1 /* Written by Nils Larsch for the OpenSSL project. */
2 /* ====================================================================
3  * Copyright (c) 2000-2003 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  *    licensing@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 #include <openssl/ec.h>
55 
56 #include <string.h>
57 
58 #include <openssl/asn1.h>
59 #include <openssl/asn1t.h>
60 #include <openssl/bn.h>
61 #include <openssl/err.h>
62 #include <openssl/mem.h>
63 #include <openssl/obj.h>
64 
65 #include "internal.h"
66 
67 
68 typedef struct x9_62_fieldid_st {
69   ASN1_OBJECT *fieldType;
70   union {
71     char *ptr;
72     /* NID_X9_62_prime_field */
73     ASN1_INTEGER *prime;
74     /* anything else */
75     ASN1_TYPE *other;
76   } p;
77 } X9_62_FIELDID;
78 
79 ASN1_ADB_TEMPLATE(fieldID_def) = ASN1_SIMPLE(X9_62_FIELDID, p.other, ASN1_ANY);
80 
81 ASN1_ADB(X9_62_FIELDID) = {
82   ADB_ENTRY(NID_X9_62_prime_field, ASN1_SIMPLE(X9_62_FIELDID, p.prime, ASN1_INTEGER)),
83 } ASN1_ADB_END(X9_62_FIELDID, 0, fieldType, 0, &fieldID_def_tt, NULL);
84 
85 ASN1_SEQUENCE(X9_62_FIELDID) = {
86   ASN1_SIMPLE(X9_62_FIELDID, fieldType, ASN1_OBJECT),
87   ASN1_ADB_OBJECT(X9_62_FIELDID)
88 } ASN1_SEQUENCE_END(X9_62_FIELDID);
89 
90 typedef struct x9_62_curve_st {
91   ASN1_OCTET_STRING *a;
92   ASN1_OCTET_STRING *b;
93   ASN1_BIT_STRING *seed;
94 } X9_62_CURVE;
95 
96 ASN1_SEQUENCE(X9_62_CURVE) = {
97   ASN1_SIMPLE(X9_62_CURVE, a, ASN1_OCTET_STRING),
98   ASN1_SIMPLE(X9_62_CURVE, b, ASN1_OCTET_STRING),
99   ASN1_OPT(X9_62_CURVE, seed, ASN1_BIT_STRING)
100 } ASN1_SEQUENCE_END(X9_62_CURVE);
101 
102 typedef struct ec_parameters_st {
103   long version;
104   X9_62_FIELDID *fieldID;
105   X9_62_CURVE *curve;
106   ASN1_OCTET_STRING *base;
107   ASN1_INTEGER *order;
108   ASN1_INTEGER *cofactor;
109 } ECPARAMETERS;
110 
111 DECLARE_ASN1_ALLOC_FUNCTIONS(ECPARAMETERS);
112 
113 ASN1_SEQUENCE(ECPARAMETERS) = {
114     ASN1_SIMPLE(ECPARAMETERS, version, LONG),
115     ASN1_SIMPLE(ECPARAMETERS, fieldID, X9_62_FIELDID),
116     ASN1_SIMPLE(ECPARAMETERS, curve, X9_62_CURVE),
117     ASN1_SIMPLE(ECPARAMETERS, base, ASN1_OCTET_STRING),
118     ASN1_SIMPLE(ECPARAMETERS, order, ASN1_INTEGER),
119     ASN1_OPT(ECPARAMETERS, cofactor, ASN1_INTEGER)
120 } ASN1_SEQUENCE_END(ECPARAMETERS);
121 
122 IMPLEMENT_ASN1_ALLOC_FUNCTIONS(ECPARAMETERS);
123 
124 typedef struct ecpk_parameters_st {
125   int type;
126   union {
127     ASN1_OBJECT *named_curve;
128     ECPARAMETERS *parameters;
129   } value;
130 } ECPKPARAMETERS;
131 
132 /* SEC1 ECPrivateKey */
133 typedef struct ec_privatekey_st {
134   long version;
135   ASN1_OCTET_STRING *privateKey;
136   ECPKPARAMETERS *parameters;
137   ASN1_BIT_STRING *publicKey;
138 } EC_PRIVATEKEY;
139 
140 DECLARE_ASN1_FUNCTIONS_const(ECPKPARAMETERS);
141 DECLARE_ASN1_ENCODE_FUNCTIONS_const(ECPKPARAMETERS, ECPKPARAMETERS);
