1 // SPDX-License-Identifier: Apache-2.0 2 /* 3 * Public Key layer for writing key files and structures 4 * 5 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved 6 * 7 * Licensed under the Apache License, Version 2.0 (the "License"); you may 8 * not use this file except in compliance with the License. 9 * You may obtain a copy of the License at 10 * 11 * http://www.apache.org/licenses/LICENSE-2.0 12 * 13 * Unless required by applicable law or agreed to in writing, software 14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 16 * See the License for the specific language governing permissions and 17 * limitations under the License. 18 * 19 * This file is part of mbed TLS (https://tls.mbed.org) 20 */ 21 22 #if !defined(MBEDTLS_CONFIG_FILE) 23 #include "mbedtls/config.h" 24 #else 25 #include MBEDTLS_CONFIG_FILE 26 #endif 27 28 #if defined(MBEDTLS_PK_WRITE_C) 29 30 #include "mbedtls/pk.h" 31 #include "mbedtls/asn1write.h" 32 #include "mbedtls/oid.h" 33 #include "mbedtls/platform_util.h" 34 35 #include <string.h> 36 37 #if defined(MBEDTLS_RSA_C) 38 #include "mbedtls/rsa.h" 39 #endif 40 #if defined(MBEDTLS_ECP_C) 41 #include "mbedtls/bignum.h" 42 #include "mbedtls/ecp.h" 43 #include "mbedtls/platform_util.h" 44 #endif 45 #if defined(MBEDTLS_ECDSA_C) 46 #include "mbedtls/ecdsa.h" 47 #endif 48 #if defined(MBEDTLS_PEM_WRITE_C) 49 #include "mbedtls/pem.h" 50 #endif 51 52 #if defined(MBEDTLS_PLATFORM_C) 53 #include "mbedtls/platform.h" 54 #else 55 #include <stdlib.h> 56 #define mbedtls_calloc calloc 57 #define mbedtls_free free 58 #endif 59 60 /* Parameter validation macros based on platform_util.h */ 61 #define PK_VALIDATE_RET( cond ) \ 62 MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_PK_BAD_INPUT_DATA ) 63 #define PK_VALIDATE( cond ) \ 64 MBEDTLS_INTERNAL_VALIDATE( cond ) 65 66 #if defined(MBEDTLS_RSA_C) 67 /* 68 * RSAPublicKey ::= SEQUENCE { 69 * modulus INTEGER, -- n 70 * publicExponent INTEGER -- e 71 * } 72 */ 73 static int pk_write_rsa_pubkey( unsigned char **p, unsigned char *start, 74 mbedtls_rsa_context *rsa ) 75 { 76 int ret; 77 size_t len = 0; 78 mbedtls_mpi T; 79 80 mbedtls_mpi_init( &T ); 81 82 /* Export E */ 83 if ( ( ret = mbedtls_rsa_export( rsa, NULL, NULL, NULL, NULL, &T ) ) != 0 || 84 ( ret = mbedtls_asn1_write_mpi( p, start, &T ) ) < 0 ) 85 goto end_of_export; 86 len += ret; 87 88 /* Export N */ 89 if ( ( ret = mbedtls_rsa_export( rsa, &T, NULL, NULL, NULL, NULL ) ) != 0 || 90 ( ret = mbedtls_asn1_write_mpi( p, start, &T ) ) < 0 ) 91 goto end_of_export; 92 len += ret; 93 94 end_of_export: 95 96 mbedtls_mpi_free( &T ); 97 if( ret < 0 ) 98 return( ret ); 99 100 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) ); 101 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_CONSTRUCTED | 102 MBEDTLS_ASN1_SEQUENCE ) ); 103 104 return( (int) len ); 105 } 106 #endif /* MBEDTLS_RSA_C */ 107 108 #if defined(MBEDTLS_ECP_C) 109 /* 110 * EC public key is an EC point 111 */ 112 static int pk_write_ec_pubkey( unsigned char **p, unsigned char *start, 113 mbedtls_ecp_keypair *ec ) 114 { 115 int ret; 116 size_t len = 0; 117 unsigned char buf[MBEDTLS_ECP_MAX_PT_LEN]; 118 119 if( ( ret = mbedtls_ecp_point_write_binary( &ec->grp, &ec->Q, 120 MBEDTLS_ECP_PF_UNCOMPRESSED, 121 &len, buf, sizeof( buf ) ) ) != 0 ) 122 { 123 return( ret ); 124 } 125 126 if( *p < start || (size_t)( *p - start ) < len ) 127 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); 128 129 *p -= len; 130 memcpy( *p, buf, len ); 131 132 return( (int) len ); 133 } 134 135 /* 136 * ECParameters ::= CHOICE { 137 * namedCurve OBJECT IDENTIFIER 138 * } 139 */ 140 static int pk_write_ec_param( unsigned char **p, unsigned char *start, 141 mbedtls_ecp_keypair *ec ) 142 { 143 int ret; 144 size_t len = 0; 145 const char *oid; 146 size_t oid_len; 147 148 if( ( ret = mbedtls_oid_get_oid_by_ec_grp( ec->grp.id, &oid, &oid_len ) ) != 0 ) 149 return( ret ); 150 151 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_oid( p, start, oid, oid_len ) ); 152 153 return( (int) len ); 154 } 155 156 /* 157 * privateKey OCTET STRING -- always of length ceil(log2(n)/8) 158 */ 159 static int pk_write_ec_private( unsigned char **p, unsigned char *start, 160 mbedtls_ecp_keypair *ec ) 161 { 162 int ret; 163 size_t byte_length = ( ec->grp.pbits + 7 ) / 8; 164 unsigned char tmp[MBEDTLS_ECP_MAX_BYTES]; 165 166 ret = mbedtls_mpi_write_binary( &ec->d, tmp, byte_length ); 167 if( ret != 0 ) 168 goto exit; 169 ret = mbedtls_asn1_write_octet_string( p, start, tmp, byte_length ); 170 171 exit: 172 mbedtls_platform_zeroize( tmp, byte_length ); 173 return( ret ); 174 } 175 #endif /* MBEDTLS_ECP_C */ 176 177 int mbedtls_pk_write_pubkey( unsigned char **p, unsigned char *start, 178 const mbedtls_pk_context *key ) 179 { 180 int ret; 181 size_t len = 0; 182 183 PK_VALIDATE_RET( p != NULL ); 184 PK_VALIDATE_RET( *p != NULL ); 185 PK_VALIDATE_RET( start != NULL ); 186 PK_VALIDATE_RET( key != NULL ); 187 188 #if defined(MBEDTLS_RSA_C) 189 if( mbedtls_pk_get_type( key ) == MBEDTLS_PK_RSA ) 190 MBEDTLS_ASN1_CHK_ADD( len, pk_write_rsa_pubkey( p, start, mbedtls_pk_rsa( *key ) ) ); 191 else 192 #endif 193 #if defined(MBEDTLS_ECP_C) 194 if( mbedtls_pk_get_type( key ) == MBEDTLS_PK_ECKEY ) 195 MBEDTLS_ASN1_CHK_ADD( len, pk_write_ec_pubkey( p, start, mbedtls_pk_ec( *key ) ) ); 196 else 197 #endif 198 return( MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE ); 199 200 return( (int) len ); 201 } 202 203 int mbedtls_pk_write_pubkey_der( mbedtls_pk_context *key, unsigned char *buf, size_t