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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 
DEFINE_STATIC_EX_DATA_CLASS(g_ec_ex_data_class)85 DEFINE_STATIC_EX_DATA_CLASS(g_ec_ex_data_class)
86 
87 static EC_WRAPPED_SCALAR *ec_wrapped_scalar_new(const EC_GROUP *group) {
88   EC_WRAPPED_SCALAR *wrapped = OPENSSL_malloc(sizeof(EC_WRAPPED_SCALAR));
89   if (wrapped == NULL) {
90     OPENSSL_PUT_ERROR(EC, ERR_R_MALLOC_FAILURE);
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     OPENSSL_PUT_ERROR(EC, ERR_R_MALLOC_FAILURE);
112     return NULL;
113   }
114 
115   OPENSSL_memset(ret, 0, sizeof(EC_KEY));
116 
117   if (engine) {
118     ret->ecdsa_meth = ENGINE_get_ECDSA_method(engine);
119   }
120   if (ret->ecdsa_meth) {
121     METHOD_ref(ret->ecdsa_meth);
122   }
123 
124   ret->conv_form = POINT_CONVERSION_UNCOMPRESSED;
125   ret->references = 1;
126 
127   CRYPTO_new_ex_data(&ret->ex_data);
128 
129   if (ret->ecdsa_meth && ret->ecdsa_meth->init && !ret->ecdsa_meth->init(ret)) {
130     CRYPTO_free_ex_data(g_ec_ex_data_class_bss_get(), ret, &ret->ex_data);
131     if (ret->ecdsa_meth) {
132       METHOD_unref(ret->ecdsa_meth);
133     }
134     OPENSSL_free(ret);
135     return NULL;
136   }
137 
138   return ret;
139 }
140 
EC_KEY_new_by_curve_name(int nid)141 EC_KEY *EC_KEY_new_by_curve_name(int nid) {
142   EC_KEY *ret = EC_KEY_new();
143   if (ret == NULL) {
144     OPENSSL_PUT_ERROR(EC, ERR_R_MALLOC_FAILURE);
145     return NULL;
146   }
147   ret->group = EC_GROUP_new_by_curve_name(nid);
148   if (ret->group == NULL) {
149     EC_KEY_free(ret);
150     return NULL;
151   }
152   return ret;
153 }
154 
EC_KEY_free(EC_KEY * r)155 void EC_KEY_free(EC_KEY *r) {
156   if (r == NULL) {
157     return;
158   }
159 
160   if (!CRYPTO_refcount_dec_and_test_zero(&r->references)) {
161     return;
162   }
163 
164   if (r->ecdsa_meth) {
165     if (r->ecdsa_meth->finish) {
166       r->ecdsa_meth->finish(r);
167     }
168     METHOD_unref(r->ecdsa_meth);
169   }
170 
171   EC_GROUP_free(r->group);
172   EC_POINT_free(r->pub_key);
173   ec_wrapped_scalar_free(r->priv_key);
174 
175   CRYPTO_free_ex_data(g_ec_ex_data_class_bss_get(), r, &r->ex_data);
176 
177   OPENSSL_free(r);
178 }
179 
EC_KEY_dup(const EC_KEY * src)180 EC_KEY *EC_KEY_dup(const EC_KEY *src) {
181   if (src == NULL) {
182     OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
183     return NULL;
184   }
185 
186   EC_KEY *ret = EC_KEY_new();
187   if (ret == NULL) {
188     return NULL;
189   }
190 
191   if ((src->group != NULL &&
192        !EC_KEY_set_group(ret, src->group)) ||
193       (src->pub_key != NULL &&
194        !EC_KEY_set_public_key(ret, src->pub_key)) ||
195       (src->priv_key != NULL &&
196        !EC_KEY_set_private_key(ret, EC_KEY_get0_private_key(src)))) {
197     EC_KEY_free(ret);
198     return NULL;
199   }
200 
201   ret->enc_flag = src->enc_flag;
202   ret->conv_form = src->conv_form;
203   return ret;
204 }
205 
EC_KEY_up_ref(EC_KEY * r)206 int EC_KEY_up_ref(EC_KEY *r) {
207   CRYPTO_refcount_inc(&r->references);
208   return 1;
209 }
210 
EC_KEY_is_opaque(const EC_KEY * key)211 int EC_KEY_is_opaque(const EC_KEY *key) {
212   return key->ecdsa_meth && (key->ecdsa_meth->flags & ECDSA_FLAG_OPAQUE);
213 }
214 
EC_KEY_get0_group(const EC_KEY * key)215 const EC_GROUP *EC_KEY_get0_group(const EC_KEY *key) { return key->group; }
216 
EC_KEY_set_group(EC_KEY * key,const EC_GROUP * group)217 int EC_KEY_set_group(EC_KEY *key, const EC_GROUP *group) {
218   // If |key| already has a group, it is an error to switch to another one.
