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 <limits.h>
57 #include <string.h>
58
59 #include <openssl/bytestring.h>
60 #include <openssl/bn.h>
61 #include <openssl/err.h>
62 #include <openssl/mem.h>
63 #include <openssl/nid.h>
64
65 #include "internal.h"
66 #include "../bytestring/internal.h"
67 #include "../internal.h"
68
69
70 static const uint8_t kParametersTag =
71 CBS_ASN1_CONSTRUCTED | CBS_ASN1_CONTEXT_SPECIFIC | 0;
72 static const uint8_t kPublicKeyTag =
73 CBS_ASN1_CONSTRUCTED | CBS_ASN1_CONTEXT_SPECIFIC | 1;
74
EC_KEY_parse_private_key(CBS * cbs,const EC_GROUP * group)75 EC_KEY *EC_KEY_parse_private_key(CBS *cbs, const EC_GROUP *group) {
76 CBS ec_private_key, private_key;
77 uint64_t version;
78 if (!CBS_get_asn1(cbs, &ec_private_key, CBS_ASN1_SEQUENCE) ||
79 !CBS_get_asn1_uint64(&ec_private_key, &version) ||
80 version != 1 ||
81 !CBS_get_asn1(&ec_private_key, &private_key, CBS_ASN1_OCTETSTRING)) {
82 OPENSSL_PUT_ERROR(EC, EC_R_DECODE_ERROR);
83 return NULL;
84 }
85
86 /* Parse the optional parameters field. */
87 EC_GROUP *inner_group = NULL;
88 EC_KEY *ret = NULL;
89 if (CBS_peek_asn1_tag(&ec_private_key, kParametersTag)) {
90 /* Per SEC 1, as an alternative to omitting it, one is allowed to specify
91 * this field and put in a NULL to mean inheriting this value. This was
92 * omitted in a previous version of this logic without problems, so leave it
93 * unimplemented. */
94 CBS child;
95 if (!CBS_get_asn1(&ec_private_key, &child, kParametersTag)) {
96 OPENSSL_PUT_ERROR(EC, EC_R_DECODE_ERROR);
97 goto err;
98 }
99 inner_group = EC_KEY_parse_parameters(&child);
100 if (inner_group == NULL) {
101 goto err;
102 }
103 if (group == NULL) {
104 group = inner_group;
105 } else if (EC_GROUP_cmp(group, inner_group, NULL) != 0) {
106 /* If a group was supplied externally, it must match. */
107 OPENSSL_PUT_ERROR(EC, EC_R_GROUP_MISMATCH);
108 goto err;
109 }
110 if (CBS_len(&child) != 0) {
111 OPENSSL_PUT_ERROR(EC, EC_R_DECODE_ERROR);
112 goto err;
113 }
114 }
115
116 if (group == NULL) {
117 OPENSSL_PUT_ERROR(EC, EC_R_MISSING_PARAMETERS);
118 goto err;
119 }
120
121 ret = EC_KEY_new();
122 if (ret == NULL || !EC_KEY_set_group(ret, group)) {
123 goto err;
124 }
125
126 /* Although RFC 5915 specifies the length of the key, OpenSSL historically
127 * got this wrong, so accept any length. See upstream's
128 * 30cd4ff294252c4b6a4b69cbef6a5b4117705d22. */
129 ret->priv_key =
130 BN_bin2bn(CBS_data(&private_key), CBS_len(&private_key), NULL);
131 ret->pub_key = EC_POINT_new(group);
132 if (ret->priv_key == NULL || ret->pub_key == NULL) {
133 goto err;
134 }
135
136 if (BN_cmp(ret->priv_key, EC_GROUP_get0_order(group)) >= 0) {
137 OPENSSL_PUT_ERROR(EC, EC_R_WRONG_ORDER);
138 goto err;
139 }
140
141 if (CBS_peek_asn1_tag(&ec_private_key, kPublicKeyTag)) {
142 CBS child, public_key;
143 uint8_t padding;
144 if (!CBS_get_asn1(&ec_private_key, &child, kPublicKeyTag) ||
145 !CBS_get_asn1(&child, &public_key, CBS_ASN1_BITSTRING) ||
146 /* As in a SubjectPublicKeyInfo, the byte-encoded public key is then
147 * encoded as a BIT STRING with bits ordered as in the DER encoding. */
148 !CBS_get_u8(&public_key, &padding) ||
149 padding != 0 ||
150 /* Explicitly check |public_key| is non-empty to save the conversion
151 * form later. */
152 CBS_len(&public_key) == 0 ||
153 !EC_POINT_oct2point(group, ret->pub_key, CBS_data(&public_key),
154 CBS_len(&public_key), NULL) ||
155 CBS_len(&child) != 0) {
156 OPENSSL_PUT_ERROR(EC, EC_R_DECODE_ERROR);
157 goto err;
158 }
159
160 /* Save the point conversion form.
