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: stable@vger.kernel.org Signed-off-by: Takashi Iwai tiwai@suse.de --- 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 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;