Commit f658f17b authored Nov 21, 2017 by Takashi Iwai

ALSA: usb-audio: Fix potential out-of-bound access at parsing SU



The usb-audio driver may trigger an out-of-bound access at parsing a
malformed selector unit, as it checks the header length only after
evaluating bNrInPins field, which can be already above the given
length.  Fix it by adding the length check beforehand.

Fixes: 99fc8645 ("ALSA: usb-mixer: parse descriptors with structs")
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

parent d937cd67

sound/usb/mixer.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -2098,7 +2098,8 @@ static int parse_audio_selector_unit(struct mixer_build *state, int unitid,
		const struct usbmix_name_map *map;
		char **namelist;

		if (!desc->bNrInPins \|\| desc->bLength < 5 + desc->bNrInPins) {
		if (desc->bLength < 5 \|\| !desc->bNrInPins \|\|
		desc->bLength < 5 + desc->bNrInPins) {
		usb_audio_err(state->chip,
		"invalid SELECTOR UNIT descriptor %d\n", unitid);
		return -EINVAL;