mirror of
https://github.com/yuzu-emu/mbedtls
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536 lines
13 KiB
C
536 lines
13 KiB
C
/*
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* NIST SP800-38B compliant CMAC implementation
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*
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* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
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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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* This file is part of mbed TLS (https://tls.mbed.org)
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*/
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/*
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* Definition of CMAC:
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* http://csrc.nist.gov/publications/nistpubs/800-38B/SP_800-38B.pdf
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* RFC 4493 "The AES-CMAC Algorithm"
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*/
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#if !defined(MBEDTLS_CONFIG_FILE)
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#include "mbedtls/config.h"
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#else
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#include MBEDTLS_CONFIG_FILE
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#endif
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#if defined(MBEDTLS_CMAC_C)
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#include "mbedtls/cmac.h"
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#include <string.h>
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#if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
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#if defined(MBEDTLS_PLATFORM_C)
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#include "mbedtls/platform.h"
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#else
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#include <stdio.h>
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#define mbedtls_printf printf
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#endif /* MBEDTLS_PLATFORM_C */
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#endif /* MBEDTLS_SELF_TEST && MBEDTLS_AES_C */
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/*
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* Macros for common operations.
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* Results in smaller compiled code than static inline functions.
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*/
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/*
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* XOR 128-bit
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*/
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#define XOR_128( i1, i2, o ) \
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for( i = 0; i < 16; i++ ) \
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( o )[i] = ( i1 )[i] ^ ( i2 )[i];
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/*
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* Update the CMAC state in Mn using an input block x
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* TODO: Compiler optimisation
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*/
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#define UPDATE_CMAC( x ) \
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XOR_128( Mn, ( x ), Mn ); \
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if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, \
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Mn, 16, Mn, &olen ) ) != 0 ) \
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return( ret );
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/* Implementation that should never be optimized out by the compiler */
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static void mbedtls_zeroize( void *v, size_t n ) {
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volatile unsigned char *p = v; while( n-- ) *p++ = 0;
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}
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/*
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* Initialize context
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*/
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void mbedtls_cmac_init( mbedtls_cmac_context *ctx )
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{
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memset( ctx, 0, sizeof( mbedtls_cmac_context ) );
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}
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/*
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* Leftshift a 16-byte block by 1 bit
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* \note output can be same as input
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*/
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static void leftshift_onebit( unsigned char *input, unsigned char *output )
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{
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int i;
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unsigned char temp;
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unsigned char overflow = 0;
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for( i = 15; i >= 0; i-- )
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{
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temp = input[i];
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output[i] = temp << 1;
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output[i] |= overflow;
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overflow = temp >> 7;
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}
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return;
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}
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/*
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* Generate subkeys
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*/
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static int generate_subkeys( mbedtls_cmac_context *ctx )
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{
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static const unsigned char Rb[2] = { 0x00, 0x87 }; /* block size 16 only */
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int ret;
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unsigned char L[16];
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size_t olen;
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/* Calculate Ek(0) */
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memset( L, 0, 16 );
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if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx,
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L, 16, L, &olen ) ) != 0 )
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{
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return( ret );
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}
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/*
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* Generate K1
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* If MSB(L) = 0, then K1 = (L << 1)
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* If MSB(L) = 1, then K1 = (L << 1) ^ Rb
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*/
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leftshift_onebit( L, ctx->K1 );
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ctx->K1[15] ^= Rb[L[0] >> 7]; /* "Constant-time" operation */
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/*
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* Generate K2
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* If MSB(K1) == 0, then K2 = (K1 << 1)
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* If MSB(K1) == 1, then K2 = (K1 << 1) ^ Rb
