mbedtls/library/cipher.c

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/**
* \file cipher.c
*
* \brief Generic cipher wrapper for PolarSSL
*
* \author Adriaan de Jong <dejong@fox-it.com>
*
* Copyright (C) 2006-2010, Brainspark B.V.
*
* This file is part of PolarSSL (http://www.polarssl.org)
* Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
*
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "polarssl/config.h"
#if defined(POLARSSL_CIPHER_C)
#include "polarssl/cipher.h"
#include "polarssl/cipher_wrap.h"
#include <string.h>
#include <stdlib.h>
static const int supported_ciphers[] = {
#if defined(POLARSSL_AES_C)
POLARSSL_CIPHER_AES_128_CBC,
POLARSSL_CIPHER_AES_192_CBC,
POLARSSL_CIPHER_AES_256_CBC,
#endif /* defined(POLARSSL_AES_C) */
#if defined(POLARSSL_CAMELLIA_C)
POLARSSL_CIPHER_CAMELLIA_128_CBC,
POLARSSL_CIPHER_CAMELLIA_192_CBC,
POLARSSL_CIPHER_CAMELLIA_256_CBC,
#endif /* defined(POLARSSL_CAMELLIA_C) */
#if defined(POLARSSL_DES_C)
POLARSSL_CIPHER_DES_CBC,
POLARSSL_CIPHER_DES_EDE_CBC,
POLARSSL_CIPHER_DES_EDE3_CBC,
#endif /* defined(POLARSSL_DES_C) */
0
};
const int *cipher_list( void )
{
return supported_ciphers;
}
const cipher_info_t *cipher_info_from_type( cipher_type_t cipher_type )
{
/* Find static cipher information */
switch ( cipher_type )
{
#if defined(POLARSSL_AES_C)
case POLARSSL_CIPHER_AES_128_CBC:
return &aes_128_cbc_info;
case POLARSSL_CIPHER_AES_192_CBC:
return &aes_192_cbc_info;
case POLARSSL_CIPHER_AES_256_CBC:
return &aes_256_cbc_info;
#endif
#if defined(POLARSSL_CAMELLIA_C)
case POLARSSL_CIPHER_CAMELLIA_128_CBC:
return &camellia_128_cbc_info;
case POLARSSL_CIPHER_CAMELLIA_192_CBC:
return &camellia_192_cbc_info;
case POLARSSL_CIPHER_CAMELLIA_256_CBC:
return &camellia_256_cbc_info;
#endif
#if defined(POLARSSL_DES_C)
case POLARSSL_CIPHER_DES_CBC:
return &des_cbc_info;
case POLARSSL_CIPHER_DES_EDE_CBC:
return &des_ede_cbc_info;
case POLARSSL_CIPHER_DES_EDE3_CBC:
return &des_ede3_cbc_info;
#endif
default:
return NULL;
}
}
const cipher_info_t *cipher_info_from_string( const char *cipher_name )
{
if( NULL == cipher_name )
return NULL;
/* Get the appropriate digest information */
#if defined(POLARSSL_CAMELLIA_C)
if( !strcasecmp( "CAMELLIA-128-CBC", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_CAMELLIA_128_CBC );
if( !strcasecmp( "CAMELLIA-192-CBC", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_CAMELLIA_192_CBC );
if( !strcasecmp( "CAMELLIA-256-CBC", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_CAMELLIA_256_CBC );
#endif
#if defined(POLARSSL_AES_C)
if( !strcasecmp( "AES-128-CBC", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_AES_128_CBC );
if( !strcasecmp( "AES-192-CBC", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_AES_192_CBC );
if( !strcasecmp( "AES-256-CBC", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_AES_256_CBC );
#endif
#if defined(POLARSSL_DES_C)
if( !strcasecmp( "DES-CBC", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_DES_CBC );
if( !strcasecmp( "DES-EDE-CBC", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_DES_EDE_CBC );
if( !strcasecmp( "DES-EDE3-CBC", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_DES_EDE3_CBC );
#endif
return NULL;
}
int cipher_init_ctx( cipher_context_t *ctx, const cipher_info_t *cipher_info )
{
if( NULL == cipher_info || NULL == ctx )
return 1;
memset( ctx, 0, sizeof( ctx ) );
if( NULL == ( ctx->cipher_ctx = cipher_info->ctx_alloc_func() ) )
return 2;
ctx->cipher_info = cipher_info;
return 0;
}
int cipher_free_ctx( cipher_context_t *ctx )
{
if( ctx == NULL || ctx->cipher_info == NULL )
return 1;
ctx->cipher_info->ctx_free_func( ctx->cipher_ctx );
return 0;
}
int cipher_setkey( cipher_context_t *ctx, const unsigned char *key,
int key_length, const operation_t operation )
{
if( NULL == ctx || NULL == ctx->cipher_info )
return 1;
ctx->key_length = key_length;
ctx->operation = operation;
if (POLARSSL_ENCRYPT == operation)
return ctx->cipher_info->setkey_enc_func( ctx->cipher_ctx, key,
ctx->key_length );
if (POLARSSL_DECRYPT == operation)
return ctx->cipher_info->setkey_dec_func( ctx->cipher_ctx, key,
ctx->key_length );
return 1;
}
int cipher_reset( cipher_context_t *ctx, const unsigned char *iv )
{
if( NULL == ctx || NULL == ctx->cipher_info || NULL == iv )
return 1;
ctx->unprocessed_len = 0;
memcpy( ctx->iv, iv, cipher_get_iv_size( ctx ) );
return 0;
}
int cipher_update( cipher_context_t *ctx, const unsigned char *input, int ilen,
unsigned char *output, int *olen )
{
int copy_len = 0;
if( NULL == ctx || NULL == ctx->cipher_info || NULL == olen ||
input == output )
{
return 1;
}
*olen = 0;
if( ctx->cipher_info->mode == POLARSSL_MODE_CBC )
{
/*
* If there is not enough data for a full block, cache it.
