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mbedtls/library/cipher.c
Paul Bakker 48e93c84b7 Made padding modes configurable from config.h
2013-08-14 14:02:48 +02:00

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/**
* \file cipher.c
*
* \brief Generic cipher wrapper for PolarSSL
*
* \author Adriaan de Jong <dejong@fox-it.com>
*
* Copyright (C) 2006-2013, 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 <stdlib.h>
#if defined _MSC_VER && !defined strcasecmp
#define strcasecmp _stricmp
#endif
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,
#if defined(POLARSSL_CIPHER_MODE_CFB)
POLARSSL_CIPHER_AES_128_CFB128,
POLARSSL_CIPHER_AES_192_CFB128,
POLARSSL_CIPHER_AES_256_CFB128,
#endif /* defined(POLARSSL_CIPHER_MODE_CFB) */
#if defined(POLARSSL_CIPHER_MODE_CTR)
POLARSSL_CIPHER_AES_128_CTR,
POLARSSL_CIPHER_AES_192_CTR,
POLARSSL_CIPHER_AES_256_CTR,
#endif /* defined(POLARSSL_CIPHER_MODE_CTR) */
#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,
#if defined(POLARSSL_CIPHER_MODE_CFB)
POLARSSL_CIPHER_CAMELLIA_128_CFB128,
POLARSSL_CIPHER_CAMELLIA_192_CFB128,
POLARSSL_CIPHER_CAMELLIA_256_CFB128,
#endif /* defined(POLARSSL_CIPHER_MODE_CFB) */
#if defined(POLARSSL_CIPHER_MODE_CTR)
POLARSSL_CIPHER_CAMELLIA_128_CTR,
POLARSSL_CIPHER_CAMELLIA_192_CTR,
POLARSSL_CIPHER_CAMELLIA_256_CTR,
#endif /* defined(POLARSSL_CIPHER_MODE_CTR) */
#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) */
#if defined(POLARSSL_BLOWFISH_C)
POLARSSL_CIPHER_BLOWFISH_CBC,
#if defined(POLARSSL_CIPHER_MODE_CFB)
POLARSSL_CIPHER_BLOWFISH_CFB64,
#endif /* defined(POLARSSL_CIPHER_MODE_CFB) */
#if defined(POLARSSL_CIPHER_MODE_CTR)
POLARSSL_CIPHER_BLOWFISH_CTR,
#endif /* defined(POLARSSL_CIPHER_MODE_CTR) */
#endif /* defined(POLARSSL_BLOWFISH_C) */
#if defined(POLARSSL_CIPHER_NULL_CIPHER)
POLARSSL_CIPHER_NULL,
#endif /* defined(POLARSSL_CIPHER_NULL_CIPHER) */
0
};
const int *cipher_list( void )
{
return supported_ciphers;
}
const cipher_info_t *cipher_info_from_type( const 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;
#if defined(POLARSSL_CIPHER_MODE_CFB)
case POLARSSL_CIPHER_AES_128_CFB128:
return &aes_128_cfb128_info;
case POLARSSL_CIPHER_AES_192_CFB128:
return &aes_192_cfb128_info;
case POLARSSL_CIPHER_AES_256_CFB128:
return &aes_256_cfb128_info;
#endif /* defined(POLARSSL_CIPHER_MODE_CFB) */
#if defined(POLARSSL_CIPHER_MODE_CTR)
case POLARSSL_CIPHER_AES_128_CTR:
return &aes_128_ctr_info;
case POLARSSL_CIPHER_AES_192_CTR:
return &aes_192_ctr_info;
case POLARSSL_CIPHER_AES_256_CTR:
return &aes_256_ctr_info;
#endif /* defined(POLARSSL_CIPHER_MODE_CTR) */
#if defined(POLARSSL_GCM_C)
case POLARSSL_CIPHER_AES_128_GCM:
return &aes_128_gcm_info;
case POLARSSL_CIPHER_AES_256_GCM:
return &aes_256_gcm_info;
#endif /* defined(POLARSSL_GCM_C) */
#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;
#if defined(POLARSSL_CIPHER_MODE_CFB)
case POLARSSL_CIPHER_CAMELLIA_128_CFB128:
return &camellia_128_cfb128_info;
case POLARSSL_CIPHER_CAMELLIA_192_CFB128:
return &camellia_192_cfb128_info;
case POLARSSL_CIPHER_CAMELLIA_256_CFB128:
return &camellia_256_cfb128_info;
#endif /* defined(POLARSSL_CIPHER_MODE_CFB) */
#if defined(POLARSSL_CIPHER_MODE_CTR)
case POLARSSL_CIPHER_CAMELLIA_128_CTR:
return &camellia_128_ctr_info;
case POLARSSL_CIPHER_CAMELLIA_192_CTR:
return &camellia_192_ctr_info;
