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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 = (EC_KEY *)OPENSSL_malloc(sizeof(EC_KEY));
     89   if (ret == NULL) {
     90     OPENSSL_PUT_ERROR(EC, EC_KEY_new_method, ERR_R_MALLOC_FAILURE);
     91     return NULL;
     92   }
     93 
     94   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->version = 1;
    104   ret->conv_form = POINT_CONVERSION_UNCOMPRESSED;
    105   ret->references = 1;
    106 
    107   if (!CRYPTO_new_ex_data(&g_ex_data_class, ret, &ret->ex_data)) {
    108     goto err1;
    109   }
    110 
    111   if (ret->ecdsa_meth && ret->ecdsa_meth->init && !ret->ecdsa_meth->init(ret)) {
    112     goto err2;
    113   }
    114 
    115   return ret;
    116 
    117 err2:
    118   CRYPTO_free_ex_data(&g_ex_data_class, ret, &ret->ex_data);
    119 err1:
    120   if (ret->ecdsa_meth) {
    121     METHOD_unref(ret->ecdsa_meth);
    122   }
    123   OPENSSL_free(ret);
    124   return NULL;
    125 }
    126 
    127 EC_KEY *EC_KEY_new_by_curve_name(int nid) {
    128   EC_KEY *ret = EC_KEY_new();
    129   if (ret == NULL) {
    130     OPENSSL_PUT_ERROR(EC, EC_KEY_new_by_curve_name, ERR_R_MALLOC_FAILURE);
    131     return NULL;
    132   }
    133   ret->group = EC_GROUP_new_by_curve_name(nid);
    134   if (ret->group == NULL) {
    135     EC_KEY_free(ret);
    136     return NULL;
    137   }
    138   return ret;
    139 }
    140 
    141 void EC_KEY_free(EC_KEY *r) {
    142   if (r == NULL) {
    143     return;
    144   }
    145 
    146   if (!CRYPTO_refcount_dec_and_test_zero(&r->references)) {
    147     return;
    148   }
    149 
    150   if (r->ecdsa_meth) {
    151     if (r->ecdsa_meth->finish) {
    152       r->ecdsa_meth->finish(r);
    153     }
    154     METHOD_unref(r->ecdsa_meth);
    155   }
    156 
    157   EC_GROUP_free(r->group);
    158   EC_POINT_free(r->pub_key);
    159   BN_clear_free(r->priv_key);
    160 
    161   CRYPTO_free_ex_data(&g_ex_data_class, r, &r->ex_data);
    162 
    163   OPENSSL_cleanse((void *)r, sizeof(EC_KEY));
    164   OPENSSL_free(r);
    165 }
    166 
    167 EC_KEY *EC_KEY_copy(EC_KEY *dest, const EC_KEY *src) {
    168   if (dest == NULL || src == NULL) {
    169     OPENSSL_PUT_ERROR(EC, EC_KEY_copy, ERR_R_PASSED_NULL_PARAMETER);
    170     return NULL;
    171   }
    172   /* Copy the parameters. */
    173   if (src->group) {
    174     /* TODO(fork): duplicating the group seems wasteful. */
    175     EC_GROUP_free(dest->group);
    176     dest->group = EC_GROUP_dup(src->group);
    177     if (dest->group == NULL) {
    178       return NULL;
    179     }
    180   }
    181 
    182   /* Copy the public key. */
    183   if (src->pub_key && src->group) {
    184     EC_POINT_free(dest->pub_key);
    185     dest->pub_key = EC_POINT_dup(src->pub_key, src->group);
    186     if (dest->pub_key == NULL) {
    187       return NULL;
    188     }
    189   }
    190 
    191   /* copy the private key */
    192   if (src->priv_key) {
    193     if (dest->priv_key == NULL) {
    194       dest->priv_key = BN_new();
    195       if (dest->priv_key == NULL) {
    196         return NULL;
    197       }
    198     }
    199     if (!BN_copy(dest->priv_key, src->priv_key)) {
