1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2016, Daniel Stenberg, <daniel@haxx.se>, et al.
9 *
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 https://curl.haxx.se/docs/copyright.html.
13 *
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.
17 *
18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19 * KIND, either express or implied.
20 *
21 * RFC2104 Keyed-Hashing for Message Authentication
22 *
23 ***************************************************************************/
24
25 #include "curl_setup.h"
26
27 #ifndef CURL_DISABLE_CRYPTO_AUTH
28
29 #include <curl/curl.h>
30
31 #include "curl_hmac.h"
32 #include "curl_memory.h"
33
34 /* The last #include file should be: */
35 #include "memdebug.h"
36
37 /*
38 * Generic HMAC algorithm.
39 *
40 * This module computes HMAC digests based on any hash function. Parameters
41 * and computing procedures are set-up dynamically at HMAC computation
42 * context initialisation.
43 */
44
45 static const unsigned char hmac_ipad = 0x36;
46 static const unsigned char hmac_opad = 0x5C;
47
48
49
50 HMAC_context *
Curl_HMAC_init(const HMAC_params * hashparams,const unsigned char * key,unsigned int keylen)51 Curl_HMAC_init(const HMAC_params * hashparams,
52 const unsigned char *key,
53 unsigned int keylen)
54 {
55 size_t i;
56 HMAC_context *ctxt;
57 unsigned char *hkey;
58 unsigned char b;
59
60 /* Create HMAC context. */
61 i = sizeof *ctxt + 2 * hashparams->hmac_ctxtsize +
62 hashparams->hmac_resultlen;
63 ctxt = malloc(i);
64
65 if(!ctxt)
66 return ctxt;
67
68 ctxt->hmac_hash = hashparams;
69 ctxt->hmac_hashctxt1 = (void *) (ctxt + 1);
70 ctxt->hmac_hashctxt2 = (void *) ((char *) ctxt->hmac_hashctxt1 +
71 hashparams->hmac_ctxtsize);
72
73 /* If the key is too long, replace it by its hash digest. */
74 if(keylen > hashparams->hmac_maxkeylen) {
75 (*hashparams->hmac_hinit)(ctxt->hmac_hashctxt1);
76 (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, key, keylen);
77 hkey = (unsigned char *) ctxt->hmac_hashctxt2 + hashparams->hmac_ctxtsize;
78 (*hashparams->hmac_hfinal)(hkey, ctxt->hmac_hashctxt1);
79 key = hkey;
80 keylen = hashparams->hmac_resultlen;
81 }
82
83 /* Prime the two hash contexts with the modified key. */
84 (*hashparams->hmac_hinit)(ctxt->hmac_hashctxt1);
85 (*hashparams->hmac_hinit)(ctxt->hmac_hashctxt2);
86
87 for(i = 0; i < keylen; i++) {
88 b = (unsigned char)(*key ^ hmac_ipad);
89 (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, &b, 1);
90 b = (unsigned char)(*key++ ^ hmac_opad);
91 (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2, &b, 1);
92 }
93
94 for(; i < hashparams->hmac_maxkeylen; i++) {
95 (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, &hmac_ipad, 1);
96 (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2, &hmac_opad, 1);
97 }
98
99 /* Done, return pointer to HMAC context. */
100 return ctxt;
101 }
102
Curl_HMAC_update(HMAC_context * ctxt,const unsigned char * data,unsigned int len)103 int Curl_HMAC_update(HMAC_context * ctxt,
104 const unsigned char *data,
105 unsigned int len)
106 {
107 /* Update first hash calculation. */
108 (*ctxt->hmac_hash->hmac_hupdate)(ctxt->hmac_hashctxt1, data, len);
109 return 0;
110 }
111
112
Curl_HMAC_final(HMAC_context * ctxt,unsigned char * result)113 int Curl_HMAC_final(HMAC_context *ctxt, unsigned char *result)
114 {
115 const HMAC_params * hashparams = ctxt->hmac_hash;
116
117 /* Do not get result if called with a null parameter: only release
118 storage. */
119
120 if(!result)
121 result = (unsigned char *) ctxt->hmac_hashctxt2 +
122 ctxt->hmac_hash->hmac_ctxtsize;
123
124 (*hashparams->hmac_hfinal)(result, ctxt->hmac_hashctxt1);
125 (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2,
126 result, hashparams->hmac_resultlen);
127 (*hashparams->hmac_hfinal)(result, ctxt->hmac_hashctxt2);
128 free((char *) ctxt);
129 return 0;
130 }
131
132 #endif /* CURL_DISABLE_CRYPTO_AUTH */
133