1/*
2 * Copyright 2002-2019 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
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
8 */
9
10#include "ec_local.h"
11#include <openssl/err.h>
12
13int EC_GROUP_check_named_curve(const EC_GROUP *group, int nist_only,
14 BN_CTX *ctx)
15{
16 int nid = NID_undef;
17#ifndef FIPS_MODE
18 BN_CTX *new_ctx = NULL;
19
20 if (ctx == NULL) {
21 ctx = new_ctx = BN_CTX_new();
22 if (ctx == NULL) {
23 ECerr(EC_F_EC_GROUP_CHECK_NAMED_CURVE, ERR_R_MALLOC_FAILURE);
24 goto err;
25 }
26 }
27#endif
28
29 nid = ec_curve_nid_from_params(group, ctx);
30 if (nid > 0 && nist_only && EC_curve_nid2nist(nid) == NULL)
31 nid = NID_undef;
32
33#ifndef FIPS_MODE
34 err:
35 BN_CTX_free(ctx);
36#endif
37 return nid;
38}
39
40int EC_GROUP_check(const EC_GROUP *group, BN_CTX *ctx)
41{
42#ifdef FIPS_MODE
43 /*
44 * ECC domain parameter validation.
45 * See SP800-56A R3 5.5.2 "Assurances of Domain-Parameter Validity" Part 1b.
46 */
47 return EC_GROUP_check_named_curve(group, 1, ctx) >= 0 ? 1 : 0;
48#else
49 int ret = 0;
50 const BIGNUM *order;
51 BN_CTX *new_ctx = NULL;
52 EC_POINT *point = NULL;
53
54 if (group == NULL || group->meth == NULL) {
55 ECerr(EC_F_EC_GROUP_CHECK, ERR_R_PASSED_NULL_PARAMETER);
56 return 0;
57 }
58
59 /* Custom curves assumed to be correct */
60 if ((group->meth->flags & EC_FLAGS_CUSTOM_CURVE) != 0)
61 return 1;
62
63 if (ctx == NULL) {
64 ctx = new_ctx = BN_CTX_new();
65 if (ctx == NULL) {
66 ECerr(EC_F_EC_GROUP_CHECK, ERR_R_MALLOC_FAILURE);
67 goto err;
68 }
69 }
70
71 /* check the discriminant */
72 if (!EC_GROUP_check_discriminant(group, ctx)) {
73 ECerr(EC_F_EC_GROUP_CHECK, EC_R_DISCRIMINANT_IS_ZERO);
74 goto err;
75 }
76
77 /* check the generator */
78 if (group->generator == NULL) {
79 ECerr(EC_F_EC_GROUP_CHECK, EC_R_UNDEFINED_GENERATOR);
80 goto err;
81 }
82 if (EC_POINT_is_on_curve(group, group->generator, ctx) <= 0) {
83 ECerr(EC_F_EC_GROUP_CHECK, EC_R_POINT_IS_NOT_ON_CURVE);
84 goto err;
85 }
86
87 /* check the order of the generator */
88 if ((point = EC_POINT_new(group)) == NULL)
89 goto err;
90 order = EC_GROUP_get0_order(group);
91 if (order == NULL)
92 goto err;
93 if (BN_is_zero(order)) {
94 ECerr(EC_F_EC_GROUP_CHECK, EC_R_UNDEFINED_ORDER);
95 goto err;
96 }
97
98 if (!EC_POINT_mul(group, point, order, NULL, NULL, ctx))
99 goto err;
100 if (!EC_POINT_is_at_infinity(group, point)) {
101 ECerr(EC_F_EC_GROUP_CHECK, EC_R_INVALID_GROUP_ORDER);
102 goto err;
103 }
104
105 ret = 1;
106
107 err:
108 BN_CTX_free(new_ctx);
109 EC_POINT_free(point);
110 return ret;
111#endif /* FIPS_MODE */
112}
113