case POLARSSL_CIPHER_CAMELLIA_256_CTR:
return &camellia_256_ctr_info;
#endif /* defined(POLARSSL_CIPHER_MODE_CTR) */
#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
#if defined(POLARSSL_ARC4_C)
case POLARSSL_CIPHER_ARC4_128:
return &arc4_128_info;
#endif
#if defined(POLARSSL_BLOWFISH_C)
case POLARSSL_CIPHER_BLOWFISH_CBC:
return &blowfish_cbc_info;
#if defined(POLARSSL_CIPHER_MODE_CFB)
case POLARSSL_CIPHER_BLOWFISH_CFB64:
return &blowfish_cfb64_info;
#endif /* defined(POLARSSL_CIPHER_MODE_CFB) */
#if defined(POLARSSL_CIPHER_MODE_CTR)
case POLARSSL_CIPHER_BLOWFISH_CTR:
return &blowfish_ctr_info;
#endif /* defined(POLARSSL_CIPHER_MODE_CTR) */
#endif
#if defined(POLARSSL_CIPHER_NULL_CIPHER)
case POLARSSL_CIPHER_NULL:
return &null_cipher_info;
#endif /* defined(POLARSSL_CIPHER_NULL_CIPHER) */
default:
return NULL;
}
}
const cipher_info_t *cipher_info_from_string( const char *cipher_name )
{
if( NULL == cipher_name )
return NULL;
/* Get the appropriate cipher 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 );
#if defined(POLARSSL_CIPHER_MODE_CFB)
if( !strcasecmp( "CAMELLIA-128-CFB128", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_CAMELLIA_128_CFB128 );
if( !strcasecmp( "CAMELLIA-192-CFB128", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_CAMELLIA_192_CFB128 );
if( !strcasecmp( "CAMELLIA-256-CFB128", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_CAMELLIA_256_CFB128 );
#endif /* defined(POLARSSL_CIPHER_MODE_CFB) */
#if defined(POLARSSL_CIPHER_MODE_CTR)
if( !strcasecmp( "CAMELLIA-128-CTR", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_CAMELLIA_128_CTR );
if( !strcasecmp( "CAMELLIA-192-CTR", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_CAMELLIA_192_CTR );
if( !strcasecmp( "CAMELLIA-256-CTR", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_CAMELLIA_256_CTR );
#endif /* defined(POLARSSL_CIPHER_MODE_CTR) */
#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 );
#if defined(POLARSSL_CIPHER_MODE_CFB)
if( !strcasecmp( "AES-128-CFB128", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_AES_128_CFB128 );
if( !strcasecmp( "AES-192-CFB128", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_AES_192_CFB128 );
if( !strcasecmp( "AES-256-CFB128", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_AES_256_CFB128 );
#endif /* defined(POLARSSL_CIPHER_MODE_CFB) */
#if defined(POLARSSL_CIPHER_MODE_CTR)
if( !strcasecmp( "AES-128-CTR", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_AES_128_CTR );
if( !strcasecmp( "AES-192-CTR", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_AES_192_CTR );
if( !strcasecmp( "AES-256-CTR", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_AES_256_CTR );
#endif /* defined(POLARSSL_CIPHER_MODE_CTR) */
#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
#if defined(POLARSSL_BLOWFISH_C)
if( !strcasecmp( "BLOWFISH-CBC", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_BLOWFISH_CBC );
#if defined(POLARSSL_CIPHER_MODE_CFB)
if( !strcasecmp( "BLOWFISH-CFB64", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_BLOWFISH_CFB64 );
#endif /* defined(POLARSSL_CIPHER_MODE_CFB) */
#if defined(POLARSSL_CIPHER_MODE_CTR)
if( !strcasecmp( "BLOWFISH-CTR", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_BLOWFISH_CTR );
#endif /* defined(POLARSSL_CIPHER_MODE_CTR) */
#endif
#if defined(POLARSSL_CIPHER_NULL_CIPHER)