size ) 204 { 205 int ret; 206 unsigned char *c; 207 size_t len = 0, par_len = 0, oid_len; 208 const char *oid; 209 210 PK_VALIDATE_RET( key != NULL ); 211 if( size == 0 ) 212 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); 213 PK_VALIDATE_RET( buf != NULL ); 214 215 c = buf + size; 216 217 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_pk_write_pubkey( &c, buf, key ) ); 218 219 if( c - buf < 1 ) 220 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); 221 222 /* 223 * SubjectPublicKeyInfo ::= SEQUENCE { 224 * algorithm AlgorithmIdentifier, 225 * subjectPublicKey BIT STRING } 226 */ 227 *--c = 0; 228 len += 1; 229 230 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) ); 231 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_BIT_STRING ) ); 232 233 if( ( ret = mbedtls_oid_get_oid_by_pk_alg( mbedtls_pk_get_type( key ), 234 &oid, &oid_len ) ) != 0 ) 235 { 236 return( ret ); 237 } 238 239 #if defined(MBEDTLS_ECP_C) 240 if( mbedtls_pk_get_type( key ) == MBEDTLS_PK_ECKEY ) 241 { 242 MBEDTLS_ASN1_CHK_ADD( par_len, pk_write_ec_param( &c, buf, mbedtls_pk_ec( *key ) ) ); 243 } 244 #endif 245 246 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_algorithm_identifier( &c, buf, oid, oid_len, 247 par_len ) ); 248 249 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) ); 250 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_CONSTRUCTED | 251 MBEDTLS_ASN1_SEQUENCE ) ); 252 253 return( (int) len ); 254 } 255 256 int mbedtls_pk_write_key_der( mbedtls_pk_context *key, unsigned char *buf, size_t size ) 257 { 258 int ret; 259 unsigned char *c; 260 size_t len = 0; 261 262 PK_VALIDATE_RET( key != NULL ); 263 if( size == 0 ) 264 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); 265 PK_VALIDATE_RET( buf != NULL ); 266 267 c = buf + size; 268 269 #if defined(MBEDTLS_RSA_C) 270 if( mbedtls_pk_get_type( key ) == MBEDTLS_PK_RSA ) 271 { 272 mbedtls_mpi T; /* Temporary holding the exported parameters */ 273 mbedtls_rsa_context *rsa = mbedtls_pk_rsa( *key ); 274 275 /* 276 * Export the parameters one after another to avoid simultaneous copies. 277 */ 278 279 mbedtls_mpi_init( &T ); 280 281 /* Export QP */ 282 if( ( ret = mbedtls_rsa_export_crt( rsa, NULL, NULL, &T ) ) != 0 || 283 ( ret = mbedtls_asn1_write_mpi( &c, buf, &T ) ) < 0 ) 284 goto end_of_export; 285 len += ret; 286 287 /* Export DQ */ 288 if( ( ret = mbedtls_rsa_export_crt( rsa, NULL, &T, NULL ) ) != 0 || 289 ( ret = mbedtls_asn1_write_mpi( &c, buf, &T ) ) < 0 ) 290 goto end_of_export; 291 len += ret; 292 293 /* Export DP */ 294 if( ( ret = mbedtls_rsa_export_crt( rsa, &T, NULL, NULL ) ) != 0 || 295 ( ret = mbedtls_asn1_write_mpi( &c, buf, &T ) ) < 0 ) 296 goto end_of_export; 297 len += ret; 298 299 /* Export Q */ 300 if ( ( ret = mbedtls_rsa_export( rsa, NULL, NULL, 301 &T, NULL, NULL ) ) != 0 || 302 ( ret = mbedtls_asn1_write_mpi( &c, buf, &T ) ) < 0 ) 303 goto end_of_export; 304 len += ret; 305 306 /* Export P */ 307 if ( ( ret = mbedtls_rsa_export( rsa, NULL, &T, 308 NULL, NULL, NULL ) ) != 0 || 309 ( ret = mbedtls_asn1_write_mpi( &c, buf, &T ) ) < 0 ) 310 goto end_of_export; 311 len += ret; 312 313 /* Export D */ 314 if ( ( ret = mbedtls_rsa_export( rsa, NULL, NULL, 315 NULL, &T, NULL ) ) != 0 || 316 ( ret = mbedtls_asn1_write_mpi( &c, buf, &T ) ) < 0 ) 317 goto end_of_export; 318 len += ret; 319 320 /* Export E */ 321 if ( ( ret = mbedtls_rsa_export( rsa, NULL, NULL, 322 NULL, NULL, &T ) ) != 0 || 323 ( ret = mbedtls_asn1_write_mpi( &c, buf, &T ) ) < 0 ) 324 goto end_of_export; 325 len += ret; 326 327 /* Export N */ 328 if ( ( ret = mbedtls_rsa_export( rsa, &T, NULL, 329 NULL, NULL, NULL ) ) != 0 || 330 ( ret = mbedtls_asn1_write_mpi( &c, buf, &T ) ) < 0 ) 331 goto end_of_export; 332 len += ret; 333 334 end_of_export: 335 336 mbedtls_mpi_free( &T ); 337 if( ret < 0 ) 338 return( ret ); 339 340 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_int( &c, buf, 0 ) ); 341 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) ); 342 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, 343 buf, MBEDTLS_ASN1_CONSTRUCTED | 344 MBEDTLS_ASN1_SEQUENCE ) ); 345 } 346 else 347 #endif /* MBEDTLS_RSA_C */ 348 #if defined(MBEDTLS_ECP_C) 349 if( mbedtls_pk_get_type( key ) == MBEDTLS_PK_ECKEY ) 350 { 351 mbedtls_ecp_keypair *ec = mbedtls_pk_ec( *key ); 352 size_t pub_len = 0, par_len = 0; 353 354 /* 355 * RFC 5915, or SEC1 Appendix C.4 356 * 357 * ECPrivateKey ::= SEQUENCE { 358 * version INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1), 359 * privateKey OCTET STRING, 360 * parameters [0] ECParameters {{ NamedCurve }} OPTIONAL, 361 * publicKey [1] BIT STRING OPTIONAL 362 * } 363 */ 364 365 /* publicKey */ 366 MBEDTLS_ASN1_CHK_ADD( pub_len, pk_write_ec_pubkey( &c, buf, ec ) ); 367 368 if( c - buf < 1 ) 369 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); 370 *--c = 0; 371 pub_len += 1; 372 373 MBEDTLS_ASN1_CHK_ADD( pub_len, mbedtls_asn1_write_len( &c, buf, pub_len ) ); 374 MBEDTLS_ASN1_CHK_ADD( pub_len, mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_BIT_STRING ) ); 375 376 MBEDTLS_ASN1_CHK_ADD( pub_len, mbedtls_asn1_write_len( &c, buf, pub_len ) ); 377 MBEDTLS_ASN1_CHK_ADD( pub_len, mbedtls_asn1_write_tag( &c, buf, 378 MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | 1 ) ); 379 len += pub_len; 380 381 /* parameters */ 382 MBEDTLS_ASN1_CHK_ADD( par_len, pk_write_ec_param( &c, buf, ec ) ); 383 384 MBEDTLS_ASN1_CHK_ADD( par_len, mbedtls_asn1_write_len( &c, buf, par_len ) ); 385 MBEDTLS_ASN1_CHK_ADD( par_len, mbedtls_asn1_write_tag( &c, buf, 