142 
143 ASN1_CHOICE(ECPKPARAMETERS) = {
144     ASN1_SIMPLE(ECPKPARAMETERS, value.named_curve, ASN1_OBJECT),
145     ASN1_SIMPLE(ECPKPARAMETERS, value.parameters, ECPARAMETERS),
146 } ASN1_CHOICE_END(ECPKPARAMETERS);
147 
148 IMPLEMENT_ASN1_FUNCTIONS_const(ECPKPARAMETERS);
149 
150 DECLARE_ASN1_FUNCTIONS_const(EC_PRIVATEKEY);
151 DECLARE_ASN1_ENCODE_FUNCTIONS_const(EC_PRIVATEKEY, EC_PRIVATEKEY);
152 
153 ASN1_SEQUENCE(EC_PRIVATEKEY) = {
154     ASN1_SIMPLE(EC_PRIVATEKEY, version, LONG),
155     ASN1_SIMPLE(EC_PRIVATEKEY, privateKey, ASN1_OCTET_STRING),
156     ASN1_EXP_OPT(EC_PRIVATEKEY, parameters, ECPKPARAMETERS, 0),
157     ASN1_EXP_OPT(EC_PRIVATEKEY, publicKey, ASN1_BIT_STRING, 1),
158 } ASN1_SEQUENCE_END(EC_PRIVATEKEY);
159 
160 IMPLEMENT_ASN1_FUNCTIONS_const(EC_PRIVATEKEY);
161 
162 
ec_asn1_group2pkparameters(const EC_GROUP * group,ECPKPARAMETERS * params)163 ECPKPARAMETERS *ec_asn1_group2pkparameters(const EC_GROUP *group,
164                                            ECPKPARAMETERS *params) {
165   int ok = 0, nid;
166   ECPKPARAMETERS *ret = params;
167 
168   if (ret == NULL) {
169     ret = ECPKPARAMETERS_new();
170     if (ret == NULL) {
171       OPENSSL_PUT_ERROR(EC, ec_asn1_group2pkparameters, ERR_R_MALLOC_FAILURE);
172       return NULL;
173     }
174   } else {
175     ASN1_OBJECT_free(ret->value.named_curve);
176   }
177 
178   /* use the ASN.1 OID to describe the the elliptic curve parameters. */
179   nid = EC_GROUP_get_curve_name(group);
180   if (nid) {
181     ret->type = 0;
182     ret->value.named_curve = (ASN1_OBJECT*) OBJ_nid2obj(nid);
183     ok = ret->value.named_curve != NULL;
184   }
185 
186   if (!ok) {
187     ECPKPARAMETERS_free(ret);
188     return NULL;
189   }
190 
191   return ret;
192 }
193 
ec_asn1_pkparameters2group(const ECPKPARAMETERS * params)194 EC_GROUP *ec_asn1_pkparameters2group(const ECPKPARAMETERS *params) {
195   EC_GROUP *ret = NULL;
196   int nid = NID_undef;
197 
198   if (params == NULL) {
199     OPENSSL_PUT_ERROR(EC, ec_asn1_pkparameters2group, EC_R_MISSING_PARAMETERS);
200     return NULL;
201   }
202 
203   if (params->type == 0) {
204     nid = OBJ_obj2nid(params->value.named_curve);
205   } else if (params->type == 1) {
206     /* We don't support arbitary curves so we attempt to recognise it from the
207      * group order. */
208     const ECPARAMETERS *ecparams = params->value.parameters;
209     unsigned i;
210     const struct built_in_curve *curve;
211 
212     for (i = 0; OPENSSL_built_in_curves[i].nid != NID_undef; i++) {
213       curve = &OPENSSL_built_in_curves[i];
214       const unsigned param_len = curve->data->param_len;
215       if (ecparams->order->length == param_len &&
216           memcmp(ecparams->order->data, &curve->data->data[param_len * 5],
217                  param_len) == 0) {
218         nid = curve->nid;