    200       return NULL;
    201     }
    202   }
    203   /* copy method/extra data */
    204   if (src->ecdsa_meth) {
    205       METHOD_unref(dest->ecdsa_meth);
    206       dest->ecdsa_meth = src->ecdsa_meth;
    207       METHOD_ref(dest->ecdsa_meth);
    208   }
    209   CRYPTO_free_ex_data(&g_ex_data_class, dest, &dest->ex_data);
    210   if (!CRYPTO_dup_ex_data(&g_ex_data_class, &dest->ex_data,
    211                           &src->ex_data)) {
    212     return NULL;
    213   }
    214 
    215   /* copy the rest */
    216   dest->enc_flag = src->enc_flag;
    217   dest->conv_form = src->conv_form;
    218   dest->version = src->version;
    219   dest->flags = src->flags;
    220 
    221   return dest;
    222 }
    223 
    224 EC_KEY *EC_KEY_dup(const EC_KEY *ec_key) {
    225   EC_KEY *ret = EC_KEY_new();
    226   if (ret == NULL) {
    227     return NULL;
    228   }
    229   if (EC_KEY_copy(ret, ec_key) == NULL) {
    230     EC_KEY_free(ret);
    231     return NULL;
    232   }
    233   return ret;
    234 }
    235 
    236 int EC_KEY_up_ref(EC_KEY *r) {
    237   CRYPTO_refcount_inc(&r->references);
    238   return 1;
    239 }
    240 
    241 int EC_KEY_is_opaque(const EC_KEY *key) {
    242   return key->ecdsa_meth && (key->ecdsa_meth->flags & ECDSA_FLAG_OPAQUE);
    243 }
    244 
    245 const EC_GROUP *EC_KEY_get0_group(const EC_KEY *key) { return key->group; }
    246 
    247 int EC_KEY_set_group(EC_KEY *key, const EC_GROUP *group) {
    248   EC_GROUP_free(key->group);
    249   /* TODO(fork): duplicating the group seems wasteful but see
    250    * |EC_KEY_set_conv_form|. */
    251   key->group = EC_GROUP_dup(group);
    252   return (key->group == NULL) ? 0 : 1;
    253 }
    254 
    255 const BIGNUM *EC_KEY_get0_private_key(const EC_KEY *key) {
    256   return key->priv_key;
    257 }
    258 
    259 int EC_KEY_set_private_key(EC_KEY *key, const BIGNUM *priv_key) {
    260   BN_clear_free(key->priv_key);
    261   key->priv_key = BN_dup(priv_key);
    262   return (key->priv_key == NULL) ? 0 : 1;
    263 }
    264 
    265 const EC_POINT *EC_KEY_get0_public_key(const EC_KEY *key) {
    266   return key->pub_key;
    267 }
    268 
    269 int EC_KEY_set_public_key(EC_KEY *key, const EC_POINT *pub_key) {
    270   EC_POINT_free(key->pub_key);
    271   key->pub_key = EC_POINT_dup(pub_key, key->group);
    272   return (key->pub_key == NULL) ? 0 : 1;
    273 }
    274 
    275 unsigned int EC_KEY_get_enc_flags(const EC_KEY *key) { return key->enc_flag; }
    276 
    277 void EC_KEY_set_enc_flags(EC_KEY *key, unsigned int flags) {
    278   key->enc_flag = flags;
    279 }
    280 
    281 point_conversion_form_t EC_KEY_get_conv_form(const EC_KEY *key) {
    282   return key->conv_form;
    283 }
    284 
    285 void EC_KEY_set_conv_form(EC_KEY *key, point_conversion_form_t cform) {
    286   key->conv_form = cform;
    287 }
    288 
    289 int EC_KEY_precompute_mult(EC_KEY *key, BN_CTX *ctx) {
    290   if (key->group == NULL) {
    291     return 0;
    292   }
    293   return EC_GROUP_precompute_mult(key->group, ctx);
    294 }
    295 
    296 int EC_KEY_check_key(const EC_KEY *eckey) {
    297   int ok = 0;
    298   BN_CTX *ctx = NULL;
    299   const BIGNUM *order = NULL;
    300   EC_POINT *point = NULL;