if( !strcasecmp( "NULL", cipher_name ) )
return cipher_info_from_type( POLARSSL_CIPHER_NULL );
#endif /* defined(POLARSSL_CIPHER_NULL_CIPHER) */
return NULL;
}
int cipher_init_ctx( cipher_context_t *ctx, const cipher_info_t *cipher_info )
{
if( NULL == cipher_info || NULL == ctx )
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
memset( ctx, 0, sizeof( cipher_context_t ) );
if( NULL == ( ctx->cipher_ctx = cipher_info->base->ctx_alloc_func() ) )
return POLARSSL_ERR_CIPHER_ALLOC_FAILED;
ctx->cipher_info = cipher_info;
/*
* Ignore possible errors caused by a cipher mode that doesn't use padding
*/
#if defined(POLARSSL_CIPHER_PADDING_PKCS7)
(void) cipher_set_padding_mode( ctx, POLARSSL_PADDING_PKCS7 );
#else
(void) cipher_set_padding_mode( ctx, POLARSSL_PADDING_NONE );
#endif
return 0;
}
int cipher_free_ctx( cipher_context_t *ctx )
{
if( ctx == NULL || ctx->cipher_info == NULL )
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
ctx->cipher_info->base->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 POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
ctx->key_length = key_length;
ctx->operation = operation;
#if defined(POLARSSL_CIPHER_NULL_CIPHER)
if( ctx->cipher_info->mode == POLARSSL_MODE_NULL )
return 0;
#endif /* defined(POLARSSL_CIPHER_NULL_CIPHER) */
/*
* For CFB and CTR mode always use the encryption key schedule
*/
if( POLARSSL_ENCRYPT == operation ||
POLARSSL_MODE_CFB == ctx->cipher_info->mode ||
POLARSSL_MODE_CTR == ctx->cipher_info->mode )
{
return ctx->cipher_info->base->setkey_enc_func( ctx->cipher_ctx, key,
ctx->key_length );
}
if( POLARSSL_DECRYPT == operation )
return ctx->cipher_info->base->setkey_dec_func( ctx->cipher_ctx, key,
ctx->key_length );
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
}
int cipher_reset( cipher_context_t *ctx, const unsigned char *iv )
{
if( NULL == ctx || NULL == ctx->cipher_info || NULL == iv )
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
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, size_t ilen,
unsigned char *output, size_t *olen )
{
int ret;
size_t copy_len = 0;
*olen = 0;
if( NULL == ctx || NULL == ctx->cipher_info || NULL == olen )
{
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
}
if( input == output &&
( ctx->unprocessed_len != 0 || ilen % cipher_get_block_size( ctx ) ) )
{
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
}
#if defined(POLARSSL_CIPHER_NULL_CIPHER)
if( ctx->cipher_info->mode == POLARSSL_MODE_NULL )
{
*olen = ilen;
if( output == input )
return( 0 );
memcpy( output, input, ilen );
return 0;
}
#endif /* defined(POLARSSL_CIPHER_NULL_CIPHER) */
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 != ( ret = ctx->cipher_info->base->cbc_func( ctx->cipher_ctx,
ctx->operation, cipher_get_block_size( ctx ), ctx->iv,
ctx->unprocessed_data, output ) ) )
{
return ret;
}
*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 != ( ret = ctx->cipher_info->base->cbc_func( ctx->cipher_ctx,
ctx->operation, ilen, ctx->iv, input, output ) ) )
{
return ret;
}
*olen += ilen;
}
return 0;
}
#if defined(POLARSSL_CIPHER_MODE_CFB)
if( ctx->cipher_info->mode == POLARSSL_MODE_CFB )
{
if( 0 != ( ret = ctx->cipher_info->base->cfb_func( ctx->cipher_ctx,
ctx->operation, ilen, &ctx->unprocessed_len, ctx->iv,
input, output ) ) )
{
return ret;
}
*olen = ilen;
return 0;
}
#endif
