programs/pkey/rsa_verify.c

   1 /*
   2  *  RSA/SHA-1 signature verification program
   3  *
   4  *  Based on XySSL: Copyright (C) 2006-2008  Christophe Devine
   5  *
   6  *  Copyright (C) 2009  Paul Bakker <polarssl_maintainer at polarssl dot org>
   7  *
   8  *  All rights reserved.
   9  *
  10  *  Redistribution and use in source and binary forms, with or without
  11  *  modification, are permitted provided that the following conditions
  12  *  are met:
  13  *
  14  *    * Redistributions of source code must retain the above copyright
  15  *      notice, this list of conditions and the following disclaimer.
  16  *    * Redistributions in binary form must reproduce the above copyright
  17  *      notice, this list of conditions and the following disclaimer in the
  18  *      documentation and/or other materials provided with the distribution.
  19  *    * Neither the names of PolarSSL or XySSL nor the names of its contributors
  20  *      may be used to endorse or promote products derived from this software
  21  *      without specific prior written permission.
  22  *
  23  *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  24  *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  25  *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  26  *  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  27  *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  28  *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
  29  *  TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  30  *  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  31  *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  32  *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  33  *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  34  */
  35
  36 #ifndef _CRT_SECURE_NO_DEPRECATE
  37 #define _CRT_SECURE_NO_DEPRECATE 1
  38 #endif
  39
  40 #include <string.h>
  41 #include <stdio.h>
  42
  43 #include "tropicssl/rsa.h"
  44 #include "tropicssl/sha1.h"
  45
  46 int main(int argc, char *argv[])
  47 {
  48         FILE *f;
  49         int ret, i, c;
  50         rsa_context rsa;
  51         unsigned char hash[20];
  52         unsigned char buf[512];
  53
  54         ret = 1;
  55         if (argc != 2) {
  56                 printf("usage: rsa_verify <filename>\n");
  57
  58 #ifdef WIN32
  59                 printf("\n");
  60 #endif
  61
  62                 goto exit;
  63         }
  64
  65         printf("\n  . Reading public key from rsa_pub.txt");
  66         fflush(stdout);
  67
  68         if ((f = fopen("rsa_pub.txt", "rb")) == NULL) {
  69                 printf(" failed\n  ! Could not open rsa_pub.txt\n"
  70                        "  ! Please run rsa_genkey first\n\n");
  71                 goto exit;
  72         }
  73
  74         rsa_init(&rsa, RSA_PKCS_V15, 0, NULL, NULL);
  75
  76         if ((ret = mpi_read_file(&rsa.N, 16, f)) != 0 ||
  77             (ret = mpi_read_file(&rsa.E, 16, f)) != 0) {
  78                 printf(" failed\n  ! mpi_read_file returned %d\n\n", ret);
  79                 goto exit;
  80         }
  81
  82         rsa.len = (mpi_msb(&rsa.N) + 7) >> 3;
  83
  84         fclose(f);
  85
  86         /*
  87          * Extract the RSA signature from the text file
  88          */
  89         ret = 1;
  90         i = strlen(argv[1]);
  91         memcpy(argv[1] + i, ".sig", 5);
  92
  93         if ((f = fopen(argv[1], "rb")) == NULL) {
  94                 printf("\n  ! Could not open %s\n\n", argv[1]);
  95                 goto exit;
  96         }
  97
  98         argv[1][i] = '\0', i = 0;
  99
 100         while (fscanf(f, "%02X", &c) > 0 && i < (int)sizeof(buf))
 101                 buf[i++] = (unsigned char)c;
 102
 103         fclose(f);
 104
 105         if (i != rsa.len) {
 106                 printf("\n  ! Invalid RSA signature format\n\n");
 107                 goto exit;
 108         }
 109
 110         /*
 111          * Compute the SHA-1 hash of the input file and compare
 112          * it with the hash decrypted from the RSA signature.
 113          */
 114         printf("\n  . Verifying the RSA/SHA-1 signature");
 115         fflush(stdout);
 116
 117         if ((ret = sha1_file(argv[1], hash)) != 0) {
 118                 printf(" failed\n  ! Could not open or read %s\n\n", argv[1]);
 119                 goto exit;
 120         }
 121
 122         if ((ret = rsa_pkcs1_verify(&rsa, RSA_PUBLIC, RSA_SHA1,
 123                                     20, hash, buf)) != 0) {
 124                 printf(" failed\n  ! rsa_pkcs1_verify returned %d\n\n", ret);
 125                 goto exit;
 126         }
 127
 128         printf("\n  . OK (the decrypted SHA-1 hash matches)\n\n");
 129
 130         ret = 0;
 131
 132 exit:
 133
 134 #ifdef WIN32
 135         printf("  + Press Enter to exit this program.\n");
 136         fflush(stdout);
 137         getchar();
 138 #endif
 139
 140         return (ret);
 141 }