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      1 /* Originally written by Bodo Moeller for the OpenSSL project.
      2  * ====================================================================
      3  * Copyright (c) 1998-2005 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 (at) 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 (at) cryptsoft.com).  This product includes software written by Tim
     52  * Hudson (tjh (at) cryptsoft.com).
     53  *
     54  */
     55 /* ====================================================================
     56  * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
     57  *
     58  * Portions of the attached software ("Contribution") are developed by
     59  * SUN MICROSYSTEMS, INC., and are contributed to the OpenSSL project.
     60  *
     61  * The Contribution is licensed pursuant to the OpenSSL open source
     62  * license provided above.
     63  *
     64  * The elliptic curve binary polynomial software is originally written by
     65  * Sheueling Chang Shantz and Douglas Stebila of Sun Microsystems
     66  * Laboratories. */
     67 
     68 #include <openssl/ec_key.h>
     69 
     70 #include <string.h>
     71 
     72 #include <openssl/ec.h>
     73 #include <openssl/engine.h>
     74 #include <openssl/err.h>
     75 #include <openssl/ex_data.h>
     76 #include <openssl/mem.h>
     77 #include <openssl/thread.h>
     78 
     79 #include "internal.h"
     80 #include "../internal.h"
     81 
     82 
     83 static CRYPTO_EX_DATA_CLASS g_ex_data_class = CRYPTO_EX_DATA_CLASS_INIT;
     84 
     85 EC_KEY *EC_KEY_new(void) { return EC_KEY_new_method(NULL); }
     86 
     87 EC_KEY *EC_KEY_new_method(const ENGINE *engine) {
     88   EC_KEY *ret = OPENSSL_malloc(sizeof(EC_KEY));
     89   if (ret == NULL) {
     90     OPENSSL_PUT_ERROR(EC, ERR_R_MALLOC_FAILURE);
     91     return NULL;
     92   }
     93 
     94   OPENSSL_memset(ret, 0, sizeof(EC_KEY));
     95 
     96   if (engine) {
     97     ret->ecdsa_meth = ENGINE_get_ECDSA_method(engine);
     98   }
     99   if (ret->ecdsa_meth) {
    100     METHOD_ref(ret->ecdsa_meth);
    101   }
    102 
    103   ret->conv_form = POINT_CONVERSION_UNCOMPRESSED;
    104   ret->references = 1;
    105 
    106   CRYPTO_new_ex_data(&ret->ex_data);
    107 
    108   if (ret->ecdsa_meth && ret->ecdsa_meth->init && !ret->ecdsa_meth->init(ret)) {
    109     CRYPTO_free_ex_data(&g_ex_data_class, ret, &ret->ex_data);
    110     if (ret->ecdsa_meth) {
    111       METHOD_unref(ret->ecdsa_meth);
    112     }
    113     OPENSSL_free(ret);
    114     return NULL;
    115   }
    116 
    117   return ret;
    118 }
    119 
    120 EC_KEY *EC_KEY_new_by_curve_name(int nid) {
    121   EC_KEY *ret = EC_KEY_new();
    122   if (ret == NULL) {
    123     OPENSSL_PUT_ERROR(EC, ERR_R_MALLOC_FAILURE);
    124     return NULL;
    125   }
    126   ret->group = EC_GROUP_new_by_curve_name(nid);
    127   if (ret->group == NULL) {
    128     EC_KEY_free(ret);
    129     return NULL;
    130   }
    131   return ret;
    132 }
    133 
    134 void EC_KEY_free(EC_KEY *r) {
    135   if (r == NULL) {
    136     return;
    137   }
    138 
    139   if (!CRYPTO_refcount_dec_and_test_zero(&r->references)) {
    140     return;
    141   }
    142 
    143   if (r->ecdsa_meth) {
    144     if (r->ecdsa_meth->finish) {
    145       r->ecdsa_meth->finish(r);
    146     }
    147     METHOD_unref(r->ecdsa_meth);
