KASAN: slab-out-of-bounds Read in hci_event_packet
Status: fixed on 2020/09/17 01:43
Reported-by: syzbot+3068e9adbae6a7481631@syzkaller.appspotmail.com
Fix commit: 68bb9eddbf5d Bluetooth: Prevent out-of-bounds read in hci_inquiry_result_with_rssi_evt()
First crash: 1116d, last: 642d

Fix bisection: fixed by (bisect log) :
commit 68bb9eddbf5da767131079325b2097341ab05dca
Author: Peilin Ye <yepeilin.cs@gmail.com>
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
linux-4.19 KASAN: slab-out-of-bounds Read in hci_event_packet C done 15 649d 858d 1/1 fixed on 2020/09/11 09:49
upstream KASAN: slab-out-of-bounds Read in hci_event_packet C done error 67 597d 1230d 0/22 upstream: reported C repro on 2019/01/07 18:31

Sample crash report:
audit: type=1400 audit(1594324216.173:8): avc:  denied  { execmem } for  pid=6318 comm="syz-executor886" scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=process permissive=1
==================================================================
BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:347 [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 net/bluetooth/hci_event.c:3629 [inline]
BUG: KASAN: slab-out-of-bounds in hci_event_packet+0x6b22/0x7324 net/bluetooth/hci_event.c:5363
Read of size 6 at addr ffff888094fb727b by task kworker/u5:0/1190

CPU: 1 PID: 1190 Comm: kworker/u5:0 Not tainted 4.14.184-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+0x54/0x1dc mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report mm/kasan/report.c:409 [inline]
 kasan_report.cold+0xa9/0x2b9 mm/kasan/report.c:393
 memcpy include/linux/string.h:347 [inline]
 bacpy include/net/bluetooth/bluetooth.h:233 [inline]
 hci_inquiry_result_with_rssi_evt net/bluetooth/hci_event.c:3629 [inline]
 hci_event_packet+0x6b22/0x7324 net/bluetooth/hci_event.c:5363
 hci_rx_work+0x3da/0x950 net/bluetooth/hci_core.c:4244
 process_one_work+0x7c0/0x14c0 kernel/workqueue.c:2116
 worker_thread+0x5d7/0x1080 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 6327:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc.part.0+0x4f/0xd0 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.isra.0+0x35/0xd0 net/core/skbuff.c:137
 __alloc_skb+0xca/0x4c0 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+0x44e/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 4406:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xaf/0x190 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xcb/0x260 mm/slab.c:3815
 kernfs_fop_release+0x10d/0x180 fs/kernfs/file.c:783
 __fput+0x25f/0x7a0 fs/file_table.c:210
 task_work_run+0x113/0x190 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 ffff888094fb7080
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 507 bytes inside of
 512-byte region [ffff888094fb7080, ffff888094fb7280)
The buggy address belongs to the page:
page:ffffea000253edc0 count:1 mapcount:0 mapping:ffff888094fb7080 index:0xffff888094fb7d00
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffff888094fb7080 ffff888094fb7d00 0000000100000005
raw: ffffea000251eb20 ffffea00029253a0 ffff8880aa800940 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888094fb7180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888094fb7200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888094fb7280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                   ^
 ffff888094fb7300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888094fb7380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (17):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-14 2020/07/09 19:52 linux-4.14.y b850307b279c edf162e8 .config log report syz C
ci2-linux-4-14 2020/07/04 03:30 linux-4.14.y b850307b279c 51095195 .config log report syz C
ci2-linux-4-14 2020/03/28 17:28 linux-4.14.y 01364dad1d45 f1ebdfba .config log report syz C
ci2-linux-4-14 2020/01/01 21:23 linux-4.14.y 4c5bf01e16a7 25a0186e .config log report syz C
ci2-linux-4-14 2019/05/02 02:28 linux-4.14.y fa5941f45d7e 7516d9fa .config log report syz C
ci2-linux-4-14 2020/08/17 20:30 linux-4.14.y 14b58326976d 5ce13532 .config log report
ci2-linux-4-14 2020/08/11 05:04 linux-4.14.y 14b58326976d d3694ffb .config log report
ci2-linux-4-14 2020/08/09 21:38 linux-4.14.y 14b58326976d 70301872 .config log report
ci2-linux-4-14 2020/08/07 14:39 linux-4.14.y 14b58326976d 28ac5c9e .config log report
ci2-linux-4-14 2020/08/03 01:33 linux-4.14.y 7f2c5eb458b8 96dd3623 .config log report
ci2-linux-4-14 2020/08/02 08:58 linux-4.14.y 7f2c5eb458b8 96dd3623 .config log report
ci2-linux-4-14 2020/08/02 08:55 linux-4.14.y 7f2c5eb458b8 96dd3623 .config log report
ci2-linux-4-14 2020/06/10 17:16 linux-4.14.y c6db52a88798 5caaad3a .config log report
ci2-linux-4-14 2020/06/10 17:16 linux-4.14.y c6db52a88798 5caaad3a .config log report
ci2-linux-4-14 2020/06/10 14:34 linux-4.14.y c6db52a88798 5caaad3a .config log report
ci2-linux-4-14 2019/08/13 11:08 linux-4.14.y 3ffe1e79c174 8620c2c2 .config log report
ci2-linux-4-14 2019/05/02 02:06 linux-4.14.y fa5941f45d7e 7516d9fa .config log report