518 lines
16 KiB
C
518 lines
16 KiB
C
/**
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* \file chachapoly.c
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*
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* \brief ChaCha20-Poly1305 AEAD construction based on RFC 7539.
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*
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* Copyright The Mbed TLS Contributors
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "common.h"
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#if defined(MBEDTLS_CHACHAPOLY_C)
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#include "mbedtls/chachapoly.h"
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#include "mbedtls/platform_util.h"
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#include "mbedtls/error.h"
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#include <string.h>
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#include "mbedtls/platform.h"
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#if !defined(MBEDTLS_CHACHAPOLY_ALT)
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/* Parameter validation macros */
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#define CHACHAPOLY_VALIDATE_RET( cond ) \
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MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_POLY1305_BAD_INPUT_DATA )
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#define CHACHAPOLY_VALIDATE( cond ) \
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MBEDTLS_INTERNAL_VALIDATE( cond )
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#define CHACHAPOLY_STATE_INIT ( 0 )
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#define CHACHAPOLY_STATE_AAD ( 1 )
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#define CHACHAPOLY_STATE_CIPHERTEXT ( 2 ) /* Encrypting or decrypting */
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#define CHACHAPOLY_STATE_FINISHED ( 3 )
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/**
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* \brief Adds nul bytes to pad the AAD for Poly1305.
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*
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* \param ctx The ChaCha20-Poly1305 context.
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*/
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static int chachapoly_pad_aad( mbedtls_chachapoly_context *ctx )
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{
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uint32_t partial_block_len = (uint32_t) ( ctx->aad_len % 16U );
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unsigned char zeroes[15];
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if( partial_block_len == 0U )
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return( 0 );
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memset( zeroes, 0, sizeof( zeroes ) );
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return( mbedtls_poly1305_update( &ctx->poly1305_ctx,
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zeroes,
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16U - partial_block_len ) );
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}
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/**
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* \brief Adds nul bytes to pad the ciphertext for Poly1305.
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*
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* \param ctx The ChaCha20-Poly1305 context.
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*/
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static int chachapoly_pad_ciphertext( mbedtls_chachapoly_context *ctx )
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{
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uint32_t partial_block_len = (uint32_t) ( ctx->ciphertext_len % 16U );
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unsigned char zeroes[15];
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if( partial_block_len == 0U )
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return( 0 );
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memset( zeroes, 0, sizeof( zeroes ) );
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return( mbedtls_poly1305_update( &ctx->poly1305_ctx,
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zeroes,
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16U - partial_block_len ) );
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}
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void mbedtls_chachapoly_init( mbedtls_chachapoly_context *ctx )
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{
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CHACHAPOLY_VALIDATE( ctx != NULL );
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mbedtls_chacha20_init( &ctx->chacha20_ctx );
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mbedtls_poly1305_init( &ctx->poly1305_ctx );
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ctx->aad_len = 0U;
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ctx->ciphertext_len = 0U;
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ctx->state = CHACHAPOLY_STATE_INIT;
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ctx->mode = MBEDTLS_CHACHAPOLY_ENCRYPT;
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}
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void mbedtls_chachapoly_free( mbedtls_chachapoly_context *ctx )
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{
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if( ctx == NULL )
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return;
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mbedtls_chacha20_free( &ctx->chacha20_ctx );
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mbedtls_poly1305_free( &ctx->poly1305_ctx );
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ctx->aad_len = 0U;
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ctx->ciphertext_len = 0U;
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ctx->state = CHACHAPOLY_STATE_INIT;
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ctx->mode = MBEDTLS_CHACHAPOLY_ENCRYPT;
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}
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int mbedtls_chachapoly_setkey( mbedtls_chachapoly_context *ctx,
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const unsigned char key[32] )
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{
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int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
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CHACHAPOLY_VALIDATE_RET( ctx != NULL );
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CHACHAPOLY_VALIDATE_RET( key != NULL );
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ret = mbedtls_chacha20_setkey( &ctx->chacha20_ctx, key );
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return( ret );
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}
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int mbedtls_chachapoly_starts( mbedtls_chachapoly_context *ctx,
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const unsigned char nonce[12],
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mbedtls_chachapoly_mode_t mode )
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{
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int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
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unsigned char poly1305_key[64];
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CHACHAPOLY_VALIDATE_RET( ctx != NULL );
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CHACHAPOLY_VALIDATE_RET( nonce != NULL );
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/* Set counter = 0, will be update to 1 when generating Poly1305 key */
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ret = mbedtls_chacha20_starts( &ctx->chacha20_ctx, nonce, 0U );
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if( ret != 0 )
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goto cleanup;
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/* Generate the Poly1305 key by getting the ChaCha20 keystream output with
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* counter = 0. This is the same as encrypting a buffer of zeroes.
