syzbot


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

Status: fixed on 2020/09/09 05:22
Reported-by: syzbot+5b7fc04f9e1c6b046b9f@syzkaller.appspotmail.com
Fix commit: 8c4a649c20fe Bluetooth: Fix slab-out-of-bounds read in hci_extended_inquiry_result_evt()
First crash: 1389d, last: 1355d
Fix bisection: fixed by (bisect log) :
commit 8c4a649c20fec015ebb326f36b47d4e39d9ff5b7
Author: Peilin Ye <yepeilin.cs@gmail.com>
Date: Fri Jul 10 16:09:15 2020 +0000

  Bluetooth: Fix slab-out-of-bounds read in hci_extended_inquiry_result_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_extended_inquiry_result_evt bluetooth C 16 1358d 1386d 15/26 fixed on 2020/09/16 22:51
linux-4.14 KASAN: slab-out-of-bounds Read in hci_extended_inquiry_result_evt C done 5 1355d 1360d 1/1 fixed on 2020/09/09 05:22

Sample crash report:
audit: type=1400 audit(1596410261.264:8): avc:  denied  { execmem } for  pid=6459 comm="syz-executor282" 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:373 [inline]
BUG: KASAN: slab-out-of-bounds in bacpy include/net/bluetooth/bluetooth.h:236 [inline]
BUG: KASAN: slab-out-of-bounds in hci_extended_inquiry_result_evt.isra.0+0x1aa/0x5b0 net/bluetooth/hci_event.c:4163
Read of size 6 at addr ffff8880a135a208 by task kworker/u5:0/1227

CPU: 0 PID: 1227 Comm: kworker/u5:0 Not tainted 4.19.136-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: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+0x8f/0x96 mm/kasan/report.c:412
 memcpy+0x20/0x50 mm/kasan/kasan.c:302
 memcpy include/linux/string.h:373 [inline]
 bacpy include/net/bluetooth/bluetooth.h:236 [inline]
 hci_extended_inquiry_result_evt.isra.0+0x1aa/0x5b0 net/bluetooth/hci_event.c:4163
 hci_event_packet+0x2025/0x858f net/bluetooth/hci_event.c:5845
 hci_rx_work+0x46b/0xa90 net/bluetooth/hci_core.c:4359
 process_one_work+0x864/0x1570 kernel/workqueue.c:2155
 worker_thread+0x64c/0x1130 kernel/workqueue.c:2298
 kthread+0x30b/0x410 kernel/kthread.c:246
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415

Allocated by task 6460:
 __do_kmalloc_node mm/slab.c:3689 [inline]
 __kmalloc_node_track_caller+0x4c/0x70 mm/slab.c:3703
 __kmalloc_reserve net/core/skbuff.c:137 [inline]
 __alloc_skb+0xae/0x560 net/core/skbuff.c:205
 alloc_skb include/linux/skbuff.h:995 [inline]
 bt_skb_alloc include/net/bluetooth/bluetooth.h:339 [inline]
 vhci_get_user drivers/bluetooth/hci_vhci.c:180 [inline]
 vhci_write+0xbd/0x450 drivers/bluetooth/hci_vhci.c:299
 call_write_iter include/linux/fs.h:1821 [inline]
 new_sync_write fs/read_write.c:474 [inline]
 __vfs_write+0x51b/0x770 fs/read_write.c:487
 vfs_write+0x1f3/0x540 fs/read_write.c:549
 ksys_write+0x12b/0x2a0 fs/read_write.c:599
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 4512:
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xcc/0x210 mm/slab.c:3822
 kernfs_fop_release+0x120/0x190 fs/kernfs/file.c:783
 __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 ffff8880a135a000
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 8 bytes to the right of
 512-byte region [ffff8880a135a000, ffff8880a135a200)
The buggy address belongs to the page:
page:ffffea000284d680 count:1 mapcount:0 mapping:ffff88812c39c940 index:0x0
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffffea000284cd08 ffffea0002825388 ffff88812c39c940
raw: 0000000000000000 ffff8880a135a000 0000000100000006 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a135a100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880a135a180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880a135a200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                      ^
 ffff8880a135a280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a135a300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/08/02 23:21 linux-4.19.y 13af6c74b14a 96dd3623 .config console log report syz C ci2-linux-4-19
2020/07/04 16:34 linux-4.19.y 399849e4654e 4f739670 .config console log report syz C ci2-linux-4-19
2020/08/07 18:26 linux-4.19.y 961f830af065 28ac5c9e .config console log report ci2-linux-4-19
2020/08/02 12:18 linux-4.19.y 13af6c74b14a 96dd3623 .config console log report ci2-linux-4-19
2020/08/02 11:19 linux-4.19.y 13af6c74b14a 96dd3623 .config console log report ci2-linux-4-19
2020/07/17 12:14 linux-4.19.y 17a87580a885 54b3c45e .config console log report ci2-linux-4-19
* Struck through repros no longer work on HEAD.