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cipher.c
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/**
* \file cipher.c
*
* \brief Generic cipher wrapper for mbed TLS
*
* \author Adriaan de Jong <[email protected]>
*
* Copyright The Mbed TLS Contributors
* 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.
*/
#include "common.h"
#if defined(MBEDTLS_CIPHER_C)
#include "mbedtls/cipher.h"
#include "cipher_wrap.h"
#include "mbedtls/platform_util.h"
#include "mbedtls/error.h"
#include "mbedtls/constant_time.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"
#include "mbedtls/psa_util.h"
#endif /* MBEDTLS_USE_PSA_CRYPTO */
#if defined(MBEDTLS_NIST_KW_C)
#include "mbedtls/nist_kw.h"
#endif
#if defined(MBEDTLS_PLATFORM_C)
#include "mbedtls/platform.h"
#else
#define mbedtls_calloc calloc
#define mbedtls_free free
#endif
#define CIPHER_VALIDATE_RET( cond ) \
MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA )
#define CIPHER_VALIDATE( cond ) \
MBEDTLS_INTERNAL_VALIDATE( cond )
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 )
{
CIPHER_VALIDATE( ctx != NULL );
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 )
{
if( ctx->cipher_ctx != NULL )
{
mbedtls_cipher_context_psa * const cipher_psa =
(mbedtls_cipher_context_psa *) ctx->cipher_ctx;
if( cipher_psa->slot_state == MBEDTLS_CIPHER_PSA_KEY_OWNED )
{
/* xxx_free() doesn't allow to return failures. */
(void) psa_destroy_key( cipher_psa->slot );
}
mbedtls_platform_zeroize( cipher_psa, sizeof( *cipher_psa ) );
mbedtls_free( cipher_psa );
}
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 )
{
CIPHER_VALIDATE_RET( ctx != NULL );
if( cipher_info == NULL )
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,
size_t taglen )
{
psa_algorithm_t alg;
mbedtls_cipher_context_psa *cipher_psa;
if( NULL == cipher_info || NULL == ctx )
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
/* Check that the underlying cipher mode and cipher type are
* supported by the underlying PSA Crypto implementation. */
alg = mbedtls_psa_translate_cipher_mode( cipher_info->mode, taglen );
if( alg == 0 )
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
if( mbedtls_psa_translate_cipher_type( cipher_info->type ) == 0 )
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
memset( ctx, 0, sizeof( mbedtls_cipher_context_t ) );
cipher_psa = mbedtls_calloc( 1, sizeof(mbedtls_cipher_context_psa ) );
if( cipher_psa == NULL )
return( MBEDTLS_ERR_CIPHER_ALLOC_FAILED );
cipher_psa->alg = alg;
ctx->cipher_ctx = cipher_psa;
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 )
{
CIPHER_VALIDATE_RET( ctx != NULL );
CIPHER_VALIDATE_RET( key != NULL );
CIPHER_VALIDATE_RET( operation == MBEDTLS_ENCRYPT ||
operation == MBEDTLS_DECRYPT );
if( ctx->cipher_info == NULL )
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
#if defined(MBEDTLS_USE_PSA_CRYPTO)
if( ctx->psa_enabled == 1 )
{
mbedtls_cipher_context_psa * const cipher_psa =
(mbedtls_cipher_context_psa *) ctx->cipher_ctx;
size_t const key_bytelen = ( (size_t) key_bitlen + 7 ) / 8;
psa_status_t status;
psa_key_type_t key_type;
psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT;
/* PSA Crypto API only accepts byte-aligned keys. */
if( key_bitlen % 8 != 0 )
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
/* Don't allow keys to be set multiple times. */
if( cipher_psa->slot_state != MBEDTLS_CIPHER_PSA_KEY_UNSET )
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
key_type = mbedtls_psa_translate_cipher_type(
ctx->cipher_info->type );
if( key_type == 0 )
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
psa_set_key_type( &attributes, key_type );
/* Mbed TLS' cipher layer doesn't enforce the mode of operation
* (encrypt vs. decrypt): it is possible to setup a key for encryption
* and use it for AEAD decryption. Until tests relying on this
* are changed, allow any usage in PSA. */
psa_set_key_usage_flags( &attributes,
/* mbedtls_psa_translate_cipher_operation( operation ); */