219         break;
220       }
221     }
222   }
223 
224   if (nid == NID_undef) {
225     OPENSSL_PUT_ERROR(EC, ec_asn1_pkparameters2group, EC_R_NON_NAMED_CURVE);
226     return NULL;
227   }
228 
229   ret = EC_GROUP_new_by_curve_name(nid);
230   if (ret == NULL) {
231     OPENSSL_PUT_ERROR(EC, ec_asn1_pkparameters2group,
232                       EC_R_EC_GROUP_NEW_BY_NAME_FAILURE);
233     return NULL;
234   }
235 
236   return ret;
237 }
238 
d2i_ECPKParameters(EC_GROUP ** groupp,const uint8_t ** inp,long len)239 static EC_GROUP *d2i_ECPKParameters(EC_GROUP **groupp, const uint8_t **inp,
240                                     long len) {
241   EC_GROUP *group = NULL;
242   ECPKPARAMETERS *params = NULL;
243 
244   params = d2i_ECPKPARAMETERS(NULL, inp, len);
245   if (params == NULL) {
246     OPENSSL_PUT_ERROR(EC, d2i_ECPKParameters, EC_R_D2I_ECPKPARAMETERS_FAILURE);
247     ECPKPARAMETERS_free(params);
248     return NULL;
249   }
250 
251   group = ec_asn1_pkparameters2group(params);
252   if (group == NULL) {
253     OPENSSL_PUT_ERROR(EC, d2i_ECPKParameters, EC_R_PKPARAMETERS2GROUP_FAILURE);
254     ECPKPARAMETERS_free(params);
255     return NULL;
256   }
257 
258   if (groupp) {
259     EC_GROUP_free(*groupp);
260     *groupp = group;
261   }
262 
263   ECPKPARAMETERS_free(params);
264   return group;
265 }
266 
i2d_ECPKParameters(const EC_GROUP * group,uint8_t ** outp)267 static int i2d_ECPKParameters(const EC_GROUP *group, uint8_t **outp) {
268   int ret = 0;
269   ECPKPARAMETERS *tmp = ec_asn1_group2pkparameters(group, NULL);
270   if (tmp == NULL) {
271     OPENSSL_PUT_ERROR(EC, i2d_ECPKParameters, EC_R_GROUP2PKPARAMETERS_FAILURE);
272     return 0;
273   }
274   ret = i2d_ECPKPARAMETERS(tmp, outp);
275   if (ret == 0) {
276     OPENSSL_PUT_ERROR(EC, i2d_ECPKParameters, EC_R_I2D_ECPKPARAMETERS_FAILURE);
277     ECPKPARAMETERS_free(tmp);
278     return 0;
279   }
280   ECPKPARAMETERS_free(tmp);
281   return ret;
282 }
283 
d2i_ECPrivateKey(EC_KEY ** a,const uint8_t ** in,long len)284 EC_KEY *d2i_ECPrivateKey(EC_KEY **a, const uint8_t **in, long len) {
285   int ok = 0;
286   EC_KEY *ret = NULL;
287   EC_PRIVATEKEY *priv_key = NULL;
288 
289   priv_key = d2i_EC_PRIVATEKEY(NULL, in, len);
290   if (priv_key == NULL) {
291     OPENSSL_PUT_ERROR(EC, d2i_ECPrivateKey, ERR_R_EC_LIB);
292     return NULL;
293   }
294 
295   if (a == NULL || *a == NULL) {
296     ret = EC_KEY_new();
297     if (ret == NULL) {
298       OPENSSL_PUT_ERROR(EC, d2i_ECPrivateKey, ERR_R_MALLOC_FAILURE);
299       goto err;
300     }
301   } else {
302     ret = *a;
303   }
304 
305   if (priv_key->parameters) {
306     EC_GROUP_free(ret->group);
307     ret->group = ec_asn1_pkparameters2group(priv_key->parameters);
308   }
309 
310   if (ret->group == NULL) {
311     OPENSSL_PUT_ERROR(EC, d2i_ECPrivateKey, ERR_R_EC_LIB);
