hmacmd5.c revision 298770 
1/*
2 * Copyright (C) 2004-2007, 2009  Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (C) 2000, 2001  Internet Software Consortium.
4 *
5 * Permission to use, copy, modify, and/or distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
10 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
11 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
13 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
14 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
15 * PERFORMANCE OF THIS SOFTWARE.
16 */
17
18/* $Id: hmacmd5.c,v 1.16 2009/02/06 23:47:42 tbox Exp $ */
19
20/*! \file
21 * This code implements the HMAC-MD5 keyed hash algorithm
22 * described in RFC2104.
23 */
24
25#include "config.h"
26
27#include <isc/assertions.h>
28#include <isc/hmacmd5.h>
29#include <isc/md5.h>
30#include <isc/platform.h>
31#include <isc/string.h>
32#include <isc/types.h>
33#include <isc/util.h>
34
35#ifdef ISC_PLATFORM_OPENSSLHASH
36
37void
38isc_hmacmd5_init(isc_hmacmd5_t *ctx, const unsigned char *key,
39		 unsigned int len)
40{
41	HMAC_Init(ctx, (const void *) key, (int) len, EVP_md5());
42}
43
44void
45isc_hmacmd5_invalidate(isc_hmacmd5_t *ctx) {
46	HMAC_CTX_cleanup(ctx);
47}
48
49void
50isc_hmacmd5_update(isc_hmacmd5_t *ctx, const unsigned char *buf,
51		   unsigned int len)
52{
53	HMAC_Update(ctx, buf, (int) len);
54}
55
56void
57isc_hmacmd5_sign(isc_hmacmd5_t *ctx, unsigned char *digest) {
58	HMAC_Final(ctx, digest, NULL);
59	HMAC_CTX_cleanup(ctx);
60}
61
62#else
63
64#define PADLEN 64
65#define IPAD 0x36
66#define OPAD 0x5C
67
68/*!
69 * Start HMAC-MD5 process.  Initialize an md5 context and digest the key.
70 */
71void
72isc_hmacmd5_init(isc_hmacmd5_t *ctx, const unsigned char *key,
73		 unsigned int len)
74{
75	unsigned char ipad[PADLEN];
76	int i;
77
78	memset(ctx->key, 0, sizeof(ctx->key));
79	if (len > sizeof(ctx->key)) {
80		isc_md5_t md5ctx;
81		isc_md5_init(&md5ctx);
82		isc_md5_update(&md5ctx, key, len);
83		isc_md5_final(&md5ctx, ctx->key);
84	} else
85		memcpy(ctx->key, key, len);
86
87	isc_md5_init(&ctx->md5ctx);
88	memset(ipad, IPAD, sizeof(ipad));
89	for (i = 0; i < PADLEN; i++)
90		ipad[i] ^= ctx->key[i];
91	isc_md5_update(&ctx->md5ctx, ipad, sizeof(ipad));
92}
93
94void
95isc_hmacmd5_invalidate(isc_hmacmd5_t *ctx) {
96	isc_md5_invalidate(&ctx->md5ctx);
97	memset(ctx->key, 0, sizeof(ctx->key));
98}
99
100/*!
101 * Update context to reflect the concatenation of another buffer full
102 * of bytes.
103 */
104void
105isc_hmacmd5_update(isc_hmacmd5_t *ctx, const unsigned char *buf,
106		   unsigned int len)
107{
108	isc_md5_update(&ctx->md5ctx, buf, len);
109}
110
111/*!
112 * Compute signature - finalize MD5 operation and reapply MD5.
113 */
114void
115isc_hmacmd5_sign(isc_hmacmd5_t *ctx, unsigned char *digest) {
116	unsigned char opad[PADLEN];
117	int i;
118
119	isc_md5_final(&ctx->md5ctx, digest);
120
121	memset(opad, OPAD, sizeof(opad));
122	for (i = 0; i < PADLEN; i++)
123		opad[i] ^= ctx->key[i];
124
125	isc_md5_init(&ctx->md5ctx);
126	isc_md5_update(&ctx->md5ctx, opad, sizeof(opad));
127	isc_md5_update(&ctx->md5ctx, digest, ISC_MD5_DIGESTLENGTH);
128	isc_md5_final(&ctx->md5ctx, digest);
129	isc_hmacmd5_invalidate(ctx);
130}
131#endif /* !ISC_PLATFORM_OPENSSLHASH */
132
133/*!
134 * Verify signature - finalize MD5 operation and reapply MD5, then
135 * compare to the supplied digest.
136 */
137isc_boolean_t
138isc_hmacmd5_verify(isc_hmacmd5_t *ctx, unsigned char *digest) {
139	return (isc_hmacmd5_verify2(ctx, digest, ISC_MD5_DIGESTLENGTH));
140}
141
142isc_boolean_t
143isc_hmacmd5_verify2(isc_hmacmd5_t *ctx, unsigned char *digest, size_t len) {
144	unsigned char newdigest[ISC_MD5_DIGESTLENGTH];
145
146	REQUIRE(len <= ISC_MD5_DIGESTLENGTH);
147	isc_hmacmd5_sign(ctx, newdigest);
148	return (ISC_TF(isc_tsmemcmp(digest, newdigest, len) == 0));
149}
150