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mbedtls/library/cipher.c
Hanno Becker 1cb36530be Add psa_enabled field to cipher ctx and add dummy implementations 
This field determines whether a cipher context should
use an external implementation of the PSA Crypto API for
cryptographic operations, or Mbed TLS' own crypto library.

The commit also adds dummy implementations for the cipher API.
2018-11-22 14:03:39 +00:00

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/**
* \file cipher.c
*
* \brief Generic cipher wrapper for mbed TLS
*
* \author Adriaan de Jong <dejong@fox-it.com>
*
* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* This file is part of mbed TLS (https://tls.mbed.org)
*/
#if !defined(MBEDTLS_CONFIG_FILE)
#include "mbedtls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif
#if defined(MBEDTLS_CIPHER_C)
#include "mbedtls/cipher.h"
#include "mbedtls/cipher_internal.h"
#include "mbedtls/platform_util.h"
#include <stdlib.h>
#include <string.h>
#if defined(MBEDTLS_CHACHAPOLY_C)
#include "mbedtls/chachapoly.h"
#endif
#if defined(MBEDTLS_GCM_C)
#include "mbedtls/gcm.h"
#endif
#if defined(MBEDTLS_CCM_C)
#include "mbedtls/ccm.h"
#endif
#if defined(MBEDTLS_CHACHA20_C)
#include "mbedtls/chacha20.h"
#endif
#if defined(MBEDTLS_CMAC_C)
#include "mbedtls/cmac.h"
#endif
#if defined(MBEDTLS_USE_PSA_CRYPTO)
#include "psa/crypto.h"
#endif /* MBEDTLS_USE_PSA_CRYPTO */
#if defined(MBEDTLS_PLATFORM_C)
#include "mbedtls/platform.h"
#else
#define mbedtls_calloc calloc
#define mbedtls_free free
#endif
#if defined(MBEDTLS_GCM_C) || defined(MBEDTLS_CHACHAPOLY_C)
/* Compare the contents of two buffers in constant time.
* Returns 0 if the contents are bitwise identical, otherwise returns
* a non-zero value.
* This is currently only used by GCM and ChaCha20+Poly1305.
*/
static int mbedtls_constant_time_memcmp( const void *v1, const void *v2,
size_t len )
{
const unsigned char *p1 = (const unsigned char*) v1;
const unsigned char *p2 = (const unsigned char*) v2;
size_t i;
unsigned char diff;
for( diff = 0, i = 0; i < len; i++ )
diff |= p1[i] ^ p2[i];
return (int)diff;
}
#endif /* MBEDTLS_GCM_C || MBEDTLS_CHACHAPOLY_C */
static int supported_init = 0;
const int *mbedtls_cipher_list( void )
{
const mbedtls_cipher_definition_t *def;
int *type;
if( ! supported_init )
{
def = mbedtls_cipher_definitions;
type = mbedtls_cipher_supported;
while( def->type != 0 )
*type++ = (*def++).type;
*type = 0;
supported_init = 1;
}
return( mbedtls_cipher_supported );
}
const mbedtls_cipher_info_t *mbedtls_cipher_info_from_type(
const mbedtls_cipher_type_t cipher_type )
{
const mbedtls_cipher_definition_t *def;
for( def = mbedtls_cipher_definitions; def->info != NULL; def++ )
if( def->type == cipher_type )
return( def->info );
return( NULL );
}
const mbedtls_cipher_info_t *mbedtls_cipher_info_from_string(
const char *cipher_name )
{
const mbedtls_cipher_definition_t *def;
if( NULL == cipher_name )
return( NULL );
for( def = mbedtls_cipher_definitions; def->info != NULL; def++ )
if( ! strcmp( def->info->name, cipher_name ) )
return( def->info );
return( NULL );
}
const mbedtls_cipher_info_t *mbedtls_cipher_info_from_values(
const mbedtls_cipher_id_t cipher_id,
int key_bitlen,
