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 #if !defined(MBEDTLS_CONFIG_FILE)
9 #include "mbedtls/config.h"
10 #else
11 #include MBEDTLS_CONFIG_FILE
12 #endif
13
14 #include "mbedtls/platform.h"
15
16 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_RSA_C) || \
17 !defined(MBEDTLS_SHA256_C) || !defined(MBEDTLS_MD_C) || \
18 !defined(MBEDTLS_FS_IO)
main(void)19 int main(void)
20 {
21 mbedtls_printf("MBEDTLS_BIGNUM_C and/or MBEDTLS_RSA_C and/or "
22 "MBEDTLS_MD_C and/or "
23 "MBEDTLS_SHA256_C and/or MBEDTLS_FS_IO not defined.\n");
24 mbedtls_exit(0);
25 }
26 #else
27
28 #include "mbedtls/rsa.h"
29 #include "mbedtls/md.h"
30
31 #include <stdio.h>
32 #include <string.h>
33
34
main(int argc,char * argv[])35 int main(int argc, char *argv[])
36 {
37 FILE *f;
38 int ret = 1;
39 unsigned c;
40 int exit_code = MBEDTLS_EXIT_FAILURE;
41 size_t i;
42 mbedtls_rsa_context rsa;
43 unsigned char hash[32];
44 unsigned char buf[MBEDTLS_MPI_MAX_SIZE];
45 char filename[512];
46
47 mbedtls_rsa_init(&rsa, MBEDTLS_RSA_PKCS_V15, 0);
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(&rsa.N, 16, f)) != 0 ||
69 (ret = mbedtls_mpi_read_file(&rsa.E, 16, f)) != 0) {
70 mbedtls_printf(" failed\n ! mbedtls_mpi_read_file returned %d\n\n", ret);
71 fclose(f);
72 goto exit;
73 }
74
75 rsa.len = (mbedtls_mpi_bitlen(&rsa.N) + 7) >> 3;
76
77 fclose(f);
78
79 /*
80 * Extract the RSA signature from the text file
81 */
82 mbedtls_snprintf(filename, sizeof(filename), "%s.sig", argv[1]);
83
84 if ((f = fopen(filename, "rb")) == NULL) {
85 mbedtls_printf("\n ! Could not open %s\n\n", filename);
86 goto exit;
87 }
88
89 i = 0;
90 while (fscanf(f, "%02X", (unsigned int *) &c) > 0 &&
91 i < (int) sizeof(buf)) {
92 buf[i++] = (unsigned char) c;
93 }
94
95 fclose(f);
96
97 if (i != rsa.len) {
98 mbedtls_printf("\n ! Invalid RSA signature format\n\n");
99 goto exit;
100 }
101
102 /*
103 * Compute the SHA-256 hash of the input file and
104 * verify the signature
105 */
106 mbedtls_printf("\n . Verifying the RSA/SHA-256 signature");
107 fflush(stdout);
108
109 if ((ret = mbedtls_md_file(
110 mbedtls_md_info_from_type(MBEDTLS_MD_SHA256),
111 argv[1], hash)) != 0) {
112 mbedtls_printf(" failed\n ! Could not open or read %s\n\n", argv[1]);
113 goto exit;
114 }
115
116 if ((ret = mbedtls_rsa_pkcs1_verify(&rsa, NULL, NULL, MBEDTLS_RSA_PUBLIC,
117 MBEDTLS_MD_SHA256, 20, hash, buf)) != 0) {
118 mbedtls_printf(" failed\n ! mbedtls_rsa_pkcs1_verify returned -0x%0x\n\n",
119 (unsigned int) -ret);
120 goto exit;
121 }
122
123 mbedtls_printf("\n . OK (the signature is valid)\n\n");
124
125 exit_code = MBEDTLS_EXIT_SUCCESS;
126
127 exit:
128
129 mbedtls_rsa_free(&rsa);
130
131 #if defined(_WIN32)
132 mbedtls_printf(" + Press Enter to exit this program.\n");
133 fflush(stdout); getchar();
134 #endif
135
136 mbedtls_exit(exit_code);
137 }
138 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_RSA_C && MBEDTLS_SHA256_C &&
139 MBEDTLS_FS_IO */
140