diff --git a/drivers/char/diag/diag_masks.c b/drivers/char/diag/diag_masks.c
index bb28958412ed..438f33d8cadb 100644
--- a/drivers/char/diag/diag_masks.c
+++ b/drivers/char/diag/diag_masks.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2008-2018, The Linux Foundation. All rights reserved.
+/* Copyright (c) 2008-2019, The Linux Foundation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
@@ -705,7 +705,7 @@ static int diag_cmd_get_msg_mask(unsigned char *src_buf, int src_len,
 
 	mask_info = (!info) ? &msg_mask : info->msg_mask;
 	if (!src_buf || !dest_buf || src_len <= 0 || dest_len <= 0 ||
-	    !mask_info) {
+	    !mask_info || (src_len < sizeof(struct diag_build_mask_req_t))) {
 		pr_err("diag: Invalid input in %s, src_buf: %pK, src_len: %d, dest_buf: %pK, dest_len: %d, mask_info: %pK\n",
 		       __func__, src_buf, src_len, dest_buf, dest_len,
 		       mask_info);