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 mbedtls_printf("This program takes exactly 1 argument\n");
58 usage();
59 mbedtls_exit(exit_code);
60 }
61
62 fp = fopen(argv[1], "r");
63 if (fp == NULL) {
64 mbedtls_printf("Could not open file '%s'\n", argv[1]);
65 mbedtls_exit(exit_code);
66 }
67
68 while ((c = fgetc(fp)) != EOF && p < end - 1) {
69 *p++ = (char) c;
70 }
71 *p = '\0';
72
73 if (p - buf != 0) {
74 mbedtls_printf("%s\n", buf);
75 exit_code = MBEDTLS_EXIT_SUCCESS;
76 } else {
77 mbedtls_printf("The file is empty!\n");
78 }
79
80 fclose(fp);
81 mbedtls_platform_zeroize(buf, sizeof(buf));
82
83 mbedtls_exit(exit_code); // GDB_BREAK_HERE -- don't remove this comment!
84 }
85
