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17d6bb81 BM |
1 | /* crypto/ec/ec_check.c */ |
2 | /* ==================================================================== | |
3 | * Copyright (c) 1998-2002 The OpenSSL Project. All rights reserved. | |
4 | * | |
5 | * Redistribution and use in source and binary forms, with or without | |
6 | * modification, are permitted provided that the following conditions | |
7 | * are met: | |
8 | * | |
9 | * 1. Redistributions of source code must retain the above copyright | |
40720ce3 | 10 | * notice, this list of conditions and the following disclaimer. |
17d6bb81 BM |
11 | * |
12 | * 2. Redistributions in binary form must reproduce the above copyright | |
13 | * notice, this list of conditions and the following disclaimer in | |
14 | * the documentation and/or other materials provided with the | |
15 | * distribution. | |
16 | * | |
17 | * 3. All advertising materials mentioning features or use of this | |
18 | * software must display the following acknowledgment: | |
19 | * "This product includes software developed by the OpenSSL Project | |
20 | * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" | |
21 | * | |
22 | * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to | |
23 | * endorse or promote products derived from this software without | |
24 | * prior written permission. For written permission, please contact | |
25 | * openssl-core@openssl.org. | |
26 | * | |
27 | * 5. Products derived from this software may not be called "OpenSSL" | |
28 | * nor may "OpenSSL" appear in their names without prior written | |
29 | * permission of the OpenSSL Project. | |
30 | * | |
31 | * 6. Redistributions of any form whatsoever must retain the following | |
32 | * acknowledgment: | |
33 | * "This product includes software developed by the OpenSSL Project | |
34 | * for use in the OpenSSL Toolkit (http://www.openssl.org/)" | |
35 | * | |
36 | * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY | |
37 | * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
38 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR | |
39 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR | |
40 | * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
41 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
42 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; | |
43 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
44 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, | |
45 | * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
46 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED | |
47 | * OF THE POSSIBILITY OF SUCH DAMAGE. | |
48 | * ==================================================================== | |
49 | * | |
50 | * This product includes cryptographic software written by Eric Young | |
51 | * (eay@cryptsoft.com). This product includes software written by Tim | |
52 | * Hudson (tjh@cryptsoft.com). | |
53 | * | |
54 | */ | |
55 | ||
56 | #include "ec_lcl.h" | |
57 | #include <openssl/err.h> | |
58 | ||
59 | int EC_GROUP_check(const EC_GROUP *group, BN_CTX *ctx) | |
40720ce3 MC |
60 | { |
61 | int ret = 0; | |
62 | BIGNUM *order; | |
63 | BN_CTX *new_ctx = NULL; | |
64 | EC_POINT *point = NULL; | |
17d6bb81 | 65 | |
40720ce3 MC |
66 | if (ctx == NULL) { |
67 | ctx = new_ctx = BN_CTX_new(); | |
68 | if (ctx == NULL) { | |
69 | ECerr(EC_F_EC_GROUP_CHECK, ERR_R_MALLOC_FAILURE); | |
70 | goto err; | |
71 | } | |
72 | } | |
73 | BN_CTX_start(ctx); | |
74 | if ((order = BN_CTX_get(ctx)) == NULL) | |
75 | goto err; | |
17d6bb81 | 76 | |
40720ce3 MC |
77 | /* check the discriminant */ |
78 | if (!EC_GROUP_check_discriminant(group, ctx)) { | |
79 | ECerr(EC_F_EC_GROUP_CHECK, EC_R_DISCRIMINANT_IS_ZERO); | |
80 | goto err; | |
81 | } | |
17d6bb81 | 82 | |
40720ce3 MC |
83 | /* check the generator */ |
84 | if (group->generator == NULL) { | |
85 | ECerr(EC_F_EC_GROUP_CHECK, EC_R_UNDEFINED_GENERATOR); | |
86 | goto err; | |
87 | } | |
50d30499 | 88 | if (EC_POINT_is_on_curve(group, group->generator, ctx) <= 0) { |
40720ce3 MC |
89 | ECerr(EC_F_EC_GROUP_CHECK, EC_R_POINT_IS_NOT_ON_CURVE); |
90 | goto err; | |
91 | } | |
17d6bb81 | 92 | |
40720ce3 MC |
93 | /* check the order of the generator */ |
94 | if ((point = EC_POINT_new(group)) == NULL) | |
95 | goto err; | |
96 | if (!EC_GROUP_get_order(group, order, ctx)) | |
97 | goto err; | |
98 | if (BN_is_zero(order)) { | |
99 | ECerr(EC_F_EC_GROUP_CHECK, EC_R_UNDEFINED_ORDER); | |
100 | goto err; | |
101 | } | |
17d6bb81 | 102 | |
40720ce3 MC |
103 | if (!EC_POINT_mul(group, point, order, NULL, NULL, ctx)) |
104 | goto err; | |
105 | if (!EC_POINT_is_at_infinity(group, point)) { | |
106 | ECerr(EC_F_EC_GROUP_CHECK, EC_R_INVALID_GROUP_ORDER); | |
107 | goto err; | |
108 | } | |
17d6bb81 | 109 | |
40720ce3 MC |
110 | ret = 1; |
111 | ||
112 | err: | |
113 | if (ctx != NULL) | |
114 | BN_CTX_end(ctx); | |
115 | if (new_ctx != NULL) | |
116 | BN_CTX_free(new_ctx); | |
117 | if (point) | |
118 | EC_POINT_free(point); | |
119 | return ret; | |
120 | } |