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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/ecdsa.h>
74 #include <openssl/engine.h>
75 #include <openssl/err.h>
76 #include <openssl/ex_data.h>
77 #include <openssl/mem.h>
78 #include <openssl/thread.h>
79 
80 #include "internal.h"
81 #include "../delocate.h"
82 #include "../../internal.h"
83 
84 
85 DEFINE_STATIC_EX_DATA_CLASS(g_ec_ex_data_class);
86 
EC_KEY_new(void)87 EC_KEY *EC_KEY_new(void) { return EC_KEY_new_method(NULL); }
88 
EC_KEY_new_method(const ENGINE * engine)89 EC_KEY *EC_KEY_new_method(const ENGINE *engine) {
90   EC_KEY *ret = OPENSSL_malloc(sizeof(EC_KEY));
91   if (ret == NULL) {
92     OPENSSL_PUT_ERROR(EC, ERR_R_MALLOC_FAILURE);
93     return NULL;
94   }
95 
96   OPENSSL_memset(ret, 0, sizeof(EC_KEY));
97 
98   if (engine) {
99     ret->ecdsa_meth = ENGINE_get_ECDSA_method(engine);
100   }
101   if (ret->ecdsa_meth) {
102     METHOD_ref(ret->ecdsa_meth);
103   }
104 
105   ret->conv_form = POINT_CONVERSION_UNCOMPRESSED;
106   ret->references = 1;
107 
108   CRYPTO_new_ex_data(&ret->ex_data);
109 
110   if (ret->ecdsa_meth && ret->ecdsa_meth->init && !ret->ecdsa_meth->init(ret)) {
111     CRYPTO_free_ex_data(g_ec_ex_data_class_bss_get(), ret, &ret->ex_data);
112     if (ret->ecdsa_meth) {
113       METHOD_unref(ret->ecdsa_meth);
114     }
115     OPENSSL_free(ret);
116     return NULL;
117   }
118 
119   return ret;
120 }
121 
EC_KEY_new_by_curve_name(int nid)122 EC_KEY *EC_KEY_new_by_curve_name(int nid) {
123   EC_KEY *ret = EC_KEY_new();
124   if (ret == NULL) {
125     OPENSSL_PUT_ERROR(EC, ERR_R_MALLOC_FAILURE);
126     return NULL;
127   }
128   ret->group = EC_GROUP_new_by_curve_name(nid);
129   if (ret->group == NULL) {
130     EC_KEY_free(ret);
131     return NULL;
132   }
133   return ret;
134 }
135 
EC_KEY_free(EC_KEY * r)136 void EC_KEY_free(EC_KEY *r) {
137   if (r == NULL) {
138     return;
139   }
140 
141   if (!CRYPTO_refcount_dec_and_test_zero(&r->references)) {
142     return;
143   }
144 
145   if (r->ecdsa_meth) {
146     if (r->ecdsa_meth->finish) {
147       r->ecdsa_meth->finish(r);
148     }
149     METHOD_unref(r->ecdsa_meth);
150   }
151 
152   EC_GROUP_free(r->group);
153   EC_POINT_free(r->pub_key);
154   BN_clear_free(r->priv_key);
155   BN_free(r->fixed_k);
156 
157   CRYPTO_free_ex_data(g_ec_ex_data_class_bss_get(), r, &r->ex_data);
158 
159   OPENSSL_free(r);
160 }
161 
EC_KEY_copy(EC_KEY * dest,const EC_KEY * src)162 EC_KEY *EC_KEY_copy(EC_KEY *dest, const EC_KEY *src) {
163   if (dest == NULL || src == NULL) {
164     OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
165     return NULL;
166   }
167   // Copy the parameters.
168   if (src->group) {
169     // TODO(fork): duplicating the group seems wasteful.
170     EC_GROUP_free(dest->group);
171     dest->group = EC_GROUP_dup(src->group);
172     if (dest->group == NULL) {
173       return NULL;
174     }
175   }
176 
177   // Copy the public key.