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*/
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leftshift_onebit( ctx->K1, ctx->K2 );
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ctx->K2[15] ^= Rb[ctx->K1[0] >> 7]; /* "Constant-time" operation */
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return( 0 );
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}
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int mbedtls_cmac_setkey( mbedtls_cmac_context *ctx,
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mbedtls_cipher_id_t cipher,
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const unsigned char *key,
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unsigned int keybits )
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{
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int ret;
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const mbedtls_cipher_info_t *cipher_info;
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cipher_info = mbedtls_cipher_info_from_values( cipher, keybits,
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MBEDTLS_MODE_ECB );
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if( cipher_info == NULL )
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return( MBEDTLS_ERR_CMAC_BAD_INPUT );
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if( cipher_info->block_size != 16 )
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return( MBEDTLS_ERR_CMAC_BAD_INPUT );
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mbedtls_cipher_free( &ctx->cipher_ctx );
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if( ( ret = mbedtls_cipher_setup( &ctx->cipher_ctx, cipher_info ) ) != 0 )
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return( ret );
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if( ( ret = mbedtls_cipher_setkey( &ctx->cipher_ctx, key, keybits,
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MBEDTLS_ENCRYPT ) ) != 0 )
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{
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return( ret );
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}
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return( generate_subkeys( ctx ) );
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}
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/*
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* Free context
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*/
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void mbedtls_cmac_free( mbedtls_cmac_context *ctx )
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{
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mbedtls_cipher_free( &ctx->cipher_ctx );
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mbedtls_zeroize( ctx, sizeof( mbedtls_cmac_context ) );
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}
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/* TODO: Use cipher padding function? */
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static void padding( const unsigned char *lastb,
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unsigned char *pad,
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const size_t length )
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{
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size_t j;
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/* original last block */
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for( j = 0; j < 16; j++ )
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{
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if( j < length )
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{
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pad[j] = lastb[j];
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}
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else if( j == length )
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{
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pad[j] = 0x80;
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}
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else
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{
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pad[j] = 0x00;
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}
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}
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}
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/*
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* Generate tag on complete message
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*/
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static int cmac_generate( mbedtls_cmac_context *ctx,
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const unsigned char *input, size_t in_len,
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unsigned char *tag, size_t tag_len )
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{
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unsigned char Mn[16];
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unsigned char M_last[16];
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unsigned char padded[16];
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int n, i, j, ret, flag;
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size_t olen;
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/*
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* Check in_len requirements: SP800-38B A
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* 4 is a worst case bottom limit
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*/
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if( tag_len < 4 || tag_len > 16 || tag_len % 2 != 0 )
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return( MBEDTLS_ERR_CMAC_BAD_INPUT );
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/* TODO: Use cipher padding function? */
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// mbedtls_cipher_set_padding_mode( ctx->cipher, MBEDTLS_PADDING_ONE_AND_ZEROS );
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n = ( in_len + 15 ) / 16; /* n is number of rounds */
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if( n == 0 )
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{
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n = 1;
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flag = 0;
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}
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else
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{
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flag = ( ( in_len % 16 ) == 0);
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}
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/* Calculate last block */
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if( flag )
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{
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/* Last block is complete block */
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XOR_128( &input[16 * ( n - 1 )], ctx->K1, M_last );
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}
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else
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{
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/* TODO: Use cipher padding function? */
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padding( &input[16 * ( n - 1 )], padded, in_len % 16 );
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XOR_128( padded, ctx->K2, M_last );
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}
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memset( Mn, 0, 16 );
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for( j = 0; j < n - 1; j++ )
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{
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UPDATE_CMAC( &input[16 * j] );
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}
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UPDATE_CMAC( M_last );
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memcpy( tag, Mn, 16 );
