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