ALSA: usb-audio: Fix potential zero-division at parsing FU

parse_audio_feature_unit() contains a code dividing potentially with zero when a malformed FU descriptor is passed. Although there is already a sanity check, it checks only the value zero, hence it can still lead to a zero-division when a value 1 is passed there. Fix it by correcting the sanity check (and the error message thereof). Fixes: 23caaf1 ("ALSA: usb-mixer: Add support for Audio Class v2.0") Cc: <[email protected]> Signed-off-by: Takashi Iwai <[email protected]>
josf · Nov 21, 2017 · 8428a8e · 8428a8e
1 parent f658f17
commit 8428a8e
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
@@ -1476,9 +1476,9 @@ static int parse_audio_feature_unit(struct mixer_build *state, int unitid,
 			return -EINVAL;
 		}
 		csize = hdr->bControlSize;
-		if (!csize) {
+		if (csize <= 1) {
 			usb_audio_dbg(state->chip,
-				      "unit %u: invalid bControlSize == 0\n",
+				      "unit %u: invalid bControlSize <= 1\n",
 				      unitid);
 			return -EINVAL;
 		}