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 setup 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 struct HMAC_context *
Curl_HMAC_init(const struct HMAC_params * hashparams,const unsigned char * key,unsigned int keylen)53 Curl_HMAC_init(const struct HMAC_params *hashparams,
54 const unsigned char *key,
55 unsigned int keylen)
56 {
57 size_t i;
58 struct HMAC_context *ctxt;
59 unsigned char *hkey;
60 unsigned char b;
61
62 /* Create HMAC context. */
63 i = sizeof(*ctxt) + 2 * hashparams->ctxtsize + hashparams->resultlen;
64 ctxt = malloc(i);
65
66 if(!ctxt)
67 return ctxt;
68
69 ctxt->hash = hashparams;
70 ctxt->hashctxt1 = (void *) (ctxt + 1);
71 ctxt->hashctxt2 = (void *) ((char *) ctxt->hashctxt1 + hashparams->ctxtsize);
72
73 /* If the key is too long, replace it by its hash digest. */
74 if(keylen > hashparams->maxkeylen) {
75 hashparams->hinit(ctxt->hashctxt1);
76 hashparams->hupdate(ctxt->hashctxt1, key, keylen);
77 hkey = (unsigned char *) ctxt->hashctxt2 + hashparams->ctxtsize;
78 hashparams->hfinal(hkey, ctxt->hashctxt1);
79 key = hkey;
80 keylen = hashparams->resultlen;
81 }
82
83 /* Prime the two hash contexts with the modified key. */
84 hashparams->hinit(ctxt->hashctxt1);
85 hashparams->hinit(ctxt->hashctxt2);
86
87 for(i = 0; i < keylen; i++) {
88 b = (unsigned char)(*key ^ hmac_ipad);
89 hashparams->hupdate(ctxt->hashctxt1, &b, 1);
90 b = (unsigned char)(*key++ ^ hmac_opad);
91 hashparams->hupdate(ctxt->hashctxt2, &b, 1);
92 }
93
94 for(; i < hashparams->maxkeylen; i++) {
95 hashparams->hupdate(ctxt->hashctxt1, &hmac_ipad, 1);
96 hashparams->hupdate(ctxt->hashctxt2, &hmac_opad, 1);
97 }
98
99 /* Done, return pointer to HMAC context. */
100 return ctxt;
101 }
102
Curl_HMAC_update(struct HMAC_context * ctxt,const unsigned char * ptr,unsigned int len)103 int Curl_HMAC_update(struct HMAC_context *ctxt,
104 const unsigned char *ptr,
105 unsigned int len)
106 {
107 /* Update first hash calculation. */
108 ctxt->hash->hupdate(ctxt->hashctxt1, ptr, len);
109 return 0;
110 }
111
112
Curl_HMAC_final(struct HMAC_context * ctxt,unsigned char * output)113 int Curl_HMAC_final(struct HMAC_context *ctxt, unsigned char *output)
114 {
115 const struct HMAC_params *hashparams = ctxt->hash;
116
117 /* Do not get output if called with a null parameter: only release
118 storage. */
119
120 if(!output)
121 output = (unsigned char *) ctxt->hashctxt2 + ctxt->hash->ctxtsize;
122
123 hashparams->hfinal(output, ctxt->hashctxt1);
124 hashparams->hupdate(ctxt->hashctxt2, output, hashparams->resultlen);
125 hashparams->hfinal(output, ctxt->hashctxt2);
126 free(ctxt);
127 return 0;
128 }
129
130 /*
131 * Curl_hmacit()
132 *
133 * This is used to generate a HMAC hash, for the specified input data, given
134 * the specified hash function and key.
135 *
136 * Parameters:
137 *
138 * hashparams [in] - The hash function (Curl_HMAC_MD5).
139 * key [in] - The key to use.
140 * keylen [in] - The length of the key.
141 * buf [in] - The data to encrypt.
142 * buflen [in] - The length of the data.
143 * output [in/out] - The output buffer.
144 *
145 * Returns CURLE_OK on success.
146 */
Curl_hmacit(const struct HMAC_params * hashparams,const unsigned char * key,const size_t keylen,const unsigned char * buf,const size_t buflen,unsigned char * output)147 CURLcode Curl_hmacit(const struct HMAC_params *hashparams,
148 const unsigned char *key, const size_t keylen,
149 const unsigned char *buf, const size_t buflen,
150 unsigned char *output)
151 {
152 struct HMAC_context *ctxt =
153 Curl_HMAC_init(hashparams, key, curlx_uztoui(keylen));
154
155 if(!ctxt)
156 return CURLE_OUT_OF_MEMORY;
157
158 /* Update the digest with the given challenge */
159 Curl_HMAC_update(ctxt, buf, curlx_uztoui(buflen));
160
161 /* Finalise the digest */
162 Curl_HMAC_final(ctxt, output);
163
164 return CURLE_OK;
165 }
166
167 #endif /* Using NTLM (without SSPI) or AWS */
168