312     goto err;
313   }
314 
315   ret->version = priv_key->version;
316 
317   if (priv_key->privateKey) {
318     ret->priv_key =
319         BN_bin2bn(M_ASN1_STRING_data(priv_key->privateKey),
320                   M_ASN1_STRING_length(priv_key->privateKey), ret->priv_key);
321     if (ret->priv_key == NULL) {
322       OPENSSL_PUT_ERROR(EC, d2i_ECPrivateKey, ERR_R_BN_LIB);
323       goto err;
324     }
325   } else {
326     OPENSSL_PUT_ERROR(EC, d2i_ECPrivateKey, EC_R_MISSING_PRIVATE_KEY);
327     goto err;
328   }
329 
330   EC_POINT_free(ret->pub_key);
331   ret->pub_key = EC_POINT_new(ret->group);
332   if (ret->pub_key == NULL) {
333     OPENSSL_PUT_ERROR(EC, d2i_ECPrivateKey, ERR_R_EC_LIB);
334     goto err;
335   }
336 
337   if (priv_key->publicKey) {
338     const uint8_t *pub_oct;
339     int pub_oct_len;
340 
341     pub_oct = M_ASN1_STRING_data(priv_key->publicKey);
342     pub_oct_len = M_ASN1_STRING_length(priv_key->publicKey);
343     /* The first byte (the point conversion form) must be present. */
344     if (pub_oct_len <= 0) {
345       OPENSSL_PUT_ERROR(EC, d2i_ECPrivateKey, EC_R_BUFFER_TOO_SMALL);
346       goto err;
347     }
348     /* Save the point conversion form. */
349     ret->conv_form = (point_conversion_form_t)(pub_oct[0] & ~0x01);
350     if (!EC_POINT_oct2point(ret->group, ret->pub_key, pub_oct, pub_oct_len,
351                             NULL)) {
352       OPENSSL_PUT_ERROR(EC, d2i_ECPrivateKey, ERR_R_EC_LIB);
353       goto err;
354     }
355   } else {
356     if (!EC_POINT_mul(ret->group, ret->pub_key, ret->priv_key, NULL, NULL,
357                       NULL)) {
358       OPENSSL_PUT_ERROR(EC, d2i_ECPrivateKey, ERR_R_EC_LIB);
359       goto err;
360     }
361     /* Remember the original private-key-only encoding. */
362     ret->enc_flag |= EC_PKEY_NO_PUBKEY;
363   }
364 
365   if (a) {
366     *a = ret;
367   }
368   ok = 1;
369 
370 err:
371   if (!ok) {
372     if (a == NULL || *a != ret) {
373       EC_KEY_free(ret);
374     }
375     ret = NULL;
376   }
377 
378   EC_PRIVATEKEY_free(priv_key);
379 
380   return ret;
381 }
382 
i2d_ECPrivateKey(const EC_KEY * key,uint8_t ** outp)383 int i2d_ECPrivateKey(const EC_KEY *key, uint8_t **outp) {
384   int ret = 0, ok = 0;
385   uint8_t *buffer = NULL;
386   size_t buf_len = 0, tmp_len;
387   EC_PRIVATEKEY *priv_key = NULL;
388 
389   if (key == NULL || key->group == NULL || key->priv_key == NULL) {
390     OPENSSL_PUT_ERROR(EC, i2d_ECPrivateKey, ERR_R_PASSED_NULL_PARAMETER);
391     goto err;
392   }
393 
394   priv_key = EC_PRIVATEKEY_new();
395   if (priv_key == NULL) {
396     OPENSSL_PUT_ERROR(EC, i2d_ECPrivateKey, ERR_R_MALLOC_FAILURE);
397     goto err;
398   }
399 
400   priv_key->version = key->version;
401 
402   buf_len = BN_num_bytes(&key->group->order);
403   buffer = OPENSSL_malloc(buf_len);
404   if (buffer == NULL) {
