From f658f17b5e0e339935dca23e77e0f3cad591926b Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Tue, 21 Nov 2017 17:00:32 +0100 Subject: 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: 99fc86450c43 ("ALSA: usb-mixer: parse descriptors with structs") Cc: Signed-off-by: Takashi Iwai --- sound/usb/mixer.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'sound') diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c index b8ce651e392c..61b348383de8 100644 --- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -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; -- cgit