const mbedtls_cipher_mode_t mode )
{
const mbedtls_cipher_definition_t *def;
for( def = mbedtls_cipher_definitions; def->info != NULL; def++ )
if( def->info->base->cipher == cipher_id &&
def->info->key_bitlen == (unsigned) key_bitlen &&
def->info->mode == mode )
return( def->info );
return( NULL );
}
void mbedtls_cipher_init( mbedtls_cipher_context_t *ctx )
{
memset( ctx, 0, sizeof( mbedtls_cipher_context_t ) );
}
void mbedtls_cipher_free( mbedtls_cipher_context_t *ctx )
{
if( ctx == NULL )
return;
#if defined(MBEDTLS_USE_PSA_CRYPTO)
if( ctx->psa_enabled == 1 )
{
/* TODO: Add free'ing of PSA-specific context. */
mbedtls_platform_zeroize( ctx, sizeof(mbedtls_cipher_context_t) );
return;
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */
#if defined(MBEDTLS_CMAC_C)
if( ctx->cmac_ctx )
{
mbedtls_platform_zeroize( ctx->cmac_ctx,
sizeof( mbedtls_cmac_context_t ) );
mbedtls_free( ctx->cmac_ctx );
}
#endif
if( ctx->cipher_ctx )
ctx->cipher_info->base->ctx_free_func( ctx->cipher_ctx );
mbedtls_platform_zeroize( ctx, sizeof(mbedtls_cipher_context_t) );
}
int mbedtls_cipher_setup( mbedtls_cipher_context_t *ctx,
const mbedtls_cipher_info_t *cipher_info )
{
if( NULL == cipher_info || NULL == ctx )
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
memset( ctx, 0, sizeof( mbedtls_cipher_context_t ) );
if( NULL == ( ctx->cipher_ctx = cipher_info->base->ctx_alloc_func() ) )
return( MBEDTLS_ERR_CIPHER_ALLOC_FAILED );
ctx->cipher_info = cipher_info;
#if defined(MBEDTLS_CIPHER_MODE_WITH_PADDING)
/*
* Ignore possible errors caused by a cipher mode that doesn't use padding
*/
#if defined(MBEDTLS_CIPHER_PADDING_PKCS7)
(void) mbedtls_cipher_set_padding_mode( ctx, MBEDTLS_PADDING_PKCS7 );
#else
(void) mbedtls_cipher_set_padding_mode( ctx, MBEDTLS_PADDING_NONE );
#endif
#endif /* MBEDTLS_CIPHER_MODE_WITH_PADDING */
return( 0 );
}
#if defined(MBEDTLS_USE_PSA_CRYPTO)
int mbedtls_cipher_setup_psa( mbedtls_cipher_context_t *ctx,
const mbedtls_cipher_info_t *cipher_info )
{
if( NULL == cipher_info || NULL == ctx )
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
memset( ctx, 0, sizeof( mbedtls_cipher_context_t ) );
ctx->cipher_info = cipher_info;
ctx->psa_enabled = 1;
return( 0 );
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */
int mbedtls_cipher_setkey( mbedtls_cipher_context_t *ctx,
const unsigned char *key,
int key_bitlen,
const mbedtls_operation_t operation )
{
if( NULL == ctx || NULL == ctx->cipher_info )
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
#if defined(MBEDTLS_USE_PSA_CRYPTO)
if( ctx->psa_enabled == 1 )
{
/* TODO */
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */
if( ( ctx->cipher_info->flags & MBEDTLS_CIPHER_VARIABLE_KEY_LEN ) == 0 &&
(int) ctx->cipher_info->key_bitlen != key_bitlen )
{
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
}
ctx->key_bitlen = key_bitlen;
ctx->operation = operation;
/*
* For OFB, CFB and CTR mode always use the encryption key schedule
*/
if( MBEDTLS_ENCRYPT == operation ||
MBEDTLS_MODE_CFB == ctx->cipher_info->mode ||
MBEDTLS_MODE_OFB == ctx->cipher_info->mode ||
MBEDTLS_MODE_CTR == ctx->cipher_info->mode )
{
return ctx->cipher_info->base->setkey_enc_func( ctx->cipher_ctx, key,
ctx->key_bitlen );
}
if( MBEDTLS_DECRYPT == operation )