#if defined(POLARSSL_CIPHER_MODE_CTR)
if( ctx->cipher_info->mode == POLARSSL_MODE_CTR )
{
if( 0 != ( ret = ctx->cipher_info->base->ctr_func( ctx->cipher_ctx,
ilen, &ctx->unprocessed_len, ctx->iv,
ctx->unprocessed_data, input, output ) ) )
{
return ret;
}
*olen = ilen;
return 0;
}
#endif
return POLARSSL_ERR_CIPHER_FEATURE_UNAVAILABLE;
}
#if defined(POLARSSL_CIPHER_PADDING_PKCS7)
/*
* PKCS7 (and PKCS5) padding: fill with ll bytes, with ll = padding_len
*/
static void add_pkcs_padding( unsigned char *output, size_t output_len,
size_t data_len )
{
size_t padding_len = output_len - data_len;
unsigned char i = 0;
for( i = 0; i < padding_len; i++ )
output[data_len + i] = (unsigned char) padding_len;
}
static int get_pkcs_padding( unsigned char *input, size_t input_len,
size_t *data_len )
{
unsigned int i, padding_len = 0;
if( NULL == input || NULL == data_len )
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
padding_len = input[input_len - 1];
if( padding_len > input_len || padding_len == 0 )
return POLARSSL_ERR_CIPHER_INVALID_PADDING;
for( i = input_len - padding_len; i < input_len; i++ )
if( input[i] != padding_len )
return POLARSSL_ERR_CIPHER_INVALID_PADDING;
*data_len = input_len - padding_len;
return 0;
}
#endif /* POLARSSL_CIPHER_PADDING_PKCS7 */
#if defined(POLARSSL_CIPHER_PADDING_ONE_AND_ZEROS)
/*
* One and zeros padding: fill with 80 00 ... 00
*/
static void add_one_and_zeros_padding( unsigned char *output,
size_t output_len, size_t data_len )
{
size_t padding_len = output_len - data_len;
unsigned char i = 0;
output[data_len] = 0x80;
for( i = 1; i < padding_len; i++ )
output[data_len + i] = 0x00;
}
static int get_one_and_zeros_padding( unsigned char *input, size_t input_len,
size_t *data_len )
{
unsigned char *p = input + input_len - 1;
if( NULL == input || NULL == data_len )
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
while( *p == 0x00 && p > input )
--p;
if( *p != 0x80 )
return POLARSSL_ERR_CIPHER_INVALID_PADDING;
*data_len = p - input;
return 0;
}
#endif /* POLARSSL_CIPHER_PADDING_ONE_AND_ZEROS */
#if defined(POLARSSL_CIPHER_PADDING_ZEROS_AND_LEN)
/*
* Zeros and len padding: fill with 00 ... 00 ll, where ll is padding length
*/
static void add_zeros_and_len_padding( unsigned char *output,
size_t output_len, size_t data_len )
{
size_t padding_len = output_len - data_len;
unsigned char i = 0;
for( i = 1; i < padding_len; i++ )
output[data_len + i - 1] = 0x00;
output[output_len - 1] = (unsigned char) padding_len;
}
static int get_zeros_and_len_padding( unsigned char *input, size_t input_len,
size_t *data_len )
{
unsigned int i, padding_len = 0;
if( NULL == input || NULL == data_len )
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
padding_len = input[input_len - 1];
if( padding_len > input_len || padding_len == 0 )
return POLARSSL_ERR_CIPHER_INVALID_PADDING;
for( i = input_len - padding_len; i < input_len - 1; i++ )
if( input[i] != 0x00 )
return POLARSSL_ERR_CIPHER_INVALID_PADDING;
*data_len = input_len - padding_len;
return 0;
}
#endif /* POLARSSL_CIPHER_PADDING_ZEROS_AND_LEN */
#if defined(POLARSSL_CIPHER_PADDING_ZEROS)
/*
* Zero padding: fill with 00 ... 00
*/
static void add_zeros_padding( unsigned char *output,
size_t output_len, size_t data_len )
{
unsigned char i;
for( i = data_len; i < output_len; i++ )
output[i] = 0x00;
}
