On 22/01/2024 12:22, Mingxuan Xiang wrote:
> If the user yanks out the cable before closing the file,
> dev->udev would be set to NULL therefore causing a null-ptr-deref
> in hackrf_ctrl_msg issued by hackrf_stop_streaming.
>
> This patch adds a check in hackrf_ctrl_msg before using
> dev->udev.
>
> Found by modified syzkaller.
>
> BUG: KASAN: null-ptr-deref in hackrf_ctrl_msg+0x6d/0x180 drivers/media/usb/hackrf/hackrf.c:195
> Read of size 4 at addr 0000000000000000 by task syz-executor/579
> Call Trace:
> <TASK>
> __dump_stack lib/dump_stack.c:88 [inline]
> dump_stack_lvl+0x5e/0x7c lib/dump_stack.c:106
> print_report.cold+0x49a/0x6bb mm/kasan/report.c:436
> kasan_report+0xa8/0x130 mm/kasan/report.c:495
> hackrf_ctrl_msg+0x6d/0x180 drivers/media/usb/hackrf/hackrf.c:195
> hackrf_stop_streaming+0x45/0x140 drivers/media/usb/hackrf/hackrf.c:869
> __vb2_queue_cancel+0x5c/0x550 drivers/media/common/videobuf2/videobuf2-core.c:1992
> vb2_core_streamoff+0x2f/0xb0 drivers/media/common/videobuf2/videobuf2-core.c:2149
> __vb2_cleanup_fileio+0x3e/0xa0 drivers/media/common/videobuf2/videobuf2-core.c:2710
> vb2_core_queue_release+0x1a/0x50 drivers/media/common/videobuf2/videobuf2-core.c:2430
> vb2_queue_release drivers/media/common/videobuf2/videobuf2-v4l2.c:947 [inline]
> _vb2_fop_release+0x110/0x140 drivers/media/common/videobuf2/videobuf2-v4l2.c:1132
> v4l2_release+0x1b9/0x1e0 drivers/media/v4l2-core/v4l2-dev.c:459
> __fput+0x12d/0x4b0 fs/file_table.c:320
> task_work_run+0xa8/0xf0 kernel/task_work.c:177
> resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
> exit_to_user_mode_loop kernel/entry/common.c:169 [inline]
> exit_to_user_mode_prepare+0x123/0x130 kernel/entry/common.c:201
> __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
> syscall_exit_to_user_mode+0x22/0x50 kernel/entry/common.c:294
> do_syscall_64+0x48/0x90 arch/x86/entry/common.c:86
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
>
> Signed-off-by: Mingxuan Xiang <mx_xiang@xxxxxxxxxxx>
> ---
> drivers/media/usb/hackrf/hackrf.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/media/usb/hackrf/hackrf.c b/drivers/media/usb/hackrf/hackrf.c
> index 9c0ecd5f056c..9588b8aa6e98 100644
> --- a/drivers/media/usb/hackrf/hackrf.c
> +++ b/drivers/media/usb/hackrf/hackrf.c
> @@ -186,6 +186,11 @@ static int hackrf_ctrl_msg(struct hackrf_dev *dev, u8 request, u16 value,
> unsigned int pipe;
> u8 requesttype;
>
> + if (!dev->udev) {
> + pr_err("udev is null in %s\n", __func__);
> + ret = -EINVAL;
> + goto err;
> + }
Just replace this with:
if (!dev->udev)
return -ENODEV;
-ENODEV is the correct error code for this situation, and the error
message is overkill here, I think.
Regards,
Hans
> switch (request) {
> case CMD_SET_TRANSCEIVER_MODE:
> case CMD_SET_FREQ:
