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)
main(void)34 int 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 
main(int argc,char * argv[])42 int 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     {
55         mbedtls_fprintf( stderr, "usage: %s <output filename>\n", argv[0] );
56         mbedtls_exit( exit_code );
57     }
58 
59     if( ( f = fopen( argv[1], "wb+" ) ) == NULL )
60     {
61         mbedtls_printf( "failed to open '%s' for writing.\n", argv[1] );
62         mbedtls_exit( exit_code );
63     }
64 
65     mbedtls_entropy_init( &entropy );
66     ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func, &entropy, (const unsigned char *) "RANDOM_GEN", 10 );
67     if( ret != 0 )
68     {
69         mbedtls_printf( "failed in mbedtls_ctr_drbg_seed: %d\n", ret );
70         goto cleanup;
71     }
72     mbedtls_ctr_drbg_set_prediction_resistance( &ctr_drbg, MBEDTLS_CTR_DRBG_PR_OFF );
73 
74 #if defined(MBEDTLS_FS_IO)
75     ret = mbedtls_ctr_drbg_update_seed_file( &ctr_drbg, "seedfile" );
76 
77     if( ret == MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR )
78     {
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         {
83             mbedtls_printf( "failed in mbedtls_ctr_drbg_write_seed_file: %d\n", ret );
84             goto cleanup;
85         }
86     }
87     else if( ret != 0 )
88     {
89         mbedtls_printf( "failed in mbedtls_ctr_drbg_update_seed_file: %d\n", ret );
90         goto cleanup;
91     }
92 #endif
93 
94     for( i = 0, k = 768; i < k; i++ )
95     {
96         ret = mbedtls_ctr_drbg_random( &ctr_drbg, buf, sizeof( buf ) );
97         if( ret != 0 )
98         {
99             mbedtls_printf("failed!\n");
100             goto cleanup;
101         }
102 
103         fwrite( buf, 1, sizeof( buf ), f );
104 
105         mbedtls_printf( "Generating %ldkb of data in file '%s'... %04.1f" \
106                 "%% done\r", (long)(sizeof(buf) * k / 1024), argv[1], (100 * (float) (i + 1)) / k );
107         fflush( stdout );
108     }
109 
110     exit_code = MBEDTLS_EXIT_SUCCESS;
111 
112 cleanup:
113     mbedtls_printf("\n");
114 
115     fclose( f );
116     mbedtls_ctr_drbg_free( &ctr_drbg );
117     mbedtls_entropy_free( &entropy );
118 
119     mbedtls_exit( exit_code );
120 }
121 #endif /* MBEDTLS_CTR_DRBG_C && MBEDTLS_ENTROPY_C */
122