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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 "../service_indicator/internal.h"
83 #include "../../internal.h"
84 
85 
DEFINE_STATIC_EX_DATA_CLASS(g_ec_ex_data_class)86 DEFINE_STATIC_EX_DATA_CLASS(g_ec_ex_data_class)
87 
88 static EC_WRAPPED_SCALAR *ec_wrapped_scalar_new(const EC_GROUP *group) {
89   EC_WRAPPED_SCALAR *wrapped = OPENSSL_malloc(sizeof(EC_WRAPPED_SCALAR));
90   if (wrapped == NULL) {
91     return NULL;
92   }
93 
94   OPENSSL_memset(wrapped, 0, sizeof(EC_WRAPPED_SCALAR));
95   wrapped->bignum.d = wrapped->scalar.words;
96   wrapped->bignum.width = group->order.width;
97   wrapped->bignum.dmax = group->order.width;
98   wrapped->bignum.flags = BN_FLG_STATIC_DATA;
99   return wrapped;
100 }
101 
ec_wrapped_scalar_free(EC_WRAPPED_SCALAR * scalar)102 static void ec_wrapped_scalar_free(EC_WRAPPED_SCALAR *scalar) {
103   OPENSSL_free(scalar);
104 }
105 
EC_KEY_new(void)106 EC_KEY *EC_KEY_new(void) { return EC_KEY_new_method(NULL); }
107 
EC_KEY_new_method(const ENGINE * engine)108 EC_KEY *EC_KEY_new_method(const ENGINE *engine) {
109   EC_KEY *ret = OPENSSL_malloc(sizeof(EC_KEY));
110   if (ret == NULL) {
111     return NULL;
112   }
113 
114   OPENSSL_memset(ret, 0, sizeof(EC_KEY));
115 
116   if (engine) {
117     ret->ecdsa_meth = ENGINE_get_ECDSA_method(engine);
118   }
119   if (ret->ecdsa_meth) {
120     METHOD_ref(ret->ecdsa_meth);
121   }
122 
123   ret->conv_form = POINT_CONVERSION_UNCOMPRESSED;
124   ret->references = 1;
125 
126   CRYPTO_new_ex_data(&ret->ex_data);
127 
128   if (ret->ecdsa_meth && ret->ecdsa_meth->init && !ret->ecdsa_meth->init(ret)) {
129     CRYPTO_free_ex_data(g_ec_ex_data_class_bss_get(), ret, &ret->ex_data);
130     if (ret->ecdsa_meth) {
131       METHOD_unref(ret->ecdsa_meth);
132     }
133     OPENSSL_free(ret);
134     return NULL;
135   }
136 
137   return ret;
138 }
139 
EC_KEY_new_by_curve_name(int nid)140 EC_KEY *EC_KEY_new_by_curve_name(int nid) {
141   EC_KEY *ret = EC_KEY_new();
142   if (ret == NULL) {
143     return NULL;
144   }
145   ret->group = EC_GROUP_new_by_curve_name(nid);
146   if (ret->group == NULL) {
147     EC_KEY_free(ret);
148     return NULL;
149   }
150   return ret;
151 }
152 
EC_KEY_free(EC_KEY * r)153 void EC_KEY_free(EC_KEY *r) {
154   if (r == NULL) {
155     return;
156   }
157 
158   if (!CRYPTO_refcount_dec_and_test_zero(&r->references)) {
159     return;
160   }
161 
162   if (r->ecdsa_meth) {
163     if (r->ecdsa_meth->finish) {
164       r->ecdsa_meth->finish(r);
165     }
166     METHOD_unref(r->ecdsa_meth);
167   }
168 
169   EC_GROUP_free(r->group);
170   EC_POINT_free(r->pub_key);
171   ec_wrapped_scalar_free(r->priv_key);
172 
173   CRYPTO_free_ex_data(g_ec_ex_data_class_bss_get(), r, &r->ex_data);
