85 lines
2.7 KiB
C
85 lines
2.7 KiB
C
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/*-
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* Copyright (c) 2010, 2011 Allan Saddi <allan@saddi.com>
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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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* 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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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR 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, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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void
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HMAC_INIT(HMAC_CONTEXT *ctxt, const void *key, size_t keyLen)
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{
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HASH_CONTEXT keyCtxt;
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unsigned int i;
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uint8_t pkey[HASH_BLOCK_SIZE], okey[HASH_BLOCK_SIZE], ikey[HASH_BLOCK_SIZE];
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/* Ensure key is zero-padded */
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memset(pkey, 0, sizeof(pkey));
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if (keyLen > sizeof(pkey)) {
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/* Hash key if > HASH_BLOCK_SIZE */
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HASH_INIT(&keyCtxt);
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HASH_UPDATE(&keyCtxt, key, keyLen);
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HASH_FINAL(&keyCtxt, pkey);
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}
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else {
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memcpy(pkey, key, keyLen);
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}
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/* XOR with opad, ipad */
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for (i = 0; i < sizeof(okey); i++) {
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okey[i] = pkey[i] ^ 0x5c;
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}
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for (i = 0; i < sizeof(ikey); i++) {
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ikey[i] = pkey[i] ^ 0x36;
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}
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/* Initialize hash contexts */
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HASH_INIT(&ctxt->outer);
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HASH_UPDATE(&ctxt->outer, okey, sizeof(okey));
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HASH_INIT(&ctxt->inner);
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HASH_UPDATE(&ctxt->inner, ikey, sizeof(ikey));
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/* Burn the stack */
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memset(ikey, 0, sizeof(ikey));
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memset(okey, 0, sizeof(okey));
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memset(pkey, 0, sizeof(pkey));
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memset(&keyCtxt, 0, sizeof(keyCtxt));
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}
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void
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HMAC_UPDATE(HMAC_CONTEXT *ctxt, const void *data, size_t len)
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{
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HASH_UPDATE(&ctxt->inner, data, len);
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}
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void
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HMAC_FINAL(HMAC_CONTEXT *ctxt, uint8_t hmac[HASH_SIZE])
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{
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uint8_t ihash[HASH_SIZE];
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HASH_FINAL(&ctxt->inner, ihash);
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HASH_UPDATE(&ctxt->outer, ihash, sizeof(ihash));
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HASH_FINAL(&ctxt->outer, hmac);
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memset(ihash, 0, sizeof(ihash));
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}
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