Alexandre Savard | 1b09e31 | 2012-08-07 20:33:29 -0400 | [diff] [blame] | 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 |
| 10 | * notice, this list of conditions and the following disclaimer. |
| 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) |
| 60 | { |
| 61 | int ret = 0; |
| 62 | BIGNUM *order; |
| 63 | BN_CTX *new_ctx = NULL; |
| 64 | EC_POINT *point = NULL; |
| 65 | |
| 66 | if (ctx == NULL) |
| 67 | { |
| 68 | ctx = new_ctx = BN_CTX_new(); |
| 69 | if (ctx == NULL) |
| 70 | { |
| 71 | ECerr(EC_F_EC_GROUP_CHECK, ERR_R_MALLOC_FAILURE); |
| 72 | goto err; |
| 73 | } |
| 74 | } |
| 75 | BN_CTX_start(ctx); |
| 76 | if ((order = BN_CTX_get(ctx)) == NULL) goto err; |
| 77 | |
| 78 | /* check the discriminant */ |
| 79 | if (!EC_GROUP_check_discriminant(group, ctx)) |
| 80 | { |
| 81 | ECerr(EC_F_EC_GROUP_CHECK, EC_R_DISCRIMINANT_IS_ZERO); |
| 82 | goto err; |
| 83 | } |
| 84 | |
| 85 | /* check the generator */ |
| 86 | if (group->generator == NULL) |
| 87 | { |
| 88 | ECerr(EC_F_EC_GROUP_CHECK, EC_R_UNDEFINED_GENERATOR); |
| 89 | goto err; |
| 90 | } |
| 91 | if (!EC_POINT_is_on_curve(group, group->generator, ctx)) |
| 92 | { |
| 93 | ECerr(EC_F_EC_GROUP_CHECK, EC_R_POINT_IS_NOT_ON_CURVE); |
| 94 | goto err; |
| 95 | } |
| 96 | |
| 97 | /* check the order of the generator */ |
| 98 | if ((point = EC_POINT_new(group)) == NULL) goto err; |
| 99 | if (!EC_GROUP_get_order(group, order, ctx)) goto err; |
| 100 | if (BN_is_zero(order)) |
| 101 | { |
| 102 | ECerr(EC_F_EC_GROUP_CHECK, EC_R_UNDEFINED_ORDER); |
| 103 | goto err; |
| 104 | } |
| 105 | |
| 106 | if (!EC_POINT_mul(group, point, order, NULL, NULL, ctx)) goto err; |
| 107 | if (!EC_POINT_is_at_infinity(group, point)) |
| 108 | { |
| 109 | ECerr(EC_F_EC_GROUP_CHECK, EC_R_INVALID_GROUP_ORDER); |
| 110 | goto err; |
| 111 | } |
| 112 | |
| 113 | ret = 1; |
| 114 | |
| 115 | err: |
| 116 | if (ctx != NULL) |
| 117 | BN_CTX_end(ctx); |
| 118 | if (new_ctx != NULL) |
| 119 | BN_CTX_free(new_ctx); |
| 120 | if (point) |
| 121 | EC_POINT_free(point); |
| 122 | return ret; |
| 123 | } |