From: Johan Carlsson johan.carlsson@teenage.engineering
[ Upstream commit a39d51ff1f52cd0b6fe7d379ac93bd8b4237d1b7 ]
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: 04324ccc75f9 ("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 --- sound/usb/stream.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/sound/usb/stream.c b/sound/usb/stream.c index c4f4585f9b851..f51e901a9689e 100644 --- a/sound/usb/stream.c +++ b/sound/usb/stream.c @@ -301,9 +301,12 @@ 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 */