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* Only the first 256-bits (32 bytes) of the key is used for Poly1305.
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* The other 256 bits are discarded.
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*/
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memset( poly1305_key, 0, sizeof( poly1305_key ) );
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ret = mbedtls_chacha20_update( &ctx->chacha20_ctx, sizeof( poly1305_key ),
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poly1305_key, poly1305_key );
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if( ret != 0 )
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goto cleanup;
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ret = mbedtls_poly1305_starts( &ctx->poly1305_ctx, poly1305_key );
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if( ret == 0 )
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{
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ctx->aad_len = 0U;
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ctx->ciphertext_len = 0U;
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ctx->state = CHACHAPOLY_STATE_AAD;
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ctx->mode = mode;
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}
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cleanup:
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mbedtls_platform_zeroize( poly1305_key, 64U );
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return( ret );
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}
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int mbedtls_chachapoly_update_aad( mbedtls_chachapoly_context *ctx,
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const unsigned char *aad,
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size_t aad_len )
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{
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CHACHAPOLY_VALIDATE_RET( ctx != NULL );
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CHACHAPOLY_VALIDATE_RET( aad_len == 0 || aad != NULL );
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if( ctx->state != CHACHAPOLY_STATE_AAD )
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return( MBEDTLS_ERR_CHACHAPOLY_BAD_STATE );
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ctx->aad_len += aad_len;
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return( mbedtls_poly1305_update( &ctx->poly1305_ctx, aad, aad_len ) );
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}
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int mbedtls_chachapoly_update( mbedtls_chachapoly_context *ctx,
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size_t len,
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const unsigned char *input,
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unsigned char *output )
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{
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int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
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CHACHAPOLY_VALIDATE_RET( ctx != NULL );
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CHACHAPOLY_VALIDATE_RET( len == 0 || input != NULL );
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CHACHAPOLY_VALIDATE_RET( len == 0 || output != NULL );
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if( ( ctx->state != CHACHAPOLY_STATE_AAD ) &&
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( ctx->state != CHACHAPOLY_STATE_CIPHERTEXT ) )
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{
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return( MBEDTLS_ERR_CHACHAPOLY_BAD_STATE );
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}
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if( ctx->state == CHACHAPOLY_STATE_AAD )
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{
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ctx->state = CHACHAPOLY_STATE_CIPHERTEXT;
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ret = chachapoly_pad_aad( ctx );
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if( ret != 0 )
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return( ret );
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}
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ctx->ciphertext_len += len;
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if( ctx->mode == MBEDTLS_CHACHAPOLY_ENCRYPT )
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{
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ret = mbedtls_chacha20_update( &ctx->chacha20_ctx, len, input, output );
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if( ret != 0 )
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return( ret );
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ret = mbedtls_poly1305_update( &ctx->poly1305_ctx, output, len );
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if( ret != 0 )
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return( ret );
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}
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else /* DECRYPT */
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{
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ret = mbedtls_poly1305_update( &ctx->poly1305_ctx, input, len );
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if( ret != 0 )
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return( ret );
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ret = mbedtls_chacha20_update( &ctx->chacha20_ctx, len, input, output );
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if( ret != 0 )
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return( ret );
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}
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return( 0 );
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}
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int mbedtls_chachapoly_finish( mbedtls_chachapoly_context *ctx,
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unsigned char mac[16] )
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{
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int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
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unsigned char len_block[16];
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CHACHAPOLY_VALIDATE_RET( ctx != NULL );
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CHACHAPOLY_VALIDATE_RET( mac != NULL );
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if( ctx->state == CHACHAPOLY_STATE_INIT )
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{
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return( MBEDTLS_ERR_CHACHAPOLY_BAD_STATE );
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}
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if( ctx->state == CHACHAPOLY_STATE_AAD )
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{
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ret = chachapoly_pad_aad( ctx );
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if( ret != 0 )
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return( ret );
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}
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else if( ctx->state == CHACHAPOLY_STATE_CIPHERTEXT )
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{
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ret = chachapoly_pad_ciphertext( ctx );
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if( ret != 0 )
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return( ret );
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}
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ctx->state = CHACHAPOLY_STATE_FINISHED;
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/* The lengths of the AAD and ciphertext are processed by
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* Poly1305 as the final 128-bit block, encoded as little-endian integers.
