1 /*
2 * Zeroize application for debugger-driven testing
3 *
4 * This is a simple test application used for debugger-driven testing to check
5 * whether calls to mbedtls_platform_zeroize() are being eliminated by compiler
6 * optimizations. This application is used by the GDB script at
7 * tests/scripts/test_zeroize.gdb: the script sets a breakpoint at the last
8 * return statement in the main() function of this program. The debugger
9 * facilities are then used to manually inspect the memory and verify that the
10 * call to mbedtls_platform_zeroize() was not eliminated.
11 *
12 * Copyright The Mbed TLS Contributors
13 * SPDX-License-Identifier: Apache-2.0
14 *
15 * Licensed under the Apache License, Version 2.0 (the "License"); you may
16 * not use this file except in compliance with the License.
17 * You may obtain a copy of the License at
18 *
19 * http://www.apache.org/licenses/LICENSE-2.0
20 *
21 * Unless required by applicable law or agreed to in writing, software
22 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
23 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
24 * See the License for the specific language governing permissions and
25 * limitations under the License.
26 */
27
28 #include "mbedtls/build_info.h"
29
30 #include <stdio.h>
31
32 #include "mbedtls/platform.h"
33
34 #include "mbedtls/platform_util.h"
35
36 #define BUFFER_LEN 1024
37
usage(void)38 void usage( void )
39 {
40 mbedtls_printf( "Zeroize is a simple program to assist with testing\n" );
41 mbedtls_printf( "the mbedtls_platform_zeroize() function by using the\n" );
42 mbedtls_printf( "debugger. This program takes a file as input and\n" );
43 mbedtls_printf( "prints the first %d characters. Usage:\n\n", BUFFER_LEN );
44 mbedtls_printf( " zeroize <FILE>\n" );
45 }
46
main(int argc,char ** argv)47 int main( int argc, char** argv )
48 {
49 int exit_code = MBEDTLS_EXIT_FAILURE;
50 FILE *fp;
51 char buf[BUFFER_LEN];
52 char *p = buf;
53 char *end = p + BUFFER_LEN;
54 int c;
55
56 if( argc != 2 )
57 {
58 mbedtls_printf( "This program takes exactly 1 argument\n" );
59 usage();
60 mbedtls_exit( exit_code );
61 }
62
63 fp = fopen( argv[1], "r" );
64 if( fp == NULL )
65 {
66 mbedtls_printf( "Could not open file '%s'\n", argv[1] );
67 mbedtls_exit( exit_code );
68 }
69
70 while( ( c = fgetc( fp ) ) != EOF && p < end - 1 )
71 *p++ = (char)c;
72 *p = '\0';
73
74 if( p - buf != 0 )
75 {
76 mbedtls_printf( "%s\n", buf );
77 exit_code = MBEDTLS_EXIT_SUCCESS;
78 }
79 else
80 mbedtls_printf( "The file is empty!\n" );
81
82 fclose( fp );
83 mbedtls_platform_zeroize( buf, sizeof( buf ) );
84
85 mbedtls_exit( exit_code ); // GDB_BREAK_HERE -- don't remove this comment!
86 }
87