405     OPENSSL_PUT_ERROR(EC, i2d_ECPrivateKey, ERR_R_MALLOC_FAILURE);
406     goto err;
407   }
408 
409   if (!BN_bn2bin_padded(buffer, buf_len, key->priv_key)) {
410     OPENSSL_PUT_ERROR(EC, i2d_ECPrivateKey, ERR_R_BN_LIB);
411     goto err;
412   }
413 
414   if (!M_ASN1_OCTET_STRING_set(priv_key->privateKey, buffer, buf_len)) {
415     OPENSSL_PUT_ERROR(EC, i2d_ECPrivateKey, ERR_R_ASN1_LIB);
416     goto err;
417   }
418 
419   /* TODO(fork): replace this flexibility with key sensible default? */
420   if (!(key->enc_flag & EC_PKEY_NO_PARAMETERS)) {
421     if ((priv_key->parameters = ec_asn1_group2pkparameters(
422              key->group, priv_key->parameters)) == NULL) {
423       OPENSSL_PUT_ERROR(EC, i2d_ECPrivateKey, ERR_R_EC_LIB);
424       goto err;
425     }
426   }
427 
428   /* TODO(fork): replace this flexibility with key sensible default? */
429   if (!(key->enc_flag & EC_PKEY_NO_PUBKEY) && key->pub_key != NULL) {
430     priv_key->publicKey = M_ASN1_BIT_STRING_new();
431     if (priv_key->publicKey == NULL) {
432       OPENSSL_PUT_ERROR(EC, i2d_ECPrivateKey, ERR_R_MALLOC_FAILURE);
433       goto err;
434     }
435 
436     tmp_len = EC_POINT_point2oct(key->group, key->pub_key, key->conv_form, NULL,
437                                  0, NULL);
438 
439     if (tmp_len > buf_len) {
440       uint8_t *tmp_buffer = OPENSSL_realloc(buffer, tmp_len);
441       if (!tmp_buffer) {
442         OPENSSL_PUT_ERROR(EC, i2d_ECPrivateKey, ERR_R_MALLOC_FAILURE);
443         goto err;
444       }
445       buffer = tmp_buffer;
446       buf_len = tmp_len;
447     }
448 
449     if (!EC_POINT_point2oct(key->group, key->pub_key, key->conv_form, buffer,
450                             buf_len, NULL)) {
451       OPENSSL_PUT_ERROR(EC, i2d_ECPrivateKey, ERR_R_EC_LIB);
452       goto err;
453     }
454 
455     priv_key->publicKey->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07);
456     priv_key->publicKey->flags |= ASN1_STRING_FLAG_BITS_LEFT;
457     if (!M_ASN1_BIT_STRING_set(priv_key->publicKey, buffer, buf_len)) {
458       OPENSSL_PUT_ERROR(EC, i2d_ECPrivateKey, ERR_R_ASN1_LIB);
459       goto err;
460     }
461   }
462 
463   ret = i2d_EC_PRIVATEKEY(priv_key, outp);
464   if (ret == 0) {
465     OPENSSL_PUT_ERROR(EC, i2d_ECPrivateKey, ERR_R_EC_LIB);
466     goto err;
467   }
468   ok = 1;
469 
470 err:
471   OPENSSL_free(buffer);
472   EC_PRIVATEKEY_free(priv_key);
473   return (ok ? ret : 0);
474 }
475 
i2d_ECParameters(const EC_KEY * key,uint8_t ** outp)476 int i2d_ECParameters(const EC_KEY *key, uint8_t **outp) {
477   if (key == NULL) {
478     OPENSSL_PUT_ERROR(EC, i2d_ECParameters, ERR_R_PASSED_NULL_PARAMETER);
479     return 0;
480   }
481   return i2d_ECPKParameters(key->group, outp);
482 }
483 
d2i_ECParameters(EC_KEY ** key,const uint8_t ** inp,long len)484 EC_KEY *d2i_ECParameters(EC_KEY **key, const uint8_t **inp, long len) {
