ech_ossl.c
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- /* crypto/ecdh/ech_ossl.c */
- /* ====================================================================
- * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
- *
- * The Elliptic Curve Public-Key Crypto Library (ECC Code) included
- * herein is developed by SUN MICROSYSTEMS, INC., and is contributed
- * to the OpenSSL project.
- *
- * The ECC Code is licensed pursuant to the OpenSSL open source
- * license provided below.
- *
- * The ECDH software is originally written by Douglas Stebila of
- * Sun Microsystems Laboratories.
- *
- */
- /* ====================================================================
- * Copyright (c) 1998-2003 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.
- * ====================================================================
- *
- * This product includes cryptographic software written by Eric Young
- * (eay@cryptsoft.com). This product includes software written by Tim
- * Hudson (tjh@cryptsoft.com).
- *
- */
- #include <string.h>
- #include <limits.h>
- #include "cryptlib.h"
- #include "ech_locl.h"
- #include <openssl/err.h>
- #include <openssl/sha.h>
- #include <openssl/obj_mac.h>
- #include <openssl/bn.h>
- static int ecdh_compute_key(void *out, size_t len, const EC_POINT *pub_key,
- EC_KEY *ecdh,
- void *(*KDF)(const void *in, size_t inlen, void *out, size_t *outlen));
- static ECDH_METHOD openssl_ecdh_meth = {
- "OpenSSL ECDH method",
- ecdh_compute_key,
- #if 0
- NULL, /* init */
- NULL, /* finish */
- #endif
- 0, /* flags */
- NULL /* app_data */
- };
- const ECDH_METHOD *ECDH_OpenSSL(void)
- {
- return &openssl_ecdh_meth;
- }
- /* This implementation is based on the following primitives in the IEEE 1363 standard:
- * - ECKAS-DH1
- * - ECSVDP-DH
- * Finally an optional KDF is applied.
- */
- static int ecdh_compute_key(void *out, size_t outlen, const EC_POINT *pub_key,
- EC_KEY *ecdh,
- void *(*KDF)(const void *in, size_t inlen, void *out, size_t *outlen))
- {
- BN_CTX *ctx;
- EC_POINT *tmp=NULL;
- BIGNUM *x=NULL, *y=NULL;
- const BIGNUM *priv_key;
- const EC_GROUP* group;
- int ret= -1;
- size_t buflen, len;
- unsigned char *buf=NULL;
- if (outlen > INT_MAX)
- {
- ECDHerr(ECDH_F_ECDH_COMPUTE_KEY,ERR_R_MALLOC_FAILURE); /* sort of, anyway */
- return -1;
- }
- if ((ctx = BN_CTX_new()) == NULL) goto err;
- BN_CTX_start(ctx);
- x = BN_CTX_get(ctx);
- y = BN_CTX_get(ctx);
-
- priv_key = EC_KEY_get0_private_key(ecdh);
- if (priv_key == NULL)
- {
- ECDHerr(ECDH_F_ECDH_COMPUTE_KEY,ECDH_R_NO_PRIVATE_VALUE);
- goto err;
- }
- group = EC_KEY_get0_group(ecdh);
- if ((tmp=EC_POINT_new(group)) == NULL)
- {
- ECDHerr(ECDH_F_ECDH_COMPUTE_KEY,ERR_R_MALLOC_FAILURE);
- goto err;
- }
- if (!EC_POINT_mul(group, tmp, NULL, pub_key, priv_key, ctx))
- {
- ECDHerr(ECDH_F_ECDH_COMPUTE_KEY,ECDH_R_POINT_ARITHMETIC_FAILURE);
- goto err;
- }
-
- if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) == NID_X9_62_prime_field)
- {
- if (!EC_POINT_get_affine_coordinates_GFp(group, tmp, x, y, ctx))
- {
- ECDHerr(ECDH_F_ECDH_COMPUTE_KEY,ECDH_R_POINT_ARITHMETIC_FAILURE);
- goto err;
- }
- }
- else
- {
- if (!EC_POINT_get_affine_coordinates_GF2m(group, tmp, x, y, ctx))
- {
- ECDHerr(ECDH_F_ECDH_COMPUTE_KEY,ECDH_R_POINT_ARITHMETIC_FAILURE);
- goto err;
- }
- }
- buflen = (EC_GROUP_get_degree(group) + 7)/8;
- len = BN_num_bytes(x);
- if (len > buflen)
- {
- ECDHerr(ECDH_F_ECDH_COMPUTE_KEY,ERR_R_INTERNAL_ERROR);
- goto err;
- }
- if ((buf = OPENSSL_malloc(buflen)) == NULL)
- {
- ECDHerr(ECDH_F_ECDH_COMPUTE_KEY,ERR_R_MALLOC_FAILURE);
- goto err;
- }
-
- memset(buf, 0, buflen - len);
- if (len != (size_t)BN_bn2bin(x, buf + buflen - len))
- {
- ECDHerr(ECDH_F_ECDH_COMPUTE_KEY,ERR_R_BN_LIB);
- goto err;
- }
- if (KDF != 0)
- {
- if (KDF(buf, buflen, out, &outlen) == NULL)
- {
- ECDHerr(ECDH_F_ECDH_COMPUTE_KEY,ECDH_R_KDF_FAILED);
- goto err;
- }
- ret = outlen;
- }
- else
- {
- /* no KDF, just copy as much as we can */
- if (outlen > buflen)
- outlen = buflen;
- memcpy(out, buf, outlen);
- ret = outlen;
- }
-
- err:
- if (tmp) EC_POINT_free(tmp);
- if (ctx) BN_CTX_end(ctx);
- if (ctx) BN_CTX_free(ctx);
- if (buf) OPENSSL_free(buf);
- return(ret);
- }