115 lines
3.7 KiB
C
115 lines
3.7 KiB
C
/**
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* Copyright (C) 2015-2016 Virgil Security Inc.
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*
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* Lead Maintainer: Virgil Security Inc. <support@virgilsecurity.com>
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*
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met:
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*
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* (1) Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* (2) Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* (3) Neither the name of the copyright holder nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ''AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
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* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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* This file is part of extension to mbed TLS (https://tls.mbed.org)
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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_KDF2_C)
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#include "mbedtls/kdf2.h"
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#include "mbedtls/md.h"
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#include <math.h>
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#include <string.h>
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#define KDF2_TRY(invocation) \
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do { \
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result = invocation; \
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if((result) < 0) { \
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goto exit; \
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} \
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} while (0)
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#define KDF2_CEIL(x,y) (1 + ((x - 1) / y))
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int mbedtls_kdf2(const mbedtls_md_info_t *md_info, const unsigned char *input, size_t ilen,
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unsigned char * output, size_t olen)
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{
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int result = 0;
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size_t counter = 1;
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size_t counter_len = 0;
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unsigned char counter_string[4] = {0x0};
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unsigned char hash[MBEDTLS_MD_MAX_SIZE] = {0x0};
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unsigned char hash_len = 0;
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size_t olen_actual = 0;
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mbedtls_md_context_t md_ctx;
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if (md_info == NULL)
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return( MBEDTLS_ERR_KDF2_BAD_INPUT_DATA );
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// Initialize digest context
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mbedtls_md_init(&md_ctx);
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KDF2_TRY(mbedtls_md_setup(&md_ctx, md_info, 0));
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// Get hash parameters
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hash_len = mbedtls_md_get_size(md_info);
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// Get KDF parameters
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counter_len = KDF2_CEIL(olen, hash_len);
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// Start hashing
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for(; counter <= counter_len; ++counter) {
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counter_string[0] = (unsigned char)((counter >> 24) & 255);
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counter_string[1] = (unsigned char)((counter >> 16) & 255);
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counter_string[2] = (unsigned char)((counter >> 8)) & 255;
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counter_string[3] = (unsigned char)(counter & 255);
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KDF2_TRY(mbedtls_md_starts(&md_ctx));
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KDF2_TRY(mbedtls_md_update(&md_ctx, input, ilen));
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KDF2_TRY(mbedtls_md_update(&md_ctx, counter_string, 4));
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if (olen_actual + hash_len <= olen) {
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KDF2_TRY(mbedtls_md_finish(&md_ctx, output + olen_actual));
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olen_actual += hash_len;
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} else {
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KDF2_TRY(mbedtls_md_finish(&md_ctx, hash));
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memcpy(output + olen_actual, hash, olen - olen_actual);
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olen_actual = olen;
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}
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}
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exit:
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mbedtls_md_free(&md_ctx);
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return result;
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}
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#endif /* MBEDTLS_KDF2_C */
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