98 lines
2.9 KiB
C
Executable File
98 lines
2.9 KiB
C
Executable File
/*
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* Copyright (c) 2015, Secure Endpoints Inc.
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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
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* are met:
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*
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* - 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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* - 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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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT HOLDER OR CONTRIBUTORS 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)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#include "krb5_locl.h"
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/*
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* SP800-108 KDF
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*/
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/**
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* As described in SP800-108 5.1 (for HMAC)
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*
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* @param context Kerberos 5 context
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* @param kdc_K1 Base key material.
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* @param kdf_label A string that identifies the purpose for the derived key.
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* @param kdf_context A binary string containing parties, nonce, etc.
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* @param md Message digest function to use for PRF.
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* @param kdf_K0 Derived key data.
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*
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* @return Return an error code for an failure or 0 on success.
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* @ingroup krb5_crypto
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*/
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krb5_error_code
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_krb5_SP800_108_HMAC_KDF(krb5_context context,
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const krb5_data *kdf_K1,
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const krb5_data *kdf_label,
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const krb5_data *kdf_context,
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const EVP_MD *md,
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krb5_data *kdf_K0)
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{
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HMAC_CTX c;
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unsigned char *p = kdf_K0->data;
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size_t i, n, left = kdf_K0->length;
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unsigned char hmac[EVP_MAX_MD_SIZE];
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unsigned int h = EVP_MD_size(md);
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const size_t L = kdf_K0->length;
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heim_assert(md != NULL, "SP800-108 KDF internal error");
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HMAC_CTX_init(&c);
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n = L / h;
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for (i = 0; i <= n; i++) {
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unsigned char tmp[4];
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size_t len;
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HMAC_Init_ex(&c, kdf_K1->data, kdf_K1->length, md, NULL);
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_krb5_put_int(tmp, i + 1, 4);
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HMAC_Update(&c, tmp, 4);
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HMAC_Update(&c, kdf_label->data, kdf_label->length);
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HMAC_Update(&c, (unsigned char *)"", 1);
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if (kdf_context)
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HMAC_Update(&c, kdf_context->data, kdf_context->length);
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_krb5_put_int(tmp, L * 8, 4);
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HMAC_Update(&c, tmp, 4);
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HMAC_Final(&c, hmac, &h);
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len = h > left ? left : h;
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memcpy(p, hmac, len);
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p += len;
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left -= len;
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}
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HMAC_CTX_cleanup(&c);
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return 0;
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}
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