174 
175   OPENSSL_free(r);
176 }
177 
EC_KEY_dup(const EC_KEY * src)178 EC_KEY *EC_KEY_dup(const EC_KEY *src) {
179   if (src == NULL) {
180     OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
181     return NULL;
182   }
183 
184   EC_KEY *ret = EC_KEY_new();
185   if (ret == NULL) {
186     return NULL;
187   }
188 
189   if ((src->group != NULL &&
190        !EC_KEY_set_group(ret, src->group)) ||
191       (src->pub_key != NULL &&
192        !EC_KEY_set_public_key(ret, src->pub_key)) ||
193       (src->priv_key != NULL &&
194        !EC_KEY_set_private_key(ret, EC_KEY_get0_private_key(src)))) {
195     EC_KEY_free(ret);
196     return NULL;
197   }
198 
199   ret->enc_flag = src->enc_flag;
200   ret->conv_form = src->conv_form;
201   return ret;
202 }
203 
EC_KEY_up_ref(EC_KEY * r)204 int EC_KEY_up_ref(EC_KEY *r) {
205   CRYPTO_refcount_inc(&r->references);
206   return 1;
207 }
208 
EC_KEY_is_opaque(const EC_KEY * key)209 int EC_KEY_is_opaque(const EC_KEY *key) {
210   return key->ecdsa_meth && (key->ecdsa_meth->flags & ECDSA_FLAG_OPAQUE);
211 }
212 
EC_KEY_get0_group(const EC_KEY * key)213 const EC_GROUP *EC_KEY_get0_group(const EC_KEY *key) { return key->group; }
214 
EC_KEY_set_group(EC_KEY * key,const EC_GROUP * group)215 int EC_KEY_set_group(EC_KEY *key, const EC_GROUP *group) {
216   // If |key| already has a group, it is an error to switch to another one.
217   if (key->group != NULL) {
218     if (EC_GROUP_cmp(key->group, group, NULL) != 0) {
219       OPENSSL_PUT_ERROR(EC, EC_R_GROUP_MISMATCH);
220       return 0;
221     }
222     return 1;
223   }
224 
225   assert(key->priv_key == NULL);
226   assert(key->pub_key == NULL);
227 
228   EC_GROUP_free(key->group);
229   key->group = EC_GROUP_dup(group);
230   return key->group != NULL;
231 }
232 
EC_KEY_get0_private_key(const EC_KEY * key)233 const BIGNUM *EC_KEY_get0_private_key(const EC_KEY *key) {
234   return key->priv_key != NULL ? &key->priv_key->bignum : NULL;
235 }
236 
EC_KEY_set_private_key(EC_KEY * key,const BIGNUM * priv_key)237 int EC_KEY_set_private_key(EC_KEY *key, const BIGNUM *priv_key) {
238   if (key->group == NULL) {
239     OPENSSL_PUT_ERROR(EC, EC_R_MISSING_PARAMETERS);
240     return 0;
241   }
242 
243   EC_WRAPPED_SCALAR *scalar = ec_wrapped_scalar_new(key->group);
244   if (scalar == NULL) {
245     return 0;
246   }
247   if (!ec_bignum_to_scalar(key->group, &scalar->scalar, priv_key) ||
248       ec_scalar_is_zero(key->group, &scalar->scalar)) {
249     OPENSSL_PUT_ERROR(EC, EC_R_INVALID_PRIVATE_KEY);
250     ec_wrapped_scalar_free(scalar);
251     return 0;
252   }
253   ec_wrapped_scalar_free(key->priv_key);
254   key->priv_key = scalar;
255   return 1;
256 }
257 
EC_KEY_get0_public_key(const EC_KEY * key)258 const EC_POINT *EC_KEY_get0_public_key(const EC_KEY *key) {