178   if (src->pub_key && src->group) {
179     EC_POINT_free(dest->pub_key);
180     dest->pub_key = EC_POINT_dup(src->pub_key, src->group);
181     if (dest->pub_key == NULL) {
182       return NULL;
183     }
184   }
185 
186   // copy the private key
187   if (src->priv_key) {
188     if (dest->priv_key == NULL) {
189       dest->priv_key = BN_new();
190       if (dest->priv_key == NULL) {
191         return NULL;
192       }
193     }
194     if (!BN_copy(dest->priv_key, src->priv_key)) {
195       return NULL;
196     }
197   }
198   // copy method/extra data
199   if (src->ecdsa_meth) {
200       METHOD_unref(dest->ecdsa_meth);
201       dest->ecdsa_meth = src->ecdsa_meth;
202       METHOD_ref(dest->ecdsa_meth);
203   }
204 
205   // copy the rest
206   dest->enc_flag = src->enc_flag;
207   dest->conv_form = src->conv_form;
208 
209   return dest;
210 }
211 
EC_KEY_dup(const EC_KEY * ec_key)212 EC_KEY *EC_KEY_dup(const EC_KEY *ec_key) {
213   EC_KEY *ret = EC_KEY_new();
214   if (ret == NULL) {
215     return NULL;
216   }
217   if (EC_KEY_copy(ret, ec_key) == NULL) {
218     EC_KEY_free(ret);
219     return NULL;
220   }
221   return ret;
222 }
223 
EC_KEY_up_ref(EC_KEY * r)224 int EC_KEY_up_ref(EC_KEY *r) {
225   CRYPTO_refcount_inc(&r->references);
226   return 1;
227 }
228 
EC_KEY_is_opaque(const EC_KEY * key)229 int EC_KEY_is_opaque(const EC_KEY *key) {
230   return key->ecdsa_meth && (key->ecdsa_meth->flags & ECDSA_FLAG_OPAQUE);
231 }
232 
EC_KEY_get0_group(const EC_KEY * key)233 const EC_GROUP *EC_KEY_get0_group(const EC_KEY *key) { return key->group; }
234 
EC_KEY_set_group(EC_KEY * key,const EC_GROUP * group)235 int EC_KEY_set_group(EC_KEY *key, const EC_GROUP *group) {
236   // If |key| already has a group, it is an error to switch to another one.
237   if (key->group != NULL) {
238     if (EC_GROUP_cmp(key->group, group, NULL) != 0) {
239       OPENSSL_PUT_ERROR(EC, EC_R_GROUP_MISMATCH);
240       return 0;
241     }
242     return 1;
243   }
244 
245   assert(key->priv_key == NULL);
246   assert(key->pub_key == NULL);
247 
248   EC_GROUP_free(key->group);
249   key->group = EC_GROUP_dup(group);
250   return key->group != NULL;
251 }
252 
EC_KEY_get0_private_key(const EC_KEY * key)253 const BIGNUM *EC_KEY_get0_private_key(const EC_KEY *key) {
254   return key->priv_key;
255 }
256 
EC_KEY_set_private_key(EC_KEY * key,const BIGNUM * priv_key)257 int EC_KEY_set_private_key(EC_KEY *key, const BIGNUM *priv_key) {
258   if (key->group == NULL) {
259     OPENSSL_PUT_ERROR(EC, EC_R_MISSING_PARAMETERS);
260     return 0;
261   }
262 
263   // XXX: |BN_cmp| is not constant time.
