Re: [PATCH v2 2/3] HID: logitech-hidpp: check WTP report length

[Benjamin Tissoires]

On Tue, Dec 16, 2014 at 10:55 AM, Peter Wu <peter@xxxxxxxxxxxxx> wrote:
> Malicious USB devices can send bogus reports smaller than the expected
> buffer size. Ensure that the length for WTP reports is valid to avoid
> reading out of bounds.
>
> Signed-off-by: Peter Wu <peter@xxxxxxxxxxxxx>
> ---
>  v1: patch 2/3 HID: logitech-{dj,hidpp}: check report length
>  v2: splitted original report length check patch
> ---

Reviewed-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>

Cheers,
Benjamin

>  drivers/hid/hid-logitech-hidpp.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
> index b32f751..2f1b0ac 100644
> --- a/drivers/hid/hid-logitech-hidpp.c
> +++ b/drivers/hid/hid-logitech-hidpp.c
> @@ -805,6 +805,11 @@ static int wtp_raw_event(struct hid_device *hdev, u8 *data, int size)
>
>         switch (data[0]) {
>         case 0x02:
> +               if (size < 2) {
> +                       hid_err(hdev, "Received HID report of bad size (%d)",
> +                               size);
> +                       return 1;
> +               }
>                 if (hidpp->quirks & HIDPP_QUIRK_WTP_PHYSICAL_BUTTONS) {
>                         input_event(wd->input, EV_KEY, BTN_LEFT,
>                                         !!(data[1] & 0x01));
> @@ -818,6 +823,7 @@ static int wtp_raw_event(struct hid_device *hdev, u8 *data, int size)
>                         return wtp_mouse_raw_xy_event(hidpp, &data[7]);
>                 }
>         case REPORT_ID_HIDPP_LONG:
> +               /* size is already checked in hidpp_raw_event. */
>                 if ((report->fap.feature_index != wd->mt_feature_index) ||
>                     (report->fap.funcindex_clientid != EVENT_TOUCHPAD_RAW_XY))
>                         return 1;
> --
> 2.1.3
>
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