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 38void 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 47int 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