    148   }
    149 
    150   EC_GROUP_free(r->group);
    151   EC_POINT_free(r->pub_key);
    152   BN_clear_free(r->priv_key);
    153 
    154   CRYPTO_free_ex_data(&g_ex_data_class, r, &r->ex_data);
    155 
    156   OPENSSL_cleanse((void *)r, sizeof(EC_KEY));
    157   OPENSSL_free(r);
    158 }
    159 
    160 EC_KEY *EC_KEY_copy(EC_KEY *dest, const EC_KEY *src) {
    161   if (dest == NULL || src == NULL) {
    162     OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
    163     return NULL;
    164   }
    165   /* Copy the parameters. */
    166   if (src->group) {
    167     /* TODO(fork): duplicating the group seems wasteful. */
    168     EC_GROUP_free(dest->group);
    169     dest->group = EC_GROUP_dup(src->group);
    170     if (dest->group == NULL) {
    171       return NULL;
    172     }
    173   }
    174 
    175   /* Copy the public key. */
    176   if (src->pub_key && src->group) {
    177     EC_POINT_free(dest->pub_key);
    178     dest->pub_key = EC_POINT_dup(src->pub_key, src->group);
    179     if (dest->pub_key == NULL) {
    180       return NULL;
    181     }
    182   }
    183 
    184   /* copy the private key */
    185   if (src->priv_key) {
    186     if (dest->priv_key == NULL) {
    187       dest->priv_key = BN_new();
    188       if (dest->priv_key == NULL) {
    189         return NULL;
    190       }
    191     }
    192     if (!BN_copy(dest->priv_key, src->priv_key)) {
    193       return NULL;
    194     }
    195   }
    196   /* copy method/extra data */
    197   if (src->ecdsa_meth) {
    198       METHOD_unref(dest->ecdsa_meth);
    199       dest->ecdsa_meth = src->ecdsa_meth;
    200       METHOD_ref(dest->ecdsa_meth);
    201   }
    202   CRYPTO_free_ex_data(&g_ex_data_class, dest, &dest->ex_data);
    203   if (!CRYPTO_dup_ex_data(&g_ex_data_class, &dest->ex_data,
    204                           &src->ex_data)) {
    205     return NULL;
    206   }
    207 
    208   /* copy the rest */
    209   dest->enc_flag = src->enc_flag;
    210   dest->conv_form = src->conv_form;
    211 
    212   return dest;
    213 }
    214 
    215 EC_KEY *EC_KEY_dup(const EC_KEY *ec_key) {
    216   EC_KEY *ret = EC_KEY_new();
    217   if (ret == NULL) {
    218     return NULL;
    219   }
    220   if (EC_KEY_copy(ret, ec_key) == NULL) {
    221     EC_KEY_free(ret);
    222     return NULL;
    223   }
    224   return ret;
    225 }
    226 
    227 int EC_KEY_up_ref(EC_KEY *r) {
    228   CRYPTO_refcount_inc(&r->references);
    229   return 1;
    230 }
    231 
    232 int EC_KEY_is_opaque(const EC_KEY *key) {
    233   return key->ecdsa_meth && (key->ecdsa_meth->flags & ECDSA_FLAG_OPAQUE);
    234 }
    235 
    236 const EC_GROUP *EC_KEY_get0_group(const EC_KEY *key) { return key->group; }
    237 
    238 int EC_KEY_set_group(EC_KEY *key, const EC_GROUP *group) {
    239   EC_GROUP_free(key->group);
    240   /* TODO(fork): duplicating the group seems wasteful but see
    241    * |EC_KEY_set_conv_form|. */
    242   key->group = EC_GROUP_dup(group);
    243   if (key->group == NULL) {
    244     return 0;
    245   }
    246   /* XXX: |BN_cmp| is not constant time. */
    247   if (key->priv_key != NULL &&
    248       BN_cmp(key->priv_key, EC_GROUP_get0_order(group)) >= 0) {
    249     return 0;
    250   }
    251   return 1;
    252 }
    253 
    254 const BIGNUM *EC_KEY_get0_private_key(const EC_KEY *key) {
    255   return key->priv_key;
    256 }