return ctx->cipher_info->base->setkey_dec_func( ctx->cipher_ctx, key,
ctx->key_bitlen );
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
}
int mbedtls_cipher_set_iv( mbedtls_cipher_context_t *ctx,
const unsigned char *iv, size_t iv_len )
{
size_t actual_iv_size;
if( NULL == ctx || NULL == ctx->cipher_info )
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
else if( NULL == iv && iv_len != 0 )
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
#if defined(MBEDTLS_USE_PSA_CRYPTO)
if( ctx->psa_enabled == 1 )
{
/* While PSA Crypto has an API for multipart
* operations, we currently don't make it
* accessible through the cipher layer. */
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */
if( NULL == iv && iv_len == 0 )
ctx->iv_size = 0;
/* avoid buffer overflow in ctx->iv */
if( iv_len > MBEDTLS_MAX_IV_LENGTH )
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
if( ( ctx->cipher_info->flags & MBEDTLS_CIPHER_VARIABLE_IV_LEN ) != 0 )
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( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
}
#if defined(MBEDTLS_CHACHA20_C)
if ( ctx->cipher_info->type == MBEDTLS_CIPHER_CHACHA20 )
{
if ( 0 != mbedtls_chacha20_starts( (mbedtls_chacha20_context*)ctx->cipher_ctx,
iv,
0U ) ) /* Initial counter value */
{
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
}
}
#endif
if ( actual_iv_size != 0 )
{
memcpy( ctx->iv, iv, actual_iv_size );
ctx->iv_size = actual_iv_size;
}
return( 0 );
}
int mbedtls_cipher_reset( mbedtls_cipher_context_t *ctx )
{
if( NULL == ctx || NULL == ctx->cipher_info )
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
#if defined(MBEDTLS_USE_PSA_CRYPTO)
if( ctx->psa_enabled == 1 )
{
/* We don't support resetting PSA-based
* cipher contexts, yet. */
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */
ctx->unprocessed_len = 0;
return( 0 );
}
#if defined(MBEDTLS_GCM_C) || defined(MBEDTLS_CHACHAPOLY_C)
int mbedtls_cipher_update_ad( mbedtls_cipher_context_t *ctx,
const unsigned char *ad, size_t ad_len )
{
if( NULL == ctx || NULL == ctx->cipher_info )
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
#if defined(MBEDTLS_USE_PSA_CRYPTO)
if( ctx->psa_enabled == 1 )
{
/* While PSA Crypto has an API for multipart
* operations, we currently don't make it
* accessible through the cipher layer. */
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */
#if defined(MBEDTLS_GCM_C)
if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode )
{
return mbedtls_gcm_starts( (mbedtls_gcm_context *) ctx->cipher_ctx, ctx->operation,
ctx->iv, ctx->iv_size, ad, ad_len );
}
#endif
#if defined(MBEDTLS_CHACHAPOLY_C)
if (MBEDTLS_CIPHER_CHACHA20_POLY1305 == ctx->cipher_info->type )
{
int result;
mbedtls_chachapoly_mode_t mode;
mode = ( ctx->operation == MBEDTLS_ENCRYPT )
? MBEDTLS_CHACHAPOLY_ENCRYPT
: MBEDTLS_CHACHAPOLY_DECRYPT;
result = mbedtls_chachapoly_starts( (mbedtls_chachapoly_context*) ctx->cipher_ctx,
ctx->iv,
mode );
if ( result != 0 )
return( result );
return mbedtls_chachapoly_update_aad( (mbedtls_chachapoly_context*) ctx->cipher_ctx,
ad, ad_len );
}
#endif
return( 0 );
}
#endif /* MBEDTLS_GCM_C || MBEDTLS_CHACHAPOLY_C */
int mbedtls_cipher_update( mbedtls_cipher_context_t *ctx, const unsigned char *input,