259   return key->pub_key;
260 }
261 
EC_KEY_set_public_key(EC_KEY * key,const EC_POINT * pub_key)262 int EC_KEY_set_public_key(EC_KEY *key, const EC_POINT *pub_key) {
263   if (key->group == NULL) {
264     OPENSSL_PUT_ERROR(EC, EC_R_MISSING_PARAMETERS);
265     return 0;
266   }
267 
268   if (pub_key != NULL && EC_GROUP_cmp(key->group, pub_key->group, NULL) != 0) {
269     OPENSSL_PUT_ERROR(EC, EC_R_GROUP_MISMATCH);
270     return 0;
271   }
272 
273   EC_POINT_free(key->pub_key);
274   key->pub_key = EC_POINT_dup(pub_key, key->group);
275   return (key->pub_key == NULL) ? 0 : 1;
276 }
277 
EC_KEY_get_enc_flags(const EC_KEY * key)278 unsigned int EC_KEY_get_enc_flags(const EC_KEY *key) { return key->enc_flag; }
279 
EC_KEY_set_enc_flags(EC_KEY * key,unsigned int flags)280 void EC_KEY_set_enc_flags(EC_KEY *key, unsigned int flags) {
281   key->enc_flag = flags;
282 }
283 
EC_KEY_get_conv_form(const EC_KEY * key)284 point_conversion_form_t EC_KEY_get_conv_form(const EC_KEY *key) {
285   return key->conv_form;
286 }
287 
EC_KEY_set_conv_form(EC_KEY * key,point_conversion_form_t cform)288 void EC_KEY_set_conv_form(EC_KEY *key, point_conversion_form_t cform) {
289   key->conv_form = cform;
290 }
291 
EC_KEY_check_key(const EC_KEY * eckey)292 int EC_KEY_check_key(const EC_KEY *eckey) {
293   if (!eckey || !eckey->group || !eckey->pub_key) {
294     OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
295     return 0;
296   }
297 
298   if (EC_POINT_is_at_infinity(eckey->group, eckey->pub_key)) {
299     OPENSSL_PUT_ERROR(EC, EC_R_POINT_AT_INFINITY);
300     return 0;
301   }
302 
303   // Test whether the public key is on the elliptic curve.
304   if (!EC_POINT_is_on_curve(eckey->group, eckey->pub_key, NULL)) {
305     OPENSSL_PUT_ERROR(EC, EC_R_POINT_IS_NOT_ON_CURVE);
306     return 0;
307   }
308 
309   // Check the public and private keys match.
310   //
311   // NOTE: this is a FIPS pair-wise consistency check for the ECDH case. See SP
312   // 800-56Ar3, page 36.
313   if (eckey->priv_key != NULL) {
314     EC_RAW_POINT point;
315     if (!ec_point_mul_scalar_base(eckey->group, &point,
316                                   &eckey->priv_key->scalar)) {
317       OPENSSL_PUT_ERROR(EC, ERR_R_EC_LIB);
318       return 0;
319     }
320     if (!ec_GFp_simple_points_equal(eckey->group, &point,
321                                     &eckey->pub_key->raw)) {
322       OPENSSL_PUT_ERROR(EC, EC_R_INVALID_PRIVATE_KEY);
323       return 0;
324     }
325   }
326 
327   return 1;
328 }
329 
EC_KEY_check_fips(const EC_KEY * key)330 int EC_KEY_check_fips(const EC_KEY *key) {
331   int ret = 0;
332   FIPS_service_indicator_lock_state();
333 
334   if (EC_KEY_is_opaque(key)) {
335     // Opaque keys can't be checked.
