ALSA: usb-audio: Stop parsing channels bits when all channels are found.

[ Upstream commit a39d51ff1f ]

If a usb audio device sets more bits than the amount of channels
it could write outside of the map array.

Signed-off-by: Johan Carlsson <johan.carlsson@teenage.engineering>
Fixes: 04324ccc75 ("ALSA: usb-audio: add channel map support")
Message-ID: <20240313081509.9801-1-johan.carlsson@teenage.engineering>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Johan Carlsson 2024-03-13 09:15:09 +01:00 committed by Sasha Levin
parent de4bfe60b0
commit 22cad1b841
1 changed files with 4 additions and 1 deletions

View File

@ -300,9 +300,12 @@ static struct snd_pcm_chmap_elem *convert_chmap(int channels, unsigned int bits,
c = 0;
if (bits) {
for (; bits && *maps; maps++, bits >>= 1)
for (; bits && *maps; maps++, bits >>= 1) {
if (bits & 1)
chmap->map[c++] = *maps;
if (c == chmap->channels)
break;
}
} else {
/* If we're missing wChannelConfig, then guess something
to make sure the channel map is not skipped entirely */