[PATCH AUTOSEL 4.19 03/22] ALSA: usb-audio: US16x08: Move overflow check before array access

[Sasha Levin <sashal@kernel.org>]

From: Daniil Dementev <d.dementev@ispras.ru>

[ Upstream commit 3ddbe35d9a2ebd4924d458e0246b4ba6c13bb456 ]

Buffer overflow could occur in the loop "while", due to accessing an
array element before checking the index.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Daniil Dementev <d.dementev@ispras.ru>
Reviewed-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Link: https://lore.kernel.org/r/20220610165732.2904-1-d.dementev@ispras.ru
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 sound/usb/mixer_us16x08.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/sound/usb/mixer_us16x08.c b/sound/usb/mixer_us16x08.c
index 7db3032e723a..5e3b7fd43fc2 100644
--- a/sound/usb/mixer_us16x08.c
+++ b/sound/usb/mixer_us16x08.c
@@ -647,10 +647,10 @@ static int snd_get_meter_comp_index(struct snd_us16x08_meter_store *store)
 		}
 	} else {
 		/* skip channels with no compressor active */
-		while (!store->comp_store->val[
+		while (store->comp_index <= SND_US16X08_MAX_CHANNELS
+			&& !store->comp_store->val[
 			COMP_STORE_IDX(SND_US16X08_ID_COMP_SWITCH)]
-			[store->comp_index - 1]
-			&& store->comp_index <= SND_US16X08_MAX_CHANNELS) {
+			[store->comp_index - 1]) {
 			store->comp_index++;
 		}
 		ret = store->comp_index++;
-- 
2.35.1