386 MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | 0 ) ); 387 len += par_len; 388 389 /* privateKey */ 390 MBEDTLS_ASN1_CHK_ADD( len, pk_write_ec_private( &c, buf, ec ) ); 391 392 /* version */ 393 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_int( &c, buf, 1 ) ); 394 395 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) ); 396 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_CONSTRUCTED | 397 MBEDTLS_ASN1_SEQUENCE ) ); 398 } 399 else 400 #endif /* MBEDTLS_ECP_C */ 401 return( MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE ); 402 403 return( (int) len ); 404 } 405 406 #if defined(MBEDTLS_PEM_WRITE_C) 407 408 #define PEM_BEGIN_PUBLIC_KEY "-----BEGIN PUBLIC KEY-----\n" 409 #define PEM_END_PUBLIC_KEY "-----END PUBLIC KEY-----\n" 410 411 #define PEM_BEGIN_PRIVATE_KEY_RSA "-----BEGIN RSA PRIVATE KEY-----\n" 412 #define PEM_END_PRIVATE_KEY_RSA "-----END RSA PRIVATE KEY-----\n" 413 #define PEM_BEGIN_PRIVATE_KEY_EC "-----BEGIN EC PRIVATE KEY-----\n" 414 #define PEM_END_PRIVATE_KEY_EC "-----END EC PRIVATE KEY-----\n" 415 416 /* 417 * Max sizes of key per types. Shown as tag + len (+ content). 418 */ 419 420 #if defined(MBEDTLS_RSA_C) 421 /* 422 * RSA public keys: 423 * SubjectPublicKeyInfo ::= SEQUENCE { 1 + 3 424 * algorithm AlgorithmIdentifier, 1 + 1 (sequence) 425 * + 1 + 1 + 9 (rsa oid) 426 * + 1 + 1 (params null) 427 * subjectPublicKey BIT STRING } 1 + 3 + (1 + below) 428 * RSAPublicKey ::= SEQUENCE { 1 + 3 429 * modulus INTEGER, -- n 1 + 3 + MPI_MAX + 1 430 * publicExponent INTEGER -- e 1 + 3 + MPI_MAX + 1 431 * } 432 */ 433 #define RSA_PUB_DER_MAX_BYTES 38 + 2 * MBEDTLS_MPI_MAX_SIZE 434 435 /* 436 * RSA private keys: 437 * RSAPrivateKey ::= SEQUENCE { 1 + 3 438 * version Version, 1 + 1 + 1 439 * modulus INTEGER, 1 + 3 + MPI_MAX + 1 440 * publicExponent INTEGER, 1 + 3 + MPI_MAX + 1 441 * privateExponent INTEGER, 1 + 3 + MPI_MAX + 1 442 * prime1 INTEGER, 1 + 3 + MPI_MAX / 2 + 1 443 * prime2 INTEGER, 1 + 3 + MPI_MAX / 2 + 1 444 * exponent1 INTEGER, 1 + 3 + MPI_MAX / 2 + 1 445 * exponent2 INTEGER, 1 + 3 + MPI_MAX / 2 + 1 446 * coefficient INTEGER, 1 + 3 + MPI_MAX / 2 + 1 447 * otherPrimeInfos OtherPrimeInfos OPTIONAL 0 (not supported) 448 * } 449 */ 450 #define MPI_MAX_SIZE_2 MBEDTLS_MPI_MAX_SIZE / 2 + \ 451 MBEDTLS_MPI_MAX_SIZE % 2 452 #define RSA_PRV_DER_MAX_BYTES 47 + 3 * MBEDTLS_MPI_MAX_SIZE \ 453 + 5 * MPI_MAX_SIZE_2 454 455 #else /* MBEDTLS_RSA_C */ 456 457 #define RSA_PUB_DER_MAX_BYTES 0 458 #define RSA_PRV_DER_MAX_BYTES 0 459 460 #endif /* MBEDTLS_RSA_C */ 461 462 #if defined(MBEDTLS_ECP_C) 463 /* 464 * EC public keys: 465 * SubjectPublicKeyInfo ::= SEQUENCE { 1 + 2 466 * algorithm AlgorithmIdentifier, 1 + 1 (sequence) 467 * + 1 + 1 + 7 (ec oid) 468 * + 1 + 1 + 9 (namedCurve oid) 469 * subjectPublicKey BIT STRING 1 + 2 + 1 [1] 470 * + 1 (point format) [1] 471 * + 2 * ECP_MAX (coords) [1] 472 * } 473 */ 474 #define ECP_PUB_DER_MAX_BYTES 30 + 2 * MBEDTLS_ECP_MAX_BYTES 475 476 /* 477 * EC private keys: 478 * ECPrivateKey ::= SEQUENCE { 1 + 2 479 * version INTEGER , 1 + 1 + 1 480 * privateKey OCTET STRING, 1 + 1 + ECP_MAX 481 * parameters [0] ECParameters OPTIONAL, 1 + 1 + (1 + 1 + 9) 482 * publicKey [1] BIT STRING OPTIONAL 1 + 2 + [1] above 483 * } 484 */ 485 #define ECP_PRV_DER_MAX_BYTES 29 + 3 * MBEDTLS_ECP_MAX_BYTES 486 487 #else /* MBEDTLS_ECP_C */ 488 489 #define ECP_PUB_DER_MAX_BYTES 0 490 #define ECP_PRV_DER_MAX_BYTES 0 491 492 #endif /* MBEDTLS_ECP_C */ 493 494 #define PUB_DER_MAX_BYTES RSA_PUB_DER_MAX_BYTES > ECP_PUB_DER_MAX_BYTES ? \ 495 RSA_PUB_DER_MAX_BYTES : ECP_PUB_DER_MAX_BYTES 496 #define PRV_DER_MAX_BYTES RSA_PRV_DER_MAX_BYTES > ECP_PRV_DER_MAX_BYTES ? \ 497 RSA_PRV_DER_MAX_BYTES : ECP_PRV_DER_MAX_BYTES 498 499 int mbedtls_pk_write_pubkey_pem( mbedtls_pk_context *key, unsigned char *buf, size_t size ) 500 { 501 int ret; 502 unsigned char output_buf[PUB_DER_MAX_BYTES]; 503 size_t olen = 0; 504 505 PK_VALIDATE_RET( key != NULL ); 506 PK_VALIDATE_RET( buf != NULL || size == 0 ); 507 508 if( ( ret = mbedtls_pk_write_pubkey_der( key, output_buf, 509 sizeof(output_buf) ) ) < 0 ) 510 { 511 return( ret ); 512 } 513 514 if( ( ret = mbedtls_pem_write_buffer( PEM_BEGIN_PUBLIC_KEY, PEM_END_PUBLIC_KEY, 515 output_buf + sizeof(output_buf) - ret, 516 ret, buf, size, &olen ) ) != 0 ) 517 { 518 return( ret ); 519 } 520 521 return( 0 ); 522 } 523 524 int mbedtls_pk_write_key_pem( mbedtls_pk_context *key, unsigned char *buf, size_t size ) 525 { 526 int ret; 527 unsigned char output_buf[PRV_DER_MAX_BYTES]; 528 const char *begin, *end; 529 size_t olen = 0; 530 531 PK_VALIDATE_RET( key != NULL ); 532 PK_VALIDATE_RET( buf != NULL || size == 0 ); 533 534 if( ( ret = mbedtls_pk_write_key_der( key, output_buf, sizeof(output_buf) ) ) < 0 ) 535 return( ret ); 536 537 #if defined(MBEDTLS_RSA_C) 538 if( mbedtls_pk_get_type( key ) == MBEDTLS_PK_RSA ) 539 { 540 begin = PEM_BEGIN_PRIVATE_KEY_RSA; 541 end = PEM_END_PRIVATE_KEY_RSA; 542 } 543 else 544 #endif 545 #if defined(MBEDTLS_ECP_C) 546 if( mbedtls_pk_get_type( key ) == MBEDTLS_PK_ECKEY ) 547 { 548 begin = PEM_BEGIN_PRIVATE_KEY_EC; 549 end = PEM_END_PRIVATE_KEY_EC; 550 } 551 else 552 #endif 553 return( MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE ); 554 555 if( ( ret = mbedtls_pem_write_buffer( begin, end, 556 output_buf + sizeof(output_buf) - ret, 557 ret, buf, size, &olen ) ) != 0 ) 558 { 559 return( ret ); 560 } 561 562 return( 0 ); 563 } 564 #endif /* MBEDTLS_PEM_WRITE_C */ 565 566 #endif /* MBEDTLS_PK_WRITE_C */ 567