1 /*
2 * RSA/SHA-256 signature verification program
3 *
4 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
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 * This file is part of mbed TLS (https://tls.mbed.org)
20 */
21
22 #if !defined(MBEDTLS_CONFIG_FILE)
23 #include "mbedtls/config.h"
24 #else
25 #include MBEDTLS_CONFIG_FILE
26 #endif
27
28 #if defined(MBEDTLS_PLATFORM_C)
29 #include "mbedtls/platform.h"
30 #else
31 #include <stdio.h>
32 #define mbedtls_printf printf
33 #define mbedtls_snprintf snprintf
34 #endif
35
36 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_RSA_C) || \
37 !defined(MBEDTLS_SHA256_C) || !defined(MBEDTLS_MD_C) || \
38 !defined(MBEDTLS_FS_IO)
main(void)39 int main( void )
40 {
41 mbedtls_printf("MBEDTLS_BIGNUM_C and/or MBEDTLS_RSA_C and/or "
42 "MBEDTLS_MD_C and/or "
43 "MBEDTLS_SHA256_C and/or MBEDTLS_FS_IO not defined.\n");
44 return( 0 );
45 }
46 #else
47
48 #include "mbedtls/rsa.h"
49 #include "mbedtls/md.h"
50
51 #include <stdio.h>
52 #include <string.h>
53
main(int argc,char * argv[])54 int main( int argc, char *argv[] )
55 {
56 FILE *f;
57 int ret, c;
58 size_t i;
59 mbedtls_rsa_context rsa;
60 unsigned char hash[32];
61 unsigned char buf[MBEDTLS_MPI_MAX_SIZE];
62 char filename[512];
63
64 mbedtls_rsa_init( &rsa, MBEDTLS_RSA_PKCS_V15, 0 );
65 ret = 1;
66
67 if( argc != 2 )
68 {
69 mbedtls_printf( "usage: rsa_verify <filename>\n" );
70
71 #if defined(_WIN32)
72 mbedtls_printf( "\n" );
73 #endif
74
75 goto exit;
76 }
77
78 mbedtls_printf( "\n . Reading public key from rsa_pub.txt" );
79 fflush( stdout );
80
81 if( ( f = fopen( "rsa_pub.txt", "rb" ) ) == NULL )
82 {
83 mbedtls_printf( " failed\n ! Could not open rsa_pub.txt\n" \
84 " ! Please run rsa_genkey first\n\n" );
85 goto exit;
86 }
87
88 if( ( ret = mbedtls_mpi_read_file( &rsa.N, 16, f ) ) != 0 ||
89 ( ret = mbedtls_mpi_read_file( &rsa.E, 16, f ) ) != 0 )
90 {
91 mbedtls_printf( " failed\n ! mbedtls_mpi_read_file returned %d\n\n", ret );
92 fclose( f );
93 goto exit;
94 }
95
96 rsa.len = ( mbedtls_mpi_bitlen( &rsa.N ) + 7 ) >> 3;
97
98 fclose( f );
99
100 /*
101 * Extract the RSA signature from the text file
102 */
103 ret = 1;
104 mbedtls_snprintf( filename, sizeof(filename), "%s.sig", argv[1] );
105
106 if( ( f = fopen( filename, "rb" ) ) == NULL )
107 {
108 mbedtls_printf( "\n ! Could not open %s\n\n", filename );
109 goto exit;
110 }
111
112 i = 0;
113 while( fscanf( f, "%02X", &c ) > 0 &&
114 i < (int) sizeof( buf ) )
115 buf[i++] = (unsigned char) c;
116
117 fclose( f );
118
119 if( i != rsa.len )
120 {
121 mbedtls_printf( "\n ! Invalid RSA signature format\n\n" );
122 goto exit;
123 }
124
125 /*
126 * Compute the SHA-256 hash of the input file and
127 * verify the signature
128 */
129 mbedtls_printf( "\n . Verifying the RSA/SHA-256 signature" );
130 fflush( stdout );
131
132 if( ( ret = mbedtls_md_file(
133 mbedtls_md_info_from_type( MBEDTLS_MD_SHA256 ),
134 argv[1], hash ) ) != 0 )
135 {
136 mbedtls_printf( " failed\n ! Could not open or read %s\n\n", argv[1] );
137 goto exit;
138 }
139
140 if( ( ret = mbedtls_rsa_pkcs1_verify( &rsa, NULL, NULL, MBEDTLS_RSA_PUBLIC,
141 MBEDTLS_MD_SHA256, 20, hash, buf ) ) != 0 )
142 {
143 mbedtls_printf( " failed\n ! mbedtls_rsa_pkcs1_verify returned -0x%0x\n\n", -ret );
144 goto exit;
145 }
146
147 mbedtls_printf( "\n . OK (the signature is valid)\n\n" );
148
149 ret = 0;
150
151 exit:
152
153 mbedtls_rsa_free( &rsa );
154
155 #if defined(_WIN32)
156 mbedtls_printf( " + Press Enter to exit this program.\n" );
157 fflush( stdout ); getchar();
158 #endif
159
160 return( ret );
161 }
162 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_RSA_C && MBEDTLS_SHA256_C &&
163 MBEDTLS_FS_IO */
164
