1/*
2 * Copyright (C) 2004-2007, 2009, 2013, 2014  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/safe.h>
32#include <isc/string.h>
33#include <isc/types.h>
34#include <isc/util.h>
35
36#ifdef ISC_PLATFORM_OPENSSLHASH
37
38void
39isc_hmacmd5_init(isc_hmacmd5_t *ctx, const unsigned char *key,
40		 unsigned int len)
41{
42	HMAC_Init(ctx, (const void *) key, (int) len, EVP_md5());
43}
44
45void
46isc_hmacmd5_invalidate(isc_hmacmd5_t *ctx) {
47	HMAC_CTX_cleanup(ctx);
48}
49
50void
51isc_hmacmd5_update(isc_hmacmd5_t *ctx, const unsigned char *buf,
52		   unsigned int len)
53{
54	HMAC_Update(ctx, buf, (int) len);
55}
56
57void
58isc_hmacmd5_sign(isc_hmacmd5_t *ctx, unsigned char *digest) {
59	HMAC_Final(ctx, digest, NULL);
60	HMAC_CTX_cleanup(ctx);
61}
62
63#else
64
65#define PADLEN 64
66#define IPAD 0x36
67#define OPAD 0x5C
68
69/*!
70 * Start HMAC-MD5 process.  Initialize an md5 context and digest the key.
71 */
72void
73isc_hmacmd5_init(isc_hmacmd5_t *ctx, const unsigned char *key,
74		 unsigned int len)
75{
76	unsigned char ipad[PADLEN];
77	int i;
78
79	memset(ctx->key, 0, sizeof(ctx->key));
80	if (len > sizeof(ctx->key)) {
81		isc_md5_t md5ctx;
82		isc_md5_init(&md5ctx);
83		isc_md5_update(&md5ctx, key, len);
84		isc_md5_final(&md5ctx, ctx->key);
85	} else
86		memmove(ctx->key, key, len);
87
88	isc_md5_init(&ctx->md5ctx);
89	memset(ipad, IPAD, sizeof(ipad));
90	for (i = 0; i < PADLEN; i++)
91		ipad[i] ^= ctx->key[i];
92	isc_md5_update(&ctx->md5ctx, ipad, sizeof(ipad));
93}
94
95void
96isc_hmacmd5_invalidate(isc_hmacmd5_t *ctx) {
97	isc_md5_invalidate(&ctx->md5ctx);
98	memset(ctx->key, 0, sizeof(ctx->key));
99}
100
101/*!
102 * Update context to reflect the concatenation of another buffer full
103 * of bytes.
104 */
105void
106isc_hmacmd5_update(isc_hmacmd5_t *ctx, const unsigned char *buf,
107		   unsigned int len)
108{
109	isc_md5_update(&ctx->md5ctx, buf, len);
110}
111
112/*!
113 * Compute signature - finalize MD5 operation and reapply MD5.
114 */
115void
116isc_hmacmd5_sign(isc_hmacmd5_t *ctx, unsigned char *digest) {
117	unsigned char opad[PADLEN];
118	int i;
119
120	isc_md5_final(&ctx->md5ctx, digest);
121
122	memset(opad, OPAD, sizeof(opad));
123	for (i = 0; i < PADLEN; i++)
124		opad[i] ^= ctx->key[i];
125
126	isc_md5_init(&ctx->md5ctx);
127	isc_md5_update(&ctx->md5ctx, opad, sizeof(opad));
128	isc_md5_update(&ctx->md5ctx, digest, ISC_MD5_DIGESTLENGTH);
129	isc_md5_final(&ctx->md5ctx, digest);
130	isc_hmacmd5_invalidate(ctx);
131}
132#endif /* !ISC_PLATFORM_OPENSSLHASH */
133
134/*!
135 * Verify signature - finalize MD5 operation and reapply MD5, then
136 * compare to the supplied digest.
137 */
138isc_boolean_t
139isc_hmacmd5_verify(isc_hmacmd5_t *ctx, unsigned char *digest) {
140	return (isc_hmacmd5_verify2(ctx, digest, ISC_MD5_DIGESTLENGTH));
141}
142
143isc_boolean_t
144isc_hmacmd5_verify2(isc_hmacmd5_t *ctx, unsigned char *digest, size_t len) {
145	unsigned char newdigest[ISC_MD5_DIGESTLENGTH];
146
147	REQUIRE(len <= ISC_MD5_DIGESTLENGTH);
148	isc_hmacmd5_sign(ctx, newdigest);
149	return (isc_safe_memcmp(digest, newdigest, len));
150}
151