    257 
    258 int EC_KEY_set_private_key(EC_KEY *key, const BIGNUM *priv_key) {
    259   /* XXX: |BN_cmp| is not constant time. */
    260   if (key->group != NULL &&
    261       BN_cmp(priv_key, EC_GROUP_get0_order(key->group)) >= 0) {
    262     OPENSSL_PUT_ERROR(EC, EC_R_WRONG_ORDER);
    263     return 0;
    264   }
    265   BN_clear_free(key->priv_key);
    266   key->priv_key = BN_dup(priv_key);
    267   return (key->priv_key == NULL) ? 0 : 1;
    268 }
    269 
    270 const EC_POINT *EC_KEY_get0_public_key(const EC_KEY *key) {
    271   return key->pub_key;
    272 }
    273 
    274 int EC_KEY_set_public_key(EC_KEY *key, const EC_POINT *pub_key) {
    275   EC_POINT_free(key->pub_key);
    276   key->pub_key = EC_POINT_dup(pub_key, key->group);
    277   return (key->pub_key == NULL) ? 0 : 1;
    278 }
    279 
    280 unsigned int EC_KEY_get_enc_flags(const EC_KEY *key) { return key->enc_flag; }
    281 
    282 void EC_KEY_set_enc_flags(EC_KEY *key, unsigned int flags) {
    283   key->enc_flag = flags;
    284 }
    285 
    286 point_conversion_form_t EC_KEY_get_conv_form(const EC_KEY *key) {
    287   return key->conv_form;
    288 }
    289 
    290 void EC_KEY_set_conv_form(EC_KEY *key, point_conversion_form_t cform) {
    291   key->conv_form = cform;
    292 }
    293 
    294 int EC_KEY_check_key(const EC_KEY *eckey) {
    295   int ok = 0;
    296   BN_CTX *ctx = NULL;
    297   EC_POINT *point = NULL;
    298 
    299   if (!eckey || !eckey->group || !eckey->pub_key) {
    300     OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
    301     return 0;
    302   }
    303 
    304   if (EC_POINT_is_at_infinity(eckey->group, eckey->pub_key)) {
    305     OPENSSL_PUT_ERROR(EC, EC_R_POINT_AT_INFINITY);
    306     goto err;
    307   }
    308 
    309   ctx = BN_CTX_new();
    310 
    311   if (ctx == NULL) {
    312     goto err;
    313   }
    314 
    315   /* testing whether the pub_key is on the elliptic curve */
    316   if (!EC_POINT_is_on_curve(eckey->group, eckey->pub_key, ctx)) {
    317     OPENSSL_PUT_ERROR(EC, EC_R_POINT_IS_NOT_ON_CURVE);
    318     goto err;
    319   }
    320   /* in case the priv_key is present :
    321    * check if generator * priv_key == pub_key
    322    */
    323   if (eckey->priv_key) {
    324     /* XXX: |BN_cmp| is not constant time. */
    325     if (BN_cmp(eckey->priv_key, EC_GROUP_get0_order(eckey->group)) >= 0) {
    326       OPENSSL_PUT_ERROR(EC, EC_R_WRONG_ORDER);
    327       goto err;
    328     }
    329     point = EC_POINT_new(eckey->group);
    330     if (point == NULL ||
    331         !EC_POINT_mul(eckey->group, point, eckey->priv_key, NULL, NULL, ctx)) {
    332       OPENSSL_PUT_ERROR(EC, ERR_R_EC_LIB);
    333       goto err;
    334     }
    335     if (EC_POINT_cmp(eckey->group, point, eckey->pub_key, ctx) != 0) {
    336       OPENSSL_PUT_ERROR(EC, EC_R_INVALID_PRIVATE_KEY);
    337       goto err;
    338     }
    339   }
    340   ok = 1;
    341 
    342 err:
    343   BN_CTX_free(ctx);
    344   EC_POINT_free(point);
    345   return ok;
    346 }
    347 
    348 int EC_KEY_set_public_key_affine_coordinates(EC_KEY *key, BIGNUM *x,
    349                                              BIGNUM *y) {
    350   BN_CTX *ctx = NULL;
    351   BIGNUM *tx, *ty;
    352   EC_POINT *point = NULL;
    353   int ok = 0;
    354 
    355   if (!key || !key->group || !x || !y) {
    356     OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
