1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
|
/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, 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.
*
* RFC2104 Keyed-Hashing for Message Authentication
*
***************************************************************************/
#include "curl_setup.h"
#ifndef CURL_DISABLE_CRYPTO_AUTH
#include <curl/curl.h>
#include "curl_hmac.h"
#include "curl_memory.h"
#include "warnless.h"
/* The last #include file should be: */
#include "memdebug.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 initialisation.
*/
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, curlx_uztoui(keylen));
if(!ctxt)
return CURLE_OUT_OF_MEMORY;
/* Update the digest with the given challenge */
Curl_HMAC_update(ctxt, data, curlx_uztoui(datalen));
/* Finalise the digest */
Curl_HMAC_final(ctxt, output);
return CURLE_OK;
}
#endif /* CURL_DISABLE_CRYPTO_AUTH */
|