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*/
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MBEDTLS_PUT_UINT64_LE(ctx->aad_len, len_block, 0);
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MBEDTLS_PUT_UINT64_LE(ctx->ciphertext_len, len_block, 8);
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ret = mbedtls_poly1305_update( &ctx->poly1305_ctx, len_block, 16U );
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if( ret != 0 )
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return( ret );
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ret = mbedtls_poly1305_finish( &ctx->poly1305_ctx, mac );
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return( ret );
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}
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static int chachapoly_crypt_and_tag( mbedtls_chachapoly_context *ctx,
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mbedtls_chachapoly_mode_t mode,
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size_t length,
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const unsigned char nonce[12],
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const unsigned char *aad,
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size_t aad_len,
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const unsigned char *input,
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unsigned char *output,
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unsigned char tag[16] )
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{
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int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
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ret = mbedtls_chachapoly_starts( ctx, nonce, mode );
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if( ret != 0 )
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goto cleanup;
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ret = mbedtls_chachapoly_update_aad( ctx, aad, aad_len );
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if( ret != 0 )
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goto cleanup;
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ret = mbedtls_chachapoly_update( ctx, length, input, output );
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if( ret != 0 )
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goto cleanup;
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ret = mbedtls_chachapoly_finish( ctx, tag );
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cleanup:
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return( ret );
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}
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int mbedtls_chachapoly_encrypt_and_tag( mbedtls_chachapoly_context *ctx,
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size_t length,
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const unsigned char nonce[12],
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const unsigned char *aad,
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size_t aad_len,
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const unsigned char *input,
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unsigned char *output,
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unsigned char tag[16] )
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{
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CHACHAPOLY_VALIDATE_RET( ctx != NULL );
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CHACHAPOLY_VALIDATE_RET( nonce != NULL );
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CHACHAPOLY_VALIDATE_RET( tag != NULL );
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CHACHAPOLY_VALIDATE_RET( aad_len == 0 || aad != NULL );
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CHACHAPOLY_VALIDATE_RET( length == 0 || input != NULL );
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CHACHAPOLY_VALIDATE_RET( length == 0 || output != NULL );
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return( chachapoly_crypt_and_tag( ctx, MBEDTLS_CHACHAPOLY_ENCRYPT,
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length, nonce, aad, aad_len,
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input, output, tag ) );
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}
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int mbedtls_chachapoly_auth_decrypt( mbedtls_chachapoly_context *ctx,
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size_t length,
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const unsigned char nonce[12],
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const unsigned char *aad,
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size_t aad_len,
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const unsigned char tag[16],
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const unsigned char *input,
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unsigned char *output )
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{