size_t ilen, unsigned char *output, size_t *olen )
{
int ret;
size_t block_size = 0;
if( NULL == ctx || NULL == ctx->cipher_info || NULL == olen )
{
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
}
#if defined(MBEDTLS_USE_PSA_CRYPTO)
if( ctx->psa_enabled == 1 )
{
/* While PSA Crypto has an API for multipart
* operations, we currently don't make it
* accessible through the cipher layer. */
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */
*olen = 0;
block_size = mbedtls_cipher_get_block_size( ctx );
if( ctx->cipher_info->mode == MBEDTLS_MODE_ECB )
{
if( ilen != block_size )
return( MBEDTLS_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(MBEDTLS_GCM_C)
if( ctx->cipher_info->mode == MBEDTLS_MODE_GCM )
{
*olen = ilen;
return mbedtls_gcm_update( (mbedtls_gcm_context *) ctx->cipher_ctx, ilen, input,
output );
}
#endif
#if defined(MBEDTLS_CHACHAPOLY_C)
if ( ctx->cipher_info->type == MBEDTLS_CIPHER_CHACHA20_POLY1305 )
{
*olen = ilen;
return mbedtls_chachapoly_update( (mbedtls_chachapoly_context*) ctx->cipher_ctx,
ilen, input, output );
}
#endif
if ( 0 == block_size )
{
return MBEDTLS_ERR_CIPHER_INVALID_CONTEXT;
}
if( input == output &&
( ctx->unprocessed_len != 0 || ilen % block_size ) )
{
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
}
#if defined(MBEDTLS_CIPHER_MODE_CBC)
if( ctx->cipher_info->mode == MBEDTLS_MODE_CBC )
{
size_t copy_len = 0;
/*
* If there is not enough data for a full block, cache it.
*/
if( ( ctx->operation == MBEDTLS_DECRYPT && NULL != ctx->add_padding &&
ilen <= block_size - ctx->unprocessed_len ) ||
( ctx->operation == MBEDTLS_DECRYPT && NULL == ctx->add_padding &&
ilen < block_size - ctx->unprocessed_len ) ||
( ctx->operation == MBEDTLS_ENCRYPT &&
ilen < block_size - ctx->unprocessed_len ) )
{
memcpy( &( ctx->unprocessed_data[ctx->unprocessed_len] ), input,
ilen );
ctx->unprocessed_len += ilen;
return( 0 );
}
/*
* Process cached data first
*/
if( 0 != ctx->unprocessed_len )
{
copy_len = block_size - 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, block_size, ctx->iv,
ctx->unprocessed_data, output ) ) )
{
return( ret );
}
*olen += block_size;
output += block_size;
ctx->unprocessed_len = 0;
input += copy_len;
ilen -= copy_len;
}
/*
* Cache final, incomplete block
*/
if( 0 != ilen )
{
if( 0 == block_size )
{
return MBEDTLS_ERR_CIPHER_INVALID_CONTEXT;
}
/* Encryption: only cache partial blocks
* Decryption w/ padding: always keep at least one whole block
* Decryption w/o padding: only cache partial blocks
*/
copy_len = ilen % block_size;
if( copy_len == 0 &&
ctx->operation == MBEDTLS_DECRYPT &&
NULL != ctx->add_padding)
{
copy_len = block_size;
}
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 /* MBEDTLS_CIPHER_MODE_CBC */
#if defined(MBEDTLS_CIPHER_MODE_CFB)
if( ctx->cipher_info->mode == MBEDTLS_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 /* MBEDTLS_CIPHER_MODE_CFB */
#if defined(MBEDTLS_CIPHER_MODE_OFB)
if( ctx->cipher_info->mode == MBEDTLS_MODE_OFB )
{
if( 0 != ( ret = ctx->cipher_info->base->ofb_func( ctx->cipher_ctx,
ilen, &ctx->unprocessed_len, ctx->iv, input, output ) ) )
{
return( ret );
}
*olen = ilen;
return( 0 );
}
#endif /* MBEDTLS_CIPHER_MODE_OFB */
#if defined(MBEDTLS_CIPHER_MODE_CTR)
