/** | |
* \file chachapoly.c | |
* | |
* \brief ChaCha20-Poly1305 AEAD construction based on RFC 7539. | |
* | |
* Copyright (C) 2006-2016, 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_CHACHAPOLY_C) | |
#include "mbedtls/chachapoly.h" | |
#include "mbedtls/platform_util.h" | |
#include <string.h> | |
#if defined(MBEDTLS_SELF_TEST) | |
#if defined(MBEDTLS_PLATFORM_C) | |
#include "mbedtls/platform.h" | |
#else | |
#include <stdio.h> | |
#define mbedtls_printf printf | |
#endif /* MBEDTLS_PLATFORM_C */ | |
#endif /* MBEDTLS_SELF_TEST */ | |
#if !defined(MBEDTLS_CHACHAPOLY_ALT) | |
/* Parameter validation macros */ | |
#define CHACHAPOLY_VALIDATE_RET( cond ) \ | |
MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_POLY1305_BAD_INPUT_DATA ) | |
#define CHACHAPOLY_VALIDATE( cond ) \ | |
MBEDTLS_INTERNAL_VALIDATE( cond ) | |
#define CHACHAPOLY_STATE_INIT ( 0 ) | |
#define CHACHAPOLY_STATE_AAD ( 1 ) | |
#define CHACHAPOLY_STATE_CIPHERTEXT ( 2 ) /* Encrypting or decrypting */ | |
#define CHACHAPOLY_STATE_FINISHED ( 3 ) | |
/** | |
* \brief Adds nul bytes to pad the AAD for Poly1305. | |
* | |
* \param ctx The ChaCha20-Poly1305 context. | |
*/ | |
static int chachapoly_pad_aad( mbedtls_chachapoly_context *ctx ) | |
{ | |
uint32_t partial_block_len = (uint32_t) ( ctx->aad_len % 16U ); | |
unsigned char zeroes[15]; | |
if( partial_block_len == 0U ) | |
return( 0 ); | |
memset( zeroes, 0, sizeof( zeroes ) ); | |
return( mbedtls_poly1305_update( &ctx->poly1305_ctx, | |
zeroes, | |
16U - partial_block_len ) ); | |
} | |
/** | |
* \brief Adds nul bytes to pad the ciphertext for Poly1305. | |
* | |
* \param ctx The ChaCha20-Poly1305 context. | |
*/ | |
static int chachapoly_pad_ciphertext( mbedtls_chachapoly_context *ctx ) | |
{ | |
uint32_t partial_block_len = (uint32_t) ( ctx->ciphertext_len % 16U ); | |
unsigned char zeroes[15]; | |
if( partial_block_len == 0U ) | |
return( 0 ); | |
memset( zeroes, 0, sizeof( zeroes ) ); | |
return( mbedtls_poly1305_update( &ctx->poly1305_ctx, | |
zeroes, | |
16U - partial_block_len ) ); | |
} | |
void mbedtls_chachapoly_init( mbedtls_chachapoly_context *ctx ) | |
{ | |
CHACHAPOLY_VALIDATE( ctx != NULL ); | |
mbedtls_chacha20_init( &ctx->chacha20_ctx ); | |
mbedtls_poly1305_init( &ctx->poly1305_ctx ); | |
ctx->aad_len = 0U; | |
ctx->ciphertext_len = 0U; | |
ctx->state = CHACHAPOLY_STATE_INIT; | |
ctx->mode = MBEDTLS_CHACHAPOLY_ENCRYPT; | |
} | |
void mbedtls_chachapoly_free( mbedtls_chachapoly_context *ctx ) | |
{ | |
if( ctx == NULL ) | |
return; | |
mbedtls_chacha20_free( &ctx->chacha20_ctx ); | |
mbedtls_poly1305_free( &ctx->poly1305_ctx ); | |
ctx->aad_len = 0U; | |
ctx->ciphertext_len = 0U; | |
