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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@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 = (EC_KEY *)OPENSSL_malloc(sizeof(EC_KEY));
89   if (ret == NULL) {
90     OPENSSL_PUT_ERROR(EC, 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   CRYPTO_new_ex_data(&ret->ex_data);
108 
109   if (ret->ecdsa_meth && ret->ecdsa_meth->init && !ret->ecdsa_meth->init(ret)) {
110     CRYPTO_free_ex_data(&g_ex_data_class, ret, &ret->ex_data);
111     if (ret->ecdsa_meth) {
112       METHOD_unref(ret->ecdsa_meth);
113     }
114     OPENSSL_free(ret);
115     return NULL;
116   }
117 
118   return ret;
119 }
120 
EC_KEY_new_by_curve_name(int nid)121 EC_KEY *EC_KEY_new_by_curve_name(int nid) {
122   EC_KEY *ret = EC_KEY_new();
123   if (ret == NULL) {
124     OPENSSL_PUT_ERROR(EC, ERR_R_MALLOC_FAILURE);
125     return NULL;
126   }
127   ret->group = EC_GROUP_new_by_curve_name(nid);
128   if (ret->group == NULL) {
129     EC_KEY_free(ret);
130     return NULL;
131   }
132   return ret;
133 }
134 
EC_KEY_free(EC_KEY * r)135 void EC_KEY_free(EC_KEY *r) {
136   if (r == NULL) {
137     return;
138   }
139 
140   if (!CRYPTO_refcount_dec_and_test_zero(&r->references)) {
141     return;
142   }
143 
144   if (r->ecdsa_meth) {
145     if (r->ecdsa_meth->finish) {
146       r->ecdsa_meth->finish(r);
147     }
148     METHOD_unref(r->ecdsa_meth);
149   }
150 
151   EC_GROUP_free(r->group);
152   EC_POINT_free(r->pub_key);
153   BN_clear_free(r->priv_key);
154 
155   CRYPTO_free_ex_data(&g_ex_data_class, r, &r->ex_data);
156 
157   OPENSSL_cleanse((void *)r, sizeof(EC_KEY));
158   OPENSSL_free(r);
159 }
160 
EC_KEY_copy(EC_KEY * dest,const EC_KEY * src)161 EC_KEY *EC_KEY_copy(EC_KEY *dest, const EC_KEY *src) {
162   if (dest == NULL || src == NULL) {
163     OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
164     return NULL;
165   }
166   /* Copy the parameters. */
167   if (src->group) {
168     /* TODO(fork): duplicating the group seems wasteful. */
169     EC_GROUP_free(dest->group);
170     dest->group = EC_GROUP_dup(src->group);
171     if (dest->group == NULL) {
172       return NULL;
173     }
174   }
175 
176   /* Copy the public key. */
177   if (src->pub_key && src->group) {
178     EC_POINT_free(dest->pub_key);
179     dest->pub_key = EC_POINT_dup(src->pub_key, src->group);
180     if (dest->pub_key == NULL) {
181       return NULL;
182     }
183   }
184 
185   /* copy the private key */
186   if (src->priv_key) {
187     if (dest->priv_key == NULL) {
188       dest->priv_key = BN_new();
189       if (dest->priv_key == NULL) {
190         return NULL;
191       }
192     }
193     if (!BN_copy(dest->priv_key, src->priv_key)) {
194       return NULL;
195     }
196   }
197   /* copy method/extra data */
198   if (src->ecdsa_meth) {
199       METHOD_unref(dest->ecdsa_meth);
200       dest->ecdsa_meth = src->ecdsa_meth;
201       METHOD_ref(dest->ecdsa_meth);
202   }
203   CRYPTO_free_ex_data(&g_ex_data_class, dest, &dest->ex_data);
204   if (!CRYPTO_dup_ex_data(&g_ex_data_class, &dest->ex_data,
205                           &src->ex_data)) {
206     return NULL;
207   }
208 
209   /* copy the rest */
210   dest->enc_flag = src->enc_flag;
211   dest->conv_form = src->conv_form;
212   dest->version = src->version;
213   dest->flags = src->flags;
214 
215   return dest;
216 }
217 
EC_KEY_dup(const EC_KEY * ec_key)218 EC_KEY *EC_KEY_dup(const EC_KEY *ec_key) {
219   EC_KEY *ret = EC_KEY_new();
220   if (ret == NULL) {
221     return NULL;
222   }
223   if (EC_KEY_copy(ret, ec_key) == NULL) {
224     EC_KEY_free(ret);
225     return NULL;
226   }
227   return ret;
228 }
229 
EC_KEY_up_ref(EC_KEY * r)230 int EC_KEY_up_ref(EC_KEY *r) {
231   CRYPTO_refcount_inc(&r->references);
232   return 1;
233 }
234 
EC_KEY_is_opaque(const EC_KEY * key)235 int EC_KEY_is_opaque(const EC_KEY *key) {
236   return key->ecdsa_meth && (key->ecdsa_meth->flags & ECDSA_FLAG_OPAQUE);
