187 lines
6.3 KiB
C
187 lines
6.3 KiB
C
/* crypto/dh/dh_kdf.c */
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/*
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* Written by Stephen Henson for the OpenSSL project.
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*/
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/* ====================================================================
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* Copyright (c) 2013 The OpenSSL Project. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* 3. All advertising materials mentioning features or use of this
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* software must display the following acknowledgment:
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* "This product includes software developed by the OpenSSL Project
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* for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
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*
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* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
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* endorse or promote products derived from this software without
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* prior written permission. For written permission, please contact
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* openssl-core@openssl.org.
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*
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* 5. Products derived from this software may not be called "OpenSSL"
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* nor may "OpenSSL" appear in their names without prior written
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* permission of the OpenSSL Project.
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*
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* 6. Redistributions of any form whatsoever must retain the following
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* acknowledgment:
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* "This product includes software developed by the OpenSSL Project
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* for use in the OpenSSL Toolkit (http://www.openssl.org/)"
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*
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* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
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* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
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* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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* ====================================================================
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*/
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#include <string.h>
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#include <openssl/dh.h>
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#include <openssl/evp.h>
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#include <openssl/asn1.h>
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#include <openssl/cms.h>
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/* Key derivation from X9.42/RFC2631 */
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#define DH_KDF_MAX (1L << 30)
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/* Skip past an ASN1 structure: for OBJECT skip content octets too */
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static int skip_asn1(unsigned char **pp, long *plen, int exptag)
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{
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const unsigned char *q = *pp;
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int i, tag, xclass;
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long tmplen;
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i = ASN1_get_object(&q, &tmplen, &tag, &xclass, *plen);
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if (i & 0x80)
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return 0;
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if (tag != exptag || xclass != V_ASN1_UNIVERSAL)
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return 0;
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if (tag == V_ASN1_OBJECT)
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q += tmplen;
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*plen -= q - *pp;
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*pp = (unsigned char *)q;
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return 1;
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}
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/*
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* Encode the DH shared info structure, return an offset to the counter value
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* so we can update the structure without reencoding it.
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*/
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static int dh_sharedinfo_encode(unsigned char **pder, unsigned char **pctr,
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ASN1_OBJECT *key_oid, size_t outlen,
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const unsigned char *ukm, size_t ukmlen)
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{
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unsigned char *p;
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int derlen;
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long tlen;
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/* "magic" value to check offset is sane */
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static unsigned char ctr[4] = { 0xF3, 0x17, 0x22, 0x53 };
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X509_ALGOR atmp;
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ASN1_OCTET_STRING ctr_oct, ukm_oct, *pukm_oct;
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ASN1_TYPE ctr_atype;
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if (ukmlen > DH_KDF_MAX || outlen > DH_KDF_MAX)
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return 0;
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ctr_oct.data = ctr;
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ctr_oct.length = 4;
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ctr_oct.flags = 0;
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ctr_oct.type = V_ASN1_OCTET_STRING;
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ctr_atype.type = V_ASN1_OCTET_STRING;
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ctr_atype.value.octet_string = &ctr_oct;
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atmp.algorithm = key_oid;
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atmp.parameter = &ctr_atype;
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if (ukm) {
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ukm_oct.type = V_ASN1_OCTET_STRING;
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ukm_oct.flags = 0;
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ukm_oct.data = (unsigned char *)ukm;
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ukm_oct.length = ukmlen;
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pukm_oct = &ukm_oct;
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} else
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pukm_oct = NULL;
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derlen = CMS_SharedInfo_encode(pder, &atmp, pukm_oct, outlen);
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if (derlen <= 0)
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return 0;
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p = *pder;
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tlen = derlen;
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if (!skip_asn1(&p, &tlen, V_ASN1_SEQUENCE))
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return 0;
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if (!skip_asn1(&p, &tlen, V_ASN1_SEQUENCE))
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return 0;
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if (!skip_asn1(&p, &tlen, V_ASN1_OBJECT))
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return 0;
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if (!skip_asn1(&p, &tlen, V_ASN1_OCTET_STRING))
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return 0;
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if (CRYPTO_memcmp(p, ctr, 4))
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return 0;
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*pctr = p;
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return derlen;
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}
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int DH_KDF_X9_42(unsigned char *out, size_t outlen,
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const unsigned char *Z, size_t Zlen,
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ASN1_OBJECT *key_oid,
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const unsigned char *ukm, size_t ukmlen, const EVP_MD *md)
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{
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EVP_MD_CTX mctx;
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int rv = 0;
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unsigned int i;
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size_t mdlen;
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unsigned char *der = NULL, *ctr;
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int derlen;
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if (Zlen > DH_KDF_MAX)
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return 0;
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mdlen = EVP_MD_size(md);
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EVP_MD_CTX_init(&mctx);
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derlen = dh_sharedinfo_encode(&der, &ctr, key_oid, outlen, ukm, ukmlen);
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if (derlen == 0)
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goto err;
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for (i = 1;; i++) {
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unsigned char mtmp[EVP_MAX_MD_SIZE];
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EVP_DigestInit_ex(&mctx, md, NULL);
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if (!EVP_DigestUpdate(&mctx, Z, Zlen))
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goto err;
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ctr[3] = i & 0xFF;
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ctr[2] = (i >> 8) & 0xFF;
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ctr[1] = (i >> 16) & 0xFF;
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ctr[0] = (i >> 24) & 0xFF;
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if (!EVP_DigestUpdate(&mctx, der, derlen))
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goto err;
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if (outlen >= mdlen) {
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if (!EVP_DigestFinal(&mctx, out, NULL))
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goto err;
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outlen -= mdlen;
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if (outlen == 0)
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break;
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out += mdlen;
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} else {
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if (!EVP_DigestFinal(&mctx, mtmp, NULL))
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goto err;
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memcpy(out, mtmp, outlen);
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OPENSSL_cleanse(mtmp, mdlen);
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break;
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}
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}
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rv = 1;
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err:
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if (der)
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OPENSSL_free(der);
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EVP_MD_CTX_cleanup(&mctx);
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return rv;
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}
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