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return( 0 );
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}
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int mbedtls_cmac_generate( mbedtls_cmac_context *ctx,
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const unsigned char *input, size_t in_len,
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unsigned char *tag, size_t tag_len )
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{
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return( cmac_generate( ctx, input, in_len, tag, tag_len ) );
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}
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/*
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* Authenticated decryption
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*/
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int mbedtls_cmac_verify( mbedtls_cmac_context *ctx,
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const unsigned char *input, size_t in_len,
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const unsigned char *tag, size_t tag_len )
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{
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int ret;
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unsigned char check_tag[16];
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unsigned char i;
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int diff;
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if( ( ret = cmac_generate( ctx, input, in_len, check_tag, tag_len ) ) != 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 < tag_len; i++ )
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{
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diff |= tag[i] ^ check_tag[i];
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}
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if( diff != 0 )
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{
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return( MBEDTLS_ERR_CMAC_VERIFY_FAILED );
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}
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return( 0 );
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}
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int mbedtls_aes_cmac_prf_128( mbedtls_cmac_context *ctx,
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const unsigned char *key, size_t key_length,
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const unsigned char *input, size_t in_len,
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unsigned char *tag )
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{
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int ret;
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unsigned char zero_key[16];
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unsigned char int_key[16];
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if( key_length == 16 )
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{
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/* Use key as is */
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memcpy( int_key, key, 16 );
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}
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else
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{
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mbedtls_cmac_context zero_ctx;
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/* Key is AES_CMAC(0, key) */
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mbedtls_cmac_init( &zero_ctx );
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memset( zero_key, 0, 16 );
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ret = mbedtls_cmac_setkey( &zero_ctx, MBEDTLS_CIPHER_ID_AES,
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zero_key, 8 * sizeof zero_key );
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if( ret != 0 )
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{
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return( ret );
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}
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ret = mbedtls_cmac_generate( &zero_ctx, key, key_length, int_key, 16 );
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if( ret != 0 )
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{
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return( ret );
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}
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}
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ret = mbedtls_cmac_setkey( ctx, MBEDTLS_CIPHER_ID_AES,
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int_key, 8 * sizeof int_key );
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if( ret != 0 )
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{
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return( ret );
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}
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return( mbedtls_cmac_generate( ctx, input, in_len, tag, 16 ) );
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}
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#if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
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/*
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* Examples 1 to 4 from SP800-3B corrected Appendix D.1
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* http://csrc.nist.gov/publications/nistpubs/800-38B/Updated_CMAC_Examples.pdf
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*/
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#define NB_CMAC_TESTS 4
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#define NB_PRF_TESTS 3
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/* Key */
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static const unsigned char key[] = {
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0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6,
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0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c
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};
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/* Assume we don't need to test Ek0 as this is a function of the cipher */
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/* Subkey K1 */
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static const unsigned char K1[] = {
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0xfb, 0xee, 0xd6, 0x18, 0x35, 0x71, 0x33, 0x66,
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0x7c, 0x85, 0xe0, 0x8f, 0x72, 0x36, 0xa8, 0xde
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};
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/* Subkey K2 */
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static const unsigned char K2[] = {
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0xf7, 0xdd, 0xac, 0x30, 0x6a, 0xe2, 0x66, 0xcc,
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0xf9, 0x0b, 0xc1, 0x1e, 0xe4, 0x6d, 0x51, 0x3b
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};
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/* All Messages */
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static const unsigned char M[] = {
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0x6b, 0xc1, 0xbe, 0xe2, 0x2e, 0x40, 0x9f, 0x96,
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0xe9, 0x3d, 0x7e, 0x11, 0x73, 0x93, 0x17, 0x2a,
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0xae, 0x2d, 0x8a, 0x57, 0x1e, 0x03, 0xac, 0x9c,
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0x9e, 0xb7, 0x6f, 0xac, 0x45, 0xaf, 0x8e, 0x51,
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0x30, 0xc8, 0x1c, 0x46, 0xa3, 0x5c, 0xe4, 0x11,
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0xe5, 0xfb, 0xc1, 0x19, 0x1a, 0x0a, 0x52, 0xef,
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0xf6, 0x9f, 0x24, 0x45, 0xdf, 0x4f, 0x9b, 0x17,