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int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
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unsigned char check_tag[16];
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size_t i;
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int diff;
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CHACHAPOLY_VALIDATE_RET( ctx != NULL );
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CHACHAPOLY_VALIDATE_RET( nonce != NULL );
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CHACHAPOLY_VALIDATE_RET( tag != NULL );
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CHACHAPOLY_VALIDATE_RET( aad_len == 0 || aad != NULL );
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CHACHAPOLY_VALIDATE_RET( length == 0 || input != NULL );
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CHACHAPOLY_VALIDATE_RET( length == 0 || output != NULL );
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if( ( ret = chachapoly_crypt_and_tag( ctx,
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MBEDTLS_CHACHAPOLY_DECRYPT, length, nonce,
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aad, aad_len, input, output, check_tag ) ) != 0 )
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{
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return( ret );
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}
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/* Check tag in "constant-time" */
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for( diff = 0, i = 0; i < sizeof( check_tag ); i++ )
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diff |= tag[i] ^ check_tag[i];
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if( diff != 0 )
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{
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mbedtls_platform_zeroize( output, length );
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return( MBEDTLS_ERR_CHACHAPOLY_AUTH_FAILED );
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}
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return( 0 );
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}
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#endif /* MBEDTLS_CHACHAPOLY_ALT */
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#if defined(MBEDTLS_SELF_TEST)
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static const unsigned char test_key[1][32] =
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{
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{
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0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
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0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
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0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97,
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0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f
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}
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};
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static const unsigned char test_nonce[1][12] =
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{
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{
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0x07, 0x00, 0x00, 0x00, /* 32-bit common part */
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0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47 /* 64-bit IV */
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}
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};
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static const unsigned char test_aad[1][12] =
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{
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{
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0x50, 0x51, 0x52, 0x53, 0xc0, 0xc1, 0xc2, 0xc3,
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0xc4, 0xc5, 0xc6, 0xc7
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}
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};
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static const size_t test_aad_len[1] =
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{
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12U
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};
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static const unsigned char test_input[1][114] =
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{
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{
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0x4c, 0x61, 0x64, 0x69, 0x65, 0x73, 0x20, 0x61,
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0x6e, 0x64, 0x20, 0x47, 0x65, 0x6e, 0x74, 0x6c,
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0x65, 0x6d, 0x65, 0x6e, 0x20, 0x6f, 0x66, 0x20,
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0x74, 0x68, 0x65, 0x20, 0x63, 0x6c, 0x61, 0x73,
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0x73, 0x20, 0x6f, 0x66, 0x20, 0x27, 0x39, 0x39,
