1/**
2 *  \brief Use and generate random data into a file via the CTR_DBRG based on AES
3 *
4 *  Copyright The Mbed TLS Contributors
5 *  SPDX-License-Identifier: Apache-2.0
6 *
7 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
8 *  not use this file except in compliance with the License.
9 *  You may obtain a copy of the License at
10 *
11 *  http://www.apache.org/licenses/LICENSE-2.0
12 *
13 *  Unless required by applicable law or agreed to in writing, software
14 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
15 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 *  See the License for the specific language governing permissions and
17 *  limitations under the License.
18 */
19
20#include "mbedtls/build_info.h"
21
22#include "mbedtls/platform.h"
23
24#if defined(MBEDTLS_CTR_DRBG_C) && defined(MBEDTLS_ENTROPY_C) && \
25    defined(MBEDTLS_FS_IO)
26#include "mbedtls/entropy.h"
27#include "mbedtls/ctr_drbg.h"
28
29#include <stdio.h>
30#endif
31
32#if !defined(MBEDTLS_CTR_DRBG_C) || !defined(MBEDTLS_ENTROPY_C) || \
33    !defined(MBEDTLS_FS_IO)
34int main(void)
35{
36    mbedtls_printf("MBEDTLS_CTR_DRBG_C and/or MBEDTLS_ENTROPY_C and/or MBEDTLS_FS_IO not defined.\n");
37    mbedtls_exit(0);
38}
39#else
40
41
42int main(int argc, char *argv[])
43{
44    FILE *f;
45    int i, k, ret = 1;
46    int exit_code = MBEDTLS_EXIT_FAILURE;
47    mbedtls_ctr_drbg_context ctr_drbg;
48    mbedtls_entropy_context entropy;
49    unsigned char buf[1024];
50
51    mbedtls_ctr_drbg_init(&ctr_drbg);
52
53    if (argc < 2) {
54        mbedtls_fprintf(stderr, "usage: %s <output filename>\n", argv[0]);
55        mbedtls_exit(exit_code);
56    }
57
58    if ((f = fopen(argv[1], "wb+")) == NULL) {
59        mbedtls_printf("failed to open '%s' for writing.\n", argv[1]);
60        mbedtls_exit(exit_code);
61    }
62
63    mbedtls_entropy_init(&entropy);
64    ret = mbedtls_ctr_drbg_seed(&ctr_drbg,
65                                mbedtls_entropy_func,
66                                &entropy,
67                                (const unsigned char *) "RANDOM_GEN",
68                                10);
69    if (ret != 0) {
70        mbedtls_printf("failed in mbedtls_ctr_drbg_seed: %d\n", ret);
71        goto cleanup;
72    }
73    mbedtls_ctr_drbg_set_prediction_resistance(&ctr_drbg, MBEDTLS_CTR_DRBG_PR_OFF);
74
75#if defined(MBEDTLS_FS_IO)
76    ret = mbedtls_ctr_drbg_update_seed_file(&ctr_drbg, "seedfile");
77
78    if (ret == MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR) {
79        mbedtls_printf("Failed to open seedfile. Generating one.\n");
80        ret = mbedtls_ctr_drbg_write_seed_file(&ctr_drbg, "seedfile");
81        if (ret != 0) {
82            mbedtls_printf("failed in mbedtls_ctr_drbg_write_seed_file: %d\n", ret);
83            goto cleanup;
84        }
85    } else if (ret != 0) {
86        mbedtls_printf("failed in mbedtls_ctr_drbg_update_seed_file: %d\n", ret);
87        goto cleanup;
88    }
89#endif
90
91    for (i = 0, k = 768; i < k; i++) {
92        ret = mbedtls_ctr_drbg_random(&ctr_drbg, buf, sizeof(buf));
93        if (ret != 0) {
94            mbedtls_printf("failed!\n");
95            goto cleanup;
96        }
97
98        fwrite(buf, 1, sizeof(buf), f);
99
100        mbedtls_printf("Generating %ldkb of data in file '%s'... %04.1f" \
101                       "%% done\r",
102                       (long) (sizeof(buf) * k / 1024),
103                       argv[1],
104                       (100 * (float) (i + 1)) / k);
105        fflush(stdout);
106    }
107
108    exit_code = MBEDTLS_EXIT_SUCCESS;
109
110cleanup:
111    mbedtls_printf("\n");
112
113    fclose(f);
114    mbedtls_ctr_drbg_free(&ctr_drbg);
115    mbedtls_entropy_free(&entropy);
116
117    mbedtls_exit(exit_code);
118}
119#endif /* MBEDTLS_CTR_DRBG_C && MBEDTLS_ENTROPY_C */
120