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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   BN_free(r->fixed_k);
175 
176   CRYPTO_free_ex_data(g_ec_ex_data_class_bss_get(), r, &r->ex_data);
177 
178   OPENSSL_free(r);
179 }
180 
EC_KEY_dup(const EC_KEY * src)181 EC_KEY *EC_KEY_dup(const EC_KEY *src) {
182   if (src == NULL) {
183     OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
184     return NULL;
185   }
186 
187   EC_KEY *ret = EC_KEY_new();
188   if (ret == NULL) {
189     return NULL;
190   }
191 
192   if ((src->group != NULL &&
193        !EC_KEY_set_group(ret, src->group)) ||
194       (src->pub_key != NULL &&
195        !EC_KEY_set_public_key(ret, src->pub_key)) ||
196       (src->priv_key != NULL &&
197        !EC_KEY_set_private_key(ret, EC_KEY_get0_private_key(src)))) {
198     EC_KEY_free(ret);
199     return NULL;
200   }
201 
202   ret->enc_flag = src->enc_flag;
203   ret->conv_form = src->conv_form;
204   return ret;
205 }
206 
EC_KEY_up_ref(EC_KEY * r)207 int EC_KEY_up_ref(EC_KEY *r) {
208   CRYPTO_refcount_inc(&r->references);
209   return 1;
210 }
211 
EC_KEY_is_opaque(const EC_KEY * key)212 int EC_KEY_is_opaque(const EC_KEY *key) {
213   return key->ecdsa_meth && (key->ecdsa_meth->flags & ECDSA_FLAG_OPAQUE);
214 }
215 
EC_KEY_get0_group(const EC_KEY * key)216 const EC_GROUP *EC_KEY_get0_group(const EC_KEY *key) { return key->group; }
217 
EC_KEY_set_group(EC_KEY * key,const EC_GROUP * group)218 int EC_KEY_set_group(EC_KEY *key, const EC_GROUP *group) {
219   // If |key| already has a group, it is an error to switch to another one.
220   if (key->group != NULL) {
221     if (EC_GROUP_cmp(key->group, group, NULL) != 0) {
222       OPENSSL_PUT_ERROR(EC, EC_R_GROUP_MISMATCH);
223       return 0;
224     }
225     return 1;
226   }
227 
228   assert(key->priv_key == NULL);
229   assert(key->pub_key == NULL);
230 
231   EC_GROUP_free(key->group);
232   key->group = EC_GROUP_dup(group);
233   return key->group != NULL;
234 }
235 
EC_KEY_get0_private_key(const EC_KEY * key)236 const BIGNUM *EC_KEY_get0_private_key(const EC_KEY *key) {
237   return key->priv_key != NULL ? &key->priv_key->bignum : NULL;
238 }
239 
EC_KEY_set_private_key(EC_KEY * key,const BIGNUM * priv_key)240 int EC_KEY_set_private_key(EC_KEY *key, const BIGNUM *priv_key) {
241   if (key->group == NULL) {
242     OPENSSL_PUT_ERROR(EC, EC_R_MISSING_PARAMETERS);
243     return 0;
244   }
245 
246   EC_WRAPPED_SCALAR *scalar = ec_wrapped_scalar_new(key->group);
247   if (scalar == NULL) {
248     return 0;
249   }
250   if (!ec_bignum_to_scalar(key->group, &scalar->scalar, priv_key)) {
251     OPENSSL_PUT_ERROR(EC, EC_R_WRONG_ORDER);
252     ec_wrapped_scalar_free(scalar);
253     return 0;
254   }
255   ec_wrapped_scalar_free(key->priv_key);
256   key->priv_key = scalar;
257   return 1;
258 }
259 
EC_KEY_get0_public_key(const EC_KEY * key)260 const EC_POINT *EC_KEY_get0_public_key(const EC_KEY *key) {
261   return key->pub_key;
262 }
263 
EC_KEY_set_public_key(EC_KEY * key,const EC_POINT * pub_key)264 int EC_KEY_set_public_key(EC_KEY *key, const EC_POINT *pub_key) {
265   if (key->group == NULL) {
266     OPENSSL_PUT_ERROR(EC, EC_R_MISSING_PARAMETERS);
267     return 0;
268   }
269 
270   if (pub_key != NULL && EC_GROUP_cmp(key->group, pub_key->group, NULL) != 0) {
271     OPENSSL_PUT_ERROR(EC, EC_R_GROUP_MISMATCH);
272     return 0;
273   }
274 
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   if (eckey->priv_key != NULL) {
323     point = EC_POINT_new(eckey->group);
324     if (point == NULL ||
325         !ec_point_mul_scalar(eckey->group, &point->raw,
326                              &eckey->priv_key->scalar, NULL, NULL)) {
327       OPENSSL_PUT_ERROR(EC, ERR_R_EC_LIB);
328       goto err;
329     }
330     if (EC_POINT_cmp(eckey->group, point, eckey->pub_key, ctx) != 0) {
331       OPENSSL_PUT_ERROR(EC, EC_R_INVALID_PRIVATE_KEY);
332       goto err;
333     }
334   }
335   ok = 1;
336 
337 err:
338   BN_CTX_free(ctx);
339   EC_POINT_free(point);
340   return ok;
341 }
342 
EC_KEY_check_fips(const EC_KEY * key)343 int EC_KEY_check_fips(const EC_KEY *key) {
344   if (EC_KEY_is_opaque(key)) {
345     // Opaque keys can't be checked.
