Manuel Pégourié-Gonnard | f392a02 | 2022-01-31 12:06:07 +0100 | [diff] [blame] | 1 | /** |
| 2 | * MD API multi-part HMAC demonstration. |
| 3 | * |
| 4 | * This programs computes the HMAC of two messages using the multi-part API. |
| 5 | * |
Manuel Pégourié-Gonnard | 69bb3f5 | 2022-01-31 13:09:47 +0100 | [diff] [blame] | 6 | * This is a companion to psa/hmac_demo.c, doing the same operations with the |
Manuel Pégourié-Gonnard | edf6e83 | 2022-01-27 12:36:39 +0100 | [diff] [blame] | 7 | * legacy MD API. The goal is that comparing the two programs will help people |
| 8 | * migrating to the PSA Crypto API. |
| 9 | * |
Manuel Pégourié-Gonnard | f392a02 | 2022-01-31 12:06:07 +0100 | [diff] [blame] | 10 | * When it comes to multi-part HMAC operations, the `mbedtls_md_context` |
| 11 | * serves a dual purpose (1) hold the key, and (2) save progress information |
| 12 | * for the current operation. With PSA those roles are held by two disinct |
| 13 | * objects: (1) a psa_key_id_t to hold the key, and (2) a psa_operation_t for |
| 14 | * multi-part progress. |
| 15 | * |
Manuel Pégourié-Gonnard | 69bb3f5 | 2022-01-31 13:09:47 +0100 | [diff] [blame] | 16 | * This program and its companion psa/hmac_demo.c illustrate this by doing the |
Manuel Pégourié-Gonnard | f392a02 | 2022-01-31 12:06:07 +0100 | [diff] [blame] | 17 | * same sequence of multi-part HMAC computation with both APIs; looking at the |
| 18 | * two side by side should make the differences and similarities clear. |
| 19 | */ |
| 20 | |
| 21 | /* |
Manuel Pégourié-Gonnard | edf6e83 | 2022-01-27 12:36:39 +0100 | [diff] [blame] | 22 | * Copyright The Mbed TLS Contributors |
Dave Rodgman | 16799db | 2023-11-02 19:47:20 +0000 | [diff] [blame^] | 23 | * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later |
Manuel Pégourié-Gonnard | edf6e83 | 2022-01-27 12:36:39 +0100 | [diff] [blame] | 24 | */ |
| 25 | |
Manuel Pégourié-Gonnard | f392a02 | 2022-01-31 12:06:07 +0100 | [diff] [blame] | 26 | /* First include Mbed TLS headers to get the Mbed TLS configuration and |
| 27 | * platform definitions that we'll use in this program. Also include |
| 28 | * standard C headers for functions we'll use here. */ |
Manuel Pégourié-Gonnard | edf6e83 | 2022-01-27 12:36:39 +0100 | [diff] [blame] | 29 | #include "mbedtls/build_info.h" |
| 30 | |
Manuel Pégourié-Gonnard | f392a02 | 2022-01-31 12:06:07 +0100 | [diff] [blame] | 31 | #include "mbedtls/md.h" |
| 32 | |
Manuel Pégourié-Gonnard | 6349794 | 2022-01-31 12:23:37 +0100 | [diff] [blame] | 33 | #include "mbedtls/platform_util.h" // for mbedtls_platform_zeroize |
| 34 | |
Manuel Pégourié-Gonnard | f392a02 | 2022-01-31 12:06:07 +0100 | [diff] [blame] | 35 | #include <stdlib.h> |
| 36 | #include <stdio.h> |
| 37 | |
| 38 | /* If the build options we need are not enabled, compile a placeholder. */ |
Manuel Pégourié-Gonnard | edf6e83 | 2022-01-27 12:36:39 +0100 | [diff] [blame] | 39 | #if !defined(MBEDTLS_MD_C) |
Gilles Peskine | 449bd83 | 2023-01-11 14:50:10 +0100 | [diff] [blame] | 40 | int main(void) |
Manuel Pégourié-Gonnard | edf6e83 | 2022-01-27 12:36:39 +0100 | [diff] [blame] | 41 | { |
Gilles Peskine | 449bd83 | 2023-01-11 14:50:10 +0100 | [diff] [blame] | 42 | printf("MBEDTLS_MD_C not defined\r\n"); |
| 43 | return 0; |
