1/*
2 *  RSA/SHA-256 signature creation program
3 *
4 *  Copyright The Mbed TLS Contributors
5 *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
6 */
7
8#include "mbedtls/build_info.h"
9
10#include "mbedtls/platform.h"
11/* md.h is included this early since MD_CAN_XXX macros are defined there. */
12#include "mbedtls/md.h"
13
14#if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_RSA_C) ||  \
15    !defined(MBEDTLS_MD_CAN_SHA256) || !defined(MBEDTLS_MD_C) || \
16    !defined(MBEDTLS_FS_IO)
17int main(void)
18{
19    mbedtls_printf("MBEDTLS_BIGNUM_C and/or MBEDTLS_RSA_C and/or "
20                   "MBEDTLS_MD_C and/or "
21                   "MBEDTLS_MD_CAN_SHA256 and/or MBEDTLS_FS_IO not defined.\n");
22    mbedtls_exit(0);
23}
24#else
25
26#include "mbedtls/rsa.h"
27
28#include <stdio.h>
29#include <string.h>
30
31
32int main(int argc, char *argv[])
33{
34    FILE *f;
35    int ret = 1;
36    int exit_code = MBEDTLS_EXIT_FAILURE;
37    size_t i;
38    mbedtls_rsa_context rsa;
39    unsigned char hash[32];
40    unsigned char buf[MBEDTLS_MPI_MAX_SIZE];
41    char filename[512];
42    mbedtls_mpi N, P, Q, D, E, DP, DQ, QP;
43
44    mbedtls_rsa_init(&rsa);
45
46    mbedtls_mpi_init(&N); mbedtls_mpi_init(&P); mbedtls_mpi_init(&Q);
47    mbedtls_mpi_init(&D); mbedtls_mpi_init(&E); mbedtls_mpi_init(&DP);
48    mbedtls_mpi_init(&DQ); mbedtls_mpi_init(&QP);
49
50    if (argc != 2) {
51        mbedtls_printf("usage: rsa_sign <filename>\n");
52
53#if defined(_WIN32)
54        mbedtls_printf("\n");
55#endif
56
57        goto exit;
58    }
59
60    mbedtls_printf("\n  . Reading private key from rsa_priv.txt");
61    fflush(stdout);
62
63    if ((f = fopen("rsa_priv.txt", "rb")) == NULL) {
64        mbedtls_printf(" failed\n  ! Could not open rsa_priv.txt\n" \
65                       "  ! Please run rsa_genkey first\n\n");
66        goto exit;
67    }
68
69    if ((ret = mbedtls_mpi_read_file(&N, 16, f)) != 0 ||
70        (ret = mbedtls_mpi_read_file(&E, 16, f)) != 0 ||
71        (ret = mbedtls_mpi_read_file(&D, 16, f)) != 0 ||
72        (ret = mbedtls_mpi_read_file(&P, 16, f)) != 0 ||
73        (ret = mbedtls_mpi_read_file(&Q, 16, f)) != 0 ||
74        (ret = mbedtls_mpi_read_file(&DP, 16, f)) != 0 ||
75        (ret = mbedtls_mpi_read_file(&DQ, 16, f)) != 0 ||
76        (ret = mbedtls_mpi_read_file(&QP, 16, f)) != 0) {
77        mbedtls_printf(" failed\n  ! mbedtls_mpi_read_file returned %d\n\n", ret);
78        fclose(f);
79        goto exit;
80    }
81    fclose(f);
82
83    if ((ret = mbedtls_rsa_import(&rsa, &N, &P, &Q, &D, &E)) != 0) {
84        mbedtls_printf(" failed\n  ! mbedtls_rsa_import returned %d\n\n",
85                       ret);
86        goto exit;
87    }
88
89    if ((ret = mbedtls_rsa_complete(&rsa)) != 0) {
90        mbedtls_printf(" failed\n  ! mbedtls_rsa_complete returned %d\n\n",
91                       ret);
92        goto exit;
93    }
94
95    mbedtls_printf("\n  . Checking the private key");
96    fflush(stdout);
97    if ((ret = mbedtls_rsa_check_privkey(&rsa)) != 0) {
98        mbedtls_printf(" failed\n  ! mbedtls_rsa_check_privkey failed with -0x%0x\n",
99                       (unsigned int) -ret);
100        goto exit;
101    }
102
103    /*
104     * Compute the SHA-256 hash of the input file,
105     * then calculate the RSA signature of the hash.
106     */
107    mbedtls_printf("\n  . Generating the RSA/SHA-256 signature");
108    fflush(stdout);
109
110    if ((ret = mbedtls_md_file(
111             mbedtls_md_info_from_type(MBEDTLS_MD_SHA256),
112             argv[1], hash)) != 0) {
113        mbedtls_printf(" failed\n  ! Could not open or read %s\n\n", argv[1]);
114        goto exit;
115    }
116
117    if ((ret = mbedtls_rsa_pkcs1_sign(&rsa, NULL, NULL, MBEDTLS_MD_SHA256,
118                                      32, hash, buf)) != 0) {
119        mbedtls_printf(" failed\n  ! mbedtls_rsa_pkcs1_sign returned -0x%0x\n\n",
120                       (unsigned int) -ret);
121        goto exit;
122    }
123
124    /*
125     * Write the signature into <filename>.sig
126     */
127    mbedtls_snprintf(filename, sizeof(filename), "%s.sig", argv[1]);
128
129    if ((f = fopen(filename, "wb+")) == NULL) {
130        mbedtls_printf(" failed\n  ! Could not create %s\n\n", argv[1]);
131        goto exit;
132    }
133
134    for (i = 0; i < mbedtls_rsa_get_len(&rsa); i++) {
135        mbedtls_fprintf(f, "%02X%s", buf[i],
136                        (i + 1) % 16 == 0 ? "\r\n" : " ");
137    }
138
139    fclose(f);
140
141    mbedtls_printf("\n  . Done (created \"%s\")\n\n", filename);
142
143    exit_code = MBEDTLS_EXIT_SUCCESS;
144
145exit:
146
147    mbedtls_rsa_free(&rsa);
148    mbedtls_mpi_free(&N); mbedtls_mpi_free(&P); mbedtls_mpi_free(&Q);
149    mbedtls_mpi_free(&D); mbedtls_mpi_free(&E); mbedtls_mpi_free(&DP);
150    mbedtls_mpi_free(&DQ); mbedtls_mpi_free(&QP);
151
152    mbedtls_exit(exit_code);
153}
154#endif /* MBEDTLS_BIGNUM_C && MBEDTLS_RSA_C && MBEDTLS_MD_CAN_SHA256 &&
155          MBEDTLS_FS_IO */
156