264   if (BN_is_negative(priv_key) ||
265       BN_cmp(priv_key, EC_GROUP_get0_order(key->group)) >= 0) {
266     OPENSSL_PUT_ERROR(EC, EC_R_WRONG_ORDER);
267     return 0;
268   }
269   BN_clear_free(key->priv_key);
270   key->priv_key = BN_dup(priv_key);
271   return (key->priv_key == NULL) ? 0 : 1;
272 }
273 
EC_KEY_get0_public_key(const EC_KEY * key)274 const EC_POINT *EC_KEY_get0_public_key(const EC_KEY *key) {
275   return key->pub_key;
276 }
277 
EC_KEY_set_public_key(EC_KEY * key,const EC_POINT * pub_key)278 int EC_KEY_set_public_key(EC_KEY *key, const EC_POINT *pub_key) {
279   if (key->group == NULL) {
280     OPENSSL_PUT_ERROR(EC, EC_R_MISSING_PARAMETERS);
281     return 0;
282   }
283 
284   if (EC_GROUP_cmp(key->group, pub_key->group, NULL) != 0) {
285     OPENSSL_PUT_ERROR(EC, EC_R_GROUP_MISMATCH);
286     return 0;
287   }
288 
289   EC_POINT_free(key->pub_key);
290   key->pub_key = EC_POINT_dup(pub_key, key->group);
291   return (key->pub_key == NULL) ? 0 : 1;
292 }
293 
EC_KEY_get_enc_flags(const EC_KEY * key)294 unsigned int EC_KEY_get_enc_flags(const EC_KEY *key) { return key->enc_flag; }
295 
EC_KEY_set_enc_flags(EC_KEY * key,unsigned int flags)296 void EC_KEY_set_enc_flags(EC_KEY *key, unsigned int flags) {
297   key->enc_flag = flags;
298 }
299 
EC_KEY_get_conv_form(const EC_KEY * key)300 point_conversion_form_t EC_KEY_get_conv_form(const EC_KEY *key) {
301   return key->conv_form;
302 }
303 
EC_KEY_set_conv_form(EC_KEY * key,point_conversion_form_t cform)304 void EC_KEY_set_conv_form(EC_KEY *key, point_conversion_form_t cform) {
305   key->conv_form = cform;
306 }
307 
EC_KEY_check_key(const EC_KEY * eckey)308 int EC_KEY_check_key(const EC_KEY *eckey) {
309   int ok = 0;
310   BN_CTX *ctx = NULL;
311   EC_POINT *point = NULL;
312 
313   if (!eckey || !eckey->group || !eckey->pub_key) {
314     OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
315     return 0;
316   }
317 
318   if (EC_POINT_is_at_infinity(eckey->group, eckey->pub_key)) {
319     OPENSSL_PUT_ERROR(EC, EC_R_POINT_AT_INFINITY);
320     goto err;
321   }
322 
323   ctx = BN_CTX_new();
324 
325   if (ctx == NULL) {
326     goto err;
327   }
328 
329   // testing whether the pub_key is on the elliptic curve
330   if (!EC_POINT_is_on_curve(eckey->group, eckey->pub_key, ctx)) {
331     OPENSSL_PUT_ERROR(EC, EC_R_POINT_IS_NOT_ON_CURVE);
332     goto err;
333   }
334   // in case the priv_key is present :
335   // check if generator * priv_key == pub_key
336   if (eckey->priv_key) {
337     // XXX: |BN_cmp| is not constant time.
338     if (BN_is_negative(eckey->priv_key) ||
339         BN_cmp(eckey->priv_key, EC_GROUP_get0_order(eckey->group)) >= 0) {
340       OPENSSL_PUT_ERROR(EC, EC_R_WRONG_ORDER);
341       goto err;
342     }
343     point = EC_POINT_new(eckey->group);
344     if (point == NULL ||
345         !EC_POINT_mul(eckey->group, point, eckey->priv_key, NULL, NULL, ctx)) {
346       OPENSSL_PUT_ERROR(EC, ERR_R_EC_LIB);
347       goto err;
348     }
349     if (EC_POINT_cmp(eckey->group, point, eckey->pub_key, ctx) != 0) {
350       OPENSSL_PUT_ERROR(EC, EC_R_INVALID_PRIVATE_KEY);
351       goto err;
352     }
353   }
354   ok = 1;
355 
356 err:
357   BN_CTX_free(ctx);
358   EC_POINT_free(point);
359   return ok;
360 }
361 
EC_KEY_check_fips(const EC_KEY * key)362 int EC_KEY_check_fips(const EC_KEY *key) {
363   if (EC_KEY_is_opaque(key)) {
364     // Opaque keys can't be checked.