Manuel Pégourié-Gonnard | edf6e83 | 2022-01-27 12:36:39 +0100 | [diff] [blame] | 44 | } |
| 45 | #else |
| 46 | |
Manuel Pégourié-Gonnard | f392a02 | 2022-01-31 12:06:07 +0100 | [diff] [blame] | 47 | /* The real program starts here. */ |
Manuel Pégourié-Gonnard | edf6e83 | 2022-01-27 12:36:39 +0100 | [diff] [blame] | 48 | |
Manuel Pégourié-Gonnard | f392a02 | 2022-01-31 12:06:07 +0100 | [diff] [blame] | 49 | /* Dummy inputs for HMAC */ |
Manuel Pégourié-Gonnard | edf6e83 | 2022-01-27 12:36:39 +0100 | [diff] [blame] | 50 | const unsigned char msg1_part1[] = { 0x01, 0x02 }; |
| 51 | const unsigned char msg1_part2[] = { 0x03, 0x04 }; |
| 52 | const unsigned char msg2_part1[] = { 0x05, 0x05 }; |
| 53 | const unsigned char msg2_part2[] = { 0x06, 0x06 }; |
| 54 | |
Manuel Pégourié-Gonnard | f392a02 | 2022-01-31 12:06:07 +0100 | [diff] [blame] | 55 | /* Dummy key material - never do this in production! |
| 56 | * This example program uses SHA-256, so a 32-byte key makes sense. */ |
Manuel Pégourié-Gonnard | edf6e83 | 2022-01-27 12:36:39 +0100 | [diff] [blame] | 57 | const unsigned char key_bytes[32] = { 0 }; |
| 58 | |
Manuel Pégourié-Gonnard | 6349794 | 2022-01-31 12:23:37 +0100 | [diff] [blame] | 59 | /* Print the contents of a buffer in hex */ |
Gilles Peskine | 449bd83 | 2023-01-11 14:50:10 +0100 | [diff] [blame] | 60 | void print_buf(const char *title, unsigned char *buf, size_t len) |
Manuel Pégourié-Gonnard | edf6e83 | 2022-01-27 12:36:39 +0100 | [diff] [blame] | 61 | { |
Gilles Peskine | 449bd83 | 2023-01-11 14:50:10 +0100 | [diff] [blame] | 62 | printf("%s:", title); |
| 63 | for (size_t i = 0; i < len; i++) { |
| 64 | printf(" %02x", buf[i]); |
| 65 | } |
| 66 | printf("\n"); |
Manuel Pégourié-Gonnard | edf6e83 | 2022-01-27 12:36:39 +0100 | [diff] [blame] | 67 | } |
| 68 | |
Manuel Pégourié-Gonnard | 340808c | 2022-02-08 11:15:26 +0100 | [diff] [blame] | 69 | /* Run an Mbed TLS function and bail out if it fails. |
| 70 | * A string description of the error code can be recovered with: |
| 71 | * programs/util/strerror <value> */ |
Gilles Peskine | 449bd83 | 2023-01-11 14:50:10 +0100 | [diff] [blame] | 72 | #define CHK(expr) \ |
Manuel Pégourié-Gonnard | f392a02 | 2022-01-31 12:06:07 +0100 | [diff] [blame] | 73 | do \ |
| 74 | { \ |
Gilles Peskine | 449bd83 | 2023-01-11 14:50:10 +0100 | [diff] [blame] | 75 | ret = (expr); \ |
| 76 | if (ret != 0) \ |
Manuel Pégourié-Gonnard | f392a02 | 2022-01-31 12:06:07 +0100 | [diff] [blame] | 77 | { \ |
Gilles Peskine | 449bd83 | 2023-01-11 14:50:10 +0100 | [diff] [blame] | 78 | printf("Error %d at line %d: %s\n", \ |
| 79 | ret, \ |
| 80 | __LINE__, \ |
| 81 | #expr); \ |
Manuel Pégourié-Gonnard | f392a02 | 2022-01-31 12:06:07 +0100 | [diff] [blame] | 82 | goto exit; \ |
| 83 | } \ |
Gilles Peskine | 449bd83 | 2023-01-11 14:50:10 +0100 | [diff] [blame] | 84 | } while (0) |
Manuel Pégourié-Gonnard | edf6e83 | 2022-01-27 12:36:39 +0100 | [diff] [blame] | 85 | |
Manuel Pégourié-Gonnard | f392a02 | 2022-01-31 12:06:07 +0100 | [diff] [blame] | 86 | /* |
| 87 | * This function demonstrates computation of the HMAC of two messages using |
| 88 | * the multipart API. |
| 89 | */ |
Manuel Pégourié-Gonnard | edf6e83 | 2022-01-27 12:36:39 +0100 | [diff] [blame] | 90 | int hmac_demo(void) |
| 91 | { |