161 * TODO(davidben): Consider removing this. */
162 ret->conv_form = (point_conversion_form_t)(CBS_data(&public_key)[0] & ~0x01);
163 } else {
164 /* Compute the public key instead. */
165 if (!EC_POINT_mul(group, ret->pub_key, ret->priv_key, NULL, NULL, NULL)) {
166 goto err;
167 }
168 /* Remember the original private-key-only encoding.
169 * TODO(davidben): Consider removing this. */
170 ret->enc_flag |= EC_PKEY_NO_PUBKEY;
171 }
172
173 if (CBS_len(&ec_private_key) != 0) {
174 OPENSSL_PUT_ERROR(EC, EC_R_DECODE_ERROR);
175 goto err;
176 }
177
178 /* Ensure the resulting key is valid. */
179 if (!EC_KEY_check_key(ret)) {
180 goto err;
181 }
182
183 EC_GROUP_free(inner_group);
184 return ret;
185
186 err:
187 EC_KEY_free(ret);
188 EC_GROUP_free(inner_group);
189 return NULL;
190 }
191
EC_KEY_marshal_private_key(CBB * cbb,const EC_KEY * key,unsigned enc_flags)192 int EC_KEY_marshal_private_key(CBB *cbb, const EC_KEY *key,
193 unsigned enc_flags) {
194 if (key == NULL || key->group == NULL || key->priv_key == NULL) {
195 OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
196 return 0;
197 }
198
199 CBB ec_private_key, private_key;
200 if (!CBB_add_asn1(cbb, &ec_private_key, CBS_ASN1_SEQUENCE) ||
201 !CBB_add_asn1_uint64(&ec_private_key, 1 /* version */) ||
202 !CBB_add_asn1(&ec_private_key, &private_key, CBS_ASN1_OCTETSTRING) ||
203 !BN_bn2cbb_padded(&private_key,
204 BN_num_bytes(EC_GROUP_get0_order(key->group)),
205 key->priv_key)) {
206 OPENSSL_PUT_ERROR(EC, EC_R_ENCODE_ERROR);
207 return 0;
208 }
209
210 if (!(enc_flags & EC_PKEY_NO_PARAMETERS)) {
211 CBB child;
212 if (!CBB_add_asn1(&ec_private_key, &child, kParametersTag) ||
213 !EC_KEY_marshal_curve_name(&child, key->group) ||
214 !CBB_flush(&ec_private_key)) {
215 OPENSSL_PUT_ERROR(EC, EC_R_ENCODE_ERROR);
216 return 0;
217 }
218 }
219
220 /* TODO(fork): replace this flexibility with sensible default? */
221 if (!(enc_flags & EC_PKEY_NO_PUBKEY) && key->pub_key != NULL) {
222 CBB child, public_key;
223 if (!CBB_add_asn1(&ec_private_key, &child, kPublicKeyTag) ||
224 !CBB_add_asn1(&child, &public_key, CBS_ASN1_BITSTRING) ||
225 /* As in a SubjectPublicKeyInfo, the byte-encoded public key is then
226 * encoded as a BIT STRING with bits ordered as in the DER encoding. */
227 !CBB_add_u8(&public_key, 0 /* padding */) ||
228 !EC_POINT_point2cbb(&public_key, key->group, key->pub_key,
229 key->conv_form, NULL) ||
230 !CBB_flush(&ec_private_key)) {
231 OPENSSL_PUT_ERROR(EC, EC_R_ENCODE_ERROR);
232 return 0;
233 }
234 }
235
236 if (!CBB_flush(cbb)) {
237 OPENSSL_PUT_ERROR(EC, EC_R_ENCODE_ERROR);
238 return 0;
239 }
240
241 return 1;
242 }
243
244 /* is_unsigned_integer returns one if |cbs| is a valid unsigned DER INTEGER and
245 * zero otherwise. */
is_unsigned_integer(const CBS * cbs)246 static int is_unsigned_integer(const CBS *cbs) {
247 if (CBS_len(cbs) == 0) {
248 return 0;
249 }
250 uint8_t byte = CBS_data(cbs)[0];
251 if ((byte & 0x80) ||
252 (byte == 0 && CBS_len(cbs) > 1 && (CBS_data(cbs)[1] & 0x80) == 0)) {
253 /* Negative or not minimally-encoded. */
254 return 0;
255 }
256 return 1;
257 }
258
259 /* kPrimeFieldOID is the encoding of 1.2.840.10045.1.1. */
260 static const uint8_t kPrimeField[] = {0x2a, 0x86, 0x48, 0xce, 0x3d, 0x01, 0x01};