219   if (key->group != NULL) {
220     if (EC_GROUP_cmp(key->group, group, NULL) != 0) {
221       OPENSSL_PUT_ERROR(EC, EC_R_GROUP_MISMATCH);
222       return 0;
223     }
224     return 1;
225   }
226 
227   assert(key->priv_key == NULL);
228   assert(key->pub_key == NULL);
229 
230   EC_GROUP_free(key->group);
231   key->group = EC_GROUP_dup(group);
232   return key->group != NULL;
233 }
234 
EC_KEY_get0_private_key(const EC_KEY * key)235 const BIGNUM *EC_KEY_get0_private_key(const EC_KEY *key) {
236   return key->priv_key != NULL ? &key->priv_key->bignum : NULL;
237 }
238 
EC_KEY_set_private_key(EC_KEY * key,const BIGNUM * priv_key)239 int EC_KEY_set_private_key(EC_KEY *key, const BIGNUM *priv_key) {
240   if (key->group == NULL) {
241     OPENSSL_PUT_ERROR(EC, EC_R_MISSING_PARAMETERS);
242     return 0;
243   }
244 
245   EC_WRAPPED_SCALAR *scalar = ec_wrapped_scalar_new(key->group);
246   if (scalar == NULL) {
247     return 0;
248   }
249   if (!ec_bignum_to_scalar(key->group, &scalar->scalar, priv_key)) {
250     OPENSSL_PUT_ERROR(EC, EC_R_WRONG_ORDER);
251     ec_wrapped_scalar_free(scalar);
252     return 0;
253   }
254   ec_wrapped_scalar_free(key->priv_key);
255   key->priv_key = scalar;
256   return 1;
257 }
258 
EC_KEY_get0_public_key(const EC_KEY * key)259 const EC_POINT *EC_KEY_get0_public_key(const EC_KEY *key) {
260   return key->pub_key;
261 }
262 
EC_KEY_set_public_key(EC_KEY * key,const EC_POINT * pub_key)263 int EC_KEY_set_public_key(EC_KEY *key, const EC_POINT *pub_key) {
264   if (key->group == NULL) {
265     OPENSSL_PUT_ERROR(EC, EC_R_MISSING_PARAMETERS);
266     return 0;
267   }
268 
269   if (pub_key != NULL && EC_GROUP_cmp(key->group, pub_key->group, NULL) != 0) {
270     OPENSSL_PUT_ERROR(EC, EC_R_GROUP_MISMATCH);
271     return 0;
272   }
273 
274   EC_POINT_free(key->pub_key);
275   key->pub_key = EC_POINT_dup(pub_key, key->group);
276   return (key->pub_key == NULL) ? 0 : 1;
277 }
278 
EC_KEY_get_enc_flags(const EC_KEY * key)279 unsigned int EC_KEY_get_enc_flags(const EC_KEY *key) { return key->enc_flag; }
280 
EC_KEY_set_enc_flags(EC_KEY * key,unsigned int flags)281 void EC_KEY_set_enc_flags(EC_KEY *key, unsigned int flags) {
282   key->enc_flag = flags;
283 }
284 
EC_KEY_get_conv_form(const EC_KEY * key)285 point_conversion_form_t EC_KEY_get_conv_form(const EC_KEY *key) {
286   return key->conv_form;
287 }
288 
EC_KEY_set_conv_form(EC_KEY * key,point_conversion_form_t cform)289 void EC_KEY_set_conv_form(EC_KEY *key, point_conversion_form_t cform) {
290   key->conv_form = cform;
291 }
292 
EC_KEY_check_key(const EC_KEY * eckey)293 int EC_KEY_check_key(const EC_KEY *eckey) {
294   if (!eckey || !eckey->group || !eckey->pub_key) {
295     OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
296     return 0;
297   }
298 
299   if (EC_POINT_is_at_infinity(eckey->group, eckey->pub_key)) {
300     OPENSSL_PUT_ERROR(EC, EC_R_POINT_AT_INFINITY);
301     return 0;
302   }
303 
304   // Test whether the public key is on the elliptic curve.