static int get_zeros_padding( unsigned char *input, size_t input_len,
size_t *data_len )
{
unsigned char *p = input + input_len - 1;
if( NULL == input || NULL == data_len )
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
while( *p == 0x00 && p > input )
--p;
*data_len = *p == 0x00 ? 0 : p - input + 1;
return 0;
}
#endif /* POLARSSL_CIPHER_PADDING_ZEROS */
/*
* No padding: don't pad :)
*
* There is no add_padding function (check for NULL in cipher_finish)
* but a trivial get_padding function
*/
static int get_no_padding( unsigned char *input, size_t input_len,
size_t *data_len )
{
if( NULL == input || NULL == data_len )
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
*data_len = input_len;
return 0;
}
int cipher_finish( cipher_context_t *ctx, unsigned char *output, size_t *olen)
{
int ret = 0;
if( NULL == ctx || NULL == ctx->cipher_info || NULL == olen )
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
*olen = 0;
if( POLARSSL_MODE_CFB == ctx->cipher_info->mode ||
POLARSSL_MODE_CTR == ctx->cipher_info->mode ||
POLARSSL_MODE_NULL == ctx->cipher_info->mode )
{
return 0;
}
if( POLARSSL_MODE_CBC == ctx->cipher_info->mode )
{
if( POLARSSL_ENCRYPT == ctx->operation )
{
/* check for 'no padding' mode */
if( NULL == ctx->add_padding )
{
if( 0 != ctx->unprocessed_len )
return POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED;
return 0;
}
ctx->add_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,
* or an empty block if no padding
*/
if( NULL == ctx->add_padding && 0 == ctx->unprocessed_len )
return 0;
return POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED;
}
/* cipher block */
if( 0 != ( ret = ctx->cipher_info->base->cbc_func( ctx->cipher_ctx,
ctx->operation, cipher_get_block_size( ctx ), ctx->iv,
ctx->unprocessed_data, output ) ) )
{
return ret;
}
/* Set output size for decryption */
if( POLARSSL_DECRYPT == ctx->operation )
return ctx->get_padding( output, cipher_get_block_size( ctx ),
olen );
/* Set output size for encryption */
*olen = cipher_get_block_size( ctx );
return 0;
}
return POLARSSL_ERR_CIPHER_FEATURE_UNAVAILABLE;
}
int cipher_set_padding_mode( cipher_context_t *ctx, cipher_padding_t mode )
{
if( NULL == ctx ||
POLARSSL_MODE_CBC != ctx->cipher_info->mode )
{
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
}
switch( mode )
{
#if defined(POLARSSL_CIPHER_PADDING_PKCS7)
case POLARSSL_PADDING_PKCS7:
ctx->add_padding = add_pkcs_padding;
ctx->get_padding = get_pkcs_padding;
break;
#endif
#if defined(POLARSSL_CIPHER_PADDING_ONE_AND_ZEROS)
case POLARSSL_PADDING_ONE_AND_ZEROS:
ctx->add_padding = add_one_and_zeros_padding;
ctx->get_padding = get_one_and_zeros_padding;
break;
#endif
#if defined(POLARSSL_CIPHER_PADDING_ZEROS_AND_LEN)
case POLARSSL_PADDING_ZEROS_AND_LEN:
ctx->add_padding = add_zeros_and_len_padding;
ctx->get_padding = get_zeros_and_len_padding;
break;
#endif
#if defined(POLARSSL_CIPHER_PADDING_ZEROS)
case POLARSSL_PADDING_ZEROS:
ctx->add_padding = add_zeros_padding;
ctx->get_padding = get_zeros_padding;
break;
#endif
case POLARSSL_PADDING_NONE:
ctx->add_padding = NULL;
ctx->get_padding = get_no_padding;
break;
default:
return POLARSSL_ERR_CIPHER_FEATURE_UNAVAILABLE;
}
return 0;
}
#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 )
{
((void) verbose);
return( 0 );
}
#endif
#endif
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