1 | /*************************************************************************** |
2 | * _ _ ____ _ |
3 | * Project ___| | | | _ \| | |
4 | * / __| | | | |_) | | |
5 | * | (__| |_| | _ <| |___ |
6 | * \___|\___/|_| \_\_____| |
7 | * |
8 | * Copyright (C) 1998 - 2018, 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 * |
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 | |
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 | |
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 | |