261
parse_explicit_prime_curve(CBS * in,CBS * out_prime,CBS * out_a,CBS * out_b,CBS * out_base_x,CBS * out_base_y,CBS * out_order)262 static int parse_explicit_prime_curve(CBS *in, CBS *out_prime, CBS *out_a,
263 CBS *out_b, CBS *out_base_x,
264 CBS *out_base_y, CBS *out_order) {
265 /* See RFC 3279, section 2.3.5. Note that RFC 3279 calls this structure an
266 * ECParameters while RFC 5480 calls it a SpecifiedECDomain. */
267 CBS params, field_id, field_type, curve, base;
268 uint64_t version;
269 if (!CBS_get_asn1(in, ¶ms, CBS_ASN1_SEQUENCE) ||
270 !CBS_get_asn1_uint64(¶ms, &version) ||
271 version != 1 ||
272 !CBS_get_asn1(¶ms, &field_id, CBS_ASN1_SEQUENCE) ||
273 !CBS_get_asn1(&field_id, &field_type, CBS_ASN1_OBJECT) ||
274 CBS_len(&field_type) != sizeof(kPrimeField) ||
275 OPENSSL_memcmp(CBS_data(&field_type), kPrimeField, sizeof(kPrimeField)) != 0 ||
276 !CBS_get_asn1(&field_id, out_prime, CBS_ASN1_INTEGER) ||
277 !is_unsigned_integer(out_prime) ||
278 CBS_len(&field_id) != 0 ||
279 !CBS_get_asn1(¶ms, &curve, CBS_ASN1_SEQUENCE) ||
280 !CBS_get_asn1(&curve, out_a, CBS_ASN1_OCTETSTRING) ||
281 !CBS_get_asn1(&curve, out_b, CBS_ASN1_OCTETSTRING) ||
282 /* |curve| has an optional BIT STRING seed which we ignore. */
283 !CBS_get_asn1(¶ms, &base, CBS_ASN1_OCTETSTRING) ||
284 !CBS_get_asn1(¶ms, out_order, CBS_ASN1_INTEGER) ||
285 !is_unsigned_integer(out_order)) {
286 OPENSSL_PUT_ERROR(EC, EC_R_DECODE_ERROR);
287 return 0;
288 }
289
290 /* |params| has an optional cofactor which we ignore. With the optional seed
291 * in |curve|, a group already has arbitrarily many encodings. Parse enough to
292 * uniquely determine the curve. */
293
294 /* Require that the base point use uncompressed form. */
295 uint8_t form;
296 if (!CBS_get_u8(&base, &form) || form != POINT_CONVERSION_UNCOMPRESSED) {
297 OPENSSL_PUT_ERROR(EC, EC_R_INVALID_FORM);
298 return 0;
299 }
300
301 if (CBS_len(&base) % 2 != 0) {
302 OPENSSL_PUT_ERROR(EC, EC_R_DECODE_ERROR);
303 return 0;
304 }
305 size_t field_len = CBS_len(&base) / 2;
306 CBS_init(out_base_x, CBS_data(&base), field_len);
307 CBS_init(out_base_y, CBS_data(&base) + field_len, field_len);
308
309 return 1;
310 }
311
312 /* integers_equal returns one if |a| and |b| are equal, up to leading zeros, and
313 * zero otherwise. */
integers_equal(const CBS * a,const uint8_t * b,size_t b_len)314 static int integers_equal(const CBS *a, const uint8_t *b, size_t b_len) {
315 /* Remove leading zeros from |a| and |b|. */
316 CBS a_copy = *a;
317 while (CBS_len(&a_copy) > 0 && CBS_data(&a_copy)[0] == 0) {
318 CBS_skip(&a_copy, 1);
319 }
320 while (b_len > 0 && b[0] == 0) {
321 b++;
322 b_len--;
323 }
324 return CBS_mem_equal(&a_copy, b, b_len);
325 }
326
EC_KEY_parse_curve_name(CBS * cbs)327 EC_GROUP *EC_KEY_parse_curve_name(CBS *cbs) {
328 CBS named_curve;
329 if (!CBS_get_asn1(cbs, &named_curve, CBS_ASN1_OBJECT)) {
330 OPENSSL_PUT_ERROR(EC, EC_R_DECODE_ERROR);
331 return NULL;
332 }
333
334 /* Look for a matching curve. */
335 unsigned i;
336 for (i = 0; OPENSSL_built_in_curves[i].nid != NID_undef; i++) {
337 const struct built_in_curve *curve = &OPENSSL_built_in_curves[i];
338 if (CBS_len(&named_curve) == curve->oid_len &&
339 OPENSSL_memcmp(CBS_data(&named_curve), curve->oid, curve->oid_len) == 0) {
