Annotation of embedaddon/curl/lib/hmac.c, revision 1.1.1.1
1.1 misho 1: /***************************************************************************
2: * _ _ ____ _
3: * Project ___| | | | _ \| |
4: * / __| | | | |_) | |
5: * | (__| |_| | _ <| |___
6: * \___|\___/|_| \_\_____|
7: *
8: * Copyright (C) 1998 - 2020, 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: #include "warnless.h"
34:
35: /* The last #include file should be: */
36: #include "memdebug.h"
37:
38: /*
39: * Generic HMAC algorithm.
40: *
41: * This module computes HMAC digests based on any hash function. Parameters
42: * and computing procedures are set-up dynamically at HMAC computation
43: * context initialisation.
44: */
45:
46: static const unsigned char hmac_ipad = 0x36;
47: static const unsigned char hmac_opad = 0x5C;
48:
49:
50:
51: HMAC_context *
52: Curl_HMAC_init(const HMAC_params * hashparams,
53: const unsigned char *key,
54: unsigned int keylen)
55: {
56: size_t i;
57: HMAC_context *ctxt;
58: unsigned char *hkey;
59: unsigned char b;
60:
61: /* Create HMAC context. */
62: i = sizeof(*ctxt) + 2 * hashparams->hmac_ctxtsize +
63: hashparams->hmac_resultlen;
64: ctxt = malloc(i);
65:
66: if(!ctxt)
67: return ctxt;
68:
69: ctxt->hmac_hash = hashparams;
70: ctxt->hmac_hashctxt1 = (void *) (ctxt + 1);
71: ctxt->hmac_hashctxt2 = (void *) ((char *) ctxt->hmac_hashctxt1 +
72: hashparams->hmac_ctxtsize);
73:
74: /* If the key is too long, replace it by its hash digest. */
75: if(keylen > hashparams->hmac_maxkeylen) {
76: (*hashparams->hmac_hinit)(ctxt->hmac_hashctxt1);
77: (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, key, keylen);
78: hkey = (unsigned char *) ctxt->hmac_hashctxt2 + hashparams->hmac_ctxtsize;
79: (*hashparams->hmac_hfinal)(hkey, ctxt->hmac_hashctxt1);
80: key = hkey;
81: keylen = hashparams->hmac_resultlen;
82: }
83:
84: /* Prime the two hash contexts with the modified key. */
85: (*hashparams->hmac_hinit)(ctxt->hmac_hashctxt1);
86: (*hashparams->hmac_hinit)(ctxt->hmac_hashctxt2);
87:
88: for(i = 0; i < keylen; i++) {
89: b = (unsigned char)(*key ^ hmac_ipad);
90: (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, &b, 1);
91: b = (unsigned char)(*key++ ^ hmac_opad);
92: (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2, &b, 1);
93: }
94:
95: for(; i < hashparams->hmac_maxkeylen; i++) {
96: (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, &hmac_ipad, 1);
97: (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2, &hmac_opad, 1);
98: }
99:
100: /* Done, return pointer to HMAC context. */
101: return ctxt;
102: }
103:
104: int Curl_HMAC_update(HMAC_context * ctxt,
105: const unsigned char *data,
106: unsigned int len)
107: {
108: /* Update first hash calculation. */
109: (*ctxt->hmac_hash->hmac_hupdate)(ctxt->hmac_hashctxt1, data, len);
110: return 0;
111: }
112:
113:
114: int Curl_HMAC_final(HMAC_context *ctxt, unsigned char *result)
115: {
116: const HMAC_params * hashparams = ctxt->hmac_hash;
117:
118: /* Do not get result if called with a null parameter: only release
119: storage. */
120:
121: if(!result)
122: result = (unsigned char *) ctxt->hmac_hashctxt2 +
123: ctxt->hmac_hash->hmac_ctxtsize;
124:
125: (*hashparams->hmac_hfinal)(result, ctxt->hmac_hashctxt1);
126: (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2,
127: result, hashparams->hmac_resultlen);
128: (*hashparams->hmac_hfinal)(result, ctxt->hmac_hashctxt2);
129: free((char *) ctxt);
130: return 0;
131: }
132:
133: /*
134: * Curl_hmacit()
135: *
136: * This is used to generate a HMAC hash, for the specified input data, given
137: * the specified hash function and key.
138: *
139: * Parameters:
140: *
141: * hashparams [in] - The hash function (Curl_HMAC_MD5).
142: * key [in] - The key to use.
143: * keylen [in] - The length of the key.
144: * data [in] - The data to encrypt.
145: * datalen [in] - The length of the data.
146: * output [in/out] - The output buffer.
147: *
148: * Returns CURLE_OK on success.
149: */
150: CURLcode Curl_hmacit(const HMAC_params *hashparams,
151: const unsigned char *key, const size_t keylen,
152: const unsigned char *data, const size_t datalen,
153: unsigned char *output)
154: {
155: HMAC_context *ctxt = Curl_HMAC_init(hashparams, key, curlx_uztoui(keylen));
156:
157: if(!ctxt)
158: return CURLE_OUT_OF_MEMORY;
159:
160: /* Update the digest with the given challenge */
161: Curl_HMAC_update(ctxt, data, curlx_uztoui(datalen));
162:
163: /* Finalise the digest */
164: Curl_HMAC_final(ctxt, output);
165:
166: return CURLE_OK;
167: }
168:
169: #endif /* CURL_DISABLE_CRYPTO_AUTH */
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