1 /***************************************************************************
3 * Project ___| | | | _ \| |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
8 * Copyright (C) 1998 - 2010, Daniel Stenberg, <daniel@haxx.se>, et al.
10 * This software is licensed as described in the file COPYING, which
11 * you should have received as part of this distribution. The terms
12 * are also available at http://curl.haxx.se/docs/copyright.html.
14 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
15 * copies of the Software, and permit persons to whom the Software is
16 * furnished to do so, under the terms of the COPYING file.
18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19 * KIND, either express or implied.
21 * RFC2104 Keyed-Hashing for Message Authentication
23 ***************************************************************************/
25 #ifndef CURL_DISABLE_CRYPTO_AUTH
28 #include "curl_hmac.h"
31 * Generic HMAC algorithm.
33 * This module computes HMAC digests based on any hash function. Parameters
34 * and computing procedures are set-up dynamically at HMAC computation
35 * context initialisation.
38 static const unsigned char hmac_ipad = 0x36;
39 static const unsigned char hmac_opad = 0x5C;
44 Curl_HMAC_init(const HMAC_params * hashparams,
45 const unsigned char * key,
53 /* Create HMAC context. */
54 i = sizeof *ctxt + 2 * hashparams->hmac_ctxtsize + hashparams->hmac_resultlen;
55 ctxt = (HMAC_context *) malloc(i);
60 ctxt->hmac_hash = hashparams;
61 ctxt->hmac_hashctxt1 = (void *) (ctxt + 1);
62 ctxt->hmac_hashctxt2 = (void *) ((char *) ctxt->hmac_hashctxt1 +
63 hashparams->hmac_ctxtsize);
65 /* If the key is too long, replace it by its hash digest. */
66 if(keylen > hashparams->hmac_maxkeylen) {
67 (*hashparams->hmac_hinit)(ctxt->hmac_hashctxt1);
68 (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, key, keylen);
69 hkey = (unsigned char *) ctxt->hmac_hashctxt2 + hashparams->hmac_ctxtsize;
70 (*hashparams->hmac_hfinal)(hkey, ctxt->hmac_hashctxt1);
72 keylen = hashparams->hmac_resultlen;
75 /* Prime the two hash contexts with the modified key. */
76 (*hashparams->hmac_hinit)(ctxt->hmac_hashctxt1);
77 (*hashparams->hmac_hinit)(ctxt->hmac_hashctxt2);
79 for (i = 0; i < keylen; i++) {
81 (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, &b, 1);
82 b = *key++ ^ hmac_opad;
83 (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2, &b, 1);
86 for (; i < hashparams->hmac_maxkeylen; i++) {
87 (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, &hmac_ipad, 1);
88 (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2, &hmac_opad, 1);
91 /* Done, return pointer to HMAC context. */
95 int Curl_HMAC_update(HMAC_context * ctxt,
96 const unsigned char * data,
99 /* Update first hash calculation. */
100 (*ctxt->hmac_hash->hmac_hupdate)(ctxt->hmac_hashctxt1, data, len);
105 int Curl_HMAC_final(HMAC_context * ctxt, unsigned char * result)
107 const HMAC_params * hashparams = ctxt->hmac_hash;
109 /* Do not get result if called with a null parameter: only release storage. */
112 result = (unsigned char *) ctxt->hmac_hashctxt2 +
113 ctxt->hmac_hash->hmac_ctxtsize;
115 (*hashparams->hmac_hfinal)(result, ctxt->hmac_hashctxt1);
116 (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2,
117 result, hashparams->hmac_resultlen);
118 (*hashparams->hmac_hfinal)(result, ctxt->hmac_hashctxt2);