485   EC_KEY *ret;
486 
487   if (inp == NULL || *inp == NULL) {
488     OPENSSL_PUT_ERROR(EC, d2i_ECParameters, ERR_R_PASSED_NULL_PARAMETER);
489     return NULL;
490   }
491 
492   if (key == NULL || *key == NULL) {
493     ret = EC_KEY_new();
494     if (ret == NULL) {
495       OPENSSL_PUT_ERROR(EC, d2i_ECParameters, ERR_R_MALLOC_FAILURE);
496       return NULL;
497     }
498   } else {
499     ret = *key;
500   }
501 
502   if (!d2i_ECPKParameters(&ret->group, inp, len)) {
503     OPENSSL_PUT_ERROR(EC, d2i_ECParameters, ERR_R_EC_LIB);
504     if (key == NULL || *key == NULL) {
505       EC_KEY_free(ret);
506     }
507     return NULL;
508   }
509 
510   if (key) {
511     *key = ret;
512   }
513   return ret;
514 }
515 
o2i_ECPublicKey(EC_KEY ** keyp,const uint8_t ** inp,long len)516 EC_KEY *o2i_ECPublicKey(EC_KEY **keyp, const uint8_t **inp, long len) {
517   EC_KEY *ret = NULL;
518 
519   if (keyp == NULL || *keyp == NULL || (*keyp)->group == NULL) {
520     OPENSSL_PUT_ERROR(EC, o2i_ECPublicKey, ERR_R_PASSED_NULL_PARAMETER);
521     return 0;
522   }
523   ret = *keyp;
524   if (ret->pub_key == NULL &&
525       (ret->pub_key = EC_POINT_new(ret->group)) == NULL) {
526     OPENSSL_PUT_ERROR(EC, o2i_ECPublicKey, ERR_R_MALLOC_FAILURE);
527     return 0;
528   }
529   if (!EC_POINT_oct2point(ret->group, ret->pub_key, *inp, len, NULL)) {
530     OPENSSL_PUT_ERROR(EC, o2i_ECPublicKey, ERR_R_EC_LIB);
531     return 0;
532   }
533   /* save the point conversion form */
534   ret->conv_form = (point_conversion_form_t)(*inp[0] & ~0x01);
535   *inp += len;
536   return ret;
537 }
538 
i2o_ECPublicKey(const EC_KEY * key,uint8_t ** outp)539 int i2o_ECPublicKey(const EC_KEY *key, uint8_t **outp) {
540   size_t buf_len = 0;
541   int new_buffer = 0;
542 
543   if (key == NULL) {
544     OPENSSL_PUT_ERROR(EC, i2o_ECPublicKey, ERR_R_PASSED_NULL_PARAMETER);
545     return 0;
546   }
547 
548   buf_len = EC_POINT_point2oct(key->group, key->pub_key, key->conv_form, NULL,
549                                0, NULL);
550 
551   if (outp == NULL || buf_len == 0) {
552     /* out == NULL => just return the length of the octet string */
553     return buf_len;
554   }
555 
556   if (*outp == NULL) {
557     *outp = OPENSSL_malloc(buf_len);
558     if (*outp == NULL) {
559       OPENSSL_PUT_ERROR(EC, i2o_ECPublicKey, ERR_R_MALLOC_FAILURE);
560       return 0;
561     }
562     new_buffer = 1;
563   }
564   if (!EC_POINT_point2oct(key->group, key->pub_key, key->conv_form, *outp,
565                           buf_len, NULL)) {
566     OPENSSL_PUT_ERROR(EC, i2o_ECPublicKey, ERR_R_EC_LIB);
567     if (new_buffer) {
568       OPENSSL_free(*outp);
569       *outp = NULL;
570     }
571     return 0;
572   }
573 
574   if (!new_buffer) {
575     *outp += buf_len;
576   }
577   return buf_len;
578 }
579