134 lines
3.2 KiB
C
134 lines
3.2 KiB
C
/*
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* RSA/SHA-1 signature verification program
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*
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* Copyright (C) 2006-2007 Christophe Devine
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#ifndef _CRT_SECURE_NO_DEPRECATE
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#define _CRT_SECURE_NO_DEPRECATE 1
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#endif
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#include <string.h>
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#include <stdio.h>
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#include "polarssl/rsa.h"
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#include "polarssl/sha1.h"
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int main( int argc, char *argv[] )
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{
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FILE *f;
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int ret, i, c;
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rsa_context rsa;
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unsigned char hash[20];
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unsigned char buf[512];
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ret = 1;
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if( argc != 2 )
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{
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printf( "usage: rsa_verify <filename>\n" );
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#ifdef WIN32
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printf( "\n" );
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#endif
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goto exit;
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}
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printf( "\n . Reading public key from rsa_pub.txt" );
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fflush( stdout );
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if( ( f = fopen( "rsa_pub.txt", "rb" ) ) == NULL )
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{
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printf( " failed\n ! Could not open rsa_pub.txt\n" \
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" ! Please run rsa_genkey first\n\n" );
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goto exit;
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}
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rsa_init( &rsa, RSA_PKCS_V15, 0, NULL, NULL );
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if( ( ret = mpi_read_file( &rsa.N, 16, f ) ) != 0 ||
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( ret = mpi_read_file( &rsa.E, 16, f ) ) != 0 )
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{
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printf( " failed\n ! mpi_read_file returned %d\n\n", ret );
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goto exit;
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}
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rsa.len = ( mpi_msb( &rsa.N ) + 7 ) >> 3;
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fclose( f );
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/*
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* Extract the RSA signature from the text file
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*/
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ret = 1;
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i = strlen( argv[1] );
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memcpy( argv[1] + i, ".sig", 5 );
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if( ( f = fopen( argv[1], "rb" ) ) == NULL )
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{
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printf( "\n ! Could not open %s\n\n", argv[1] );
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goto exit;
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}
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argv[1][i] = '\0', i = 0;
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while( fscanf( f, "%02X", &c ) > 0 &&
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i < (int) sizeof( buf ) )
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buf[i++] = (unsigned char) c;
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fclose( f );
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if( i != rsa.len )
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{
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printf( "\n ! Invalid RSA signature format\n\n" );
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goto exit;
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}
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/*
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* Compute the SHA-1 hash of the input file and compare
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* it with the hash decrypted from the RSA signature.
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*/
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printf( "\n . Verifying the RSA/SHA-1 signature" );
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fflush( stdout );
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if( ( ret = sha1_file( argv[1], hash ) ) != 0 )
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{
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printf( " failed\n ! Could not open or read %s\n\n", argv[1] );
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goto exit;
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}
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if( ( ret = rsa_pkcs1_verify( &rsa, RSA_PUBLIC, RSA_SHA1,
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20, hash, buf ) ) != 0 )
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{
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printf( " failed\n ! rsa_pkcs1_verify returned %d\n\n", ret );
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goto exit;
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}
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printf( "\n . OK (the decrypted SHA-1 hash matches)\n\n" );
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ret = 0;
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exit:
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#ifdef WIN32
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printf( " + Press Enter to exit this program.\n" );
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fflush( stdout ); getchar();
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#endif
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return( ret );
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}
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