340 return EC_GROUP_new_by_curve_name(curve->nid);
341 }
342 }
343
344 OPENSSL_PUT_ERROR(EC, EC_R_UNKNOWN_GROUP);
345 return NULL;
346 }
347
EC_KEY_marshal_curve_name(CBB * cbb,const EC_GROUP * group)348 int EC_KEY_marshal_curve_name(CBB *cbb, const EC_GROUP *group) {
349 int nid = EC_GROUP_get_curve_name(group);
350 if (nid == NID_undef) {
351 OPENSSL_PUT_ERROR(EC, EC_R_UNKNOWN_GROUP);
352 return 0;
353 }
354
355 unsigned i;
356 for (i = 0; OPENSSL_built_in_curves[i].nid != NID_undef; i++) {
357 const struct built_in_curve *curve = &OPENSSL_built_in_curves[i];
358 if (curve->nid == nid) {
359 CBB child;
360 return CBB_add_asn1(cbb, &child, CBS_ASN1_OBJECT) &&
361 CBB_add_bytes(&child, curve->oid, curve->oid_len) &&
362 CBB_flush(cbb);
363 }
364 }
365
366 OPENSSL_PUT_ERROR(EC, EC_R_UNKNOWN_GROUP);
367 return 0;
368 }
369
EC_KEY_parse_parameters(CBS * cbs)370 EC_GROUP *EC_KEY_parse_parameters(CBS *cbs) {
371 if (!CBS_peek_asn1_tag(cbs, CBS_ASN1_SEQUENCE)) {
372 return EC_KEY_parse_curve_name(cbs);
373 }
374
375 /* OpenSSL sometimes produces ECPrivateKeys with explicitly-encoded versions
376 * of named curves.
377 *
378 * TODO(davidben): Remove support for this. */
379 CBS prime, a, b, base_x, base_y, order;
380 if (!parse_explicit_prime_curve(cbs, &prime, &a, &b, &base_x, &base_y,
381 &order)) {
382 return NULL;
383 }
384
385 /* Look for a matching prime curve. */
386 unsigned i;
387 for (i = 0; OPENSSL_built_in_curves[i].nid != NID_undef; i++) {
388 const struct built_in_curve *curve = &OPENSSL_built_in_curves[i];
389 const unsigned param_len = curve->data->param_len;
390 /* |curve->data->data| is ordered p, a, b, x, y, order, each component
391 * zero-padded up to the field length. Although SEC 1 states that the
392 * Field-Element-to-Octet-String conversion also pads, OpenSSL mis-encodes
393 * |a| and |b|, so this comparison must allow omitting leading zeros. (This
394 * is relevant for P-521 whose |b| has a leading 0.) */
395 if (integers_equal(&prime, curve->data->data, param_len) &&
396 integers_equal(&a, curve->data->data + param_len, param_len) &&
397 integers_equal(&b, curve->data->data + param_len * 2, param_len) &&
398 integers_equal(&base_x, curve->data->data + param_len * 3, param_len) &&
399 integers_equal(&base_y, curve->data->data + param_len * 4, param_len) &&
400 integers_equal(&order, curve->data->data + param_len * 5, param_len)) {
401 return EC_GROUP_new_by_curve_name(curve->nid);
402 }
403 }
404
405 OPENSSL_PUT_ERROR(EC, EC_R_UNKNOWN_GROUP);
406 return NULL;
407 }
408
d2i_ECPrivateKey(EC_KEY ** out,const uint8_t ** inp,long len)409 EC_KEY *d2i_ECPrivateKey(EC_KEY **out, const uint8_t **inp, long len) {
410 /* This function treats its |out| parameter differently from other |d2i|
411 * functions. If supplied, take the group from |*out|. */
412 const EC_GROUP *group = NULL;
413 if (out != NULL && *out != NULL) {
414 group = EC_KEY_get0_group(*out);
415 }
416
417 if (len < 0) {
418 OPENSSL_PUT_ERROR(EC, EC_R_DECODE_ERROR);
419 return NULL;
420 }
421 CBS cbs;
422 CBS_init(&cbs, *inp, (size_t)len);
423 EC_KEY *ret = EC_KEY_parse_private_key(&cbs, group);
424 if (ret == NULL) {
425 return NULL;
426 }
427 if (out != NULL) {
428 EC_KEY_free(*out);
429 *out = ret;
430 }