PSA_KEY_USAGE_ENCRYPT | PSA_KEY_USAGE_DECRYPT );
psa_set_key_algorithm( &attributes, cipher_psa->alg );
status = psa_import_key( &attributes, key, key_bytelen,
&cipher_psa->slot );
switch( status )
{
case PSA_SUCCESS:
break;
case PSA_ERROR_INSUFFICIENT_MEMORY:
return( MBEDTLS_ERR_CIPHER_ALLOC_FAILED );
case PSA_ERROR_NOT_SUPPORTED:
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
default:
return( MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED );
}
/* Indicate that we own the key slot and need to
* destroy it in mbedtls_cipher_free(). */
cipher_psa->slot_state = MBEDTLS_CIPHER_PSA_KEY_OWNED;
ctx->key_bitlen = key_bitlen;
ctx->operation = operation;
return( 0 );
}
#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;
CIPHER_VALIDATE_RET( ctx != NULL );
CIPHER_VALIDATE_RET( iv_len == 0 || iv != NULL );
if( ctx->cipher_info == NULL )
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 */
/* 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 )
{
/* Even though the actual_iv_size is overwritten with a correct value
* of 12 from the cipher info, return an error to indicate that
* the input iv_len is wrong. */
if( iv_len != 12 )
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
if ( 0 != mbedtls_chacha20_starts( (mbedtls_chacha20_context*)ctx->cipher_ctx,
iv,
0U ) ) /* Initial counter value */
{
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
}
}
#if defined(MBEDTLS_CHACHAPOLY_C)
if ( ctx->cipher_info->type == MBEDTLS_CIPHER_CHACHA20_POLY1305 &&
iv_len != 12 )
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
#endif
#endif
#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,
iv, iv_len ) );
}
#endif
#if defined(MBEDTLS_CCM_C)
if( MBEDTLS_MODE_CCM_STAR_NO_TAG == ctx->cipher_info->mode )
{
int set_lengths_result;
int ccm_star_mode;
set_lengths_result = mbedtls_ccm_set_lengths(
(mbedtls_ccm_context *) ctx->cipher_ctx,
0, 0, 0 );
if( set_lengths_result != 0 )
return set_lengths_result;
if( ctx->operation == MBEDTLS_DECRYPT )
ccm_star_mode = MBEDTLS_CCM_STAR_DECRYPT;
else if( ctx->operation == MBEDTLS_ENCRYPT )
ccm_star_mode = MBEDTLS_CCM_STAR_ENCRYPT;
else
return MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA;
return( mbedtls_ccm_starts( (mbedtls_ccm_context *) ctx->cipher_ctx,
ccm_star_mode,
iv, iv_len ) );
}
#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 )
{
CIPHER_VALIDATE_RET( ctx != NULL );
if( ctx->cipher_info == NULL )
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 )
{
CIPHER_VALIDATE_RET( ctx != NULL );
CIPHER_VALIDATE_RET( ad_len == 0 || ad != NULL );
if( ctx->cipher_info == NULL )
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_update_ad( (mbedtls_gcm_context *) ctx->cipher_ctx,
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 = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t block_size;
CIPHER_VALIDATE_RET( ctx != NULL );
CIPHER_VALIDATE_RET( ilen == 0 || input != NULL );
CIPHER_VALIDATE_RET( output != NULL );
CIPHER_VALIDATE_RET( olen != NULL );
if( ctx->cipher_info == NULL )
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 ( 0 == block_size )
{
return( MBEDTLS_ERR_CIPHER_INVALID_CONTEXT );
}
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 )
{
return( mbedtls_gcm_update( (mbedtls_gcm_context *) ctx->cipher_ctx,
input, ilen,
output, ilen, olen ) );
}
#endif
#if defined(MBEDTLS_CCM_C)
if( ctx->cipher_info->mode == MBEDTLS_MODE_CCM_STAR_NO_TAG )
{
return( mbedtls_ccm_update( (mbedtls_ccm_context *) ctx->cipher_ctx,
input, ilen,
output, ilen, olen ) );
}
#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( 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 )
{
/* 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 )
{
CIPHER_VALIDATE_RET( ctx != NULL );
CIPHER_VALIDATE_RET( output != NULL );
CIPHER_VALIDATE_RET( olen != NULL );
if( ctx->cipher_info == NULL )
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_CCM_STAR_NO_TAG == 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;