336     OPENSSL_PUT_ERROR(EC, EC_R_PUBLIC_KEY_VALIDATION_FAILED);
337     goto end;
338   }
339 
340   if (!EC_KEY_check_key(key)) {
341     goto end;
342   }
343 
344   if (key->priv_key) {
345     uint8_t data[16] = {0};
346     ECDSA_SIG *sig = ECDSA_do_sign(data, sizeof(data), key);
347     if (boringssl_fips_break_test("ECDSA_PWCT")) {
348       data[0] = ~data[0];
349     }
350     int ok = sig != NULL &&
351              ECDSA_do_verify(data, sizeof(data), sig, key);
352     ECDSA_SIG_free(sig);
353     if (!ok) {
354       OPENSSL_PUT_ERROR(EC, EC_R_PUBLIC_KEY_VALIDATION_FAILED);
355       goto end;
356     }
357   }
358 
359   ret = 1;
360 
361 end:
362   FIPS_service_indicator_unlock_state();
363   if (ret) {
364     EC_KEY_keygen_verify_service_indicator(key);
365   }
366 
367   return ret;
368 }
369 
EC_KEY_set_public_key_affine_coordinates(EC_KEY * key,const BIGNUM * x,const BIGNUM * y)370 int EC_KEY_set_public_key_affine_coordinates(EC_KEY *key, const BIGNUM *x,
371                                              const BIGNUM *y) {
372   EC_POINT *point = NULL;
373   int ok = 0;
374 
375   if (!key || !key->group || !x || !y) {
376     OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
377     return 0;
378   }
379 
380   point = EC_POINT_new(key->group);
381   if (point == NULL ||
382       !EC_POINT_set_affine_coordinates_GFp(key->group, point, x, y, NULL) ||
383       !EC_KEY_set_public_key(key, point) ||
384       !EC_KEY_check_key(key)) {
385     goto err;
386   }
387 
388   ok = 1;
389 
390 err:
391   EC_POINT_free(point);
392   return ok;
393 }
394 
EC_KEY_oct2key(EC_KEY * key,const uint8_t * in,size_t len,BN_CTX * ctx)395 int EC_KEY_oct2key(EC_KEY *key, const uint8_t *in, size_t len, BN_CTX *ctx) {
396   if (key->group == NULL) {
397     OPENSSL_PUT_ERROR(EC, EC_R_MISSING_PARAMETERS);
398     return 0;
399   }
400 
401   EC_POINT *point = EC_POINT_new(key->group);
402   int ok = point != NULL &&
403            EC_POINT_oct2point(key->group, point, in, len, ctx) &&
404            EC_KEY_set_public_key(key, point);
405   EC_POINT_free(point);
406   return ok;
407 }
408 
EC_KEY_key2buf(const EC_KEY * key,point_conversion_form_t form,uint8_t ** out_buf,BN_CTX * ctx)409 size_t EC_KEY_key2buf(const EC_KEY *key, point_conversion_form_t form,
410                       uint8_t **out_buf, BN_CTX *ctx) {
411   if (key == NULL || key->pub_key == NULL || key->group == NULL) {
412     OPENSSL_PUT_ERROR(EC, EC_R_MISSING_PARAMETERS);
413     return 0;
414   }
415 
416   return EC_POINT_point2buf(key->group, key->pub_key, form, out_buf, ctx);
417 }
418 
EC_KEY_oct2priv(EC_KEY * key,const uint8_t * in,size_t len)419 int EC_KEY_oct2priv(EC_KEY *key, const uint8_t *in, size_t len) {
420   if (key->group == NULL) {
421     OPENSSL_PUT_ERROR(EC, EC_R_MISSING_PARAMETERS);
422     return 0;
423   }
424 
425   if (len != BN_num_bytes(EC_GROUP_get0_order(key->group))) {
426     OPENSSL_PUT_ERROR(EC, EC_R_DECODE_ERROR);
427     return 0;
428   }
429 
430   BIGNUM *priv_key = BN_bin2bn(in, len, NULL);
431   int ok = priv_key != NULL &&  //
432            EC_KEY_set_private_key(key, priv_key);
433   BN_free(priv_key);
434   return ok;
435 }
436 
EC_KEY_priv2oct(const EC_KEY * key,uint8_t * out,size_t max_out)437 size_t EC_KEY_priv2oct(const EC_KEY *key, uint8_t *out, size_t max_out) {
438   if (key->group == NULL || key->priv_key == NULL) {
439     OPENSSL_PUT_ERROR(EC, EC_R_MISSING_PARAMETERS);
440     return 0;
441   }
442 
443   size_t len = BN_num_bytes(EC_GROUP_get0_order(key->group));
444   if (out == NULL) {
445     return len;
446   }
447 
448   if (max_out < len) {
449     OPENSSL_PUT_ERROR(EC, EC_R_BUFFER_TOO_SMALL);
450     return 0;
451   }
452 
453   size_t bytes_written;
454   ec_scalar_to_bytes(key->group, out, &bytes_written, &key->priv_key->scalar);
455   assert(bytes_written == len);
456   return len;
457 }
458 
EC_KEY_priv2buf(const EC_KEY * key,uint8_t ** out_buf)459 size_t EC_KEY_priv2buf(const EC_KEY *key, uint8_t **out_buf) {
460   *out_buf = NULL;
461   size_t len = EC_KEY_priv2oct(key, NULL, 0);
462   if (len == 0) {
463     return 0;
464   }
465 
466   uint8_t *buf = OPENSSL_malloc(len);
467   if (buf == NULL) {
468     return 0;
469   }
470 
471   len = EC_KEY_priv2oct(key, buf, len);
472   if (len == 0) {
473     OPENSSL_free(buf);
474     return 0;
475   }
476 
477   *out_buf = buf;
478   return len;
479 }
480 
EC_KEY_generate_key(EC_KEY * key)481 int EC_KEY_generate_key(EC_KEY *key) {
482   if (key == NULL || key->group == NULL) {
483     OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
484     return 0;
485   }
486 
487   // Check that the group order is FIPS compliant (FIPS 186-4 B.4.2).
