1 /* $OpenBSD: hm_ameth.c,v 1.12 2021/12/12 21:30:14 tb Exp $ */
2 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
3  * project 2007.
4  */
5 /* ====================================================================
6  * Copyright (c) 2007 The OpenSSL Project.  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  *
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  *
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in
17  *    the documentation and/or other materials provided with the
18  *    distribution.
19  *
20  * 3. All advertising materials mentioning features or use of this
21  *    software must display the following acknowledgment:
22  *    "This product includes software developed by the OpenSSL Project
23  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
24  *
25  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
26  *    endorse or promote products derived from this software without
27  *    prior written permission. For written permission, please contact
28  *    licensing@OpenSSL.org.
29  *
30  * 5. Products derived from this software may not be called "OpenSSL"
31  *    nor may "OpenSSL" appear in their names without prior written
32  *    permission of the OpenSSL Project.
33  *
34  * 6. Redistributions of any form whatsoever must retain the following
35  *    acknowledgment:
36  *    "This product includes software developed by the OpenSSL Project
37  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
38  *
39  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
40  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
41  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
42  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
43  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
45  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
46  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
48  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
49  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
50  * OF THE POSSIBILITY OF SUCH DAMAGE.
51  * ====================================================================
52  *
53  * This product includes cryptographic software written by Eric Young
54  * (eay@cryptsoft.com).  This product includes software written by Tim
55  * Hudson (tjh@cryptsoft.com).
56  *
57  */
58 
59 #include <stdio.h>
60 #include <string.h>
61 
62 #include <openssl/evp.h>
63 #include <openssl/hmac.h>
64 
65 #include "asn1_locl.h"
66 #include "evp_locl.h"
67 #include "hmac_local.h"
68 
69 #define HMAC_TEST_PRIVATE_KEY_FORMAT
70 
71 /* HMAC "ASN1" method. This is just here to indicate the
72  * maximum HMAC output length and to free up an HMAC
73  * key.
74  */
75 
76 static int
77 hmac_size(const EVP_PKEY *pkey)
78 {
79 	return EVP_MAX_MD_SIZE;
80 }
81 
82 static void
83 hmac_key_free(EVP_PKEY *pkey)
84 {
85 	ASN1_OCTET_STRING *os = (ASN1_OCTET_STRING *)pkey->pkey.ptr;
86 
87 	if (os) {
88 		if (os->data)
89 			explicit_bzero(os->data, os->length);
90 		ASN1_OCTET_STRING_free(os);
91 	}
92 }
93 
94 static int
95 hmac_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
96 {
97 	switch (op) {
98 	case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
99 		*(int *)arg2 = NID_sha1;
100 		return 1;
101 	default:
102 		return -2;
103 	}
104 }
105 
106 #ifdef HMAC_TEST_PRIVATE_KEY_FORMAT
107 /* A bogus private key format for test purposes. This is simply the
108  * HMAC key with "HMAC PRIVATE KEY" in the headers. When enabled the
109  * genpkey utility can be used to "generate" HMAC keys.
110  */
111 
112 static int
113 old_hmac_decode(EVP_PKEY *pkey, const unsigned char **pder, int derlen)
114 {
115 	ASN1_OCTET_STRING *os;
116 
117 	os = ASN1_OCTET_STRING_new();
118 	if (os == NULL)
119 		goto err;
120 	if (ASN1_OCTET_STRING_set(os, *pder, derlen) == 0)
121 		goto err;
122 	if (EVP_PKEY_assign(pkey, EVP_PKEY_HMAC, os) == 0)
123 		goto err;
124 	return 1;
125 
126 err:
127 	ASN1_OCTET_STRING_free(os);
128 	return 0;
129 }
130 
131 static int
132 old_hmac_encode(const EVP_PKEY *pkey, unsigned char **pder)
133 {
134 	int inc;
135 	ASN1_OCTET_STRING *os = (ASN1_OCTET_STRING *)pkey->pkey.ptr;
136 
137 	if (pder) {
138 		if (!*pder) {
139 			*pder = malloc(os->length);
140 			if (*pder == NULL)
141 				return -1;
142 			inc = 0;
143 		} else
144 			inc = 1;
145 
146 		memcpy(*pder, os->data, os->length);
147 
148 		if (inc)
149 			*pder += os->length;
150 	}
151 
152 	return os->length;
153 }
154 
155 #endif
156 
157 const EVP_PKEY_ASN1_METHOD hmac_asn1_meth = {
158 	.pkey_id = EVP_PKEY_HMAC,
159 	.pkey_base_id = EVP_PKEY_HMAC,
160 
161 	.pem_str = "HMAC",
162 	.info = "OpenSSL HMAC method",
163 
164 	.pkey_size = hmac_size,
165 
166 	.pkey_free = hmac_key_free,
167 	.pkey_ctrl = hmac_pkey_ctrl,
168 #ifdef HMAC_TEST_PRIVATE_KEY_FORMAT
169 	.old_priv_decode = old_hmac_decode,
170 	.old_priv_encode = old_hmac_encode
171 #endif
172 };
173