ctx->state = CHACHAPOLY_STATE_INIT; | |
ctx->mode = MBEDTLS_CHACHAPOLY_ENCRYPT; | |
} | |
int mbedtls_chachapoly_setkey( mbedtls_chachapoly_context *ctx, | |
const unsigned char key[32] ) | |
{ | |
int ret; | |
CHACHAPOLY_VALIDATE_RET( ctx != NULL ); | |
CHACHAPOLY_VALIDATE_RET( key != NULL ); | |
ret = mbedtls_chacha20_setkey( &ctx->chacha20_ctx, key ); | |
return( ret ); | |
} | |
int mbedtls_chachapoly_starts( mbedtls_chachapoly_context *ctx, | |
const unsigned char nonce[12], | |
mbedtls_chachapoly_mode_t mode ) | |
{ | |
int ret; | |
unsigned char poly1305_key[64]; | |
CHACHAPOLY_VALIDATE_RET( ctx != NULL ); | |
CHACHAPOLY_VALIDATE_RET( nonce != NULL ); | |
/* Set counter = 0, will be update to 1 when generating Poly1305 key */ | |
ret = mbedtls_chacha20_starts( &ctx->chacha20_ctx, nonce, 0U ); | |
if( ret != 0 ) | |
goto cleanup; | |
/* Generate the Poly1305 key by getting the ChaCha20 keystream output with | |
* counter = 0. This is the same as encrypting a buffer of zeroes. | |
* Only the first 256-bits (32 bytes) of the key is used for Poly1305. | |
* The other 256 bits are discarded. | |
*/ | |
memset( poly1305_key, 0, sizeof( poly1305_key ) ); | |
ret = mbedtls_chacha20_update( &ctx->chacha20_ctx, sizeof( poly1305_key ), | |
poly1305_key, poly1305_key ); | |
if( ret != 0 ) | |
goto cleanup; | |
ret = mbedtls_poly1305_starts( &ctx->poly1305_ctx, poly1305_key ); | |
if( ret == 0 ) | |
{ | |
ctx->aad_len = 0U; | |
ctx->ciphertext_len = 0U; | |
ctx->state = CHACHAPOLY_STATE_AAD; | |
ctx->mode = mode; | |
} | |
cleanup: | |
mbedtls_platform_zeroize( poly1305_key, 64U ); | |
return( ret ); | |
} | |
int mbedtls_chachapoly_update_aad( mbedtls_chachapoly_context *ctx, | |
const unsigned char *aad, | |
size_t aad_len ) | |
{ | |
CHACHAPOLY_VALIDATE_RET( ctx != NULL ); | |
CHACHAPOLY_VALIDATE_RET( aad_len == 0 || aad != NULL ); | |
if( ctx->state != CHACHAPOLY_STATE_AAD ) | |
return( MBEDTLS_ERR_CHACHAPOLY_BAD_STATE ); | |
ctx->aad_len += aad_len; | |
return( mbedtls_poly1305_update( &ctx->poly1305_ctx, aad, aad_len ) ); | |
} | |
int mbedtls_chachapoly_update( mbedtls_chachapoly_context *ctx, | |
size_t len, | |
const unsigned char *input, | |
unsigned char *output ) | |
{ | |
int ret; | |
CHACHAPOLY_VALIDATE_RET( ctx != NULL ); | |
CHACHAPOLY_VALIDATE_RET( len == 0 || input != NULL ); | |
CHACHAPOLY_VALIDATE_RET( len == 0 || output != NULL ); | |
if( ( ctx->state != CHACHAPOLY_STATE_AAD ) && | |
( ctx->state != CHACHAPOLY_STATE_CIPHERTEXT ) ) | |
{ | |
return( MBEDTLS_ERR_CHACHAPOLY_BAD_STATE ); | |
} | |
if( ctx->state == CHACHAPOLY_STATE_AAD ) | |
{ | |
ctx->state = CHACHAPOLY_STATE_CIPHERTEXT; | |
ret = chachapoly_pad_aad( ctx ); | |
