asoc: check payload length against structure size

Payload length must exceed structure size. Otherwise, it may
lead to out-of-boundary memory access.

Change-Id: I090de5116ab04a4ca2b9c485e17617fe9e861ad5
Signed-off-by: Xiaojun Sang <[email protected]>

asoc/msm-qti-pp-config.c

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0-only
-/* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved.
+/* Copyright (c) 2012-2019, The Linux Foundation. All rights reserved.
  */
 
 #include <linux/err.h>
@@ -1172,6 +1172,13 @@ int msm_adsp_inform_mixer_ctl(struct snd_soc_pcm_runtime *rtd,
 	}
 
 	event_data = (struct msm_adsp_event_data *)payload;
+	if (event_data->payload_len < sizeof(struct msm_adsp_event_data)) {
+		pr_err("%s: event_data size of %x is less than expected.\n",
+			__func__, event_data->payload_len);
+		ret = -EINVAL;
+		goto done;
+	}
+
 	kctl->info(kctl, &kctl_info);
 
 	if (event_data->payload_len >