346     OPENSSL_PUT_ERROR(EC, EC_R_PUBLIC_KEY_VALIDATION_FAILED);
347     return 0;
348   }
349 
350   if (!EC_KEY_check_key(key)) {
351     return 0;
352   }
353 
354   if (key->priv_key) {
355     uint8_t data[16] = {0};
356     ECDSA_SIG *sig = ECDSA_do_sign(data, sizeof(data), key);
357 #if defined(BORINGSSL_FIPS_BREAK_ECDSA_PWCT)
358     data[0] = ~data[0];
359 #endif
360     int ok = sig != NULL &&
361              ECDSA_do_verify(data, sizeof(data), sig, key);
362     ECDSA_SIG_free(sig);
363     if (!ok) {
364       OPENSSL_PUT_ERROR(EC, EC_R_PUBLIC_KEY_VALIDATION_FAILED);
365       return 0;
366     }
367   }
368 
369   return 1;
370 }
371 
EC_KEY_set_public_key_affine_coordinates(EC_KEY * key,BIGNUM * x,BIGNUM * y)372 int EC_KEY_set_public_key_affine_coordinates(EC_KEY *key, BIGNUM *x,
373                                              BIGNUM *y) {
374   EC_POINT *point = NULL;
375   int ok = 0;
376 
377   if (!key || !key->group || !x || !y) {
378     OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
379     return 0;
380   }
381 
382   point = EC_POINT_new(key->group);
383   if (point == NULL ||
384       !EC_POINT_set_affine_coordinates_GFp(key->group, point, x, y, NULL) ||
385       !EC_KEY_set_public_key(key, point) ||
386       !EC_KEY_check_key(key)) {
387     goto err;
388   }
389 
390   ok = 1;
391 
392 err:
393   EC_POINT_free(point);
394   return ok;
395 }
396 
EC_KEY_key2buf(EC_KEY * key,point_conversion_form_t form,unsigned char ** out_buf,BN_CTX * ctx)397 size_t EC_KEY_key2buf(EC_KEY *key, point_conversion_form_t form,
398                       unsigned char **out_buf, BN_CTX *ctx) {
399   if (key == NULL || key->pub_key == NULL || key->group == NULL) {
400     return 0;
401   }
402 
403   const size_t len =
404       EC_POINT_point2oct(key->group, key->pub_key, form, NULL, 0, ctx);
405   if (len == 0) {
406     return 0;
407   }
408 
409   uint8_t *buf = OPENSSL_malloc(len);
410   if (buf == NULL) {
411     return 0;
412   }
413 
414   if (EC_POINT_point2oct(key->group, key->pub_key, form, buf, len, ctx) !=
415       len) {
416     OPENSSL_free(buf);
417     return 0;
418   }
419 
420   *out_buf = buf;
421   return len;
422 }
423 
EC_KEY_generate_key(EC_KEY * key)424 int EC_KEY_generate_key(EC_KEY *key) {
425   if (key == NULL || key->group == NULL) {
426     OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
427     return 0;
428   }
429 
430   // Check that the group order is FIPS compliant (FIPS 186-4 B.4.2).
431   if (BN_num_bits(EC_GROUP_get0_order(key->group)) < 160) {
432     OPENSSL_PUT_ERROR(EC, EC_R_INVALID_GROUP_ORDER);
433     return 0;
434   }
435 
436   static const uint8_t kDefaultAdditionalData[32] = {0};
437   EC_WRAPPED_SCALAR *priv_key = ec_wrapped_scalar_new(key->group);
438   EC_POINT *pub_key = EC_POINT_new(key->group);
439   if (priv_key == NULL || pub_key == NULL ||
440       // Generate the private key by testing candidates (FIPS 186-4 B.4.2).
441       !ec_random_nonzero_scalar(key->group, &priv_key->scalar,
442                                 kDefaultAdditionalData) ||
443       !ec_point_mul_scalar(key->group, &pub_key->raw, &priv_key->scalar, NULL,
444                            NULL)) {
445     EC_POINT_free(pub_key);
446     ec_wrapped_scalar_free(priv_key);
447     return 0;
448   }
449 
450   ec_wrapped_scalar_free(key->priv_key);
451   key->priv_key = priv_key;
452   EC_POINT_free(key->pub_key);
453   key->pub_key = pub_key;
454   return 1;
455 }
456 
EC_KEY_generate_key_fips(EC_KEY * eckey)457 int EC_KEY_generate_key_fips(EC_KEY *eckey) {
458   return EC_KEY_generate_key(eckey) && EC_KEY_check_fips(eckey);
459 }
460 
EC_KEY_get_ex_new_index(long argl,void * argp,CRYPTO_EX_unused * unused,CRYPTO_EX_dup * dup_unused,CRYPTO_EX_free * free_func)461 int EC_KEY_get_ex_new_index(long argl, void *argp, CRYPTO_EX_unused *unused,
462                             CRYPTO_EX_dup *dup_unused,
463                             CRYPTO_EX_free *free_func) {
464   int index;
465   if (!CRYPTO_get_ex_new_index(g_ec_ex_data_class_bss_get(), &index, argl, argp,
466                                free_func)) {
467     return -1;
468   }
469   return index;
470 }
471 
EC_KEY_set_ex_data(EC_KEY * d,int idx,void * arg)472 int EC_KEY_set_ex_data(EC_KEY *d, int idx, void *arg) {
473   return CRYPTO_set_ex_data(&d->ex_data, idx, arg);
474 }
475 
EC_KEY_get_ex_data(const EC_KEY * d,int idx)476 void *EC_KEY_get_ex_data(const EC_KEY *d, int idx) {
477   return CRYPTO_get_ex_data(&d->ex_data, idx);
478 }
479 
EC_KEY_set_asn1_flag(EC_KEY * key,int flag)480 void EC_KEY_set_asn1_flag(EC_KEY *key, int flag) {}
481