if( ret != 0 ) | |
return( ret ); | |
} | |
ctx->ciphertext_len += len; | |
if( ctx->mode == MBEDTLS_CHACHAPOLY_ENCRYPT ) | |
{ | |
ret = mbedtls_chacha20_update( &ctx->chacha20_ctx, len, input, output ); | |
if( ret != 0 ) | |
return( ret ); | |
ret = mbedtls_poly1305_update( &ctx->poly1305_ctx, output, len ); | |
if( ret != 0 ) | |
return( ret ); | |
} | |
else /* DECRYPT */ | |
{ | |
ret = mbedtls_poly1305_update( &ctx->poly1305_ctx, input, len ); | |
if( ret != 0 ) | |
return( ret ); | |
ret = mbedtls_chacha20_update( &ctx->chacha20_ctx, len, input, output ); | |
if( ret != 0 ) | |
return( ret ); | |
} | |
return( 0 ); | |
} | |
int mbedtls_chachapoly_finish( mbedtls_chachapoly_context *ctx, | |
unsigned char mac[16] ) | |
{ | |
int ret; | |
unsigned char len_block[16]; | |
CHACHAPOLY_VALIDATE_RET( ctx != NULL ); | |
CHACHAPOLY_VALIDATE_RET( mac != NULL ); | |
if( ctx->state == CHACHAPOLY_STATE_INIT ) | |
{ | |
return( MBEDTLS_ERR_CHACHAPOLY_BAD_STATE ); | |
} | |
if( ctx->state == CHACHAPOLY_STATE_AAD ) | |
{ | |
ret = chachapoly_pad_aad( ctx ); | |
if( ret != 0 ) | |
return( ret ); | |
} | |
else if( ctx->state == CHACHAPOLY_STATE_CIPHERTEXT ) | |
{ | |
ret = chachapoly_pad_ciphertext( ctx ); | |
if( ret != 0 ) | |
return( ret ); | |
} | |
ctx->state = CHACHAPOLY_STATE_FINISHED; | |
/* The lengths of the AAD and ciphertext are processed by | |
* Poly1305 as the final 128-bit block, encoded as little-endian integers. | |
*/ | |
len_block[ 0] = (unsigned char)( ctx->aad_len ); | |
len_block[ 1] = (unsigned char)( ctx->aad_len >> 8 ); | |
len_block[ 2] = (unsigned char)( ctx->aad_len >> 16 ); | |
len_block[ 3] = (unsigned char)( ctx->aad_len >> 24 ); | |
len_block[ 4] = (unsigned char)( ctx->aad_len >> 32 ); | |
len_block[ 5] = (unsigned char)( ctx->aad_len >> 40 ); | |
len_block[ 6] = (unsigned char)( ctx->aad_len >> 48 ); | |
len_block[ 7] = (unsigned char)( ctx->aad_len >> 56 ); | |
len_block[ 8] = (unsigned char)( ctx->ciphertext_len ); | |
len_block[ 9] = (unsigned char)( ctx->ciphertext_len >> 8 ); | |
len_block[10] = (unsigned char)( ctx->ciphertext_len >> 16 ); | |
len_block[11] = (unsigned char)( ctx->ciphertext_len >> 24 ); | |
len_block[12] = (unsigned char)( ctx->ciphertext_len >> 32 ); | |
len_block[13] = (unsigned char)( ctx->ciphertext_len >> 40 ); | |
len_block[14] = (unsigned char)( ctx->ciphertext_len >> 48 ); | |
len_block[15] = (unsigned char)( ctx->ciphertext_len >> 56 ); | |
ret = mbedtls_poly1305_update( &ctx->poly1305_ctx, len_block, 16U ); | |
if( ret != 0 ) | |
return( ret ); | |
ret = mbedtls_poly1305_finish( &ctx->poly1305_ctx, mac ); | |
return( ret ); | |
} | |