if( ctx->cipher_info->mode == MBEDTLS_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 /* MBEDTLS_CIPHER_MODE_CTR */
#if defined(MBEDTLS_CIPHER_MODE_XTS)
if( ctx->cipher_info->mode == MBEDTLS_MODE_XTS )
{
if( ctx->unprocessed_len > 0 ) {
/* We can only process an entire data unit at a time. */
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
}
ret = ctx->cipher_info->base->xts_func( ctx->cipher_ctx,
ctx->operation, ilen, ctx->iv, input, output );
if( ret != 0 )
{
return( ret );
}
*olen = ilen;
return( 0 );
}
#endif /* MBEDTLS_CIPHER_MODE_XTS */
#if defined(MBEDTLS_CIPHER_MODE_STREAM)
if( ctx->cipher_info->mode == MBEDTLS_MODE_STREAM )
{
if( 0 != ( ret = ctx->cipher_info->base->stream_func( ctx->cipher_ctx,
ilen, input, output ) ) )
{
return( ret );
}
*olen = ilen;
return( 0 );
}
#endif /* MBEDTLS_CIPHER_MODE_STREAM */
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
}
#if defined(MBEDTLS_CIPHER_MODE_WITH_PADDING)
#if defined(MBEDTLS_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( MBEDTLS_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( MBEDTLS_ERR_CIPHER_INVALID_PADDING * ( bad != 0 ) );
}
#endif /* MBEDTLS_CIPHER_PADDING_PKCS7 */
#if defined(MBEDTLS_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( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
bad = 0x80;
*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] * ( done != prev_done );
}
return( MBEDTLS_ERR_CIPHER_INVALID_PADDING * ( bad != 0 ) );
}
#endif /* MBEDTLS_CIPHER_PADDING_ONE_AND_ZEROS */
#if defined(MBEDTLS_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( MBEDTLS_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( MBEDTLS_ERR_CIPHER_INVALID_PADDING * ( bad != 0 ) );
}
#endif /* MBEDTLS_CIPHER_PADDING_ZEROS_AND_LEN */
#if defined(MBEDTLS_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( MBEDTLS_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 /* MBEDTLS_CIPHER_PADDING_ZEROS */
/*
* No padding: don't pad :)
*
* There is no add_padding function (check for NULL in mbedtls_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( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
*data_len = input_len;
return( 0 );
}
#endif /* MBEDTLS_CIPHER_MODE_WITH_PADDING */
int mbedtls_cipher_finish( mbedtls_cipher_context_t *ctx,
unsigned char *output, size_t *olen )
{
if( NULL == ctx || NULL == ctx->cipher_info || NULL == olen )
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
#if defined(MBEDTLS_USE_PSA_CRYPTO)
if( ctx->psa_enabled == 1 )
{
/* While PSA Crypto has an API for multipart
* operations, we currently don't make it
* accessible through the cipher layer. */
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */
*olen = 0;
if( MBEDTLS_MODE_CFB == ctx->cipher_info->mode ||
MBEDTLS_MODE_OFB == ctx->cipher_info->mode ||
MBEDTLS_MODE_CTR == ctx->cipher_info->mode ||
MBEDTLS_MODE_GCM == ctx->cipher_info->mode ||
MBEDTLS_MODE_XTS == ctx->cipher_info->mode ||
MBEDTLS_MODE_STREAM == ctx->cipher_info->mode )
{
return( 0 );
}
if ( ( MBEDTLS_CIPHER_CHACHA20 == ctx->cipher_info->type ) ||
( MBEDTLS_CIPHER_CHACHA20_POLY1305 == ctx->cipher_info->type ) )
{
return( 0 );
}
if( MBEDTLS_MODE_ECB == ctx->cipher_info->mode )
{
if( ctx->unprocessed_len != 0 )
return( MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED );
return( 0 );
}
#if defined(MBEDTLS_CIPHER_MODE_CBC)
if( MBEDTLS_MODE_CBC == ctx->cipher_info->mode )
{
int ret = 0;
if( MBEDTLS_ENCRYPT == ctx->operation )
{
/* check for 'no padding' mode */
if( NULL == ctx->add_padding )
{
if( 0 != ctx->unprocessed_len )
return( MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED );
return( 0 );
}
ctx->add_padding( ctx->unprocessed_data, mbedtls_cipher_get_iv_size( ctx ),
ctx->unprocessed_len );
}
else if( mbedtls_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( MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED );
}
/* cipher block */
if( 0 != ( ret = ctx->cipher_info->base->cbc_func( ctx->cipher_ctx,
ctx->operation, mbedtls_cipher_get_block_size( ctx ), ctx->iv,
ctx->unprocessed_data, output ) ) )
{
return( ret );
}
/* Set output size for decryption */
if( MBEDTLS_DECRYPT == ctx->operation )
return ctx->get_padding( output, mbedtls_cipher_get_block_size( ctx ),
olen );
/* Set output size for encryption */
*olen = mbedtls_cipher_get_block_size( ctx );
return( 0 );
}
#else
((void) output);
#endif /* MBEDTLS_CIPHER_MODE_CBC */
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
}
#if defined(MBEDTLS_CIPHER_MODE_WITH_PADDING)
int mbedtls_cipher_set_padding_mode( mbedtls_cipher_context_t *ctx,
mbedtls_cipher_padding_t mode )
{
if( NULL == ctx ||
MBEDTLS_MODE_CBC != ctx->cipher_info->mode )
{
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
}
#if defined(MBEDTLS_USE_PSA_CRYPTO)
if( ctx->psa_enabled == 1 )
{
/* While PSA Crypto knows about CBC padding
* schemes, we currently don't make them
* accessible through the cipher layer. */
if( mode != MBEDTLS_PADDING_NONE )
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
return( 0 );
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */
switch( mode )
{
#if defined(MBEDTLS_CIPHER_PADDING_PKCS7)
case MBEDTLS_PADDING_PKCS7:
ctx->add_padding = add_pkcs_padding;
ctx->get_padding = get_pkcs_padding;
break;
#endif
#if defined(MBEDTLS_CIPHER_PADDING_ONE_AND_ZEROS)
case MBEDTLS_PADDING_ONE_AND_ZEROS:
ctx->add_padding = add_one_and_zeros_padding;
ctx->get_padding = get_one_and_zeros_padding;
break;
#endif
#if defined(MBEDTLS_CIPHER_PADDING_ZEROS_AND_LEN)
case MBEDTLS_PADDING_ZEROS_AND_LEN:
ctx->add_padding = add_zeros_and_len_padding;
ctx->get_padding = get_zeros_and_len_padding;
break;
#endif
#if defined(MBEDTLS_CIPHER_PADDING_ZEROS)
case MBEDTLS_PADDING_ZEROS:
ctx->add_padding = add_zeros_padding;
ctx->get_padding = get_zeros_padding;
break;
#endif
case MBEDTLS_PADDING_NONE:
ctx->add_padding = NULL;
ctx->get_padding = get_no_padding;
break;
default:
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
}
return( 0 );
}
#endif /* MBEDTLS_CIPHER_MODE_WITH_PADDING */
#if defined(MBEDTLS_GCM_C) || defined(MBEDTLS_CHACHAPOLY_C)
int mbedtls_cipher_write_tag( mbedtls_cipher_context_t *ctx,
unsigned char *tag, size_t tag_len )
{
if( NULL == ctx || NULL == ctx->cipher_info || NULL == tag )
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
if( MBEDTLS_ENCRYPT != ctx->operation )
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
#if defined(MBEDTLS_USE_PSA_CRYPTO)
if( ctx->psa_enabled == 1 )
{
/* While PSA Crypto has an API for multipart