| 92 | int ret; |
Manuel Pégourié-Gonnard | 6349794 | 2022-01-31 12:23:37 +0100 | [diff] [blame] | 93 | const mbedtls_md_type_t alg = MBEDTLS_MD_SHA256; |
| 94 | unsigned char out[MBEDTLS_MD_MAX_SIZE]; // safe but not optimal |
| 95 | |
Manuel Pégourié-Gonnard | edf6e83 | 2022-01-27 12:36:39 +0100 | [diff] [blame] | 96 | mbedtls_md_context_t ctx; |
| 97 | |
Gilles Peskine | 449bd83 | 2023-01-11 14:50:10 +0100 | [diff] [blame] | 98 | mbedtls_md_init(&ctx); |
Manuel Pégourié-Gonnard | edf6e83 | 2022-01-27 12:36:39 +0100 | [diff] [blame] | 99 | |
| 100 | /* prepare context and load key */ |
Manuel Pégourié-Gonnard | 6349794 | 2022-01-31 12:23:37 +0100 | [diff] [blame] | 101 | // the last argument to setup is 1 to enable HMAC (not just hashing) |
Gilles Peskine | 449bd83 | 2023-01-11 14:50:10 +0100 | [diff] [blame] | 102 | const mbedtls_md_info_t *info = mbedtls_md_info_from_type(alg); |
| 103 | CHK(mbedtls_md_setup(&ctx, info, 1)); |
| 104 | CHK(mbedtls_md_hmac_starts(&ctx, key_bytes, sizeof(key_bytes))); |
Manuel Pégourié-Gonnard | edf6e83 | 2022-01-27 12:36:39 +0100 | [diff] [blame] | 105 | |
| 106 | /* compute HMAC(key, msg1_part1 | msg1_part2) */ |
Gilles Peskine | 449bd83 | 2023-01-11 14:50:10 +0100 | [diff] [blame] | 107 | CHK(mbedtls_md_hmac_update(&ctx, msg1_part1, sizeof(msg1_part1))); |
| 108 | CHK(mbedtls_md_hmac_update(&ctx, msg1_part2, sizeof(msg1_part2))); |
| 109 | CHK(mbedtls_md_hmac_finish(&ctx, out)); |
| 110 | print_buf("msg1", out, mbedtls_md_get_size(info)); |
Manuel Pégourié-Gonnard | edf6e83 | 2022-01-27 12:36:39 +0100 | [diff] [blame] | 111 | |
| 112 | /* compute HMAC(key, msg2_part1 | msg2_part2) */ |
Gilles Peskine | 449bd83 | 2023-01-11 14:50:10 +0100 | [diff] [blame] | 113 | CHK(mbedtls_md_hmac_reset(&ctx)); // prepare for new operation |
| 114 | CHK(mbedtls_md_hmac_update(&ctx, msg2_part1, sizeof(msg2_part1))); |
| 115 | CHK(mbedtls_md_hmac_update(&ctx, msg2_part2, sizeof(msg2_part2))); |
| 116 | CHK(mbedtls_md_hmac_finish(&ctx, out)); |
| 117 | print_buf("msg2", out, mbedtls_md_get_size(info)); |
Manuel Pégourié-Gonnard | edf6e83 | 2022-01-27 12:36:39 +0100 | [diff] [blame] | 118 | |
| 119 | exit: |
Gilles Peskine | 449bd83 | 2023-01-11 14:50:10 +0100 | [diff] [blame] | 120 | mbedtls_md_free(&ctx); |
| 121 | mbedtls_platform_zeroize(out, sizeof(out)); |
Manuel Pégourié-Gonnard | edf6e83 | 2022-01-27 12:36:39 +0100 | [diff] [blame] | 122 | |
Gilles Peskine | 449bd83 | 2023-01-11 14:50:10 +0100 | [diff] [blame] | 123 | return ret; |
Manuel Pégourié-Gonnard | edf6e83 | 2022-01-27 12:36:39 +0100 | [diff] [blame] | 124 | } |
| 125 | |
| 126 | int main(void) |
| 127 | { |
Manuel Pégourié-Gonnard | f392a02 | 2022-01-31 12:06:07 +0100 | [diff] [blame] | 128 | int ret; |
Manuel Pégourié-Gonnard | edf6e83 | 2022-01-27 12:36:39 +0100 | [diff] [blame] | 129 | |
Gilles Peskine | 449bd83 | 2023-01-11 14:50:10 +0100 | [diff] [blame] | 130 | CHK(hmac_demo()); |
Manuel Pégourié-Gonnard | f392a02 | 2022-01-31 12:06:07 +0100 | [diff] [blame] | 131 | |
| 132 | exit: |
Gilles Peskine | 449bd83 | 2023-01-11 14:50:10 +0100 | [diff] [blame] | 133 | return ret == 0 ? EXIT_SUCCESS : EXIT_FAILURE; |
Manuel Pégourié-Gonnard | edf6e83 | 2022-01-27 12:36:39 +0100 | [diff] [blame] | 134 | } |
| 135 | |
| 136 | #endif |