Line data Source code
1 : /* crypto/dh/dh_kdf.c */
2 : /*
3 : * Written by Stephen Henson for the OpenSSL project.
4 : */
5 : /* ====================================================================
6 : * Copyright (c) 2013 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 : * openssl-core@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 :
54 : #include <string.h>
55 : #include <openssl/dh.h>
56 : #include <openssl/evp.h>
57 : #include <openssl/asn1.h>
58 : #include <openssl/cms.h>
59 :
60 : /* Key derivation from X9.42/RFC2631 */
61 :
62 : #define DH_KDF_MAX (1L << 30)
63 :
64 : /* Skip past an ASN1 structure: for OBJECT skip content octets too */
65 :
66 0 : static int skip_asn1(unsigned char **pp, long *plen, int exptag)
67 : {
68 0 : const unsigned char *q = *pp;
69 : int i, tag, xclass;
70 : long tmplen;
71 0 : i = ASN1_get_object(&q, &tmplen, &tag, &xclass, *plen);
72 0 : if (i & 0x80)
73 : return 0;
74 0 : if (tag != exptag || xclass != V_ASN1_UNIVERSAL)
75 : return 0;
76 0 : if (tag == V_ASN1_OBJECT)
77 0 : q += tmplen;
78 0 : *plen -= q - *pp;
79 0 : *pp = (unsigned char *)q;
80 0 : return 1;
81 : }
82 :
83 : /*
84 : * Encode the DH shared info structure, return an offset to the counter value
85 : * so we can update the structure without reencoding it.
86 : */
87 :
88 0 : static int dh_sharedinfo_encode(unsigned char **pder, unsigned char **pctr,
89 : ASN1_OBJECT *key_oid, size_t outlen,
90 : const unsigned char *ukm, size_t ukmlen)
91 : {
92 : unsigned char *p;
93 : int derlen;
94 : long tlen;
95 : /* "magic" value to check offset is sane */
96 : static unsigned char ctr[4] = { 0xF3, 0x17, 0x22, 0x53 };
97 : X509_ALGOR atmp;
98 : ASN1_OCTET_STRING ctr_oct, ukm_oct, *pukm_oct;
99 : ASN1_TYPE ctr_atype;
100 0 : if (ukmlen > DH_KDF_MAX || outlen > DH_KDF_MAX)
101 : return 0;
102 0 : ctr_oct.data = ctr;
103 0 : ctr_oct.length = 4;
104 0 : ctr_oct.flags = 0;
105 0 : ctr_oct.type = V_ASN1_OCTET_STRING;
106 0 : ctr_atype.type = V_ASN1_OCTET_STRING;
107 0 : ctr_atype.value.octet_string = &ctr_oct;
108 0 : atmp.algorithm = key_oid;
109 0 : atmp.parameter = &ctr_atype;
110 0 : if (ukm) {
111 0 : ukm_oct.type = V_ASN1_OCTET_STRING;
112 0 : ukm_oct.flags = 0;
113 0 : ukm_oct.data = (unsigned char *)ukm;
114 0 : ukm_oct.length = ukmlen;
115 : pukm_oct = &ukm_oct;
116 : } else
117 : pukm_oct = NULL;
118 0 : derlen = CMS_SharedInfo_encode(pder, &atmp, pukm_oct, outlen);
119 0 : if (derlen <= 0)
120 : return 0;
121 0 : p = *pder;
122 0 : tlen = derlen;
123 0 : if (!skip_asn1(&p, &tlen, V_ASN1_SEQUENCE))
124 : return 0;
125 0 : if (!skip_asn1(&p, &tlen, V_ASN1_SEQUENCE))
126 : return 0;
127 0 : if (!skip_asn1(&p, &tlen, V_ASN1_OBJECT))
128 : return 0;
129 0 : if (!skip_asn1(&p, &tlen, V_ASN1_OCTET_STRING))
130 : return 0;
131 0 : if (CRYPTO_memcmp(p, ctr, 4))
132 : return 0;
133 0 : *pctr = p;
134 0 : return derlen;
135 : }
136 :
137 0 : int DH_KDF_X9_42(unsigned char *out, size_t outlen,
138 : const unsigned char *Z, size_t Zlen,
139 : ASN1_OBJECT *key_oid,
140 : const unsigned char *ukm, size_t ukmlen, const EVP_MD *md)
141 : {
142 : EVP_MD_CTX mctx;
143 : int rv = 0;
144 : unsigned int i;
145 : size_t mdlen;
146 0 : unsigned char *der = NULL, *ctr;
147 : int derlen;
148 0 : if (Zlen > DH_KDF_MAX)
149 : return 0;
150 0 : mdlen = EVP_MD_size(md);
151 0 : EVP_MD_CTX_init(&mctx);
152 0 : derlen = dh_sharedinfo_encode(&der, &ctr, key_oid, outlen, ukm, ukmlen);
153 0 : if (derlen == 0)
154 : goto err;
155 0 : for (i = 1;; i++) {
156 : unsigned char mtmp[EVP_MAX_MD_SIZE];
157 0 : EVP_DigestInit_ex(&mctx, md, NULL);
158 0 : if (!EVP_DigestUpdate(&mctx, Z, Zlen))
159 : goto err;
160 0 : ctr[3] = i & 0xFF;
161 0 : ctr[2] = (i >> 8) & 0xFF;
162 0 : ctr[1] = (i >> 16) & 0xFF;
163 0 : ctr[0] = (i >> 24) & 0xFF;
164 0 : if (!EVP_DigestUpdate(&mctx, der, derlen))
165 : goto err;
166 0 : if (outlen >= mdlen) {
167 0 : if (!EVP_DigestFinal(&mctx, out, NULL))
168 : goto err;
169 0 : outlen -= mdlen;
170 0 : if (outlen == 0)
171 : break;
172 0 : out += mdlen;
173 : } else {
174 0 : if (!EVP_DigestFinal(&mctx, mtmp, NULL))
175 : goto err;
176 : memcpy(out, mtmp, outlen);
177 0 : OPENSSL_cleanse(mtmp, mdlen);
178 0 : break;
179 : }
180 0 : }
181 : rv = 1;
182 : err:
183 0 : if (der)
184 0 : OPENSSL_free(der);
185 0 : EVP_MD_CTX_cleanup(&mctx);
186 0 : return rv;
187 : }
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