* operations, we currently don't make it
* accessible through the cipher layer. */
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
return( 0 );
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */
#if defined(MBEDTLS_GCM_C)
if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode )
return( mbedtls_gcm_finish( (mbedtls_gcm_context *) ctx->cipher_ctx,
tag, tag_len ) );
#endif
#if defined(MBEDTLS_CHACHAPOLY_C)
if ( MBEDTLS_CIPHER_CHACHA20_POLY1305 == ctx->cipher_info->type )
{
/* Don't allow truncated MAC for Poly1305 */
if ( tag_len != 16U )
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
return( mbedtls_chachapoly_finish(
(mbedtls_chachapoly_context*) ctx->cipher_ctx, tag ) );
}
#endif
return( 0 );
}
int mbedtls_cipher_check_tag( mbedtls_cipher_context_t *ctx,
const unsigned char *tag, size_t tag_len )
{
unsigned char check_tag[16];
int ret;
if( NULL == ctx || NULL == ctx->cipher_info ||
MBEDTLS_DECRYPT != ctx->operation )
{
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
}
#if defined(MBEDTLS_USE_PSA_CRYPTO)
if( ctx->psa_enabled == 1 )
{
/* While PSA Crypto has an API for multipart
* operations, we currently don't make it
* accessible through the cipher layer. */
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */
#if defined(MBEDTLS_GCM_C)
if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode )
{
if( tag_len > sizeof( check_tag ) )
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
if( 0 != ( ret = mbedtls_gcm_finish(
(mbedtls_gcm_context *) ctx->cipher_ctx,
check_tag, tag_len ) ) )
{
return( ret );
}
/* Check the tag in "constant-time" */
if( mbedtls_constant_time_memcmp( tag, check_tag, tag_len ) != 0 )
return( MBEDTLS_ERR_CIPHER_AUTH_FAILED );
return( 0 );
}
#endif /* MBEDTLS_GCM_C */
#if defined(MBEDTLS_CHACHAPOLY_C)
if ( MBEDTLS_CIPHER_CHACHA20_POLY1305 == ctx->cipher_info->type )
{
/* Don't allow truncated MAC for Poly1305 */
if ( tag_len != sizeof( check_tag ) )
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
ret = mbedtls_chachapoly_finish(
(mbedtls_chachapoly_context*) ctx->cipher_ctx, check_tag );
if ( ret != 0 )
{
return( ret );
}
/* Check the tag in "constant-time" */
if( mbedtls_constant_time_memcmp( tag, check_tag, tag_len ) != 0 )
return( MBEDTLS_ERR_CIPHER_AUTH_FAILED );
return( 0 );
}
#endif /* MBEDTLS_CHACHAPOLY_C */
return( 0 );
}
#endif /* MBEDTLS_GCM_C || MBEDTLS_CHACHAPOLY_C */
/*
* Packet-oriented wrapper for non-AEAD modes
*/
int mbedtls_cipher_crypt( mbedtls_cipher_context_t *ctx,
const unsigned char *iv, size_t iv_len,
const unsigned char *input, size_t ilen,
unsigned char *output, size_t *olen )
{
int ret;
size_t finish_olen;
#if defined(MBEDTLS_USE_PSA_CRYPTO)
if( ctx->psa_enabled == 1 )
{
/* TODO */
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */
if( ( ret = mbedtls_cipher_set_iv( ctx, iv, iv_len ) ) != 0 )
return( ret );
if( ( ret = mbedtls_cipher_reset( ctx ) ) != 0 )
return( ret );
if( ( ret = mbedtls_cipher_update( ctx, input, ilen,
output, olen ) ) != 0 )
return( ret );
if( ( ret = mbedtls_cipher_finish( ctx, output + *olen,
&finish_olen ) ) != 0 )
return( ret );
*olen += finish_olen;
return( 0 );
}
#if defined(MBEDTLS_CIPHER_MODE_AEAD)
/*
* Packet-oriented encryption for AEAD modes
*/
