Add programs/test/zeroize.c to test mbedtls_zeroize
The idea is to use the simple program that is expected to be modified
rarely to set a breakpoint in a specific line and check that the
function mbedtls_zeroize() does actually set the buffer to 0 and is not
optimised out by the compiler.
diff --git a/programs/test/zeroize.c b/programs/test/zeroize.c
new file mode 100644
index 0000000..7f3e8b4
--- /dev/null
+++ b/programs/test/zeroize.c
@@ -0,0 +1,91 @@
+/*
+ * Zeroize demonstration program
+ *
+ * Copyright (C) 2017, ARM Limited, All Rights Reserved
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * This file is part of mbed TLS (https://tls.mbed.org)
+ */
+
+#if !defined(MBEDTLS_CONFIG_FILE)
+#include "mbedtls/config.h"
+#else
+#include MBEDTLS_CONFIG_FILE
+#endif
+
+#include <stdio.h>
+
+#if defined(MBEDTLS_PLATFORM_C)
+#include "mbedtls/platform.h"
+#else
+#include <stdlib.h>
+#define mbedtls_printf printf
+#define MBEDTLS_EXIT_SUCCESS EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE EXIT_FAILURE
+#endif
+
+#include "mbedtls/utils.h"
+
+#define BUFFER_LEN 1024
+
+void usage( void )
+{
+ mbedtls_printf( "Zeroize is a simple program to assist with testing\n" );
+ mbedtls_printf( "the mbedtls_zeroize() function by using the\n" );
+ mbedtls_printf( "debugger. This program takes a file as input and\n" );
+ mbedtls_printf( "prints the first %d characters. Usage:\n\n", BUFFER_LEN );
+ mbedtls_printf( " zeroize <FILE>\n" );
+}
+
+int main( int argc, char** argv )
+{
+ int exit_code = MBEDTLS_EXIT_FAILURE;
+ FILE * fp;
+ char buf[BUFFER_LEN];
+ char *p = buf;
+ char *end = p + BUFFER_LEN;
+ char c;
+
+ if( argc != 2 )
+ {
+ mbedtls_printf( "This program takes exactly 1 agument\n" );
+ usage();
+ return( exit_code );
+ }
+
+ fp = fopen( argv[1], "r" );
+ if( fp == NULL )
+ {
+ mbedtls_printf( "Could not open file '%s'\n", argv[1] );
+ return( exit_code );
+ }
+
+ while( ( c = fgetc( fp ) ) != EOF && p < end - 1 )
+ *p++ = c;
+ *p = '\0';
+
+ if( p - buf != 0 )
+ {
+ mbedtls_printf( "%s\n", buf );
+ mbedtls_zeroize( buf, sizeof( buf ) );
+ exit_code = MBEDTLS_EXIT_SUCCESS;
+ }
+ else
+ mbedtls_printf( "The file is empty!\n" );
+
+ fclose( fp );
+
+ return( exit_code );
+}