237 }
238 
EC_KEY_get0_group(const EC_KEY * key)239 const EC_GROUP *EC_KEY_get0_group(const EC_KEY *key) { return key->group; }
240 
EC_KEY_set_group(EC_KEY * key,const EC_GROUP * group)241 int EC_KEY_set_group(EC_KEY *key, const EC_GROUP *group) {
242   EC_GROUP_free(key->group);
243   /* TODO(fork): duplicating the group seems wasteful but see
244    * |EC_KEY_set_conv_form|. */
245   key->group = EC_GROUP_dup(group);
246   if (key->group == NULL) {
247     return 0;
248   }
249   /* XXX: |BN_cmp| is not constant time. */
250   if (key->priv_key != NULL &&
251       BN_cmp(key->priv_key, EC_GROUP_get0_order(group)) >= 0) {
252     return 0;
253   }
254   return 1;
255 }
256 
EC_KEY_get0_private_key(const EC_KEY * key)257 const BIGNUM *EC_KEY_get0_private_key(const EC_KEY *key) {
258   return key->priv_key;
259 }
260 
EC_KEY_set_private_key(EC_KEY * key,const BIGNUM * priv_key)261 int EC_KEY_set_private_key(EC_KEY *key, const BIGNUM *priv_key) {
262   /* XXX: |BN_cmp| is not constant time. */
263   if (key->group != NULL &&
264       BN_cmp(priv_key, EC_GROUP_get0_order(key->group)) >= 0) {
265     OPENSSL_PUT_ERROR(EC, EC_R_WRONG_ORDER);
266     return 0;
267   }
268   BN_clear_free(key->priv_key);
269   key->priv_key = BN_dup(priv_key);
270   return (key->priv_key == NULL) ? 0 : 1;
271 }
272 
EC_KEY_get0_public_key(const EC_KEY * key)273 const EC_POINT *EC_KEY_get0_public_key(const EC_KEY *key) {
274   return key->pub_key;
275 }
276 
EC_KEY_set_public_key(EC_KEY * key,const EC_POINT * pub_key)277 int EC_KEY_set_public_key(EC_KEY *key, const EC_POINT *pub_key) {
278   EC_POINT_free(key->pub_key);
279   key->pub_key = EC_POINT_dup(pub_key, key->group);
280   return (key->pub_key == NULL) ? 0 : 1;
281 }
282 
EC_KEY_get_enc_flags(const EC_KEY * key)283 unsigned int EC_KEY_get_enc_flags(const EC_KEY *key) { return key->enc_flag; }
284 
EC_KEY_set_enc_flags(EC_KEY * key,unsigned int flags)285 void EC_KEY_set_enc_flags(EC_KEY *key, unsigned int flags) {
286   key->enc_flag = flags;
287 }
288 
EC_KEY_get_conv_form(const EC_KEY * key)289 point_conversion_form_t EC_KEY_get_conv_form(const EC_KEY *key) {
290   return key->conv_form;
291 }
292 
EC_KEY_set_conv_form(EC_KEY * key,point_conversion_form_t cform)293 void EC_KEY_set_conv_form(EC_KEY *key, point_conversion_form_t cform) {
294   key->conv_form = cform;
295 }
296 
EC_KEY_check_key(const EC_KEY * eckey)297 int EC_KEY_check_key(const EC_KEY *eckey) {
298   int ok = 0;
299   BN_CTX *ctx = NULL;
300   EC_POINT *point = NULL;
301 
302   if (!eckey || !eckey->group || !eckey->pub_key) {
303     OPENSSL_PUT_ERROR(EC, 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_R_POINT_AT_INFINITY);
309     goto err;
310   }
311 
312   ctx = BN_CTX_new();
313 
314   if (ctx == NULL) {
315     goto err;
316   }
317 
318   /* testing whether the pub_key is on the elliptic curve */
319   if (!EC_POINT_is_on_curve(eckey->group, eckey->pub_key, ctx)) {
320     OPENSSL_PUT_ERROR(EC, EC_R_POINT_IS_NOT_ON_CURVE);
321     goto err;
322   }
323   /* TODO(fork): can this be skipped if the cofactor is one or if we're about
324    * to check the private key, below? */
325   if (eckey->group->meth->check_pub_key_order != NULL &&
326       !eckey->group->meth->check_pub_key_order(eckey->group, eckey->pub_key,
327                                                ctx)) {
328     OPENSSL_PUT_ERROR(EC, EC_R_WRONG_ORDER);
329     goto err;
330   }
331   /* in case the priv_key is present :
332    * check if generator * priv_key == pub_key
333    */
334   if (eckey->priv_key) {
335     /* XXX: |BN_cmp| is not constant time. */
336     if (BN_cmp(eckey->priv_key, EC_GROUP_get0_order(eckey->group)) >= 0) {
337       OPENSSL_PUT_ERROR(EC, EC_R_WRONG_ORDER);
338       goto err;
339     }
340     point = EC_POINT_new(eckey->group);
341     if (point == NULL ||
342         !EC_POINT_mul(eckey->group, point, eckey->priv_key, NULL, NULL, ctx)) {
