This is a note to let you know that I've just added the patch titled
ALSA: usb-audio: Stop parsing channels bits when all channels are found.
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
alsa-usb-audio-stop-parsing-channels-bits-when-all-c.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 942effbe5d532a67a8271171c5ca85faf2a09e5b
Author: Johan Carlsson <johan.carlsson@teenage.engineering>
Date: Wed Mar 13 09:15:09 2024 +0100
ALSA: usb-audio: Stop parsing channels bits when all channels are found.
[ 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@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/sound/usb/stream.c b/sound/usb/stream.c
index 1cfb30465df7d..3f20438a1b56e 100644
--- a/sound/usb/stream.c
+++ b/sound/usb/stream.c
@@ -306,9 +306,12 @@ 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 */
