[Minor] Add safety checks when decoding CT attributes

src/libmime/content_type.c

@@ -228,9 +228,11 @@ rspamd_postprocess_ct_attributes (rspamd_mempool_t *pool,
 
 		gboolean invalid_utf = FALSE;
 
-		param->value.begin = rspamd_mime_header_decode (pool, param->value.begin,
-				param->value.len, &invalid_utf);
-		param->value.len = strlen (param->value.begin);
+		if (param->value.begin != NULL && param->value.len > 0) {
+			param->value.begin = rspamd_mime_header_decode(pool, param->value.begin,
+					param->value.len, &invalid_utf);
+			param->value.len = strlen(param->value.begin);
+		}
 
 		if (invalid_utf) {
 			param->flags |= RSPAMD_CONTENT_PARAM_BROKEN;

src/libmime/mime_headers.c

@@ -1911,6 +1911,10 @@ rspamd_message_set_modified_header (struct rspamd_task *task,
 
 					raw_value = ucl_object_tolstring (value, &raw_len);
 
+					if (raw_len == 0) {
+						continue;
+					}
+
 					struct rspamd_mime_header *nhdr = rspamd_mempool_alloc0 (
 							task->task_pool, sizeof (*nhdr));