static int chachapoly_crypt_and_tag( mbedtls_chachapoly_context *ctx, | |
mbedtls_chachapoly_mode_t mode, | |
size_t length, | |
const unsigned char nonce[12], | |
const unsigned char *aad, | |
size_t aad_len, | |
const unsigned char *input, | |
unsigned char *output, | |
unsigned char tag[16] ) | |
{ | |
int ret; | |
ret = mbedtls_chachapoly_starts( ctx, nonce, mode ); | |
if( ret != 0 ) | |
goto cleanup; | |
ret = mbedtls_chachapoly_update_aad( ctx, aad, aad_len ); | |
if( ret != 0 ) | |
goto cleanup; | |
ret = mbedtls_chachapoly_update( ctx, length, input, output ); | |
if( ret != 0 ) | |
goto cleanup; | |
ret = mbedtls_chachapoly_finish( ctx, tag ); | |
cleanup: | |
return( ret ); | |
} | |
int mbedtls_chachapoly_encrypt_and_tag( mbedtls_chachapoly_context *ctx, | |
size_t length, | |
const unsigned char nonce[12], | |
const unsigned char *aad, | |
size_t aad_len, | |
const unsigned char *input, | |
unsigned char *output, | |
unsigned char tag[16] ) | |
{ | |
CHACHAPOLY_VALIDATE_RET( ctx != NULL ); | |
CHACHAPOLY_VALIDATE_RET( nonce != NULL ); | |
CHACHAPOLY_VALIDATE_RET( tag != NULL ); | |
CHACHAPOLY_VALIDATE_RET( aad_len == 0 || aad != NULL ); | |
CHACHAPOLY_VALIDATE_RET( length == 0 || input != NULL ); | |
CHACHAPOLY_VALIDATE_RET( length == 0 || output != NULL ); | |
return( chachapoly_crypt_and_tag( ctx, MBEDTLS_CHACHAPOLY_ENCRYPT, | |
length, nonce, aad, aad_len, | |
input, output, tag ) ); | |
} | |
int mbedtls_chachapoly_auth_decrypt( mbedtls_chachapoly_context *ctx, | |
size_t length, | |
const unsigned char nonce[12], | |
const unsigned char *aad, | |
size_t aad_len, | |
const unsigned char tag[16], | |
const unsigned char *input, | |
unsigned char *output ) | |
{ | |
int ret; | |
unsigned char check_tag[16]; | |
size_t i; | |
int diff; | |
CHACHAPOLY_VALIDATE_RET( ctx != NULL ); | |
CHACHAPOLY_VALIDATE_RET( nonce != NULL ); | |
CHACHAPOLY_VALIDATE_RET( tag != NULL ); | |
CHACHAPOLY_VALIDATE_RET( aad_len == 0 || aad != NULL ); | |
CHACHAPOLY_VALIDATE_RET( length == 0 || input != NULL ); | |
CHACHAPOLY_VALIDATE_RET( length == 0 || output != NULL ); | |
if( ( ret = chachapoly_crypt_and_tag( ctx, | |
MBEDTLS_CHACHAPOLY_DECRYPT, length, nonce, | |
aad, aad_len, input, output, check_tag ) ) != 0 ) | |
{ | |
return( ret ); | |
} | |
/* Check tag in "constant-time" */ | |
for( diff = 0, i = 0; i < sizeof( check_tag ); i++ ) | |
diff |= tag[i] ^ check_tag[i]; | |
if( diff != 0 ) | |
{ | |
mbedtls_platform_zeroize( output, length ); | |
return( MBEDTLS_ERR_CHACHAPOLY_AUTH_FAILED ); | |
} | |
return( 0 ); | |
} | |
#endif /* MBEDTLS_CHACHAPOLY_ALT */ | |
#if defined(MBEDTLS_SELF_TEST) | |
static const unsigned char test_key[1][32] = | |
{ | |
{ | |
