From: Takashi Iwai <tiwai@xxxxxxx> commit c6dde8ffd071aea9d1ce64279178e470977b235c upstream. The current channel-map control implementation in USB-audio driver may lead to an error message like "control 3:0:0:Playback Channel Map:0: access overflow" when CONFIG_SND_CTL_VALIDATION is set. It's because the chmap get callback clears the whole array no matter which count is set, and rather the false-positive detection. This patch fixes the problem by clearing only the needed array range at usb_chmap_ctl_get(). Cc: <stable@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20201211130048.6358-1-tiwai@xxxxxxx Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- sound/usb/stream.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/sound/usb/stream.c +++ b/sound/usb/stream.c @@ -198,16 +198,16 @@ static int usb_chmap_ctl_get(struct snd_ struct snd_pcm_chmap *info = snd_kcontrol_chip(kcontrol); struct snd_usb_substream *subs = info->private_data; struct snd_pcm_chmap_elem *chmap = NULL; - int i; + int i = 0; - memset(ucontrol->value.integer.value, 0, - sizeof(ucontrol->value.integer.value)); if (subs->cur_audiofmt) chmap = subs->cur_audiofmt->chmap; if (chmap) { for (i = 0; i < chmap->channels; i++) ucontrol->value.integer.value[i] = chmap->map[i]; } + for (; i < subs->channels_max; i++) + ucontrol->value.integer.value[i] = 0; return 0; }
