1*2139Sjp161948 /* crypto/ec/ec_check.c */
2*2139Sjp161948 /* ====================================================================
3*2139Sjp161948 * Copyright (c) 1998-2002 The OpenSSL Project. All rights reserved.
4*2139Sjp161948 *
5*2139Sjp161948 * Redistribution and use in source and binary forms, with or without
6*2139Sjp161948 * modification, are permitted provided that the following conditions
7*2139Sjp161948 * are met:
8*2139Sjp161948 *
9*2139Sjp161948 * 1. Redistributions of source code must retain the above copyright
10*2139Sjp161948 * notice, this list of conditions and the following disclaimer.
11*2139Sjp161948 *
12*2139Sjp161948 * 2. Redistributions in binary form must reproduce the above copyright
13*2139Sjp161948 * notice, this list of conditions and the following disclaimer in
14*2139Sjp161948 * the documentation and/or other materials provided with the
15*2139Sjp161948 * distribution.
16*2139Sjp161948 *
17*2139Sjp161948 * 3. All advertising materials mentioning features or use of this
18*2139Sjp161948 * software must display the following acknowledgment:
19*2139Sjp161948 * "This product includes software developed by the OpenSSL Project
20*2139Sjp161948 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
21*2139Sjp161948 *
22*2139Sjp161948 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
23*2139Sjp161948 * endorse or promote products derived from this software without
24*2139Sjp161948 * prior written permission. For written permission, please contact
25*2139Sjp161948 * openssl-core@openssl.org.
26*2139Sjp161948 *
27*2139Sjp161948 * 5. Products derived from this software may not be called "OpenSSL"
28*2139Sjp161948 * nor may "OpenSSL" appear in their names without prior written
29*2139Sjp161948 * permission of the OpenSSL Project.
30*2139Sjp161948 *
31*2139Sjp161948 * 6. Redistributions of any form whatsoever must retain the following
32*2139Sjp161948 * acknowledgment:
33*2139Sjp161948 * "This product includes software developed by the OpenSSL Project
34*2139Sjp161948 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
35*2139Sjp161948 *
36*2139Sjp161948 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
37*2139Sjp161948 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
38*2139Sjp161948 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
39*2139Sjp161948 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
40*2139Sjp161948 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
41*2139Sjp161948 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
42*2139Sjp161948 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
43*2139Sjp161948 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
44*2139Sjp161948 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
45*2139Sjp161948 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
46*2139Sjp161948 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
47*2139Sjp161948 * OF THE POSSIBILITY OF SUCH DAMAGE.
48*2139Sjp161948 * ====================================================================
49*2139Sjp161948 *
50*2139Sjp161948 * This product includes cryptographic software written by Eric Young
51*2139Sjp161948 * (eay@cryptsoft.com). This product includes software written by Tim
52*2139Sjp161948 * Hudson (tjh@cryptsoft.com).
53*2139Sjp161948 *
54*2139Sjp161948 */
55*2139Sjp161948
56*2139Sjp161948 #include "ec_lcl.h"
57*2139Sjp161948 #include <openssl/err.h>
58*2139Sjp161948
EC_GROUP_check(const EC_GROUP * group,BN_CTX * ctx)59*2139Sjp161948 int EC_GROUP_check(const EC_GROUP *group, BN_CTX *ctx)
60*2139Sjp161948 {
61*2139Sjp161948 int ret = 0;
62*2139Sjp161948 BIGNUM *order;
63*2139Sjp161948 BN_CTX *new_ctx = NULL;
64*2139Sjp161948 EC_POINT *point = NULL;
65*2139Sjp161948
66*2139Sjp161948 if (ctx == NULL)
67*2139Sjp161948 {
68*2139Sjp161948 ctx = new_ctx = BN_CTX_new();
69*2139Sjp161948 if (ctx == NULL)
70*2139Sjp161948 {
71*2139Sjp161948 ECerr(EC_F_EC_GROUP_CHECK, ERR_R_MALLOC_FAILURE);
72*2139Sjp161948 goto err;
73*2139Sjp161948 }
74*2139Sjp161948 }
75*2139Sjp161948 BN_CTX_start(ctx);
76*2139Sjp161948 if ((order = BN_CTX_get(ctx)) == NULL) goto err;
77*2139Sjp161948
78*2139Sjp161948 /* check the discriminant */
79*2139Sjp161948 if (!EC_GROUP_check_discriminant(group, ctx))
80*2139Sjp161948 {
81*2139Sjp161948 ECerr(EC_F_EC_GROUP_CHECK, EC_R_DISCRIMINANT_IS_ZERO);
82*2139Sjp161948 goto err;
83*2139Sjp161948 }
84*2139Sjp161948
85*2139Sjp161948 /* check the generator */
86*2139Sjp161948 if (group->generator == NULL)
87*2139Sjp161948 {
88*2139Sjp161948 ECerr(EC_F_EC_GROUP_CHECK, EC_R_UNDEFINED_GENERATOR);
89*2139Sjp161948 goto err;
90*2139Sjp161948 }
91*2139Sjp161948 if (!EC_POINT_is_on_curve(group, group->generator, ctx))
92*2139Sjp161948 {
93*2139Sjp161948 ECerr(EC_F_EC_GROUP_CHECK, EC_R_POINT_IS_NOT_ON_CURVE);
94*2139Sjp161948 goto err;
95*2139Sjp161948 }
96*2139Sjp161948
97*2139Sjp161948 /* check the order of the generator */
98*2139Sjp161948 if ((point = EC_POINT_new(group)) == NULL) goto err;
99*2139Sjp161948 if (!EC_GROUP_get_order(group, order, ctx)) goto err;
100*2139Sjp161948 if (BN_is_zero(order))
101*2139Sjp161948 {
102*2139Sjp161948 ECerr(EC_F_EC_GROUP_CHECK, EC_R_UNDEFINED_ORDER);
103*2139Sjp161948 goto err;
104*2139Sjp161948 }
105*2139Sjp161948
106*2139Sjp161948 if (!EC_POINT_mul(group, point, order, NULL, NULL, ctx)) goto err;
107*2139Sjp161948 if (!EC_POINT_is_at_infinity(group, point))
108*2139Sjp161948 {
109*2139Sjp161948 ECerr(EC_F_EC_GROUP_CHECK, EC_R_INVALID_GROUP_ORDER);
110*2139Sjp161948 goto err;
111*2139Sjp161948 }
112*2139Sjp161948
113*2139Sjp161948 ret = 1;
114*2139Sjp161948
115*2139Sjp161948 err:
116*2139Sjp161948 BN_CTX_end(ctx);
117*2139Sjp161948 if (new_ctx != NULL)
118*2139Sjp161948 BN_CTX_free(new_ctx);
119*2139Sjp161948 if (point)
120*2139Sjp161948 EC_POINT_free(point);
121*2139Sjp161948 return ret;
122*2139Sjp161948 }
123