1 /*
2 * RSA/SHA-256 signature verification 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)
main(void)17 int 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
main(int argc, char *argv[])32 int main(int argc, char *argv[])
33 {
34 FILE *f;
35 int ret = 1;
36 unsigned c;
37 int exit_code = MBEDTLS_EXIT_FAILURE;
38 size_t i;
39 mbedtls_rsa_context rsa;
40 mbedtls_mpi N, E;
41 unsigned char hash[32];
42 unsigned char buf[MBEDTLS_MPI_MAX_SIZE];
43 char filename[512];
44
45 mbedtls_rsa_init(&rsa);
46 mbedtls_mpi_init(&N);
47 mbedtls_mpi_init(&E);
48
49 if (argc != 2) {
50 mbedtls_printf("usage: rsa_verify <filename>\n");
51
52 #if defined(_WIN32)
53 mbedtls_printf("\n");
54 #endif
55
56 goto exit;
57 }
58
59 mbedtls_printf("\n . Reading public key from rsa_pub.txt");
60 fflush(stdout);
61
62 if ((f = fopen("rsa_pub.txt", "rb")) == NULL) {
63 mbedtls_printf(" failed\n ! Could not open rsa_pub.txt\n" \
64 " ! Please run rsa_genkey first\n\n");
65 goto exit;
66 }
67
68 if ((ret = mbedtls_mpi_read_file(&N, 16, f)) != 0 ||
69 (ret = mbedtls_mpi_read_file(&E, 16, f)) != 0 ||
70 (ret = mbedtls_rsa_import(&rsa, &N, NULL, NULL, NULL, &E) != 0)) {
71 mbedtls_printf(" failed\n ! mbedtls_mpi_read_file returned %d\n\n", ret);
72 fclose(f);
73 goto exit;
74 }
75 fclose(f);
76
77 /*
78 * Extract the RSA signature from the text file
79 */
80 mbedtls_snprintf(filename, sizeof(filename), "%s.sig", argv[1]);
81
82 if ((f = fopen(filename, "rb")) == NULL) {
83 mbedtls_printf("\n ! Could not open %s\n\n", filename);
84 goto exit;
85 }
86
87 i = 0;
88 while (fscanf(f, "%02X", (unsigned int *) &c) > 0 &&
89 i < (int) sizeof(buf)) {
90 buf[i++] = (unsigned char) c;
91 }
92
93 fclose(f);
94
95 if (i != mbedtls_rsa_get_len(&rsa)) {
96 mbedtls_printf("\n ! Invalid RSA signature format\n\n");
97 goto exit;
98 }
99
100 /*
101 * Compute the SHA-256 hash of the input file and
102 * verify the signature
103 */
104 mbedtls_printf("\n . Verifying the RSA/SHA-256 signature");
105 fflush(stdout);
106
107 if ((ret = mbedtls_md_file(
108 mbedtls_md_info_from_type(MBEDTLS_MD_SHA256),
109 argv[1], hash)) != 0) {
110 mbedtls_printf(" failed\n ! Could not open or read %s\n\n", argv[1]);
111 goto exit;
112 }
113
114 if ((ret = mbedtls_rsa_pkcs1_verify(&rsa, MBEDTLS_MD_SHA256,
115 32, hash, buf)) != 0) {
116 mbedtls_printf(" failed\n ! mbedtls_rsa_pkcs1_verify returned -0x%0x\n\n",
117 (unsigned int) -ret);
118 goto exit;
119 }
120
121 mbedtls_printf("\n . OK (the signature is valid)\n\n");
122
123 exit_code = MBEDTLS_EXIT_SUCCESS;
124
125 exit:
126
127 mbedtls_rsa_free(&rsa);
128 mbedtls_mpi_free(&N);
129 mbedtls_mpi_free(&E);
130
131 mbedtls_exit(exit_code);
132 }
133 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_RSA_C && MBEDTLS_MD_CAN_SHA256 &&
134 MBEDTLS_FS_IO */
135