1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 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.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 * SPDX-License-Identifier: curl
22 *
23 * RFC2104 Keyed-Hashing for Message Authentication
24 *
25 ***************************************************************************/
26
27 #include "curl_setup.h"
28
29 #if (defined(USE_CURL_NTLM_CORE) && !defined(USE_WINDOWS_SSPI)) \
30 || !defined(CURL_DISABLE_AWS) || !defined(CURL_DISABLE_DIGEST_AUTH)
31
32 #include <curl/curl.h>
33
34 #include "curl_hmac.h"
35 #include "curl_memory.h"
36 #include "warnless.h"
37
38 /* The last #include file should be: */
39 #include "memdebug.h"
40
41 /*
42 * Generic HMAC algorithm.
43 *
44 * This module computes HMAC digests based on any hash function. Parameters
45 * and computing procedures are set-up dynamically at HMAC computation context
46 * initialization.
47 */
48
49 static const unsigned char hmac_ipad = 0x36;
50 static const unsigned char hmac_opad = 0x5C;
51
52
53
54 struct HMAC_context *
Curl_HMAC_init(const struct HMAC_params * hashparams,const unsigned char * key,unsigned int keylen)55 Curl_HMAC_init(const struct HMAC_params *hashparams,
56 const unsigned char *key,
57 unsigned int keylen)
58 {
59 size_t i;
60 struct HMAC_context *ctxt;
61 unsigned char *hkey;
62 unsigned char b;
63
64 /* Create HMAC context. */
65 i = sizeof(*ctxt) + 2 * hashparams->hmac_ctxtsize +
66 hashparams->hmac_resultlen;
67 ctxt = malloc(i);
68
69 if(!ctxt)
70 return ctxt;
71
72 ctxt->hmac_hash = hashparams;
73 ctxt->hmac_hashctxt1 = (void *) (ctxt + 1);
74 ctxt->hmac_hashctxt2 = (void *) ((char *) ctxt->hmac_hashctxt1 +
75 hashparams->hmac_ctxtsize);
76
77 /* If the key is too long, replace it by its hash digest. */
78 if(keylen > hashparams->hmac_maxkeylen) {
79 (*hashparams->hmac_hinit)(ctxt->hmac_hashctxt1);
80 (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, key, keylen);
81 hkey = (unsigned char *) ctxt->hmac_hashctxt2 + hashparams->hmac_ctxtsize;
82 (*hashparams->hmac_hfinal)(hkey, ctxt->hmac_hashctxt1);
83 key = hkey;
84 keylen = hashparams->hmac_resultlen;
85 }
86
87 /* Prime the two hash contexts with the modified key. */
88 (*hashparams->hmac_hinit)(ctxt->hmac_hashctxt1);
89 (*hashparams->hmac_hinit)(ctxt->hmac_hashctxt2);
90
91 for(i = 0; i < keylen; i++) {
92 b = (unsigned char)(*key ^ hmac_ipad);
93 (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, &b, 1);
94 b = (unsigned char)(*key++ ^ hmac_opad);
95 (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2, &b, 1);
96 }
97
98 for(; i < hashparams->hmac_maxkeylen; i++) {
99 (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, &hmac_ipad, 1);
100 (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2, &hmac_opad, 1);
101 }
102
103 /* Done, return pointer to HMAC context. */
104 return ctxt;
105 }
106
Curl_HMAC_update(struct HMAC_context * ctxt,const unsigned char * data,unsigned int len)107 int Curl_HMAC_update(struct HMAC_context *ctxt,
108 const unsigned char *data,
109 unsigned int len)
110 {
111 /* Update first hash calculation. */
112 (*ctxt->hmac_hash->hmac_hupdate)(ctxt->hmac_hashctxt1, data, len);
113 return 0;
114 }
115
116
Curl_HMAC_final(struct HMAC_context * ctxt,unsigned char * result)117 int Curl_HMAC_final(struct HMAC_context *ctxt, unsigned char *result)
118 {
119 const struct HMAC_params *hashparams = ctxt->hmac_hash;
120
121 /* Do not get result if called with a null parameter: only release
122 storage. */
123
124 if(!result)
125 result = (unsigned char *) ctxt->hmac_hashctxt2 +
126 ctxt->hmac_hash->hmac_ctxtsize;
127
128 (*hashparams->hmac_hfinal)(result, ctxt->hmac_hashctxt1);
129 (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2,
130 result, hashparams->hmac_resultlen);
131 (*hashparams->hmac_hfinal)(result, ctxt->hmac_hashctxt2);
132 free((char *) ctxt);
133 return 0;
134 }
135
136 /*
137 * Curl_hmacit()
138 *
139 * This is used to generate a HMAC hash, for the specified input data, given
140 * the specified hash function and key.
141 *
142 * Parameters:
143 *
144 * hashparams [in] - The hash function (Curl_HMAC_MD5).
145 * key [in] - The key to use.
146 * keylen [in] - The length of the key.
147 * data [in] - The data to encrypt.
148 * datalen [in] - The length of the data.
149 * output [in/out] - The output buffer.
150 *
151 * Returns CURLE_OK on success.
152 */
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)153 CURLcode Curl_hmacit(const struct HMAC_params *hashparams,
154 const unsigned char *key, const size_t keylen,
155 const unsigned char *data, const size_t datalen,
156 unsigned char *output)
157 {
158 struct HMAC_context *ctxt =
159 Curl_HMAC_init(hashparams, key, curlx_uztoui(keylen));
160
161 if(!ctxt)
162 return CURLE_OUT_OF_MEMORY;
163
164 /* Update the digest with the given challenge */
165 Curl_HMAC_update(ctxt, data, curlx_uztoui(datalen));
166
167 /* Finalise the digest */
168 Curl_HMAC_final(ctxt, output);
169
170 return CURLE_OK;
171 }
172
173 #endif /* Using NTLM (without SSPI) or AWS */
174
