From: Johan Carlsson Date: Wed, 13 Mar 2024 08:15:09 +0000 (+0100) Subject: ALSA: usb-audio: Stop parsing channels bits when all channels are found. X-Git-Tag: v4.19.311~21 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7e2c1b0f6dd9abde9e60f0f9730026714468770f;p=thirdparty%2Fkernel%2Fstable.git 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 Fixes: 04324ccc75f9 ("ALSA: usb-audio: add channel map support") Message-ID: <20240313081509.9801-1-johan.carlsson@teenage.engineering> Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin --- 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 */