| From c6dde8ffd071aea9d1ce64279178e470977b235c Mon Sep 17 00:00:00 2001 |
| From: Takashi Iwai <tiwai@suse.de> |
| Date: Fri, 11 Dec 2020 14:00:48 +0100 |
| Subject: ALSA: usb-audio: Fix control 'access overflow' errors from chmap |
| |
| From: Takashi Iwai <tiwai@suse.de> |
| |
| 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@vger.kernel.org> |
| Link: https://lore.kernel.org/r/20201211130048.6358-1-tiwai@suse.de |
| Signed-off-by: Takashi Iwai <tiwai@suse.de> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| 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; |
| } |
| |