305   if (!EC_POINT_is_on_curve(eckey->group, eckey->pub_key, NULL)) {
306     OPENSSL_PUT_ERROR(EC, EC_R_POINT_IS_NOT_ON_CURVE);
307     return 0;
308   }
309 
310   // Check the public and private keys match.
311   if (eckey->priv_key != NULL) {
312     EC_RAW_POINT point;
313     if (!ec_point_mul_scalar_base(eckey->group, &point,
314                                   &eckey->priv_key->scalar)) {
315       OPENSSL_PUT_ERROR(EC, ERR_R_EC_LIB);
316       return 0;
317     }
318     if (!ec_GFp_simple_points_equal(eckey->group, &point,
319                                     &eckey->pub_key->raw)) {
320       OPENSSL_PUT_ERROR(EC, EC_R_INVALID_PRIVATE_KEY);
321       return 0;
322     }
323   }
324 
325   return 1;
326 }
327 
EC_KEY_check_fips(const EC_KEY * key)328 int EC_KEY_check_fips(const EC_KEY *key) {
329   if (EC_KEY_is_opaque(key)) {
330     // Opaque keys can't be checked.
331     OPENSSL_PUT_ERROR(EC, EC_R_PUBLIC_KEY_VALIDATION_FAILED);
332     return 0;
333   }
334 
335   if (!EC_KEY_check_key(key)) {
336     return 0;
337   }
338 
339   if (key->priv_key) {
340     uint8_t data[16] = {0};
341     ECDSA_SIG *sig = ECDSA_do_sign(data, sizeof(data), key);
342 #if defined(BORINGSSL_FIPS_BREAK_ECDSA_PWCT)
343     data[0] = ~data[0];
344 #endif
345     int ok = sig != NULL &&
346              ECDSA_do_verify(data, sizeof(data), sig, key);
347     ECDSA_SIG_free(sig);
348     if (!ok) {
349       OPENSSL_PUT_ERROR(EC, EC_R_PUBLIC_KEY_VALIDATION_FAILED);
350       return 0;
351     }
352   }
353 
354   return 1;
355 }
356 
EC_KEY_set_public_key_affine_coordinates(EC_KEY * key,const BIGNUM * x,const BIGNUM * y)357 int EC_KEY_set_public_key_affine_coordinates(EC_KEY *key, const BIGNUM *x,
358                                              const BIGNUM *y) {
359   EC_POINT *point = NULL;
360   int ok = 0;
361 
362   if (!key || !key->group || !x || !y) {
363     OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
364     return 0;
365   }
366 
367   point = EC_POINT_new(key->group);
368   if (point == NULL ||
369       !EC_POINT_set_affine_coordinates_GFp(key->group, point, x, y, NULL) ||
370       !EC_KEY_set_public_key(key, point) ||
371       !EC_KEY_check_key(key)) {
372     goto err;
373   }
374 
375   ok = 1;
376 
377 err:
378   EC_POINT_free(point);
379   return ok;
380 }
381 
EC_KEY_key2buf(const EC_KEY * key,point_conversion_form_t form,unsigned char ** out_buf,BN_CTX * ctx)382 size_t EC_KEY_key2buf(const EC_KEY *key, point_conversion_form_t form,
383                       unsigned char **out_buf, BN_CTX *ctx) {
384   if (key == NULL || key->pub_key == NULL || key->group == NULL) {
385     return 0;
386   }
387 
388   const size_t len =
389       EC_POINT_point2oct(key->group, key->pub_key, form, NULL, 0, ctx);
390   if (len == 0) {
391     return 0;
392   }
393 
394   uint8_t *buf = OPENSSL_malloc(len);
395   if (buf == NULL) {
396     return 0;
397   }
398 
399   if (EC_POINT_point2oct(key->group, key->pub_key, form, buf, len, ctx) !=
400       len) {
401     OPENSSL_free(buf);
402     return 0;
403   }
404 
405   *out_buf = buf;
406   return len;
407 }
408 
EC_KEY_generate_key(EC_KEY * key)409 int EC_KEY_generate_key(EC_KEY *key) {
410   if (key == NULL || key->group == NULL) {
411     OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
412     return 0;
413   }
414 
415   // Check that the group order is FIPS compliant (FIPS 186-4 B.4.2).
