Merge branch 'free'

Add functions for freeing memory of some C API results

Fixes #175

4 files changed, 86 insertions, 0 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1169e94..db8d2fb 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -216,6 +216,7 @@ IF (COMPILE_TESTS)
                 unittest/test_HOTP.cc
                 unittest/test1.cc
                 unittest/test_issues.cc
+		unittest/test_memory.c
                 unittest/test_multiple_devices.cc
                 unittest/test_strdup.cpp
                 unittest/test_safe.cpp
diff --git a/NK_C_API.cc b/NK_C_API.cc
index ddf7bef..3573404 100644
--- a/NK_C_API.cc
+++ b/NK_C_API.cc
@@ -229,6 +229,10 @@ extern "C" {
 		});
 	}
 
+        NK_C_API void NK_free_config(uint8_t* config) {
+                delete[] config;
+        }
+
 
 	NK_C_API enum NK_device_model NK_get_device_model() {
 		auto m = NitrokeyManager::instance();
@@ -460,6 +464,10 @@ extern "C" {
 
 	}
 
+        NK_C_API void NK_free_password_safe_slot_status(uint8_t* status) {
+                delete[] status;
+        }
+
 	NK_C_API uint8_t NK_get_user_retry_count() {
 		auto m = NitrokeyManager::instance();
 		return get_with_result([&]() {
diff --git a/NK_C_API.h b/NK_C_API.h
index fe4cdd0..376241e 100644
--- a/NK_C_API.h
+++ b/NK_C_API.h
@@ -466,6 +466,7 @@ extern "C" {
 
 	/**
 	 * Get currently set config - status of function Numlock/Capslock/Scrollock OTP sending and is enabled PIN protected OTP
+         * The return value must be freed using NK_free_config.
 	 * @see NK_write_config
 	 * @return  uint8_t general_config[5]:
 	 *            uint8_t numlock;
@@ -477,6 +478,12 @@ extern "C" {
 	 */
 	NK_C_API uint8_t* NK_read_config();
 
+        /**
+         * Free a value returned by NK_read_config.  May be called with a NULL
+         * argument.
+         */
+        NK_C_API void NK_free_config(uint8_t* config);
+
 	//OTP
 
 	/**
@@ -649,10 +656,17 @@ extern "C" {
 
 	/**
 	 * Get password safe slots' status
+         * The return value must be freed using NK_free_password_safe_slot_status.
 	 * @return uint8_t[16] slot statuses - each byte represents one slot with 0 (not programmed) and 1 (programmed)
 	 */
 	NK_C_API uint8_t * NK_get_password_safe_slot_status();
 
+        /**
+         * Free a value returned by NK_get_password_safe_slot_status.  May be
+         * called with a NULL argument.
+         */
+        NK_C_API void NK_free_password_safe_slot_status(uint8_t* status);
+
 	/**
 	 * Get password safe slot name
 	 * @param slot_number password safe slot number, slot_number<16
diff --git a/unittest/test_memory.c b/unittest/test_memory.c
new file mode 100644
index 0000000..20b11b2
--- /dev/null
+++ b/unittest/test_memory.c
@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2020 Nitrokey UG
+ *
+ * This file is part of libnitrokey.
+ *
+ * libnitrokey is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * any later version.
+ *
+ * libnitrokey is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with libnitrokey. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * SPDX-License-Identifier: LGPL-3.0
+ */
+
+#include <stdlib.h>
+#include "../NK_C_API.h"
+
+// This test should be run with valgrind to make sure that there are no
+// memory leaks in the tested functions:
+//     valgrind ./test_memory
+int main() {
+	int result = NK_login_auto();
+	if (result != 1)
+		return 1;
+  
+	int retry_count = NK_get_admin_retry_count();
+	if (retry_count != 3)
+		return 1;
+	retry_count = NK_get_user_retry_count();
+	if (retry_count != 3)
+		return 1;
+
+	enum NK_device_model model = NK_get_device_model();
+	if (model != NK_PRO && model != NK_STORAGE)
+		return 1;
+
+	uint8_t *config = NK_read_config();
+	if (config == NULL)
+		return 1;
+	NK_free_config(config);
+
+	result = NK_enable_password_safe("123456");
+	if (result != 0)
+		return 1;
+
+	uint8_t *slot_status = NK_get_password_safe_slot_status();
+	if (slot_status == NULL) {
+		return 1;
+	}
+	NK_free_password_safe_slot_status(slot_status);
+
+	NK_logout();
+
+	return 0;
+}
+