From patchwork series 498359

https://patchwork.ozlabs.org//project/linuxppc-dev/list/?series=498359

Author: Fox Snowpatch

arch/powerpc/kernel/rtas_flash.c

@@ -455,8 +455,10 @@ static int get_validate_flash_msg(struct rtas_validate_flash_t *args_buf,
 		n = sprintf(msg, "%d\n", args_buf->update_results);
 		if ((args_buf->update_results >= VALIDATE_CUR_UNKNOWN) ||
 		    (args_buf->update_results == VALIDATE_TMP_UPDATE))
-			n += snprintf(msg + n, msglen - n, "%s\n",
-					args_buf->buf);
+			n += snprintf(msg + n, msglen - n, "%.*s\n",
+				      (int)strnlen(args_buf->buf,
+						   args_buf->buf_size),
+				      args_buf->buf);
 	} else {
 		n = sprintf(msg, "%d\n", args_buf->status);
 	}