416   if (BN_num_bits(EC_GROUP_get0_order(key->group)) < 160) {
417     OPENSSL_PUT_ERROR(EC, EC_R_INVALID_GROUP_ORDER);
418     return 0;
419   }
420 
421   static const uint8_t kDefaultAdditionalData[32] = {0};
422   EC_WRAPPED_SCALAR *priv_key = ec_wrapped_scalar_new(key->group);
423   EC_POINT *pub_key = EC_POINT_new(key->group);
424   if (priv_key == NULL || pub_key == NULL ||
425       // Generate the private key by testing candidates (FIPS 186-4 B.4.2).
426       !ec_random_nonzero_scalar(key->group, &priv_key->scalar,
427                                 kDefaultAdditionalData) ||
428       !ec_point_mul_scalar_base(key->group, &pub_key->raw, &priv_key->scalar)) {
429     EC_POINT_free(pub_key);
430     ec_wrapped_scalar_free(priv_key);
431     return 0;
432   }
433 
434   ec_wrapped_scalar_free(key->priv_key);
435   key->priv_key = priv_key;
436   EC_POINT_free(key->pub_key);
437   key->pub_key = pub_key;
438   return 1;
439 }
440 
EC_KEY_generate_key_fips(EC_KEY * eckey)441 int EC_KEY_generate_key_fips(EC_KEY *eckey) {
442   if (EC_KEY_generate_key(eckey) && EC_KEY_check_fips(eckey)) {
443     return 1;
444   }
445 
446   EC_POINT_free(eckey->pub_key);
447   ec_wrapped_scalar_free(eckey->priv_key);
448   eckey->pub_key = NULL;
449   eckey->priv_key = NULL;
450   return 0;
451 }
452 
EC_KEY_get_ex_new_index(long argl,void * argp,CRYPTO_EX_unused * unused,CRYPTO_EX_dup * dup_unused,CRYPTO_EX_free * free_func)453 int EC_KEY_get_ex_new_index(long argl, void *argp, CRYPTO_EX_unused *unused,
454                             CRYPTO_EX_dup *dup_unused,
455                             CRYPTO_EX_free *free_func) {
456   int index;
457   if (!CRYPTO_get_ex_new_index(g_ec_ex_data_class_bss_get(), &index, argl, argp,
458                                free_func)) {
459     return -1;
460   }
461   return index;
462 }
463 
EC_KEY_set_ex_data(EC_KEY * d,int idx,void * arg)464 int EC_KEY_set_ex_data(EC_KEY *d, int idx, void *arg) {
465   return CRYPTO_set_ex_data(&d->ex_data, idx, arg);
466 }
467 
EC_KEY_get_ex_data(const EC_KEY * d,int idx)468 void *EC_KEY_get_ex_data(const EC_KEY *d, int idx) {
469   return CRYPTO_get_ex_data(&d->ex_data, idx);
470 }
471 
EC_KEY_set_asn1_flag(EC_KEY * key,int flag)472 void EC_KEY_set_asn1_flag(EC_KEY *key, int flag) {}
473