488   if (BN_num_bits(EC_GROUP_get0_order(key->group)) < 160) {
489     OPENSSL_PUT_ERROR(EC, EC_R_INVALID_GROUP_ORDER);
490     return 0;
491   }
492 
493   static const uint8_t kDefaultAdditionalData[32] = {0};
494   EC_WRAPPED_SCALAR *priv_key = ec_wrapped_scalar_new(key->group);
495   EC_POINT *pub_key = EC_POINT_new(key->group);
496   if (priv_key == NULL || pub_key == NULL ||
497       // Generate the private key by testing candidates (FIPS 186-4 B.4.2).
498       !ec_random_nonzero_scalar(key->group, &priv_key->scalar,
499                                 kDefaultAdditionalData) ||
500       !ec_point_mul_scalar_base(key->group, &pub_key->raw, &priv_key->scalar)) {
501     EC_POINT_free(pub_key);
502     ec_wrapped_scalar_free(priv_key);
503     return 0;
504   }
505 
506   ec_wrapped_scalar_free(key->priv_key);
507   key->priv_key = priv_key;
508   EC_POINT_free(key->pub_key);
509   key->pub_key = pub_key;
510   return 1;
511 }
512 
EC_KEY_generate_key_fips(EC_KEY * eckey)513 int EC_KEY_generate_key_fips(EC_KEY *eckey) {
514   boringssl_ensure_ecc_self_test();
515 
516   if (EC_KEY_generate_key(eckey) && EC_KEY_check_fips(eckey)) {
517     return 1;
518   }
519 
520   EC_POINT_free(eckey->pub_key);
521   ec_wrapped_scalar_free(eckey->priv_key);
522   eckey->pub_key = NULL;
523   eckey->priv_key = NULL;
524   return 0;
525 }
526 
EC_KEY_get_ex_new_index(long argl,void * argp,CRYPTO_EX_unused * unused,CRYPTO_EX_dup * dup_unused,CRYPTO_EX_free * free_func)527 int EC_KEY_get_ex_new_index(long argl, void *argp, CRYPTO_EX_unused *unused,
528                             CRYPTO_EX_dup *dup_unused,
529                             CRYPTO_EX_free *free_func) {
530   int index;
531   if (!CRYPTO_get_ex_new_index(g_ec_ex_data_class_bss_get(), &index, argl, argp,
532                                free_func)) {
533     return -1;
534   }
535   return index;
536 }
537 
EC_KEY_set_ex_data(EC_KEY * d,int idx,void * arg)538 int EC_KEY_set_ex_data(EC_KEY *d, int idx, void *arg) {
539   return CRYPTO_set_ex_data(&d->ex_data, idx, arg);
540 }
541 
EC_KEY_get_ex_data(const EC_KEY * d,int idx)542 void *EC_KEY_get_ex_data(const EC_KEY *d, int idx) {
543   return CRYPTO_get_ex_data(&d->ex_data, idx);
544 }
545 
EC_KEY_set_asn1_flag(EC_KEY * key,int flag)546 void EC_KEY_set_asn1_flag(EC_KEY *key, int flag) {}
547