ALSA: hda - Fix static checker warning in patch_hdmi.c

[ Upstream commit 360a8245 ]

The static checker warning is:

	sound/pci/hda/patch_hdmi.c:460 hdmi_eld_ctl_get()
	error: __memcpy() 'eld->eld_buffer' too small (256 vs 512)

I have a hard time figuring out if this can ever cause an information leak
(I don't think so), but nonetheless it does not hurt to increase the
robustness of the code.

Fixes: 68e03de9 ('ALSA: hda - hdmi: Do not expose eld data when eld is invalid')
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David Henningsson <david.henningsson@canonical.com>
Cc: <stable@vger.kernel.org> # v3.9+
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

sound/pci/hda/patch_hdmi.c

@@ -435,7 +435,8 @@ static int hdmi_eld_ctl_get(struct snd_kcontrol *kcontrol,
 	eld = &per_pin->sink_eld;
 
 	mutex_lock(&per_pin->lock);
-	if (eld->eld_size > ARRAY_SIZE(ucontrol->value.bytes.data)) {
+	if (eld->eld_size > ARRAY_SIZE(ucontrol->value.bytes.data) ||
+	    eld->eld_size > ELD_MAX_SIZE) {
 		mutex_unlock(&per_pin->lock);
 		snd_BUG();
 		return -EINVAL;