*/
if( ( ctx->operation == POLARSSL_DECRYPT &&
ilen + ctx->unprocessed_len <= cipher_get_block_size( ctx ) ) ||
( ctx->operation == POLARSSL_ENCRYPT &&
ilen + ctx->unprocessed_len < cipher_get_block_size( ctx ) ) )
{
memcpy( &( ctx->unprocessed_data[ctx->unprocessed_len] ), input,
ilen );
ctx->unprocessed_len += ilen;
return 0;
}
/*
* Process cached data first
*/
if( ctx->unprocessed_len != 0 )
{
copy_len = cipher_get_block_size( ctx ) - ctx->unprocessed_len;
memcpy( &( ctx->unprocessed_data[ctx->unprocessed_len] ), input,
copy_len );
if( 0 != ctx->cipher_info->cbc_func( ctx->cipher_ctx,
ctx->operation, cipher_get_block_size( ctx ), ctx->iv,
ctx->unprocessed_data, output) )
{
return 1;
}
*olen += cipher_get_block_size( ctx );
output += cipher_get_block_size( ctx );
ctx->unprocessed_len = 0;
input += copy_len;
ilen -= copy_len;
}
/*
* Cache final, incomplete block
*/
if( 0 != ilen )
{
copy_len = ilen % cipher_get_block_size( ctx );
if( copy_len == 0 && ctx->operation == POLARSSL_DECRYPT )
copy_len = cipher_get_block_size(ctx);
memcpy( ctx->unprocessed_data, &( input[ilen - copy_len] ),
copy_len );
ctx->unprocessed_len += copy_len;
ilen -= copy_len;
}
/*
* Process remaining full blocks
*/
if( ilen )
{
if( 0 != ctx->cipher_info->cbc_func( ctx->cipher_ctx,
ctx->operation, ilen, ctx->iv, input, output ) )
{
return 1;
}
*olen += ilen;
}
return 0;
}
return 1;
}
static void add_pkcs_padding( unsigned char *output, unsigned char output_len,
int data_len )
{
unsigned char padding_len = output_len - data_len;
unsigned char i = 0;
for( i = 0; i < padding_len; i++ )
output[data_len + i] = padding_len;
}
static int get_pkcs_padding( unsigned char *input, unsigned char input_len,
int *data_len)
{
int i = 0;
unsigned char padding_len = 0;
if( NULL == input || NULL == data_len )
return 1;
padding_len = input[input_len - 1];
if( padding_len > input_len )
return 2;
for( i = input_len - padding_len; i < input_len; i++ )
if( input[i] != padding_len )
return 2;
*data_len = input_len - padding_len;
return 0;
}
int cipher_finish( cipher_context_t *ctx, unsigned char *output, int *olen)
{
if( NULL == ctx || NULL == ctx->cipher_info || NULL == olen )
return 1;
*olen = 0;
if( POLARSSL_MODE_CBC == ctx->cipher_info->mode )
{
if( POLARSSL_ENCRYPT == ctx->operation )
{
add_pkcs_padding( ctx->unprocessed_data, cipher_get_iv_size( ctx ),
ctx->unprocessed_len );
}
else if ( cipher_get_block_size( ctx ) != ctx->unprocessed_len )
{
/* For decrypt operations, expect a full block */
return 1;
}
/* cipher block */
if( 0 != ctx->cipher_info->cbc_func( ctx->cipher_ctx, ctx->operation,
cipher_get_block_size( ctx ), ctx->iv, ctx->unprocessed_data,
output ) )
{
return 1;
}
/* Set output size for decryption */
if( POLARSSL_DECRYPT == ctx->operation )
return get_pkcs_padding( output, cipher_get_block_size( ctx ), olen );
/* Set output size for encryption */
*olen = cipher_get_block_size( ctx );
return 0;
}
return 1;
}
#if defined(POLARSSL_SELF_TEST)
#include <stdio.h>
#define ASSERT(x) if (!(x)) { \
printf( "failed with %i at %s\n", value, (#x) ); \
return( 1 ); \
}
/*
* Checkup routine
*/
int cipher_self_test( int verbose )
{
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((void) verbose);
return( 0 );
}
#endif
#endif