On Wed, Oct 11, 2017 at 04:40:36PM +0200, Takashi Iwai wrote:
> On Wed, 11 Oct 2017 16:20:31 +0200,
> Johan Hovold wrote:
> > Unrelated to this patch, but this driver fails to kill the ep1_in_urb
> > (which is submitted in this function) in case of later probe errors.
> > This can lead to use-after-free or crashes in the completion callback.
>
> Yes, a good catch. Below is the fix patch.
> -- 8< --
> From: Takashi Iwai <ti...@suse.de>
> Subject: [PATCH] ALSA: caiaq: Fix stray URB at probe error path
>
> caiaq driver doesn't kill the URB properly at its error path during
> the probe, which may lead to a use-after-free error later. This patch
> addresses it.
>
> Reported-by: Johan Hovold <jo...@kernel.org>
> Signed-off-by: Takashi Iwai <ti...@suse.de>
Looks good to me:
Reviewed-by: Johan Hovold <jo...@kernel.org>
> ---
> sound/usb/caiaq/device.c | 12 +++++++++---
> 1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/sound/usb/caiaq/device.c b/sound/usb/caiaq/device.c
> index a29674bf96e5..d55ca48de3ea 100644
> --- a/sound/usb/caiaq/device.c
> +++ b/sound/usb/caiaq/device.c
> @@ -476,10 +476,12 @@ static int init_card(struct snd_usb_caiaqdev *cdev)
>
> err = snd_usb_caiaq_send_command(cdev, EP1_CMD_GET_DEVICE_INFO, NULL,
> 0);
> if (err)
> - return err;
> + goto err_kill_urb;
>
> - if (!wait_event_timeout(cdev->ep1_wait_queue, cdev->spec_received, HZ))
> - return -ENODEV;
> + if (!wait_event_timeout(cdev->ep1_wait_queue, cdev->spec_received, HZ))
> {
> + err = -ENODEV;
> + goto err_kill_urb;
> + }
>
> usb_string(usb_dev, usb_dev->descriptor.iManufacturer,
> cdev->vendor_name, CAIAQ_USB_STR_LEN);
> @@ -514,6 +516,10 @@ static int init_card(struct snd_usb_caiaqdev *cdev)
>
> setup_card(cdev);
> return 0;
> +
> + err_kill_urb:
> + usb_kill_urb(&cdev->ep1_in_urb);
> + return err;
> }
>
> static int snd_probe(struct usb_interface *intf,
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