Ensure that YAML path matches only scalar or list of scalars

Author: jan-cerny

src/OVAL/probes/independent/yamlfilecontent_probe.c

@@ -73,11 +73,42 @@ static int yaml_path_query(const char *filepath, const char *yaml_path_cstr, uns
 	yaml_event_t event;
 	bool done = false;
 
+	bool sequence = false;
 	do {
 		if (yaml_parser_parse(&parser, &event)) {
 			done = (event.type == YAML_STREAM_END_EVENT);
 			if (yaml_path_filter_event(yaml_path, &parser, &event,
 					YAML_PATH_FILTER_RETURN_ALL)) {
+
+				if (sequence) {
+					if (event.type == YAML_SEQUENCE_END_EVENT) {
+						sequence = false;
+					} else if (event.type != YAML_SCALAR_EVENT) {
+						SEXP_t *msg = probe_msg_creatf(OVAL_MESSAGE_LEVEL_ERROR,
+							"YAML path '%s' contains non-scalar in a sequence.",
+							yaml_path_cstr);
+						probe_cobj_add_msg(probe_ctx_getresult(ctx), msg);
+						SEXP_free(msg);
+						probe_cobj_set_flag(probe_ctx_getresult(ctx), SYSCHAR_FLAG_ERROR);
+						ret = -1;
+						goto cleanup;
+					}
+				} else {
+					if (event.type == YAML_SEQUENCE_START_EVENT) {
+						sequence = true;
+					}
+					if (event.type == YAML_MAPPING_START_EVENT) {
+						SEXP_t *msg = probe_msg_creatf(OVAL_MESSAGE_LEVEL_ERROR,
+							"YAML path '%s' matches a mapping.",
+							yaml_path_cstr);
+						probe_cobj_add_msg(probe_ctx_getresult(ctx), msg);
+						SEXP_free(msg);
+						probe_cobj_set_flag(probe_ctx_getresult(ctx), SYSCHAR_FLAG_ERROR);
+						ret = -1;
+						goto cleanup;
+					}
+				}
+
 				if (!yaml_emitter_emit(&emitter, &event)) {
 					SEXP_t *msg = probe_msg_creatf(OVAL_MESSAGE_LEVEL_ERROR,
 						"YAML emitter error: yaml_emitter_emit returned 0: %s",