[331] | 1 | /*
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| 2 | * Copyright 2002-2016 The OpenSSL Project Authors. All Rights Reserved.
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| 3 | *
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| 4 | * Licensed under the OpenSSL license (the "License"). You may not use
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| 5 | * this file except in compliance with the License. You can obtain a copy
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| 6 | * in the file LICENSE in the source distribution or at
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| 7 | * https://www.openssl.org/source/license.html
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| 8 | */
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| 9 |
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| 10 | #include "ec_lcl.h"
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| 11 | #include <openssl/err.h>
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| 12 |
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| 13 | int EC_GROUP_check(const EC_GROUP *group, BN_CTX *ctx)
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| 14 | {
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| 15 | int ret = 0;
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| 16 | const BIGNUM *order;
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| 17 | BN_CTX *new_ctx = NULL;
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| 18 | EC_POINT *point = NULL;
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| 19 |
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| 20 | /* Custom curves assumed to be correct */
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| 21 | if ((group->meth->flags & EC_FLAGS_CUSTOM_CURVE) != 0)
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| 22 | return 1;
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| 23 |
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| 24 | if (ctx == NULL) {
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| 25 | ctx = new_ctx = BN_CTX_new();
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| 26 | if (ctx == NULL) {
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| 27 | ECerr(EC_F_EC_GROUP_CHECK, ERR_R_MALLOC_FAILURE);
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| 28 | goto err;
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| 29 | }
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| 30 | }
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| 31 |
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| 32 | /* check the discriminant */
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| 33 | if (!EC_GROUP_check_discriminant(group, ctx)) {
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| 34 | ECerr(EC_F_EC_GROUP_CHECK, EC_R_DISCRIMINANT_IS_ZERO);
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| 35 | goto err;
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| 36 | }
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| 37 |
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| 38 | /* check the generator */
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| 39 | if (group->generator == NULL) {
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| 40 | ECerr(EC_F_EC_GROUP_CHECK, EC_R_UNDEFINED_GENERATOR);
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| 41 | goto err;
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| 42 | }
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| 43 | if (EC_POINT_is_on_curve(group, group->generator, ctx) <= 0) {
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| 44 | ECerr(EC_F_EC_GROUP_CHECK, EC_R_POINT_IS_NOT_ON_CURVE);
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| 45 | goto err;
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| 46 | }
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| 47 |
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| 48 | /* check the order of the generator */
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| 49 | if ((point = EC_POINT_new(group)) == NULL)
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| 50 | goto err;
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| 51 | order = EC_GROUP_get0_order(group);
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| 52 | if (order == NULL)
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| 53 | goto err;
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| 54 | if (BN_is_zero(order)) {
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| 55 | ECerr(EC_F_EC_GROUP_CHECK, EC_R_UNDEFINED_ORDER);
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| 56 | goto err;
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| 57 | }
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| 58 |
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| 59 | if (!EC_POINT_mul(group, point, order, NULL, NULL, ctx))
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| 60 | goto err;
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| 61 | if (!EC_POINT_is_at_infinity(group, point)) {
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| 62 | ECerr(EC_F_EC_GROUP_CHECK, EC_R_INVALID_GROUP_ORDER);
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| 63 | goto err;
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| 64 | }
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| 65 |
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| 66 | ret = 1;
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| 67 |
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| 68 | err:
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| 69 | BN_CTX_free(new_ctx);
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| 70 | EC_POINT_free(point);
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| 71 | return ret;
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| 72 | }
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