343       OPENSSL_PUT_ERROR(EC, ERR_R_EC_LIB);
344       goto err;
345     }
346     if (EC_POINT_cmp(eckey->group, point, eckey->pub_key, ctx) != 0) {
347       OPENSSL_PUT_ERROR(EC, EC_R_INVALID_PRIVATE_KEY);
348       goto err;
349     }
350   }
351   ok = 1;
352 
353 err:
354   BN_CTX_free(ctx);
355   EC_POINT_free(point);
356   return ok;
357 }
358 
EC_KEY_set_public_key_affine_coordinates(EC_KEY * key,BIGNUM * x,BIGNUM * y)359 int EC_KEY_set_public_key_affine_coordinates(EC_KEY *key, BIGNUM *x,
360                                              BIGNUM *y) {
361   BN_CTX *ctx = NULL;
362   BIGNUM *tx, *ty;
363   EC_POINT *point = NULL;
364   int ok = 0;
365 
366   if (!key || !key->group || !x || !y) {
367     OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
368     return 0;
369   }
370   ctx = BN_CTX_new();
371   point = EC_POINT_new(key->group);
372 
373   if (ctx == NULL ||
374       point == NULL) {
375     goto err;
376   }
377 
378   tx = BN_CTX_get(ctx);
379   ty = BN_CTX_get(ctx);
380 
381   if (!EC_POINT_set_affine_coordinates_GFp(key->group, point, x, y, ctx) ||
382       !EC_POINT_get_affine_coordinates_GFp(key->group, point, tx, ty, ctx)) {
383     goto err;
384   }
385 
386   /* Check if retrieved coordinates match originals: if not values
387    * are out of range. */
388   if (BN_cmp(x, tx) || BN_cmp(y, ty)) {
389     OPENSSL_PUT_ERROR(EC, EC_R_COORDINATES_OUT_OF_RANGE);
390     goto err;
391   }
392 
393   if (!EC_KEY_set_public_key(key, point)) {
394     goto err;
395   }
396 
397   if (EC_KEY_check_key(key) == 0) {
398     goto err;
399   }
400 
401   ok = 1;
402 
403 err:
404   BN_CTX_free(ctx);
405   EC_POINT_free(point);
406   return ok;
407 }
408 
EC_KEY_generate_key(EC_KEY * eckey)409 int EC_KEY_generate_key(EC_KEY *eckey) {
410   int ok = 0;
411   BIGNUM *priv_key = NULL;
412   EC_POINT *pub_key = NULL;
413 
414   if (!eckey || !eckey->group) {
415     OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
416     return 0;
417   }
418 
419   if (eckey->priv_key == NULL) {
420     priv_key = BN_new();
421     if (priv_key == NULL) {
422       goto err;
423     }
424   } else {
425     priv_key = eckey->priv_key;
426   }
427 
428   const BIGNUM *order = EC_GROUP_get0_order(eckey->group);
429   do {
430     if (!BN_rand_range(priv_key, order)) {
431       goto err;
432     }
433   } while (BN_is_zero(priv_key));
434 
435   if (eckey->pub_key == NULL) {
436     pub_key = EC_POINT_new(eckey->group);
437     if (pub_key == NULL) {
438       goto err;
439     }
440   } else {
441     pub_key = eckey->pub_key;
442   }
443 
444   if (!EC_POINT_mul(eckey->group, pub_key, priv_key, NULL, NULL, NULL)) {
445     goto err;
446   }
447 
448   eckey->priv_key = priv_key;
449   eckey->pub_key = pub_key;
450 
451   ok = 1;
452 
453 err:
454   if (eckey->pub_key == NULL) {
455     EC_POINT_free(pub_key);
456   }
457   if (eckey->priv_key == NULL) {
458     BN_free(priv_key);
459   }
460   return ok;
461 }
462 
EC_KEY_get_ex_new_index(long argl,void * argp,CRYPTO_EX_unused * unused,CRYPTO_EX_dup * dup_func,CRYPTO_EX_free * free_func)463 int EC_KEY_get_ex_new_index(long argl, void *argp, CRYPTO_EX_unused *unused,
464                             CRYPTO_EX_dup *dup_func,
465                             CRYPTO_EX_free *free_func) {
466   int index;
467   if (!CRYPTO_get_ex_new_index(&g_ex_data_class, &index, argl, argp, dup_func,
468                                free_func)) {
469     return -1;
470   }
471   return index;
472 }
473 
EC_KEY_set_ex_data(EC_KEY * d,int idx,void * arg)474 int EC_KEY_set_ex_data(EC_KEY *d, int idx, void *arg) {
475   return CRYPTO_set_ex_data(&d->ex_data, idx, arg);
476 }
477 
EC_KEY_get_ex_data(const EC_KEY * d,int idx)478 void *EC_KEY_get_ex_data(const EC_KEY *d, int idx) {
479   return CRYPTO_get_ex_data(&d->ex_data, idx);
480 }
481 
EC_KEY_set_asn1_flag(EC_KEY * key,int flag)482 void EC_KEY_set_asn1_flag(EC_KEY *key, int flag) {}
483