1 /* crypto/dh/dh_kdf.c */
3 * Written by Stephen Henson for the OpenSSL project.
5 /* ====================================================================
6 * Copyright (c) 2013 The OpenSSL Project. All rights reserved.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
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
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/)"
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.
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.
34 * 6. Redistributions of any form whatsoever must retain the following
36 * "This product includes software developed by the OpenSSL Project
37 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
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)
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50 * OF THE POSSIBILITY OF SUCH DAMAGE.
51 * ====================================================================
56 #ifndef OPENSSL_NO_CMS
58 #include <openssl/dh.h>
59 #include <openssl/evp.h>
60 #include <openssl/asn1.h>
61 #include <openssl/cms.h>
64 /* Key derivation from X9.42/RFC2631 */
65 /* Uses CMS functions, hence the #ifdef wrapper. */
67 #define DH_KDF_MAX (1L << 30)
69 /* Skip past an ASN1 structure: for OBJECT skip content octets too */
71 static int skip_asn1(unsigned char **pp, long *plen, int exptag)
73 const unsigned char *q = *pp;
76 i = ASN1_get_object(&q, &tmplen, &tag, &xclass, *plen);
79 if (tag != exptag || xclass != V_ASN1_UNIVERSAL)
81 if (tag == V_ASN1_OBJECT)
84 *pp = (unsigned char *)q;
89 * Encode the DH shared info structure, return an offset to the counter value
90 * so we can update the structure without reencoding it.
93 static int dh_sharedinfo_encode(unsigned char **pder, unsigned char **pctr,
94 ASN1_OBJECT *key_oid, size_t outlen,
95 const unsigned char *ukm, size_t ukmlen)
100 /* "magic" value to check offset is sane */
101 static unsigned char ctr[4] = { 0xF3, 0x17, 0x22, 0x53 };
103 ASN1_OCTET_STRING ctr_oct, ukm_oct, *pukm_oct;
105 if (ukmlen > DH_KDF_MAX || outlen > DH_KDF_MAX)
110 ctr_oct.type = V_ASN1_OCTET_STRING;
111 ctr_atype.type = V_ASN1_OCTET_STRING;
112 ctr_atype.value.octet_string = &ctr_oct;
113 atmp.algorithm = key_oid;
114 atmp.parameter = &ctr_atype;
116 ukm_oct.type = V_ASN1_OCTET_STRING;
118 ukm_oct.data = (unsigned char *)ukm;
119 ukm_oct.length = ukmlen;
123 derlen = CMS_SharedInfo_encode(pder, &atmp, pukm_oct, outlen);
128 if (!skip_asn1(&p, &tlen, V_ASN1_SEQUENCE))
130 if (!skip_asn1(&p, &tlen, V_ASN1_SEQUENCE))
132 if (!skip_asn1(&p, &tlen, V_ASN1_OBJECT))
134 if (!skip_asn1(&p, &tlen, V_ASN1_OCTET_STRING))
136 if (CRYPTO_memcmp(p, ctr, 4))
142 int DH_KDF_X9_42(unsigned char *out, size_t outlen,
143 const unsigned char *Z, size_t Zlen,
144 ASN1_OBJECT *key_oid,
145 const unsigned char *ukm, size_t ukmlen, const EVP_MD *md)
147 EVP_MD_CTX *mctx = NULL;
151 unsigned char *der = NULL, *ctr;
153 if (Zlen > DH_KDF_MAX)
155 mctx = EVP_MD_CTX_new();
158 mdlen = EVP_MD_size(md);
159 derlen = dh_sharedinfo_encode(&der, &ctr, key_oid, outlen, ukm, ukmlen);
163 unsigned char mtmp[EVP_MAX_MD_SIZE];
164 EVP_DigestInit_ex(mctx, md, NULL);
165 if (!EVP_DigestUpdate(mctx, Z, Zlen))
168 ctr[2] = (i >> 8) & 0xFF;
169 ctr[1] = (i >> 16) & 0xFF;
170 ctr[0] = (i >> 24) & 0xFF;
171 if (!EVP_DigestUpdate(mctx, der, derlen))
173 if (outlen >= mdlen) {
174 if (!EVP_DigestFinal(mctx, out, NULL))
181 if (!EVP_DigestFinal(mctx, mtmp, NULL))
183 memcpy(out, mtmp, outlen);
184 OPENSSL_cleanse(mtmp, mdlen);
191 EVP_MD_CTX_free(mctx);