syzbot


KASAN: slab-out-of-bounds Read in hci_extended_inquiry_result_evt
Status: fixed on 2020/09/16 22:51
Reported-by: syzbot+d8489a79b781849b9c46@syzkaller.appspotmail.com
Fix commit: 51c19bf3d5cf Bluetooth: Fix slab-out-of-bounds read in hci_extended_inquiry_result_evt()
First crash: 692d, last: 661d
duplicates (1):
Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
KMSAN: uninit-value in hci_event_packet C 40 650d 1139d 0/22 closed as dup on 2020/07/24 21:34
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_extended_inquiry_result_evt C done 6 657d 691d 1/1 fixed on 2020/09/09 05:22
linux-4.14 KASAN: slab-out-of-bounds Read in hci_extended_inquiry_result_evt C done 5 657d 663d 1/1 fixed on 2020/09/09 05:22

Sample crash report:
==================================================================
BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:406 [inline]
BUG: KASAN: slab-out-of-bounds in bacpy include/net/bluetooth/bluetooth.h:274 [inline]
BUG: KASAN: slab-out-of-bounds in hci_extended_inquiry_result_evt.isra.0+0x1be/0x5e0 net/bluetooth/hci_event.c:4397
Read of size 6 at addr ffff8880a62b2208 by task kworker/u5:0/1531

CPU: 1 PID: 1531 Comm: kworker/u5:0 Not tainted 5.8.0-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+0x18f/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x436 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 check_memory_region_inline mm/kasan/generic.c:186 [inline]
 check_memory_region+0x13d/0x180 mm/kasan/generic.c:192
 memcpy+0x20/0x60 mm/kasan/common.c:105
 memcpy include/linux/string.h:406 [inline]
 bacpy include/net/bluetooth/bluetooth.h:274 [inline]
 hci_extended_inquiry_result_evt.isra.0+0x1be/0x5e0 net/bluetooth/hci_event.c:4397
 hci_event_packet+0x2828/0x86f5 net/bluetooth/hci_event.c:6127
 hci_rx_work+0x22e/0xb10 net/bluetooth/hci_core.c:4705
 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

Allocated by task 6831:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:494
 __kmalloc_reserve net/core/skbuff.c:142 [inline]
 __alloc_skb+0xae/0x550 net/core/skbuff.c:210
 alloc_skb include/linux/skbuff.h:1083 [inline]
 bt_skb_alloc include/net/bluetooth/bluetooth.h:377 [inline]
 vhci_get_user drivers/bluetooth/hci_vhci.c:165 [inline]
 vhci_write+0xbd/0x450 drivers/bluetooth/hci_vhci.c:285
 call_write_iter include/linux/fs.h:1909 [inline]
 new_sync_write+0x422/0x650 fs/read_write.c:503
 vfs_write+0x59d/0x6b0 fs/read_write.c:578
 ksys_write+0x12d/0x250 fs/read_write.c:631
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 6653:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0xf5/0x140 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x103/0x2c0 mm/slab.c:3757
 load_elf_binary+0x356b/0x4831 fs/binfmt_elf.c:1207
 search_binary_handler fs/exec.c:1749 [inline]
 exec_binprm fs/exec.c:1790 [inline]
 __do_execve_file+0x1652/0x2ee0 fs/exec.c:1926
 do_execveat_common fs/exec.c:1980 [inline]
 do_execve+0x35/0x50 fs/exec.c:1997
 __do_sys_execve fs/exec.c:2073 [inline]
 __se_sys_execve fs/exec.c:2068 [inline]
 __x64_sys_execve+0x7c/0xa0 fs/exec.c:2068
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff8880a62b2000
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 8 bytes to the right of
 512-byte region [ffff8880a62b2000, ffff8880a62b2200)
The buggy address belongs to the page:
page:ffffea000298ac80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea0002735e48 ffffea00025e3f88 ffff8880aa000a80
raw: 0000000000000000 ffff8880a62b2000 0000000100000004 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a62b2100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880a62b2180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880a62b2200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                      ^
 ffff8880a62b2280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a62b2300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (16):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-root 2020/08/04 13:23 upstream 3208167a865e 196277c4 .config log report syz C
ci-upstream-kasan-gce-selinux-root 2020/08/02 21:47 upstream ac3a0c847296 63a73341 .config log report syz C
ci-upstream-kasan-gce-root 2020/07/04 14:51 upstream 7cc2a8ea1048 51095195 .config log report syz C
ci-upstream-kasan-gce-selinux-root 2020/07/04 13:08 upstream 7cc2a8ea1048 51095195 .config log report syz C
ci-upstream-kasan-gce 2020/07/04 01:55 upstream 7cc2a8ea1048 51095195 .config log report syz C
ci-upstream-kasan-gce-386 2020/07/04 11:09 upstream 7cc2a8ea1048 51095195 .config log report syz C
ci-upstream-linux-next-kasan-gce-root 2020/07/04 07:39 linux-next 9e50b94b3eb0 51095195 .config log report syz C
ci-upstream-kasan-gce-root 2020/08/02 12:17 upstream ac3a0c847296 63a73341 .config log report
ci-upstream-kasan-gce-selinux-root 2020/08/02 12:15 upstream ac3a0c847296 63a73341 .config log report
ci-upstream-kasan-gce-root 2020/08/02 11:20 upstream ac3a0c847296 63a73341 .config log report
ci-upstream-kasan-gce-selinux-root 2020/08/02 11:15 upstream ac3a0c847296 63a73341 .config log report
ci-upstream-kasan-gce 2020/07/21 09:43 upstream 4fa640dc5230 d88894e6 .config log report
ci-upstream-kasan-gce 2020/07/17 12:22 upstream f8456690ba8e 54b3c45e .config log report
ci-upstream-kasan-gce-selinux-root 2020/07/17 12:18 upstream f8456690ba8e 54b3c45e .config log report
ci-qemu-upstream 2020/07/17 12:17 upstream 07a56bb875af 54b3c45e .config log report
ci-upstream-kasan-gce 2020/07/04 01:36 upstream 7cc2a8ea1048 51095195 .config log report