From: Hui Peng benquike@gmail.com
commit daac07156b330b18eb5071aec4b3ddca1c377f2c upstream.
The `uac_mixer_unit_descriptor` shown as below is read from the device side. In `parse_audio_mixer_unit`, `baSourceID` field is accessed from index 0 to `bNrInPins` - 1, the current implementation assumes that descriptor is always valid (the length of descriptor is no shorter than 5 + `bNrInPins`). If a descriptor read from the device side is invalid, it may trigger out-of-bound memory access.
``` struct uac_mixer_unit_descriptor { __u8 bLength; __u8 bDescriptorType; __u8 bDescriptorSubtype; __u8 bUnitID; __u8 bNrInPins; __u8 baSourceID[]; } ```
This patch fixes the bug by add a sanity check on the length of the descriptor.
Reported-by: Hui Peng benquike@gmail.com Reported-by: Mathias Payer mathias.payer@nebelwelt.net Cc: stable@vger.kernel.org Signed-off-by: Hui Peng benquike@gmail.com Signed-off-by: Takashi Iwai tiwai@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- sound/usb/mixer.c | 1 + 1 file changed, 1 insertion(+)
--- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -1713,6 +1713,7 @@ static int parse_audio_mixer_unit(struct int pin, ich, err;
if (desc->bLength < 11 || !(input_pins = desc->bNrInPins) || + desc->bLength < sizeof(*desc) + desc->bNrInPins || !(num_outs = uac_mixer_unit_bNrChannels(desc))) { usb_audio_err(state->chip, "invalid MIXER UNIT descriptor %d\n",