| /* ==================================================================== |
| * 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) 2000-2002 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 |
| * licensing@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 <openssl/ecdh.h> |
| |
| #include <limits.h> |
| #include <string.h> |
| |
| #include <openssl/bn.h> |
| #include <openssl/digest.h> |
| #include <openssl/err.h> |
| #include <openssl/mem.h> |
| |
| #include "../fipsmodule/ec/internal.h" |
| #include "../internal.h" |
| |
| |
| int ECDH_compute_key(void *out, size_t outlen, const EC_POINT *pub_key, |
| const EC_KEY *priv_key, |
| void *(*kdf)(const void *in, size_t inlen, void *out, |
| size_t *outlen)) { |
| if (priv_key->priv_key == NULL) { |
| OPENSSL_PUT_ERROR(ECDH, ECDH_R_NO_PRIVATE_VALUE); |
| return -1; |
| } |
| const EC_SCALAR *const priv = &priv_key->priv_key->scalar; |
| const EC_GROUP *const group = EC_KEY_get0_group(priv_key); |
| if (EC_GROUP_cmp(group, pub_key->group, NULL) != 0) { |
| OPENSSL_PUT_ERROR(EC, EC_R_INCOMPATIBLE_OBJECTS); |
| return -1; |
| } |
| |
| BN_CTX *ctx = BN_CTX_new(); |
| if (ctx == NULL) { |
| return -1; |
| } |
| BN_CTX_start(ctx); |
| |
| int ret = -1; |
| size_t buflen = 0; |
| uint8_t *buf = NULL; |
| |
| EC_POINT *tmp = EC_POINT_new(group); |
| if (tmp == NULL) { |
| OPENSSL_PUT_ERROR(ECDH, ERR_R_MALLOC_FAILURE); |
| goto err; |
| } |
| |
| if (!ec_point_mul_scalar(group, &tmp->raw, NULL, &pub_key->raw, priv)) { |
| OPENSSL_PUT_ERROR(ECDH, ECDH_R_POINT_ARITHMETIC_FAILURE); |
| goto err; |
| } |
| |
| BIGNUM *x = BN_CTX_get(ctx); |
| if (!x) { |
| OPENSSL_PUT_ERROR(ECDH, ERR_R_MALLOC_FAILURE); |
| goto err; |
| } |
| |
| if (!EC_POINT_get_affine_coordinates_GFp(group, tmp, x, NULL, ctx)) { |
| OPENSSL_PUT_ERROR(ECDH, ECDH_R_POINT_ARITHMETIC_FAILURE); |
| goto err; |
| } |
| |
| buflen = (EC_GROUP_get_degree(group) + 7) / 8; |
| buf = OPENSSL_malloc(buflen); |
| if (buf == NULL) { |
| OPENSSL_PUT_ERROR(ECDH, ERR_R_MALLOC_FAILURE); |
| goto err; |
| } |
| |
| if (!BN_bn2bin_padded(buf, buflen, x)) { |
| OPENSSL_PUT_ERROR(ECDH, ERR_R_INTERNAL_ERROR); |
| goto err; |
| } |
| |
| if (kdf != NULL) { |
| if (kdf(buf, buflen, out, &outlen) == NULL) { |
| OPENSSL_PUT_ERROR(ECDH, ECDH_R_KDF_FAILED); |
| goto err; |
| } |
| } else { |
| // no KDF, just copy as much as we can |
| if (buflen < outlen) { |
| outlen = buflen; |
| } |
| OPENSSL_memcpy(out, buf, outlen); |
| } |
| |
| if (outlen > INT_MAX) { |
| OPENSSL_PUT_ERROR(ECDH, ERR_R_OVERFLOW); |
| goto err; |
| } |
| |
| ret = (int)outlen; |
| |
| err: |
| OPENSSL_free(buf); |
| EC_POINT_free(tmp); |
| BN_CTX_end(ctx); |
| BN_CTX_free(ctx); |
| return ret; |
| } |