102 lines
No EOL
2.7 KiB
C
102 lines
No EOL
2.7 KiB
C
/* Copyright (c) 2013 Sven Weidauer
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* Code is under the MIT license, see the LICENSE file.
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*/
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#include "Common.h"
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#include "Buffer.h"
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#include <CoreFoundation/CoreFoundation.h>
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#include <CommonCrypto/CommonCrypto.h>
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void ReadHeader( struct buffer *buf, struct header *header )
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{
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Read( buf, 4, header->magic );
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header->payload_size = Read32( buf );
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Read( buf, 8, header->header_md5 );
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Read( buf, 7, header->etl );
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Read( buf, 1, &header->unused1 );
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header->password_len = Read16( buf );
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header->padding_len = Read16( buf );
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Read( buf, 4, header->unused2 );
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Read( buf, 16, header->plaintext_md5 );
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}
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int main( int argc, const char *argv[] )
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{
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if (argc != 3) {
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fprintf( stderr, "Call %s <input> <output>\n", argv[0] );
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return 1;
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}
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struct buffer buf = { 0 };
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if (!OpenFile( &buf, argv[1] )) {
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fprintf( stderr, "Cannot open file %s\n", argv[1] );
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return 1;
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}
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printf( "Openend file, size: %zu\n", buf.length );
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struct header header = { 0 };
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ReadHeader( &buf, &header );
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if (memcmp( header.magic, "CFG1", 4 ) != 0) {
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fprintf( stderr, "Error: invalid magic\n" );
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return 1;
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}
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char header_data[HeaderSize];
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memcpy( header_data, buf.start, sizeof header_data );
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memset( &header_data[8], 0, 8 );
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unsigned char header_md[CC_MD5_DIGEST_LENGTH];
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CC_MD5( header_data, sizeof header_data, header_md );
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if (memcmp( header.header_md5, header_md, sizeof header.header_md5 ) != 0) {
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printf( "Warning: Header MD5 doesn't match\n" );
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}
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printf( "Payload size: %d\n", header.payload_size );
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printf( "Padding: %d\n", header.padding_len );
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printf( "Password len: %d\n", header.password_len );
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printf( "ETL: %s\n", header.etl );
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if (buf.length - header.payload_size != HeaderSize) {
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fprintf( stderr, "Error: Invalid file size\n" );
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return 1;
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}
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size_t plain_length = header.payload_size;
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void *plain = malloc( plain_length );
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if (!plain) {
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fprintf( stderr, "Error: Not enough memory for decryption\n" );
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return 1;
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}
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CCCryptorRef cryptor;
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size_t result_length = 0;
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if (CCCrypt( kCCDecrypt, kCCAlgorithmAES, kCCOptionECBMode, aes_key, sizeof aes_key, NULL, buf.next, plain_length, plain, plain_length, &result_length ) != kCCSuccess) {
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fprintf( stderr, "Error: Cannot decrypt\n" );
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return 1;
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}
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result_length -= header.padding_len;
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int fdout = open( argv[2], O_WRONLY | O_CREAT | O_TRUNC, 0600 );
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if (fdout < 0) {
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fprintf( stderr, "Error: cannot write output file\n" );
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return 1;
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}
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if (write( fdout, plain, result_length ) != result_length) {
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fprintf( stderr, "Error: cannot write output file\n" );
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return 1;
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}
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close( fdout );
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unsigned char md[CC_MD5_DIGEST_LENGTH];
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CC_MD5( plain, plain_length, md );
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if (memcmp( md, header.plaintext_md5, sizeof md ) != 0) {
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printf( "Warning: payload md5 doesn't match\n" );
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}
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} |