    301 
    302   if (!eckey || !eckey->group || !eckey->pub_key) {
    303     OPENSSL_PUT_ERROR(EC, EC_KEY_check_key, ERR_R_PASSED_NULL_PARAMETER);
    304     return 0;
    305   }
    306 
    307   if (EC_POINT_is_at_infinity(eckey->group, eckey->pub_key)) {
    308     OPENSSL_PUT_ERROR(EC, EC_KEY_check_key, EC_R_POINT_AT_INFINITY);
    309     goto err;
    310   }
    311 
    312   ctx = BN_CTX_new();
    313   point = EC_POINT_new(eckey->group);
    314 
    315   if (ctx == NULL ||
    316       point == NULL) {
    317     goto err;
    318   }
    319 
    320   /* testing whether the pub_key is on the elliptic curve */
    321   if (!EC_POINT_is_on_curve(eckey->group, eckey->pub_key, ctx)) {
    322     OPENSSL_PUT_ERROR(EC, EC_KEY_check_key, EC_R_POINT_IS_NOT_ON_CURVE);
    323     goto err;
    324   }
    325   /* testing whether pub_key * order is the point at infinity */
    326   /* TODO(fork): can this be skipped if the cofactor is one or if we're about
    327    * to check the private key, below? */
    328   order = &eckey->group->order;
    329   if (BN_is_zero(order)) {
    330     OPENSSL_PUT_ERROR(EC, EC_KEY_check_key, EC_R_INVALID_GROUP_ORDER);
    331     goto err;
    332   }
    333   if (!EC_POINT_mul(eckey->group, point, NULL, eckey->pub_key, order, ctx)) {
    334     OPENSSL_PUT_ERROR(EC, EC_KEY_check_key, ERR_R_EC_LIB);
    335     goto err;
    336   }
    337   if (!EC_POINT_is_at_infinity(eckey->group, point)) {
    338     OPENSSL_PUT_ERROR(EC, EC_KEY_check_key, EC_R_WRONG_ORDER);
    339     goto err;
    340   }
    341   /* in case the priv_key is present :
    342    * check if generator * priv_key == pub_key
    343    */
    344   if (eckey->priv_key) {
    345     if (BN_cmp(eckey->priv_key, order) >= 0) {
    346       OPENSSL_PUT_ERROR(EC, EC_KEY_check_key, EC_R_WRONG_ORDER);
    347       goto err;
    348     }
    349     if (!EC_POINT_mul(eckey->group, point, eckey->priv_key, NULL, NULL, ctx)) {
    350       OPENSSL_PUT_ERROR(EC, EC_KEY_check_key, ERR_R_EC_LIB);
    351       goto err;
    352     }
    353     if (EC_POINT_cmp(eckey->group, point, eckey->pub_key, ctx) != 0) {
    354       OPENSSL_PUT_ERROR(EC, EC_KEY_check_key, EC_R_INVALID_PRIVATE_KEY);
    355       goto err;
    356     }
    357   }
    358   ok = 1;
    359 
    360 err:
    361   BN_CTX_free(ctx);
    362   EC_POINT_free(point);
    363   return ok;
    364 }
    365 
    366 int EC_KEY_set_public_key_affine_coordinates(EC_KEY *key, BIGNUM *x,
    367                                              BIGNUM *y) {
    368   BN_CTX *ctx = NULL;
    369   BIGNUM *tx, *ty;
    370   EC_POINT *point = NULL;
    371   int ok = 0;
    372 
    373   if (!key || !key->group || !x || !y) {
    374     OPENSSL_PUT_ERROR(EC, EC_KEY_set_public_key_affine_coordinates,
    375                       ERR_R_PASSED_NULL_PARAMETER);
    376     return 0;
    377   }
    378   ctx = BN_CTX_new();
    379   point = EC_POINT_new(key->group);
    380 
    381   if (ctx == NULL ||
    382       point == NULL) {
    383     goto err;
    384   }
    385 
    386   tx = BN_CTX_get(ctx);
    387   ty = BN_CTX_get(ctx);
    388 
    389   if (!EC_POINT_set_affine_coordinates_GFp(key->group, point, x, y, ctx) ||
    390       !EC_POINT_get_affine_coordinates_GFp(key->group, point, tx, ty, ctx)) {