int mbedtls_cipher_auth_encrypt( mbedtls_cipher_context_t *ctx,
const unsigned char *iv, size_t iv_len,
const unsigned char *ad, size_t ad_len,
const unsigned char *input, size_t ilen,
unsigned char *output, size_t *olen,
unsigned char *tag, size_t tag_len )
{
#if defined(MBEDTLS_USE_PSA_CRYPTO)
if( ctx->psa_enabled == 1 )
{
/* TODO */
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */
#if defined(MBEDTLS_GCM_C)
if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode )
{
*olen = ilen;
return( mbedtls_gcm_crypt_and_tag( ctx->cipher_ctx, MBEDTLS_GCM_ENCRYPT,
ilen, iv, iv_len, ad, ad_len,
input, output, tag_len, tag ) );
}
#endif /* MBEDTLS_GCM_C */
#if defined(MBEDTLS_CCM_C)
if( MBEDTLS_MODE_CCM == ctx->cipher_info->mode )
{
*olen = ilen;
return( mbedtls_ccm_encrypt_and_tag( ctx->cipher_ctx, ilen,
iv, iv_len, ad, ad_len, input, output,
tag, tag_len ) );
}
#endif /* MBEDTLS_CCM_C */
#if defined(MBEDTLS_CHACHAPOLY_C)
if ( MBEDTLS_CIPHER_CHACHA20_POLY1305 == ctx->cipher_info->type )
{
/* ChachaPoly has fixed length nonce and MAC (tag) */
if ( ( iv_len != ctx->cipher_info->iv_size ) ||
( tag_len != 16U ) )
{
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
}
*olen = ilen;
return( mbedtls_chachapoly_encrypt_and_tag( ctx->cipher_ctx,
ilen, iv, ad, ad_len, input, output, tag ) );
}
#endif /* MBEDTLS_CHACHAPOLY_C */
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
}
/*
* Packet-oriented decryption for AEAD modes
*/
int mbedtls_cipher_auth_decrypt( mbedtls_cipher_context_t *ctx,
const unsigned char *iv, size_t iv_len,
const unsigned char *ad, size_t ad_len,
const unsigned char *input, size_t ilen,
unsigned char *output, size_t *olen,
const unsigned char *tag, size_t tag_len )
{
#if defined(MBEDTLS_USE_PSA_CRYPTO)
if( ctx->psa_enabled == 1 )
{
/* TODO */
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */
#if defined(MBEDTLS_GCM_C)
if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode )
{
int ret;
*olen = ilen;
ret = mbedtls_gcm_auth_decrypt( ctx->cipher_ctx, ilen,
iv, iv_len, ad, ad_len,
tag, tag_len, input, output );
if( ret == MBEDTLS_ERR_GCM_AUTH_FAILED )
ret = MBEDTLS_ERR_CIPHER_AUTH_FAILED;
return( ret );
}
#endif /* MBEDTLS_GCM_C */
#if defined(MBEDTLS_CCM_C)
if( MBEDTLS_MODE_CCM == ctx->cipher_info->mode )
{
int ret;
*olen = ilen;
ret = mbedtls_ccm_auth_decrypt( ctx->cipher_ctx, ilen,
iv, iv_len, ad, ad_len,
input, output, tag, tag_len );
if( ret == MBEDTLS_ERR_CCM_AUTH_FAILED )
ret = MBEDTLS_ERR_CIPHER_AUTH_FAILED;
return( ret );
}
#endif /* MBEDTLS_CCM_C */
#if defined(MBEDTLS_CHACHAPOLY_C)
if ( MBEDTLS_CIPHER_CHACHA20_POLY1305 == ctx->cipher_info->type )
{
int ret;
/* ChachaPoly has fixed length nonce and MAC (tag) */
if ( ( iv_len != ctx->cipher_info->iv_size ) ||
( tag_len != 16U ) )
{
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
}
*olen = ilen;
ret = mbedtls_chachapoly_auth_decrypt( ctx->cipher_ctx, ilen,
iv, ad, ad_len, tag, input, output );
if( ret == MBEDTLS_ERR_CHACHAPOLY_AUTH_FAILED )
ret = MBEDTLS_ERR_CIPHER_AUTH_FAILED;
return( ret );
}
#endif /* MBEDTLS_CHACHAPOLY_C */
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
}
#endif /* MBEDTLS_CIPHER_MODE_AEAD */
#endif /* MBEDTLS_CIPHER_C */
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