| /* crypto/ec/ec_check.c */ |
| /* ==================================================================== |
| * Copyright (c) 1998-2002 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 |
| * 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 "ec_lcl.h" |
| #include <openssl/err.h> |
| |
| int EC_GROUP_check(const EC_GROUP *group, BN_CTX *ctx) |
| { |
| int ret = 0; |
| BIGNUM *order; |
| BN_CTX *new_ctx = NULL; |
| EC_POINT *point = NULL; |
| |
| if (ctx == NULL) |
| { |
| ctx = new_ctx = BN_CTX_new(); |
| if (ctx == NULL) |
| { |
| ECerr(EC_F_EC_GROUP_CHECK, ERR_R_MALLOC_FAILURE); |
| goto err; |
| } |
| } |
| BN_CTX_start(ctx); |
| if ((order = BN_CTX_get(ctx)) == NULL) goto err; |
| |
| /* check the discriminant */ |
| if (!EC_GROUP_check_discriminant(group, ctx)) |
| { |
| ECerr(EC_F_EC_GROUP_CHECK, EC_R_DISCRIMINANT_IS_ZERO); |
| goto err; |
| } |
| |
| /* check the generator */ |
| if (group->generator == NULL) |
| { |
| ECerr(EC_F_EC_GROUP_CHECK, EC_R_UNDEFINED_GENERATOR); |
| goto err; |
| } |
| if (!EC_POINT_is_on_curve(group, group->generator, ctx)) |
| { |
| ECerr(EC_F_EC_GROUP_CHECK, EC_R_POINT_IS_NOT_ON_CURVE); |
| goto err; |
| } |
| |
| /* check the order of the generator */ |
| if ((point = EC_POINT_new(group)) == NULL) goto err; |
| if (!EC_GROUP_get_order(group, order, ctx)) goto err; |
| if (BN_is_zero(order)) |
| { |
| ECerr(EC_F_EC_GROUP_CHECK, EC_R_UNDEFINED_ORDER); |
| goto err; |
| } |
| |
| if (!EC_POINT_mul(group, point, order, NULL, NULL, ctx)) goto err; |
| if (!EC_POINT_is_at_infinity(group, point)) |
| { |
| ECerr(EC_F_EC_GROUP_CHECK, EC_R_INVALID_GROUP_ORDER); |
| goto err; |
| } |
| |
| ret = 1; |
| |
| err: |
| if (ctx != NULL) |
| BN_CTX_end(ctx); |
| if (new_ctx != NULL) |
| BN_CTX_free(new_ctx); |
| if (point) |
| EC_POINT_free(point); |
| return ret; |
| } |