1 /*
2 * px-hmac.c
3 * HMAC implementation.
4 *
5 * Copyright (c) 2001 Marko Kreen
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * contrib/pgcrypto/px-hmac.c
30 */
31
32 #include "postgres.h"
33
34 #include "px.h"
35
36 #define HMAC_IPAD 0x36
37 #define HMAC_OPAD 0x5C
38
39 static unsigned
hmac_result_size(PX_HMAC * h)40 hmac_result_size(PX_HMAC *h)
41 {
42 return px_md_result_size(h->md);
43 }
44
45 static unsigned
hmac_block_size(PX_HMAC * h)46 hmac_block_size(PX_HMAC *h)
47 {
48 return px_md_block_size(h->md);
49 }
50
51 static void
hmac_init(PX_HMAC * h,const uint8 * key,unsigned klen)52 hmac_init(PX_HMAC *h, const uint8 *key, unsigned klen)
53 {
54 unsigned bs,
55 i;
56 uint8 *keybuf;
57 PX_MD *md = h->md;
58
59 bs = px_md_block_size(md);
60 keybuf = px_alloc(bs);
61 memset(keybuf, 0, bs);
62
63 if (klen > bs)
64 {
65 px_md_update(md, key, klen);
66 px_md_finish(md, keybuf);
67 px_md_reset(md);
68 }
69 else
70 memcpy(keybuf, key, klen);
71
72 for (i = 0; i < bs; i++)
73 {
74 h->p.ipad[i] = keybuf[i] ^ HMAC_IPAD;
75 h->p.opad[i] = keybuf[i] ^ HMAC_OPAD;
76 }
77
78 px_memset(keybuf, 0, bs);
79 px_free(keybuf);
80
81 px_md_update(md, h->p.ipad, bs);
82 }
83
84 static void
hmac_reset(PX_HMAC * h)85 hmac_reset(PX_HMAC *h)
86 {
87 PX_MD *md = h->md;
88 unsigned bs = px_md_block_size(md);
89
90 px_md_reset(md);
91 px_md_update(md, h->p.ipad, bs);
92 }
93
94 static void
hmac_update(PX_HMAC * h,const uint8 * data,unsigned dlen)95 hmac_update(PX_HMAC *h, const uint8 *data, unsigned dlen)
96 {
97 px_md_update(h->md, data, dlen);
98 }
99
100 static void
hmac_finish(PX_HMAC * h,uint8 * dst)101 hmac_finish(PX_HMAC *h, uint8 *dst)
102 {
103 PX_MD *md = h->md;
104 unsigned bs,
105 hlen;
106 uint8 *buf;
107
108 bs = px_md_block_size(md);
109 hlen = px_md_result_size(md);
110
111 buf = px_alloc(hlen);
112
113 px_md_finish(md, buf);
114
115 px_md_reset(md);
116 px_md_update(md, h->p.opad, bs);
117 px_md_update(md, buf, hlen);
118 px_md_finish(md, dst);
119
120 px_memset(buf, 0, hlen);
121 px_free(buf);
122 }
123
124 static void
hmac_free(PX_HMAC * h)125 hmac_free(PX_HMAC *h)
126 {
127 unsigned bs;
128
129 bs = px_md_block_size(h->md);
130 px_md_free(h->md);
131
132 px_memset(h->p.ipad, 0, bs);
133 px_memset(h->p.opad, 0, bs);
134 px_free(h->p.ipad);
135 px_free(h->p.opad);
136 px_free(h);
137 }
138
139
140 /* PUBLIC FUNCTIONS */
141
142 int
px_find_hmac(const char * name,PX_HMAC ** res)143 px_find_hmac(const char *name, PX_HMAC **res)
144 {
145 int err;
146 PX_MD *md;
147 PX_HMAC *h;
148 unsigned bs;
149
150 err = px_find_digest(name, &md);
151 if (err)
152 return err;
153
154 bs = px_md_block_size(md);
155 if (bs < 2)
156 {
157 px_md_free(md);
158 return PXE_HASH_UNUSABLE_FOR_HMAC;
159 }
160
161 h = px_alloc(sizeof(*h));
162 h->p.ipad = px_alloc(bs);
163 h->p.opad = px_alloc(bs);
164 h->md = md;
165
166 h->result_size = hmac_result_size;
167 h->block_size = hmac_block_size;
168 h->reset = hmac_reset;
169 h->update = hmac_update;
170 h->finish = hmac_finish;
171 h->free = hmac_free;
172 h->init = hmac_init;
173
174 *res = h;
175
176 return 0;
177 }
178