    391     goto err;
    392   }
    393 
    394   /* Check if retrieved coordinates match originals: if not values
    395    * are out of range. */
    396   if (BN_cmp(x, tx) || BN_cmp(y, ty)) {
    397     OPENSSL_PUT_ERROR(EC, EC_KEY_set_public_key_affine_coordinates,
    398                       EC_R_COORDINATES_OUT_OF_RANGE);
    399     goto err;
    400   }
    401 
    402   if (!EC_KEY_set_public_key(key, point)) {
    403     goto err;
    404   }
    405 
    406   if (EC_KEY_check_key(key) == 0) {
    407     goto err;
    408   }
    409 
    410   ok = 1;
    411 
    412 err:
    413   BN_CTX_free(ctx);
    414   EC_POINT_free(point);
    415   return ok;
    416 }
    417 
    418 int EC_KEY_generate_key(EC_KEY *eckey) {
    419   int ok = 0;
    420   BN_CTX *ctx = NULL;
    421   BIGNUM *priv_key = NULL, *order = NULL;
    422   EC_POINT *pub_key = NULL;
    423 
    424   if (!eckey || !eckey->group) {
    425     OPENSSL_PUT_ERROR(EC, EC_KEY_generate_key, ERR_R_PASSED_NULL_PARAMETER);
    426     return 0;
    427   }
    428 
    429   order = BN_new();
    430   ctx = BN_CTX_new();
    431 
    432   if (order == NULL ||
    433       ctx == NULL) {
    434     goto err;
    435   }
    436 
    437   if (eckey->priv_key == NULL) {
    438     priv_key = BN_new();
    439     if (priv_key == NULL) {
    440       goto err;
    441     }
    442   } else {
    443     priv_key = eckey->priv_key;
    444   }
    445 
    446   if (!EC_GROUP_get_order(eckey->group, order, ctx)) {
    447     goto err;
    448   }
    449 
    450   do {
    451     if (!BN_rand_range(priv_key, order)) {
    452       goto err;
    453     }
    454   } while (BN_is_zero(priv_key));
    455 
    456   if (eckey->pub_key == NULL) {
    457     pub_key = EC_POINT_new(eckey->group);
    458     if (pub_key == NULL) {
    459       goto err;
    460     }
    461   } else {
    462     pub_key = eckey->pub_key;
    463   }
    464 
    465   if (!EC_POINT_mul(eckey->group, pub_key, priv_key, NULL, NULL, ctx)) {
    466     goto err;
    467   }
    468 
    469   eckey->priv_key = priv_key;
    470   eckey->pub_key = pub_key;
    471 
    472   ok = 1;
    473 
    474 err:
    475   BN_free(order);
    476   if (eckey->pub_key == NULL) {
    477     EC_POINT_free(pub_key);
    478   }
    479   if (eckey->priv_key == NULL) {
    480     BN_free(priv_key);
    481   }
    482   BN_CTX_free(ctx);
    483   return ok;
    484 }
    485 
    486 int EC_KEY_get_ex_new_index(long argl, void *argp, CRYPTO_EX_new *new_func,
    487                             CRYPTO_EX_dup *dup_func,
    488                             CRYPTO_EX_free *free_func) {
    489   int index;
    490   if (!CRYPTO_get_ex_new_index(&g_ex_data_class, &index, argl, argp, new_func,
    491                                dup_func, free_func)) {
    492     return -1;
    493   }
    494   return index;
    495 }
    496 
    497 int EC_KEY_set_ex_data(EC_KEY *d, int idx, void *arg) {
    498   return CRYPTO_set_ex_data(&d->ex_data, idx, arg);
    499 }
    500 
    501 void *EC_KEY_get_ex_data(const EC_KEY *d, int idx) {
    502   return CRYPTO_get_ex_data(&d->ex_data, idx);
    503 }
    504 
    505 void EC_KEY_set_asn1_flag(EC_KEY *key, int flag) {}
    506