mirror of
https://github.com/yuzu-emu/mbedtls.git
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144 lines
3.7 KiB
C
144 lines
3.7 KiB
C
/*
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* HMAC_DRBG implementation (NIST SP 800-90)
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*
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* Copyright (C) 2014, Brainspark B.V.
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*
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* This file is part of PolarSSL (http://www.polarssl.org)
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* Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
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*
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* All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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/*
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* The NIST SP 800-90 DRBGs are described in the following publication.
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* http://csrc.nist.gov/publications/nistpubs/800-90A/SP800-90A.pdf
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*/
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#include "polarssl/config.h"
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#if defined(POLARSSL_HMAC_DRBG_C)
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#include "polarssl/hmac_drbg.h"
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/*
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* HMAC_DRBG update, using optional additional data
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*/
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void hmac_drbg_update( hmac_drbg_context *ctx,
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const unsigned char *additional, size_t add_len )
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{
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size_t md_len = ctx->md_ctx.md_info->size;
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unsigned char rounds = ( additional != NULL && add_len != 0 ) ? 2 : 1;
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unsigned char sep[1];
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for( sep[0] = 0; sep[0] < rounds; sep[0]++ )
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{
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md_hmac_starts( &ctx->md_ctx, ctx->K, md_len );
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md_hmac_update( &ctx->md_ctx, ctx->V, md_len );
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md_hmac_update( &ctx->md_ctx, sep, 1 );
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if( rounds == 2 )
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md_hmac_update( &ctx->md_ctx, additional, add_len );
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md_hmac_finish( &ctx->md_ctx, ctx->K );
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md_hmac_starts( &ctx->md_ctx, ctx->K, md_len );
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md_hmac_update( &ctx->md_ctx, ctx->V, md_len );
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md_hmac_finish( &ctx->md_ctx, ctx->V );
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}
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}
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/*
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* Simplified HMAC_DRBG initialisation.
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*/
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int hmac_drbg_init( hmac_drbg_context *ctx,
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const md_info_t * md_info,
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const unsigned char *data, size_t data_len )
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{
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int ret;
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memset( ctx, 0, sizeof( hmac_drbg_context ) );
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if( ( ret = md_init_ctx( &ctx->md_ctx, md_info ) ) != 0 )
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return( ret );
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memset( ctx->V, 0x01, md_info->size );
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/* ctx->K is already 0 */
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hmac_drbg_update( ctx, data, data_len );
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return( 0 );
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}
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/*
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* Simplified HMAC_DRBG random function
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*/
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int hmac_drbg_random( void *p_rng, unsigned char *output, size_t out_len )
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{
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hmac_drbg_context *ctx = (hmac_drbg_context *) p_rng;
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size_t md_len = ctx->md_ctx.md_info->size;
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size_t left = out_len;
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unsigned char *out = output;
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while( left != 0 )
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{
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size_t use_len = left > md_len ? md_len : left;
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md_hmac_starts( &ctx->md_ctx, ctx->K, md_len );
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md_hmac_update( &ctx->md_ctx, ctx->V, md_len );
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md_hmac_finish( &ctx->md_ctx, ctx->V );
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memcpy( out, ctx->V, use_len );
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out += use_len;
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left -= use_len;
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}
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hmac_drbg_update( ctx, NULL, 0 );
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return( 0 );
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}
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/*
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* Free an HMAC_DRBG context
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*/
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void hmac_drbg_free( hmac_drbg_context *ctx )
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{
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if( ctx == NULL )
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return;
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md_free_ctx( &ctx->md_ctx );
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memset( ctx, 0, sizeof( hmac_drbg_context ) );
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}
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#if defined(POLARSSL_SELF_TEST)
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#include <stdio.h>
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/*
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* Checkup routine
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*/
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int hmac_drbg_self_test( int verbose )
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{
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if( verbose != 0 )
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printf( "\n" );
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return( 0 );
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}
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#endif /* POLARSSL_SELF_TEST */
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#endif /* POLARSSL_HMAC_DRBG_C */
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