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Commit 7e2c1b0f authored by Johan Carlsson's avatar Johan Carlsson Committed by Sasha Levin
Browse files

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: default avatarJohan Carlsson <johan.carlsson@teenage.engineering>
Fixes: 04324ccc ("ALSA: usb-audio: add channel map support")
Message-ID: <20240313081509.9801-1-johan.carlsson@teenage.engineering>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 6bf3c350

sound/usb/stream.c

+4 −1
Original line number Diff line number Diff line
@@ -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 */