431 *inp = CBS_data(&cbs);
432 return ret;
433 }
434
i2d_ECPrivateKey(const EC_KEY * key,uint8_t ** outp)435 int i2d_ECPrivateKey(const EC_KEY *key, uint8_t **outp) {
436 CBB cbb;
437 if (!CBB_init(&cbb, 0) ||
438 !EC_KEY_marshal_private_key(&cbb, key, EC_KEY_get_enc_flags(key))) {
439 CBB_cleanup(&cbb);
440 return -1;
441 }
442 return CBB_finish_i2d(&cbb, outp);
443 }
444
d2i_ECParameters(EC_KEY ** out_key,const uint8_t ** inp,long len)445 EC_KEY *d2i_ECParameters(EC_KEY **out_key, const uint8_t **inp, long len) {
446 if (len < 0) {
447 return NULL;
448 }
449
450 CBS cbs;
451 CBS_init(&cbs, *inp, (size_t)len);
452 EC_GROUP *group = EC_KEY_parse_parameters(&cbs);
453 if (group == NULL) {
454 return NULL;
455 }
456
457 EC_KEY *ret = EC_KEY_new();
458 if (ret == NULL || !EC_KEY_set_group(ret, group)) {
459 EC_GROUP_free(group);
460 EC_KEY_free(ret);
461 return NULL;
462 }
463 EC_GROUP_free(group);
464
465 if (out_key != NULL) {
466 EC_KEY_free(*out_key);
467 *out_key = ret;
468 }
469 *inp = CBS_data(&cbs);
470 return ret;
471 }
472
i2d_ECParameters(const EC_KEY * key,uint8_t ** outp)473 int i2d_ECParameters(const EC_KEY *key, uint8_t **outp) {
474 if (key == NULL || key->group == NULL) {
475 OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
476 return -1;
477 }
478
479 CBB cbb;
480 if (!CBB_init(&cbb, 0) ||
481 !EC_KEY_marshal_curve_name(&cbb, key->group)) {
482 CBB_cleanup(&cbb);
483 return -1;
484 }
485 return CBB_finish_i2d(&cbb, outp);
486 }
487
o2i_ECPublicKey(EC_KEY ** keyp,const uint8_t ** inp,long len)488 EC_KEY *o2i_ECPublicKey(EC_KEY **keyp, const uint8_t **inp, long len) {
489 EC_KEY *ret = NULL;
490
491 if (keyp == NULL || *keyp == NULL || (*keyp)->group == NULL) {
492 OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
493 return NULL;
494 }
495 ret = *keyp;
496 if (ret->pub_key == NULL &&
497 (ret->pub_key = EC_POINT_new(ret->group)) == NULL) {
498 OPENSSL_PUT_ERROR(EC, ERR_R_MALLOC_FAILURE);
499 return NULL;
500 }
501 if (!EC_POINT_oct2point(ret->group, ret->pub_key, *inp, len, NULL)) {
502 OPENSSL_PUT_ERROR(EC, ERR_R_EC_LIB);
503 return NULL;
504 }
505 /* save the point conversion form */
506 ret->conv_form = (point_conversion_form_t)(*inp[0] & ~0x01);
507 *inp += len;
508 return ret;
509 }
510
i2o_ECPublicKey(const EC_KEY * key,uint8_t ** outp)511 int i2o_ECPublicKey(const EC_KEY *key, uint8_t **outp) {
512 size_t buf_len = 0;
513 int new_buffer = 0;
514
515 if (key == NULL) {
516 OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
517 return 0;
518 }
519
520 buf_len = EC_POINT_point2oct(key->group, key->pub_key, key->conv_form, NULL,
521 0, NULL);
522
523 if (outp == NULL || buf_len == 0) {
524 /* out == NULL => just return the length of the octet string */
525 return buf_len;
526 }
527
528 if (*outp == NULL) {
529 *outp = OPENSSL_malloc(buf_len);
530 if (*outp == NULL) {
531 OPENSSL_PUT_ERROR(EC, ERR_R_MALLOC_FAILURE);
532 return 0;
533 }
534 new_buffer = 1;
535 }
536 if (!EC_POINT_point2oct(key->group, key->pub_key, key->conv_form, *outp,
537 buf_len, NULL)) {
538 OPENSSL_PUT_ERROR(EC, ERR_R_EC_LIB);
539 if (new_buffer) {
540 OPENSSL_free(*outp);
541 *outp = NULL;
542 }
543 return 0;
544 }
545
546 if (!new_buffer) {
547 *outp += buf_len;
548 }
549 return buf_len;
550 }
551