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0x3a, 0x20, 0x49, 0x66, 0x20, 0x49, 0x20, 0x63,
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0x6f, 0x75, 0x6c, 0x64, 0x20, 0x6f, 0x66, 0x66,
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0x65, 0x72, 0x20, 0x79, 0x6f, 0x75, 0x20, 0x6f,
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0x6e, 0x6c, 0x79, 0x20, 0x6f, 0x6e, 0x65, 0x20,
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0x74, 0x69, 0x70, 0x20, 0x66, 0x6f, 0x72, 0x20,
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0x74, 0x68, 0x65, 0x20, 0x66, 0x75, 0x74, 0x75,
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0x72, 0x65, 0x2c, 0x20, 0x73, 0x75, 0x6e, 0x73,
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0x63, 0x72, 0x65, 0x65, 0x6e, 0x20, 0x77, 0x6f,
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0x75, 0x6c, 0x64, 0x20, 0x62, 0x65, 0x20, 0x69,
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0x74, 0x2e
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}
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};
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static const unsigned char test_output[1][114] =
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{
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{
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0xd3, 0x1a, 0x8d, 0x34, 0x64, 0x8e, 0x60, 0xdb,
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0x7b, 0x86, 0xaf, 0xbc, 0x53, 0xef, 0x7e, 0xc2,
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0xa4, 0xad, 0xed, 0x51, 0x29, 0x6e, 0x08, 0xfe,
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0xa9, 0xe2, 0xb5, 0xa7, 0x36, 0xee, 0x62, 0xd6,
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0x3d, 0xbe, 0xa4, 0x5e, 0x8c, 0xa9, 0x67, 0x12,
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0x82, 0xfa, 0xfb, 0x69, 0xda, 0x92, 0x72, 0x8b,
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0x1a, 0x71, 0xde, 0x0a, 0x9e, 0x06, 0x0b, 0x29,
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0x05, 0xd6, 0xa5, 0xb6, 0x7e, 0xcd, 0x3b, 0x36,
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0x92, 0xdd, 0xbd, 0x7f, 0x2d, 0x77, 0x8b, 0x8c,
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0x98, 0x03, 0xae, 0xe3, 0x28, 0x09, 0x1b, 0x58,
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0xfa, 0xb3, 0x24, 0xe4, 0xfa, 0xd6, 0x75, 0x94,
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0x55, 0x85, 0x80, 0x8b, 0x48, 0x31, 0xd7, 0xbc,
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0x3f, 0xf4, 0xde, 0xf0, 0x8e, 0x4b, 0x7a, 0x9d,
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0xe5, 0x76, 0xd2, 0x65, 0x86, 0xce, 0xc6, 0x4b,
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0x61, 0x16
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}
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};
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static const size_t test_input_len[1] =
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{
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114U
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};
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static const unsigned char test_mac[1][16] =
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{
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{
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0x1a, 0xe1, 0x0b, 0x59, 0x4f, 0x09, 0xe2, 0x6a,
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0x7e, 0x90, 0x2e, 0xcb, 0xd0, 0x60, 0x06, 0x91
|
|
}
|
|
};
|
|
|
|
/* Make sure no other definition is already present. */
|
|
#undef ASSERT
|
|
|
|
#define ASSERT( cond, args ) \
|
|
do \
|
|
{ \
|
|
if( ! ( cond ) ) \
|
|
{ \
|
|
if( verbose != 0 ) \
|
|
mbedtls_printf args; \
|
|
\
|
|
return( -1 ); \
|
|
} \
|
|
} \
|
|
while( 0 )
|
|
|
|
int mbedtls_chachapoly_self_test( int verbose )
|
|
{
|
|
mbedtls_chachapoly_context ctx;
|
|
unsigned i;
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
unsigned char output[200];
|
|
unsigned char mac[16];
|
|
|
|
for( i = 0U; i < 1U; i++ )
|
|
{
|
|
if( verbose != 0 )
|
|
mbedtls_printf( " ChaCha20-Poly1305 test %u ", i );
|
|
|
|
mbedtls_chachapoly_init( &ctx );
|
|
|
|
ret = mbedtls_chachapoly_setkey( &ctx, test_key[i] );
|
|
ASSERT( 0 == ret, ( "setkey() error code: %i\n", ret ) );
|
|
|
|
ret = mbedtls_chachapoly_encrypt_and_tag( &ctx,
|
|
test_input_len[i],
|
|
test_nonce[i],
|
|
test_aad[i],
|
|
test_aad_len[i],
|
|
test_input[i],
|
|
output,
|
|
mac );
|
|
|
|
ASSERT( 0 == ret, ( "crypt_and_tag() error code: %i\n", ret ) );
|
|
|
|
ASSERT( 0 == memcmp( output, test_output[i], test_input_len[i] ),
|
|
( "failure (wrong output)\n" ) );
|
|
|
|
ASSERT( 0 == memcmp( mac, test_mac[i], 16U ),
|
|
( "failure (wrong MAC)\n" ) );
|
|
|
|
mbedtls_chachapoly_free( &ctx );
|
|
|
|
if( verbose != 0 )
|
|
mbedtls_printf( "passed\n" );
|
|
}
|
|
|
|
if( verbose != 0 )
|
|
mbedtls_printf( "\n" );
|
|
|
|
return( 0 );
|
|
}
|
|
|
|
#endif /* MBEDTLS_SELF_TEST */
|
|
|
|
#endif /* MBEDTLS_CHACHAPOLY_C */
|