/********************************************************************* * Copyright 2018, UCAR/Unidata * See netcdf/COPYRIGHT file for copying and redistribution conditions. * ********************************************************************/ /*************************************************************************** * _ _ ____ _ * Project ___| | | | _ \| | * / __| | | | |_) | | * | (__| |_| | _ <| |___ * \___|\___/|_| \_\_____| * * Copyright (C) Daniel Stenberg, , et al. * * This software is licensed as described in the file COPYING, which * you should have received as part of this distribution. The terms * are also available at https://curl.se/docs/copyright.html. * * You may opt to use, copy, modify, merge, publish, distribute and/or sell * copies of the Software, and permit persons to whom the Software is * furnished to do so, under the terms of the COPYING file. * * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY * KIND, either express or implied. * * SPDX-License-Identifier: curl * * RFC2104 Keyed-Hashing for Message Authentication * ***************************************************************************/ #include "nccurl_setup.h" #include "nccurl_hmac.h" /* * Generic HMAC algorithm. * * This module computes HMAC digests based on any hash function. Parameters * and computing procedures are set-up dynamically at HMAC computation context * initialization. */ static const unsigned char hmac_ipad = 0x36; static const unsigned char hmac_opad = 0x5C; struct HMAC_context * Curl_HMAC_init(const struct HMAC_params *hashparams, const unsigned char *key, unsigned int keylen) { size_t i; struct HMAC_context *ctxt; unsigned char *hkey; unsigned char b; /* Create HMAC context. */ i = sizeof(*ctxt) + 2 * hashparams->hmac_ctxtsize + hashparams->hmac_resultlen; ctxt = malloc(i); if(!ctxt) return ctxt; ctxt->hmac_hash = hashparams; ctxt->hmac_hashctxt1 = (void *) (ctxt + 1); ctxt->hmac_hashctxt2 = (void *) ((char *) ctxt->hmac_hashctxt1 + hashparams->hmac_ctxtsize); /* If the key is too long, replace it by its hash digest. */ if(keylen > hashparams->hmac_maxkeylen) { (*hashparams->hmac_hinit)(ctxt->hmac_hashctxt1); (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, key, keylen); hkey = (unsigned char *) ctxt->hmac_hashctxt2 + hashparams->hmac_ctxtsize; (*hashparams->hmac_hfinal)(hkey, ctxt->hmac_hashctxt1); key = hkey; keylen = hashparams->hmac_resultlen; } /* Prime the two hash contexts with the modified key. */ (*hashparams->hmac_hinit)(ctxt->hmac_hashctxt1); (*hashparams->hmac_hinit)(ctxt->hmac_hashctxt2); for(i = 0; i < keylen; i++) { b = (unsigned char)(*key ^ hmac_ipad); (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, &b, 1); b = (unsigned char)(*key++ ^ hmac_opad); (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2, &b, 1); } for(; i < hashparams->hmac_maxkeylen; i++) { (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, &hmac_ipad, 1); (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2, &hmac_opad, 1); } /* Done, return pointer to HMAC context. */ return ctxt; } int Curl_HMAC_update(struct HMAC_context *ctxt, const unsigned char *data, unsigned int len) { /* Update first hash calculation. */ (*ctxt->hmac_hash->hmac_hupdate)(ctxt->hmac_hashctxt1, data, len); return 0; } int Curl_HMAC_final(struct HMAC_context *ctxt, unsigned char *result) { const struct HMAC_params *hashparams = ctxt->hmac_hash; /* Do not get result if called with a null parameter: only release storage. */ if(!result) result = (unsigned char *) ctxt->hmac_hashctxt2 + ctxt->hmac_hash->hmac_ctxtsize; (*hashparams->hmac_hfinal)(result, ctxt->hmac_hashctxt1); (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2, result, hashparams->hmac_resultlen); (*hashparams->hmac_hfinal)(result, ctxt->hmac_hashctxt2); free((char *) ctxt); return 0; } /* * Curl_hmacit() * * This is used to generate a HMAC hash, for the specified input data, given * the specified hash function and key. * * Parameters: * * hashparams [in] - The hash function (Curl_HMAC_MD5). * key [in] - The key to use. * keylen [in] - The length of the key. * data [in] - The data to encrypt. * datalen [in] - The length of the data. * output [in/out] - The output buffer. * * Returns CURLE_OK on success. */ CURLcode Curl_hmacit(const struct HMAC_params *hashparams, const unsigned char *key, const size_t keylen, const unsigned char *data, const size_t datalen, unsigned char *output) { struct HMAC_context *ctxt = Curl_HMAC_init(hashparams, key, nccurlx_uztoui(keylen)); if(!ctxt) return CURLE_OUT_OF_MEMORY; /* Update the digest with the given challenge */ Curl_HMAC_update(ctxt, data, nccurlx_uztoui(datalen)); /* Finalise the digest */ Curl_HMAC_final(ctxt, output); return CURLE_OK; }