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Commit | Line | Data |
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4f22f405 RS |
1 | /* |
2 | * Copyright 2002-2016 The OpenSSL Project Authors. All Rights Reserved. | |
17d6bb81 | 3 | * |
a7f182b7 | 4 | * Licensed under the Apache License 2.0 (the "License"). You may not use |
4f22f405 RS |
5 | * this file except in compliance with the License. You can obtain a copy |
6 | * in the file LICENSE in the source distribution or at | |
7 | * https://www.openssl.org/source/license.html | |
17d6bb81 BM |
8 | */ |
9 | ||
10 | #include "ec_lcl.h" | |
11 | #include <openssl/err.h> | |
12 | ||
13 | int EC_GROUP_check(const EC_GROUP *group, BN_CTX *ctx) | |
0f113f3e MC |
14 | { |
15 | int ret = 0; | |
be2e334f | 16 | const BIGNUM *order; |
0f113f3e MC |
17 | BN_CTX *new_ctx = NULL; |
18 | EC_POINT *point = NULL; | |
17d6bb81 | 19 | |
6903e2e7 DSH |
20 | /* Custom curves assumed to be correct */ |
21 | if ((group->meth->flags & EC_FLAGS_CUSTOM_CURVE) != 0) | |
22 | return 1; | |
23 | ||
0f113f3e MC |
24 | if (ctx == NULL) { |
25 | ctx = new_ctx = BN_CTX_new(); | |
26 | if (ctx == NULL) { | |
27 | ECerr(EC_F_EC_GROUP_CHECK, ERR_R_MALLOC_FAILURE); | |
28 | goto err; | |
29 | } | |
30 | } | |
17d6bb81 | 31 | |
0f113f3e MC |
32 | /* check the discriminant */ |
33 | if (!EC_GROUP_check_discriminant(group, ctx)) { | |
34 | ECerr(EC_F_EC_GROUP_CHECK, EC_R_DISCRIMINANT_IS_ZERO); | |
35 | goto err; | |
36 | } | |
17d6bb81 | 37 | |
0f113f3e MC |
38 | /* check the generator */ |
39 | if (group->generator == NULL) { | |
40 | ECerr(EC_F_EC_GROUP_CHECK, EC_R_UNDEFINED_GENERATOR); | |
41 | goto err; | |
42 | } | |
68886be7 | 43 | if (EC_POINT_is_on_curve(group, group->generator, ctx) <= 0) { |
0f113f3e MC |
44 | ECerr(EC_F_EC_GROUP_CHECK, EC_R_POINT_IS_NOT_ON_CURVE); |
45 | goto err; | |
46 | } | |
17d6bb81 | 47 | |
0f113f3e MC |
48 | /* check the order of the generator */ |
49 | if ((point = EC_POINT_new(group)) == NULL) | |
50 | goto err; | |
be2e334f DSH |
51 | order = EC_GROUP_get0_order(group); |
52 | if (order == NULL) | |
0f113f3e MC |
53 | goto err; |
54 | if (BN_is_zero(order)) { | |
55 | ECerr(EC_F_EC_GROUP_CHECK, EC_R_UNDEFINED_ORDER); | |
56 | goto err; | |
57 | } | |
17d6bb81 | 58 | |
0f113f3e MC |
59 | if (!EC_POINT_mul(group, point, order, NULL, NULL, ctx)) |
60 | goto err; | |
61 | if (!EC_POINT_is_at_infinity(group, point)) { | |
62 | ECerr(EC_F_EC_GROUP_CHECK, EC_R_INVALID_GROUP_ORDER); | |
63 | goto err; | |
64 | } | |
17d6bb81 | 65 | |
0f113f3e MC |
66 | ret = 1; |
67 | ||
68 | err: | |
23a1d5e9 | 69 | BN_CTX_free(new_ctx); |
8fdc3734 | 70 | EC_POINT_free(point); |
0f113f3e MC |
71 | return ret; |
72 | } |