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polarssl/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) 2006-2013, 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"
#if defined(POLARSSL_GCM_C)
#include "polarssl/gcm.h"
#endif
#include <stdlib.h>
#if defined(POLARSSL_ARC4_C) || defined(POLARSSL_CIPHER_NULL_CIPHER)
#define POLARSSL_CIPHER_MODE_STREAM
#endif
#if defined(_MSC_VER) && !defined strcasecmp && !defined(EFIX64) && \
!defined(EFI32)
#define strcasecmp _stricmp
#endif
static int supported_init = 0;
const int *cipher_list( void )
{
const cipher_definition_t *def;
int *type;
if( ! supported_init )
{
def = cipher_definitions;
type = supported_ciphers;
while( def->type != 0 )
*type++ = (*def++).type;
*type = 0;
supported_init = 1;
}
return supported_ciphers;
}
const cipher_info_t *cipher_info_from_type( const cipher_type_t cipher_type )
{
const cipher_definition_t *def;
for( def = cipher_definitions; def->info != NULL; def++ )
if( def->type == cipher_type )
return( def->info );
return NULL;
}
const cipher_info_t *cipher_info_from_string( const char *cipher_name )
{
const cipher_definition_t *def;
if( NULL == cipher_name )
return NULL;
for( def = cipher_definitions; def->info != NULL; def++ )
if( ! strcasecmp( def->info->name, cipher_name ) )
return( def->info );
return NULL;
}
const cipher_info_t *cipher_info_from_values( const cipher_id_t cipher_id,
int key_length,
const cipher_mode_t mode )
{
const cipher_definition_t *def;
for( def = cipher_definitions; def->info != NULL; def++ )
if( def->info->base->cipher == cipher_id &&
def->info->key_length == (unsigned) key_length &&
def->info->mode == mode )
return( def->info );
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;
#if defined(POLARSSL_CIPHER_MODE_WITH_PADDING)
/*
* 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
#endif /* POLARSSL_CIPHER_MODE_WITH_PADDING */
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;
if( (int) ctx->cipher_info->key_length != key_length )
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
ctx->key_length = key_length;
ctx->operation = operation;
/*
* 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_set_iv( cipher_context_t *ctx,
const unsigned char *iv, size_t iv_len )
{
size_t actual_iv_size;
if( NULL == ctx || NULL == ctx->cipher_info || NULL == iv )
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
/* avoid buffer overflow in ctx->iv */
if( iv_len > POLARSSL_MAX_IV_LENGTH )
return POLARSSL_ERR_CIPHER_FEATURE_UNAVAILABLE;
if( ctx->cipher_info->accepts_variable_iv_size )
actual_iv_size = iv_len;
else
{
actual_iv_size = ctx->cipher_info->iv_size;
/* avoid reading past the end of input buffer */
if( actual_iv_size > iv_len )
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
}
memcpy( ctx->iv, iv, actual_iv_size );
ctx->iv_size = actual_iv_size;
return 0;
}
int cipher_reset( cipher_context_t *ctx )
{
if( NULL == ctx || NULL == ctx->cipher_info )
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
ctx->unprocessed_len = 0;
return 0;
}
#if defined(POLARSSL_CIPHER_MODE_AEAD)
int cipher_update_ad( cipher_context_t *ctx,
const unsigned char *ad, size_t ad_len )
{
if( NULL == ctx || NULL == ctx->cipher_info )
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
#if defined(POLARSSL_GCM_C)
if( POLARSSL_MODE_GCM == ctx->cipher_info->mode )
{
return gcm_starts( (gcm_context *) ctx->cipher_ctx, ctx->operation,
ctx->iv, ctx->iv_size, ad, ad_len );
}
#endif
return 0;
}
#endif /* POLARSSL_CIPHER_MODE_AEAD */
int cipher_update( cipher_context_t *ctx, const unsigned char *input, size_t ilen,
unsigned char *output, size_t *olen )
{
int ret;
if( NULL == ctx || NULL == ctx->cipher_info || NULL == olen )
{
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
}
*olen = 0;
if( ctx->cipher_info->mode == POLARSSL_MODE_ECB )
{
if( ilen != cipher_get_block_size( ctx ) )
return POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED;
*olen = ilen;
if( 0 != ( ret = ctx->cipher_info->base->ecb_func( ctx->cipher_ctx,
ctx->operation, input, output ) ) )
{
return ret;
}
return 0;
}
#if defined(POLARSSL_GCM_C)
if( ctx->cipher_info->mode == POLARSSL_MODE_GCM )
{
*olen = ilen;
return gcm_update( (gcm_context *) ctx->cipher_ctx, ilen, input,
output );
}
#endif
if( input == output &&
( ctx->unprocessed_len != 0 || ilen % cipher_get_block_size( ctx ) ) )
{
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
}
#if defined(POLARSSL_CIPHER_MODE_CBC)
if( ctx->cipher_info->mode == POLARSSL_MODE_CBC )
{
size_t copy_len = 0;
/*
* 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;
}
#endif /* POLARSSL_CIPHER_MODE_CBC */
#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
#if defined(POLARSSL_CIPHER_MODE_STREAM)
if( ctx->cipher_info->mode == POLARSSL_MODE_STREAM )
{
