130 строки
4.0 KiB
C
130 строки
4.0 KiB
C
/***************************************************************************
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* _ _ ____ _
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* Project ___| | | | _ \| |
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* / __| | | | |_) | |
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* | (__| |_| | _ <| |___
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* \___|\___/|_| \_\_____|
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*
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* Copyright (C) 1998 - 2015, Daniel Stenberg, <daniel@haxx.se>, et al.
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*
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* This software is licensed as described in the file COPYING, which
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* you should have received as part of this distribution. The terms
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* are also available at http://curl.haxx.se/docs/copyright.html.
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*
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* You may opt to use, copy, modify, merge, publish, distribute and/or sell
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* copies of the Software, and permit persons to whom the Software is
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* furnished to do so, under the terms of the COPYING file.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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* RFC2104 Keyed-Hashing for Message Authentication
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*
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***************************************************************************/
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#include "curl_setup.h"
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#ifndef CURL_DISABLE_CRYPTO_AUTH
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#include "curl_hmac.h"
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#include "curl_memory.h"
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/* The last #include file should be: */
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#include "memdebug.h"
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/*
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* Generic HMAC algorithm.
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*
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* This module computes HMAC digests based on any hash function. Parameters
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* and computing procedures are set-up dynamically at HMAC computation
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* context initialisation.
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*/
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static const unsigned char hmac_ipad = 0x36;
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static const unsigned char hmac_opad = 0x5C;
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HMAC_context *
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Curl_HMAC_init(const HMAC_params * hashparams,
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const unsigned char * key,
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unsigned int keylen)
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{
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size_t i;
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HMAC_context * ctxt;
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unsigned char * hkey;
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unsigned char b;
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/* Create HMAC context. */
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i = sizeof *ctxt + 2 * hashparams->hmac_ctxtsize +
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hashparams->hmac_resultlen;
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ctxt = malloc(i);
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if(!ctxt)
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return ctxt;
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ctxt->hmac_hash = hashparams;
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ctxt->hmac_hashctxt1 = (void *) (ctxt + 1);
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ctxt->hmac_hashctxt2 = (void *) ((char *) ctxt->hmac_hashctxt1 +
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hashparams->hmac_ctxtsize);
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/* If the key is too long, replace it by its hash digest. */
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if(keylen > hashparams->hmac_maxkeylen) {
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(*hashparams->hmac_hinit)(ctxt->hmac_hashctxt1);
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(*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, key, keylen);
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hkey = (unsigned char *) ctxt->hmac_hashctxt2 + hashparams->hmac_ctxtsize;
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(*hashparams->hmac_hfinal)(hkey, ctxt->hmac_hashctxt1);
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key = hkey;
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keylen = hashparams->hmac_resultlen;
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}
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/* Prime the two hash contexts with the modified key. */
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(*hashparams->hmac_hinit)(ctxt->hmac_hashctxt1);
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(*hashparams->hmac_hinit)(ctxt->hmac_hashctxt2);
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for(i = 0; i < keylen; i++) {
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b = (unsigned char)(*key ^ hmac_ipad);
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(*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, &b, 1);
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b = (unsigned char)(*key++ ^ hmac_opad);
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(*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2, &b, 1);
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}
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for(; i < hashparams->hmac_maxkeylen; i++) {
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(*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, &hmac_ipad, 1);
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(*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2, &hmac_opad, 1);
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}
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/* Done, return pointer to HMAC context. */
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return ctxt;
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}
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int Curl_HMAC_update(HMAC_context * ctxt,
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const unsigned char * data,
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unsigned int len)
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{
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/* Update first hash calculation. */
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(*ctxt->hmac_hash->hmac_hupdate)(ctxt->hmac_hashctxt1, data, len);
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return 0;
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}
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int Curl_HMAC_final(HMAC_context * ctxt, unsigned char * result)
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{
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const HMAC_params * hashparams = ctxt->hmac_hash;
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/* Do not get result if called with a null parameter: only release
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storage. */
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if(!result)
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result = (unsigned char *) ctxt->hmac_hashctxt2 +
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ctxt->hmac_hash->hmac_ctxtsize;
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(*hashparams->hmac_hfinal)(result, ctxt->hmac_hashctxt1);
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(*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2,
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result, hashparams->hmac_resultlen);
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(*hashparams->hmac_hfinal)(result, ctxt->hmac_hashctxt2);
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free((char *) ctxt);
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return 0;
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}
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#endif /* CURL_DISABLE_CRYPTO_AUTH */
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