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0xad, 0x2b, 0x41, 0x7b, 0xe6, 0x6c, 0x37, 0x10
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};
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static const unsigned char T[NB_CMAC_TESTS][16] = {
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{
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0xbb, 0x1d, 0x69, 0x29, 0xe9, 0x59, 0x37, 0x28,
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0x7f, 0xa3, 0x7d, 0x12, 0x9b, 0x75, 0x67, 0x46
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},
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{
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0x07, 0x0a, 0x16, 0xb4, 0x6b, 0x4d, 0x41, 0x44,
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0xf7, 0x9b, 0xdd, 0x9d, 0xd0, 0x4a, 0x28, 0x7c
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},
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{
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0xdf, 0xa6, 0x67, 0x47, 0xde, 0x9a, 0xe6, 0x30,
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0x30, 0xca, 0x32, 0x61, 0x14, 0x97, 0xc8, 0x27
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},
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{
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0x51, 0xf0, 0xbe, 0xbf, 0x7e, 0x3b, 0x9d, 0x92,
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0xfc, 0x49, 0x74, 0x17, 0x79, 0x36, 0x3c, 0xfe
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}
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};
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/* Sizes in bytes */
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static const size_t Mlen[NB_CMAC_TESTS] = {
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0,
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16,
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40,
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64
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};
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/* PRF K */
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static const unsigned char PRFK[] = {
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0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
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0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
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0xed, 0xcb
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};
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/* Sizes in bytes */
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static const size_t PRFKlen[NB_PRF_TESTS] = {
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18,
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16,
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10
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};
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/* PRF M */
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static const unsigned char PRFM[] = {
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0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
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0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
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0x10, 0x11, 0x12, 0x13
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};
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static const unsigned char PRFT[NB_PRF_TESTS][16] = {
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{
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0x84, 0xa3, 0x48, 0xa4, 0xa4, 0x5d, 0x23, 0x5b,
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0xab, 0xff, 0xfc, 0x0d, 0x2b, 0x4d, 0xa0, 0x9a
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},
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{
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0x98, 0x0a, 0xe8, 0x7b, 0x5f, 0x4c, 0x9c, 0x52,
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0x14, 0xf5, 0xb6, 0xa8, 0x45, 0x5e, 0x4c, 0x2d
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},
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{
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0x29, 0x0d, 0x9e, 0x11, 0x2e, 0xdb, 0x09, 0xee,
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0x14, 0x1f, 0xcf, 0x64, 0xc0, 0xb7, 0x2f, 0x3d
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}
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};
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int mbedtls_cmac_self_test( int verbose )
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{
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mbedtls_cmac_context ctx;
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unsigned char tag[16];
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int i;
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int ret;
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mbedtls_cmac_init( &ctx );
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if( mbedtls_cmac_setkey( &ctx, MBEDTLS_CIPHER_ID_AES, key, 8 * sizeof key ) != 0 )
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{
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if( verbose != 0 )
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mbedtls_printf( " CMAC: setup failed" );
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return( 1 );
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}
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if( ( memcmp( ctx.K1, K1, 16 ) != 0 ) ||
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( memcmp( ctx.K2, K2, 16 ) != 0 ) )
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{
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if( verbose != 0 )
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mbedtls_printf( " CMAC: subkey generation failed" );
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return( 1 );
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}
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for( i = 0; i < NB_CMAC_TESTS; i++ )
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{
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mbedtls_printf( " AES-128-CMAC #%u: ", i );
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ret = mbedtls_cmac_generate( &ctx, M, Mlen[i], tag, 16 );
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if( ret != 0 ||
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memcmp( tag, T[i], 16 ) != 0 )
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{
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if( verbose != 0 )
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mbedtls_printf( "failed\n" );
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return( 1 );
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}
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ret = mbedtls_cmac_verify( &ctx, M, Mlen[i], T[i], 16 );
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if( ret != 0 )
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{
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if( verbose != 0 )
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mbedtls_printf( "failed\n" );
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return( 1 );
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}
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if( verbose != 0 )
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mbedtls_printf( "passed\n" );
|
|
}
|
|
|
|
for( i = 0; i < NB_PRF_TESTS; i++ )
|
|
{
|
|
mbedtls_printf( " AES-CMAC-128-PRF #%u: ", i );
|
|
|
|
mbedtls_aes_cmac_prf_128( &ctx, PRFK, PRFKlen[i], PRFM, 20, tag );
|
|
|
|
if( ret != 0 ||
|
|
memcmp( tag, PRFT[i], 16 ) != 0 )
|
|
{
|
|
if( verbose != 0 )
|
|
mbedtls_printf( "failed\n" );
|
|
|
|
return( 1 );
|
|
}
|
|
|
|
if( verbose != 0 )
|
|
mbedtls_printf( "passed\n" );
|
|
}
|
|
|
|
mbedtls_cmac_free( &ctx );
|
|
|
|
if( verbose != 0 )
|
|
mbedtls_printf( "\n" );
|
|
|
|
return( 0 );
|
|
}
|
|
|
|
#endif /* MBEDTLS_SELF_TEST && MBEDTLS_AES_C */
|
|
|
|
#endif /* MBEDTLS_CMAC_C */
|