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 unsigned char hash[32];
41 unsigned char buf[MBEDTLS_MPI_MAX_SIZE];
42 char filename[512];
43
44 mbedtls_rsa_init(&rsa);
45
46 if (argc != 2) {
47 mbedtls_printf("usage: rsa_verify <filename>\n");
48
49 #if defined(_WIN32)
50 mbedtls_printf("\n");
51 #endif
52
53 goto exit;
54 }
55
56 mbedtls_printf("\n . Reading public key from rsa_pub.txt");
57 fflush(stdout);
58
59 if ((f = fopen("rsa_pub.txt", "rb")) == NULL) {
60 mbedtls_printf(" failed\n ! Could not open rsa_pub.txt\n" \
61 " ! Please run rsa_genkey first\n\n");
62 goto exit;
63 }
64
65 if ((ret = mbedtls_mpi_read_file(&rsa.MBEDTLS_PRIVATE(N), 16, f)) != 0 ||
66 (ret = mbedtls_mpi_read_file(&rsa.MBEDTLS_PRIVATE(E), 16, f)) != 0) {
67 mbedtls_printf(" failed\n ! mbedtls_mpi_read_file returned %d\n\n", ret);
68 fclose(f);
69 goto exit;
70 }
71
72 rsa.MBEDTLS_PRIVATE(len) = (mbedtls_mpi_bitlen(&rsa.MBEDTLS_PRIVATE(N)) + 7) >> 3;
73
74 fclose(f);
75
76 /*
77 * Extract the RSA signature from the text file
78 */
79 mbedtls_snprintf(filename, sizeof(filename), "%s.sig", argv[1]);
80
81 if ((f = fopen(filename, "rb")) == NULL) {
82 mbedtls_printf("\n ! Could not open %s\n\n", filename);
83 goto exit;
84 }
85
86 i = 0;
87 while (fscanf(f, "%02X", (unsigned int *) &c) > 0 &&
88 i < (int) sizeof(buf)) {
89 buf[i++] = (unsigned char) c;
90 }
91
92 fclose(f);
93
94 if (i != rsa.MBEDTLS_PRIVATE(len)) {
95 mbedtls_printf("\n ! Invalid RSA signature format\n\n");
96 goto exit;
97 }
98
99 /*
100 * Compute the SHA-256 hash of the input file and
101 * verify the signature
102 */
103 mbedtls_printf("\n . Verifying the RSA/SHA-256 signature");
104 fflush(stdout);
105
106 if ((ret = mbedtls_md_file(
107 mbedtls_md_info_from_type(MBEDTLS_MD_SHA256),
108 argv[1], hash)) != 0) {
109 mbedtls_printf(" failed\n ! Could not open or read %s\n\n", argv[1]);
110 goto exit;
111 }
112
113 if ((ret = mbedtls_rsa_pkcs1_verify(&rsa, MBEDTLS_MD_SHA256,
114 32, hash, buf)) != 0) {
115 mbedtls_printf(" failed\n ! mbedtls_rsa_pkcs1_verify returned -0x%0x\n\n",
116 (unsigned int) -ret);
117 goto exit;
118 }
119
120 mbedtls_printf("\n . OK (the signature is valid)\n\n");
121
122 exit_code = MBEDTLS_EXIT_SUCCESS;
123
124 exit:
125
126 mbedtls_rsa_free(&rsa);
127
128 mbedtls_exit(exit_code);
129 }
130 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_RSA_C && MBEDTLS_MD_CAN_SHA256 &&
131 MBEDTLS_FS_IO */
132