Add fuzzing test for handling registration message

Registration message fuzzig test with random input.

Author: LukasWoodtli

fuzzing/CMakeLists.txt

@@ -5,3 +5,4 @@ project(fuzzing_tests C)
 include(Fuzzing.cmake)
 
 add_subdirectory(coap_parse_message)
+add_subdirectory(registration_handleRequest)

fuzzing/registration_handleRequest/CMakeLists.txt

@@ -0,0 +1,3 @@
+add_fuzzing_test(TARGET_NAME fuz_registration_handleRequest SOURCE_FILES fuz_registration_handleRequest.c)
+# workaround to be able to test private functions
+target_include_directories(fuz_registration_handleRequest PRIVATE ../../coap ../../core)

fuzzing/registration_handleRequest/fuz_registration_handleRequest.c

@@ -0,0 +1,90 @@
+/*******************************************************************************
+ *
+ * Copyright (c) 2023 GARDENA GmbH
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v2.0
+ * and Eclipse Distribution License v1.0 which accompany this distribution.
+ *
+ * The Eclipse Public License is available at
+ *    http://www.eclipse.org/legal/epl-v20.html
+ * The Eclipse Distribution License is available at
+ *    http://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * Contributors:
+ *   Lukas Woodtli, GARDENA GmbH - Please refer to git log
+ *
+ *******************************************************************************/
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <string.h>
+
+#include "liblwm2m.h"
+
+#include "er-coap-13/er-coap-13.h"
+#include "registration.h"
+
+// stub function
+void *lwm2m_connect_server(uint16_t secObjInstID, void *userData) {
+    (void)userData;
+    return (void *)(uintptr_t)secObjInstID;
+}
+
+void lwm2m_close_connection(void *sessionH, void *userData) {
+    (void)sessionH;
+    (void)userData;
+    return;
+}
+
+static void init_test_packet(coap_packet_t *message, const char *registration_message, uint8_t *payload,
+                             const size_t payload_len) {
+
+    memset(message, 0, sizeof(coap_packet_t));
+    message->code = COAP_POST;
+    coap_set_header_uri_query(message, "lwm2m=1.1&ep=abc");
+
+    memcpy(payload, registration_message, payload_len);
+    message->payload = payload;
+    message->payload_len = payload_len;
+
+    message->content_type = (coap_content_type_t)LWM2M_CONTENT_LINK;
+}
+
+void init_uri(lwm2m_uri_t *const uri) {
+    memset(uri, 0, sizeof(*uri));
+    uri->objectId = LWM2M_MAX_ID;
+}
+
+static int call_test_function(const char *reg_msg, const size_t reg_msg_len) {
+    int ret;
+
+    uint8_t user_data[1] = {0};
+    lwm2m_context_t *context = lwm2m_init(user_data);
+
+    lwm2m_uri_t uri;
+    init_uri(&uri);
+    coap_packet_t message;
+
+    uint8_t payload[reg_msg_len == 0 ? 1 : reg_msg_len];
+    init_test_packet(&message, reg_msg, payload, reg_msg_len);
+
+    coap_packet_t response;
+    memset(&response, 0, sizeof(coap_packet_t));
+
+    ret = registration_handleRequest(context, &uri, NULL, &message, &response);
+
+    free_multi_option(message.uri_query);
+    free_multi_option(response.location_path);
+
+    lwm2m_close(context);
+
+    return ret;
+}
+
+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+
+    call_test_function((const char *)data, size);
+
+    return 0;
+}