Re: KASAN: use-after-free Read in h5_rx_3wire_hdr

[Marcel Holtmann]

Hi Dmitry,

>>>> syzbot found the following crash on:
>>>> 
>>>> HEAD commit:    6d21a41b Add linux-next specific files for 20190718
>>>> git tree:       linux-next
>>>> console output: https://syzkaller.appspot.com/x/log.txt?x=1377958fa00000
>>>> kernel config:  https://syzkaller.appspot.com/x/.config?x=3430a151e1452331
>>>> dashboard link: https://syzkaller.appspot.com/bug?extid=0abbda0523882250a97a
>>>> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
>>>> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=113e2bb7a00000
>>> 
>>> +drivers/bluetooth/hci_h5.c maintainers
>>> 
>>>> IMPORTANT: if you fix the bug, please add the following tag to the commit:
>>>> Reported-by: syzbot+0abbda0523882250a97a@xxxxxxxxxxxxxxxxxxxxxxxxx
>>>> 
>>>> ==================================================================
>>>> BUG: KASAN: use-after-free in h5_rx_3wire_hdr+0x35d/0x3c0
>>>> /drivers/bluetooth/hci_h5.c:438
>>>> Read of size 1 at addr ffff8880a161d1c8 by task syz-executor.4/12040
>>>> 
>>>> CPU: 1 PID: 12040 Comm: syz-executor.4 Not tainted 5.2.0-next-20190718 #41
>>>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
>>>> Google 01/01/2011
>>>> Call Trace:
>>>> __dump_stack /lib/dump_stack.c:77 [inline]
>>>> dump_stack+0x172/0x1f0 /lib/dump_stack.c:113
>>>> print_address_description.cold+0xd4/0x306 /mm/kasan/report.c:351
>>>> __kasan_report.cold+0x1b/0x36 /mm/kasan/report.c:482
>>>> kasan_report+0x12/0x17 /mm/kasan/common.c:612
>>>> __asan_report_load1_noabort+0x14/0x20 /mm/kasan/generic_report.c:129
>>>> h5_rx_3wire_hdr+0x35d/0x3c0 /drivers/bluetooth/hci_h5.c:438
>>>> h5_recv+0x32f/0x500 /drivers/bluetooth/hci_h5.c:563
>>>> hci_uart_tty_receive+0x279/0x790 /drivers/bluetooth/hci_ldisc.c:600
>>>> tiocsti /drivers/tty/tty_io.c:2197 [inline]
>>>> tty_ioctl+0x949/0x14f0 /drivers/tty/tty_io.c:2573
>>>> vfs_ioctl /fs/ioctl.c:46 [inline]
>>>> file_ioctl /fs/ioctl.c:509 [inline]
>>>> do_vfs_ioctl+0xdb6/0x13e0 /fs/ioctl.c:696
>>>> ksys_ioctl+0xab/0xd0 /fs/ioctl.c:713
>>>> __do_sys_ioctl /fs/ioctl.c:720 [inline]
>>>> __se_sys_ioctl /fs/ioctl.c:718 [inline]
>>>> __x64_sys_ioctl+0x73/0xb0 /fs/ioctl.c:718
>>>> do_syscall_64+0xfd/0x6a0 /arch/x86/entry/common.c:296
>>>> entry_SYSCALL_64_after_hwframe+0x49/0xbe
>>>> RIP: 0033:0x459819
>>>> Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7
>>>> 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff
>>>> ff 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
>>>> RSP: 002b:00007f7a3b459c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
>>>> RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459819
>>>> RDX: 0000000020000080 RSI: 0000000000005412 RDI: 0000000000000003
>>>> RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
>>>> R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7a3b45a6d4
>>>> R13: 00000000004c408a R14: 00000000004d7ff0 R15: 00000000ffffffff
>> 
>> Is this happening on specific hardware?
> 
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS

funny ;)

I meant the Bluetooth chip on this machine.

Regards

Marcel