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@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  * 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 
EC_KEY_new(void)85 EC_KEY *EC_KEY_new(void) { return EC_KEY_new_method(NULL); }
86 
EC_KEY_new_method(const ENGINE * engine)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 
EC_KEY_new_by_curve_name(int nid)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 
EC_KEY_free(EC_KEY * r)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 
EC_KEY_copy(EC_KEY * dest,const EC_KEY * src)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 
EC_KEY_dup(const EC_KEY * ec_key)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 
EC_KEY_up_ref(EC_KEY * r)227 int EC_KEY_up_ref(EC_KEY *r) {
228   CRYPTO_refcount_inc(&r->references);
229   return 1;
230 }
231 
EC_KEY_is_opaque(const EC_KEY * key)232 int EC_KEY_is_opaque(const EC_KEY *key) {
233   return key->ecdsa_meth && (key->ecdsa_meth->flags & ECDSA_FLAG_OPAQUE);
234 }
235 
EC_KEY_get0_group(const EC_KEY * key)236 const EC_GROUP *EC_KEY_get0_group(const EC_KEY *key) { return key->group; }
237 
EC_KEY_set_group(EC_KEY * key,const EC_GROUP * group)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 
EC_KEY_get0_private_key(const EC_KEY * key)254 const BIGNUM *EC_KEY_get0_private_key(const EC_KEY *key) {
255   return key->priv_key;
256 }
257 
EC_KEY_set_private_key(EC_KEY * key,const BIGNUM * priv_key)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 
EC_KEY_get0_public_key(const EC_KEY * key)270 const EC_POINT *EC_KEY_get0_public_key(const EC_KEY *key) {
271   return key->pub_key;
272 }
273 
EC_KEY_set_public_key(EC_KEY * key,const EC_POINT * pub_key)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 
EC_KEY_get_enc_flags(const EC_KEY * key)280 unsigned int EC_KEY_get_enc_flags(const EC_KEY *key) { return key->enc_flag; }
281 
EC_KEY_set_enc_flags(EC_KEY * key,unsigned int flags)282 void EC_KEY_set_enc_flags(EC_KEY *key, unsigned int flags) {
283   key->enc_flag = flags;
284 }
285 
EC_KEY_get_conv_form(const EC_KEY * key)286 point_conversion_form_t EC_KEY_get_conv_form(const EC_KEY *key) {
287   return key->conv_form;
288 }
289 
EC_KEY_set_conv_form(EC_KEY * key,point_conversion_form_t cform)290 void EC_KEY_set_conv_form(EC_KEY *key, point_conversion_form_t cform) {
291   key->conv_form = cform;
292 }
293 
EC_KEY_check_key(const EC_KEY * eckey)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 
EC_KEY_set_public_key_affine_coordinates(EC_KEY * key,BIGNUM * x,BIGNUM * y)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 
EC_KEY_generate_key(EC_KEY * eckey)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 
EC_KEY_get_ex_new_index(long argl,void * argp,CRYPTO_EX_unused * unused,CRYPTO_EX_dup * dup_func,CRYPTO_EX_free * free_func)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 
EC_KEY_set_ex_data(EC_KEY * d,int idx,void * arg)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 
EC_KEY_get_ex_data(const EC_KEY * d,int idx)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 
EC_KEY_set_asn1_flag(EC_KEY * key,int flag)479 void EC_KEY_set_asn1_flag(EC_KEY *key, int flag) {}
480