if( 0 != ( ret = ctx->cipher_info->base->stream_func( ctx->cipher_ctx,
ilen, input, output ) ) )
{
return ret;
}
*olen = ilen;
return 0;
}
#endif
return POLARSSL_ERR_CIPHER_FEATURE_UNAVAILABLE;
}
#if defined(POLARSSL_CIPHER_MODE_WITH_PADDING)
#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;
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 )
{
size_t i, pad_idx;
unsigned char padding_len, bad = 0;
if( NULL == input || NULL == data_len )
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
padding_len = input[input_len - 1];
*data_len = input_len - padding_len;
/* Avoid logical || since it results in a branch */
bad |= padding_len > input_len;
bad |= padding_len == 0;
/* The number of bytes checked must be independent of padding_len,
* so pick input_len, which is usually 8 or 16 (one block) */
pad_idx = input_len - padding_len;
for( i = 0; i < input_len; i++ )
bad |= ( input[i] ^ padding_len ) * ( i >= pad_idx );
return POLARSSL_ERR_CIPHER_INVALID_PADDING * (bad != 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 )
{
size_t i;
unsigned char done = 0, prev_done, bad;
if( NULL == input || NULL == data_len )
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
bad = 0xFF;
*data_len = 0;
for( i = input_len; i > 0; i-- )
{
prev_done = done;
done |= ( input[i-1] != 0 );
*data_len |= ( i - 1 ) * ( done != prev_done );
bad &= ( input[i-1] ^ 0x80 ) | ( done == prev_done );
}
return POLARSSL_ERR_CIPHER_INVALID_PADDING * (bad != 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 )
{
size_t i, pad_idx;
unsigned char padding_len, bad = 0;
if( NULL == input || NULL == data_len )
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
padding_len = input[input_len - 1];
*data_len = input_len - padding_len;
/* Avoid logical || since it results in a branch */
bad |= padding_len > input_len;
bad |= padding_len == 0;
/* The number of bytes checked must be independent of padding_len */
pad_idx = input_len - padding_len;
for( i = 0; i < input_len - 1; i++ )
bad |= input[i] * ( i >= pad_idx );
return POLARSSL_ERR_CIPHER_INVALID_PADDING * (bad != 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 )
{
size_t 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 )
{
size_t i;
unsigned char done = 0, prev_done;
if( NULL == input || NULL == data_len )
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
*data_len = 0;
for( i = input_len; i > 0; i-- )
{
prev_done = done;
done |= ( input[i-1] != 0 );
*data_len |= i * ( done != prev_done );
}
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;
}
#endif /* POLARSSL_CIPHER_MODE_WITH_PADDING */
int cipher_finish( cipher_context_t *ctx,
unsigned char *output, size_t *olen )
{
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_GCM == ctx->cipher_info->mode ||
POLARSSL_MODE_STREAM == ctx->cipher_info->mode )
{
return 0;
}
if( POLARSSL_MODE_ECB == ctx->cipher_info->mode )
{
if( ctx->unprocessed_len != 0 )
return POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED;
return 0;
}
#if defined(POLARSSL_CIPHER_MODE_CBC)
if( POLARSSL_MODE_CBC == ctx->cipher_info->mode )
{
int ret = 0;
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;
}
#else
((void) output);
#endif /* POLARSSL_CIPHER_MODE_CBC */
return POLARSSL_ERR_CIPHER_FEATURE_UNAVAILABLE;
}
#if defined(POLARSSL_CIPHER_MODE_WITH_PADDING)
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;
}
#endif /* POLARSSL_CIPHER_MODE_WITH_PADDING */
#if defined(POLARSSL_CIPHER_MODE_AEAD)
int cipher_write_tag( cipher_context_t *ctx,
unsigned char *tag, size_t tag_len )
{
if( NULL == ctx || NULL == ctx->cipher_info || NULL == tag )
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
if( POLARSSL_ENCRYPT != ctx->operation )
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
#if defined(POLARSSL_GCM_C)
if( POLARSSL_MODE_GCM == ctx->cipher_info->mode )
return gcm_finish( (gcm_context *) ctx->cipher_ctx, tag, tag_len );
#endif
return 0;
}
int cipher_check_tag( cipher_context_t *ctx,
const unsigned char *tag, size_t tag_len )
{
int ret;
if( NULL == ctx || NULL == ctx->cipher_info ||
POLARSSL_DECRYPT != ctx->operation )
{
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
}
#if defined(POLARSSL_GCM_C)
if( POLARSSL_MODE_GCM == ctx->cipher_info->mode )
{
unsigned char check_tag[16];
size_t i;
int diff;
if( tag_len > sizeof( check_tag ) )
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
if( 0 != ( ret = gcm_finish( (gcm_context *) ctx->cipher_ctx,
check_tag, tag_len ) ) )
{
return( ret );
}
/* Check the tag in "constant-time" */
for( diff = 0, i = 0; i < tag_len; i++ )
diff |= tag[i] ^ check_tag[i];
if( diff != 0 )
return( POLARSSL_ERR_CIPHER_AUTH_FAILED );
return( 0 );
}
#endif
return( 0 );
}
#endif /* POLARSSL_CIPHER_MODE_AEAD */
#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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