365     OPENSSL_PUT_ERROR(EC, EC_R_PUBLIC_KEY_VALIDATION_FAILED);
366     return 0;
367   }
368 
369   if (!EC_KEY_check_key(key)) {
370     return 0;
371   }
372 
373   if (key->priv_key) {
374     uint8_t data[16] = {0};
375     ECDSA_SIG *sig = ECDSA_do_sign(data, sizeof(data), key);
376 #if defined(BORINGSSL_FIPS_BREAK_ECDSA_PWCT)
377     data[0] = ~data[0];
378 #endif
379     int ok = sig != NULL &&
380              ECDSA_do_verify(data, sizeof(data), sig, key);
381     ECDSA_SIG_free(sig);
382     if (!ok) {
383       OPENSSL_PUT_ERROR(EC, EC_R_PUBLIC_KEY_VALIDATION_FAILED);
384       return 0;
385     }
386   }
387 
388   return 1;
389 }
390 
EC_KEY_set_public_key_affine_coordinates(EC_KEY * key,BIGNUM * x,BIGNUM * y)391 int EC_KEY_set_public_key_affine_coordinates(EC_KEY *key, BIGNUM *x,
392                                              BIGNUM *y) {
393   EC_POINT *point = NULL;
394   int ok = 0;
395 
396   if (!key || !key->group || !x || !y) {
397     OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
398     return 0;
399   }
400 
401   point = EC_POINT_new(key->group);
402   if (point == NULL ||
403       !EC_POINT_set_affine_coordinates_GFp(key->group, point, x, y, NULL) ||
404       !EC_KEY_set_public_key(key, point) ||
405       !EC_KEY_check_key(key)) {
406     goto err;
407   }
408 
409   ok = 1;
410 
411 err:
412   EC_POINT_free(point);
413   return ok;
414 }
415 
EC_KEY_generate_key(EC_KEY * eckey)416 int EC_KEY_generate_key(EC_KEY *eckey) {
417   int ok = 0;
418   BIGNUM *priv_key = NULL;
419   EC_POINT *pub_key = NULL;
420 
421   if (!eckey || !eckey->group) {
422     OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
423     return 0;
424   }
425 
426   if (eckey->priv_key == NULL) {
427     priv_key = BN_new();
428     if (priv_key == NULL) {
429       goto err;
430     }
431   } else {
432     priv_key = eckey->priv_key;
433   }
434 
435   const BIGNUM *order = EC_GROUP_get0_order(eckey->group);
436 
437   // Check that the size of the group order is FIPS compliant (FIPS 186-4
438   // B.4.2).
439   if (BN_num_bits(order) < 160) {
440     OPENSSL_PUT_ERROR(EC, EC_R_INVALID_GROUP_ORDER);
441     goto err;
442   }
443 
444   // Generate the private key by testing candidates (FIPS 186-4 B.4.2).
445   if (!BN_rand_range_ex(priv_key, 1, order)) {
446     goto err;
447   }
448 
449   if (eckey->pub_key == NULL) {
450     pub_key = EC_POINT_new(eckey->group);
451     if (pub_key == NULL) {
452       goto err;
453     }
454   } else {
455     pub_key = eckey->pub_key;
456   }
457 
458   if (!EC_POINT_mul(eckey->group, pub_key, priv_key, NULL, NULL, NULL)) {
459     goto err;
460   }
461 
462   eckey->priv_key = priv_key;
463   eckey->pub_key = pub_key;
464 
465   ok = 1;
466 
467 err:
468   if (eckey->pub_key == NULL) {
469     EC_POINT_free(pub_key);
470   }
471   if (eckey->priv_key == NULL) {
472     BN_free(priv_key);
473   }
474   return ok;
475 }
476 
EC_KEY_generate_key_fips(EC_KEY * eckey)477 int EC_KEY_generate_key_fips(EC_KEY *eckey) {
478   return EC_KEY_generate_key(eckey) && EC_KEY_check_fips(eckey);
479 }
480 
EC_KEY_get_ex_new_index(long argl,void * argp,CRYPTO_EX_unused * unused,CRYPTO_EX_dup * dup_unused,CRYPTO_EX_free * free_func)481 int EC_KEY_get_ex_new_index(long argl, void *argp, CRYPTO_EX_unused *unused,
482                             CRYPTO_EX_dup *dup_unused,
483                             CRYPTO_EX_free *free_func) {
484   int index;
485   if (!CRYPTO_get_ex_new_index(g_ec_ex_data_class_bss_get(), &index, argl, argp,
486                                free_func)) {
487     return -1;
488   }
489   return index;
490 }
491 
EC_KEY_set_ex_data(EC_KEY * d,int idx,void * arg)492 int EC_KEY_set_ex_data(EC_KEY *d, int idx, void *arg) {
493   return CRYPTO_set_ex_data(&d->ex_data, idx, arg);
494 }
495 
EC_KEY_get_ex_data(const EC_KEY * d,int idx)496 void *EC_KEY_get_ex_data(const EC_KEY *d, int idx) {
497   return CRYPTO_get_ex_data(&d->ex_data, idx);
498 }
499 
EC_KEY_set_asn1_flag(EC_KEY * key,int flag)500 void EC_KEY_set_asn1_flag(EC_KEY *key, int flag) {}
501