    357     return 0;
    358   }
    359   ctx = BN_CTX_new();
    360 
    361   if (ctx == NULL) {
    362     return 0;
    363   }
    364 
    365   BN_CTX_start(ctx);
    366   point = EC_POINT_new(key->group);
    367 
    368   if (point == NULL) {
    369     goto err;
    370   }
    371 
    372   tx = BN_CTX_get(ctx);
    373   ty = BN_CTX_get(ctx);
    374   if (tx == NULL ||
    375       ty == NULL) {
    376     goto err;
    377   }
    378 
    379   if (!EC_POINT_set_affine_coordinates_GFp(key->group, point, x, y, ctx) ||
    380       !EC_POINT_get_affine_coordinates_GFp(key->group, point, tx, ty, ctx)) {
    381     goto err;
    382   }
    383 
    384   /* Check if retrieved coordinates match originals: if not values
    385    * are out of range. */
    386   if (BN_cmp(x, tx) || BN_cmp(y, ty)) {
    387     OPENSSL_PUT_ERROR(EC, EC_R_COORDINATES_OUT_OF_RANGE);
    388     goto err;
    389   }
    390 
    391   if (!EC_KEY_set_public_key(key, point)) {
    392     goto err;
    393   }
    394 
    395   if (EC_KEY_check_key(key) == 0) {
    396     goto err;
    397   }
    398 
    399   ok = 1;
    400 
    401 err:
    402   BN_CTX_end(ctx);
    403   BN_CTX_free(ctx);
    404   EC_POINT_free(point);
    405   return ok;
    406 }
    407 
    408 int EC_KEY_generate_key(EC_KEY *eckey) {
    409   int ok = 0;
    410   BIGNUM *priv_key = NULL;
    411   EC_POINT *pub_key = NULL;
    412 
    413   if (!eckey || !eckey->group) {
    414     OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
    415     return 0;
    416   }
    417 
    418   if (eckey->priv_key == NULL) {
    419     priv_key = BN_new();
    420     if (priv_key == NULL) {
    421       goto err;
    422     }
    423   } else {
    424     priv_key = eckey->priv_key;
    425   }
    426 
    427   const BIGNUM *order = EC_GROUP_get0_order(eckey->group);
    428   if (!BN_rand_range_ex(priv_key, 1, order)) {
    429     goto err;
    430   }
    431 
    432   if (eckey->pub_key == NULL) {
    433     pub_key = EC_POINT_new(eckey->group);
    434     if (pub_key == NULL) {
    435       goto err;
    436     }
    437   } else {
    438     pub_key = eckey->pub_key;
    439   }
    440 
    441   if (!EC_POINT_mul(eckey->group, pub_key, priv_key, NULL, NULL, NULL)) {
    442     goto err;
    443   }
    444 
    445   eckey->priv_key = priv_key;
    446   eckey->pub_key = pub_key;
    447 
    448   ok = 1;
    449 
    450 err:
    451   if (eckey->pub_key == NULL) {
    452     EC_POINT_free(pub_key);
    453   }
    454   if (eckey->priv_key == NULL) {
    455     BN_free(priv_key);
    456   }
    457   return ok;
    458 }
    459 
    460 int EC_KEY_get_ex_new_index(long argl, void *argp, CRYPTO_EX_unused *unused,
    461                             CRYPTO_EX_dup *dup_func,
    462                             CRYPTO_EX_free *free_func) {
    463   int index;
    464   if (!CRYPTO_get_ex_new_index(&g_ex_data_class, &index, argl, argp, dup_func,
    465                                free_func)) {
    466     return -1;
    467   }
    468   return index;
    469 }
    470 
    471 int EC_KEY_set_ex_data(EC_KEY *d, int idx, void *arg) {
    472   return CRYPTO_set_ex_data(&d->ex_data, idx, arg);
    473 }
    474 
    475 void *EC_KEY_get_ex_data(const EC_KEY *d, int idx) {
    476   return CRYPTO_get_ex_data(&d->ex_data, idx);
    477 }
    478 
    479 void EC_KEY_set_asn1_flag(EC_KEY *key, int flag) {}
    480