0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, | |
0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, | |
0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, | |
0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f | |
} | |
}; | |
static const unsigned char test_nonce[1][12] = | |
{ | |
{ | |
0x07, 0x00, 0x00, 0x00, /* 32-bit common part */ | |
0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47 /* 64-bit IV */ | |
} | |
}; | |
static const unsigned char test_aad[1][12] = | |
{ | |
{ | |
0x50, 0x51, 0x52, 0x53, 0xc0, 0xc1, 0xc2, 0xc3, | |
0xc4, 0xc5, 0xc6, 0xc7 | |
} | |
}; | |
static const size_t test_aad_len[1] = | |
{ | |
12U | |
}; | |
static const unsigned char test_input[1][114] = | |
{ | |
{ | |
0x4c, 0x61, 0x64, 0x69, 0x65, 0x73, 0x20, 0x61, | |
0x6e, 0x64, 0x20, 0x47, 0x65, 0x6e, 0x74, 0x6c, | |
0x65, 0x6d, 0x65, 0x6e, 0x20, 0x6f, 0x66, 0x20, | |
0x74, 0x68, 0x65, 0x20, 0x63, 0x6c, 0x61, 0x73, | |
0x73, 0x20, 0x6f, 0x66, 0x20, 0x27, 0x39, 0x39, | |
0x3a, 0x20, 0x49, 0x66, 0x20, 0x49, 0x20, 0x63, | |
0x6f, 0x75, 0x6c, 0x64, 0x20, 0x6f, 0x66, 0x66, | |
0x65, 0x72, 0x20, 0x79, 0x6f, 0x75, 0x20, 0x6f, | |
0x6e, 0x6c, 0x79, 0x20, 0x6f, 0x6e, 0x65, 0x20, | |
0x74, 0x69, 0x70, 0x20, 0x66, 0x6f, 0x72, 0x20, | |
0x74, 0x68, 0x65, 0x20, 0x66, 0x75, 0x74, 0x75, | |
0x72, 0x65, 0x2c, 0x20, 0x73, 0x75, 0x6e, 0x73, | |
0x63, 0x72, 0x65, 0x65, 0x6e, 0x20, 0x77, 0x6f, | |
0x75, 0x6c, 0x64, 0x20, 0x62, 0x65, 0x20, 0x69, | |
0x74, 0x2e | |
} | |
}; | |
static const unsigned char test_output[1][114] = | |
{ | |
{ | |
0xd3, 0x1a, 0x8d, 0x34, 0x64, 0x8e, 0x60, 0xdb, | |
0x7b, 0x86, 0xaf, 0xbc, 0x53, 0xef, 0x7e, 0xc2, | |
0xa4, 0xad, 0xed, 0x51, 0x29, 0x6e, 0x08, 0xfe, | |
0xa9, 0xe2, 0xb5, 0xa7, 0x36, 0xee, 0x62, 0xd6, | |
0x3d, 0xbe, 0xa4, 0x5e, 0x8c, 0xa9, 0x67, 0x12, | |
0x82, 0xfa, 0xfb, 0x69, 0xda, 0x92, 0x72, 0x8b, | |
0x1a, 0x71, 0xde, 0x0a, 0x9e, 0x06, 0x0b, 0x29, | |
0x05, 0xd6, 0xa5, 0xb6, 0x7e, 0xcd, 0x3b, 0x36, | |
0x92, 0xdd, 0xbd, 0x7f, 0x2d, 0x77, 0x8b, 0x8c, | |
0x98, 0x03, 0xae, 0xe3, 0x28, 0x09, 0x1b, 0x58, | |
0xfa, 0xb3, 0x24, 0xe4, 0xfa, 0xd6, 0x75, 0x94, | |
0x55, 0x85, 0x80, 0x8b, 0x48, 0x31, 0xd7, 0xbc, | |
0x3f, 0xf4, 0xde, 0xf0, 0x8e, 0x4b, 0x7a, 0x9d, | |
0xe5, 0x76, 0xd2, 0x65, 0x86, 0xce, 0xc6, 0x4b, | |
0x61, 0x16 | |
} | |
}; | |
static const size_t test_input_len[1] = | |
{ | |
114U | |
}; | |
static const unsigned char test_mac[1][16] = | |
{ | |
{ | |
0x1a, 0xe1, 0x0b, 0x59, 0x4f, 0x09, 0xe2, 0x6a, | |
0x7e, 0x90, 0x2e, 0xcb, 0xd0, 0x60, 0x06, 0x91 | |
} | |
}; | |
#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; | |
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 */ |