[PATCH AUTOSEL 5.4 03/27] ALSA: usb-audio: US16x08: Move overflow check before array access

Sasha Levin
2022-06-28T02:30:24Z

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 c6c834ac83ac..5e4aa1207c1b 100644
--- a/sound/usb/mixer_us16x08.c
+++ b/sound/usb/mixer_us16x08.c
@@ -637,10 +637,10 @@ 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