From 23353220b53f7b1cd700842d54d01784c58a5438 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Tue, 21 Nov 2017 17:00:32 +0100 Subject: [PATCH] ALSA: usb-audio: Fix potential out-of-bound access at parsing SU commit f658f17b5e0e339935dca23e77e0f3cad591926b upstream. 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: 99fc86450c43 ("ALSA: usb-mixer: parse descriptors with structs") Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/usb/mixer.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c index a6921d8b19a3..9133d3e53d9d 100644 --- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -2092,7 +2092,8 @@ 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;