| /** |
| * \file chachapoly.c |
| * |
| * \brief ChaCha20-Poly1305 AEAD construction based on RFC 7539. |
| * |
| * 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_CHACHAPOLY_C) |
| |
| #include "mbedtls/chachapoly.h" |
| #include "mbedtls/platform_util.h" |
| #include "mbedtls/error.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 = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| 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 = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| 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 = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| 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 = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| 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. |
| */ |
| MBEDTLS_PUT_UINT64_LE(ctx->aad_len, len_block, 0); |
| MBEDTLS_PUT_UINT64_LE(ctx->ciphertext_len, len_block, 8); |
| |
| 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 = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| 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 = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| 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 |
| } |
| }; |
| |
| /* 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 */ |
