1 /* 2 * Public Key layer for writing key files and structures 3 * 4 * Copyright The Mbed TLS Contributors 5 * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later 6 * 7 * This file is provided under the Apache License 2.0, or the 8 * GNU General Public License v2.0 or later. 9 * 10 * ********** 11 * Apache License 2.0: 12 * 13 * Licensed under the Apache License, Version 2.0 (the "License"); you may 14 * not use this file except in compliance with the License. 15 * You may obtain a copy of the License at 16 * 17 * http://www.apache.org/licenses/LICENSE-2.0 18 * 19 * Unless required by applicable law or agreed to in writing, software 20 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 21 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 22 * See the License for the specific language governing permissions and 23 * limitations under the License. 24 * 25 * ********** 26 * 27 * ********** 28 * GNU General Public License v2.0 or later: 29 * 30 * This program is free software; you can redistribute it and/or modify 31 * it under the terms of the GNU General Public License as published by 32 * the Free Software Foundation; either version 2 of the License, or 33 * (at your option) any later version. 34 * 35 * This program is distributed in the hope that it will be useful, 36 * but WITHOUT ANY WARRANTY; without even the implied warranty of 37 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 38 * GNU General Public License for more details. 39 * 40 * You should have received a copy of the GNU General Public License along 41 * with this program; if not, write to the Free Software Foundation, Inc., 42 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. 43 * 44 * ********** 45 */ 46 47 #if !defined(MBEDTLS_CONFIG_FILE) 48 #include "mbedtls/config.h" 49 #else 50 #include MBEDTLS_CONFIG_FILE 51 #endif 52 53 #if defined(MBEDTLS_PK_WRITE_C) 54 55 #include "mbedtls/pk.h" 56 #include "mbedtls/asn1write.h" 57 #include "mbedtls/oid.h" 58 #include "mbedtls/platform_util.h" 59 60 #include <string.h> 61 62 #if defined(MBEDTLS_RSA_C) 63 #include "mbedtls/rsa.h" 64 #endif 65 #if defined(MBEDTLS_ECP_C) 66 #include "mbedtls/bignum.h" 67 #include "mbedtls/ecp.h" 68 #include "mbedtls/platform_util.h" 69 #endif 70 #if defined(MBEDTLS_ECDSA_C) 71 #include "mbedtls/ecdsa.h" 72 #endif 73 #if defined(MBEDTLS_PEM_WRITE_C) 74 #include "mbedtls/pem.h" 75 #endif 76 77 #if defined(MBEDTLS_PLATFORM_C) 78 #include "mbedtls/platform.h" 79 #else 80 #include <stdlib.h> 81 #define mbedtls_calloc calloc 82 #define mbedtls_free free 83 #endif 84 85 /* Parameter validation macros based on platform_util.h */ 86 #define PK_VALIDATE_RET( cond ) \ 87 MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_PK_BAD_INPUT_DATA ) 88 #define PK_VALIDATE( cond ) \ 89 MBEDTLS_INTERNAL_VALIDATE( cond ) 90 91 #if defined(MBEDTLS_RSA_C) 92 /* 93 * RSAPublicKey ::= SEQUENCE { 94 * modulus INTEGER, -- n 95 * publicExponent INTEGER -- e 96 * } 97 */ 98 static int pk_write_rsa_pubkey( unsigned char **p, unsigned char *start, 99 mbedtls_rsa_context *rsa ) 100 { 101 int ret; 102 size_t len = 0; 103 mbedtls_mpi T; 104 105 mbedtls_mpi_init( &T ); 106 107 /* Export E */ 108 if ( ( ret = mbedtls_rsa_export( rsa, NULL, NULL, NULL, NULL, &T ) ) != 0 || 109 ( ret = mbedtls_asn1_write_mpi( p, start, &T ) ) < 0 ) 110 goto end_of_export; 111 len += ret; 112 113 /* Export N */ 114 if ( ( ret = mbedtls_rsa_export( rsa, &T, NULL, NULL, NULL, NULL ) ) != 0 || 115 ( ret = mbedtls_asn1_write_mpi( p, start, &T ) ) < 0 ) 116 goto end_of_export; 117 len += ret; 118 119 end_of_export: 120 121 mbedtls_mpi_free( &T ); 122 if( ret < 0 ) 123 return( ret ); 124 125 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) ); 126 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_CONSTRUCTED | 127 MBEDTLS_ASN1_SEQUENCE ) ); 128 129 return( (int) len ); 130 } 131 #endif /* MBEDTLS_RSA_C */ 132 133 #if defined(MBEDTLS_ECP_C) 134 /* 135 * EC public key is an EC point 136 */ 137 static int pk_write_ec_pubkey( unsigned char **p, unsigned char *start, 138 mbedtls_ecp_keypair *ec ) 139 { 140 int ret; 141 size_t len = 0; 142 unsigned char buf[MBEDTLS_ECP_MAX_PT_LEN]; 143 144 if( ( ret = mbedtls_ecp_point_write_binary( &ec->grp, &ec->Q, 145 MBEDTLS_ECP_PF_UNCOMPRESSED, 146 &len, buf, sizeof( buf ) ) ) != 0 ) 147 { 148 return( ret ); 149 } 150 151 if( *p < start || (size_t)( *p - start ) < len ) 152 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); 153 154 *p -= len; 155 memcpy( *p, buf, len ); 156 157 return( (int) len ); 158 } 159 160 /* 161 * ECParameters ::= CHOICE { 162 * namedCurve OBJECT IDENTIFIER 163 * } 164 */ 165 static int pk_write_ec_param( unsigned char **p, unsigned char *start, 166 mbedtls_ecp_keypair *ec ) 167 { 168 int ret; 169 size_t len = 0; 170 const char *oid; 171 size_t oid_len; 172 173 if( ( ret = mbedtls_oid_get_oid_by_ec_grp( ec->grp.id, &oid, &oid_len ) ) != 0 ) 174 return( ret ); 175 176 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_oid( p, start, oid, oid_len ) ); 177 178 return( (int) len ); 179 } 180 181 /* 182 * privateKey OCTET STRING -- always of length ceil(log2(n)/8) 183 */ 184 static int pk_write_ec_private( unsigned char **p, unsigned char *start, 185 mbedtls_ecp_keypair *ec ) 186 { 187 int ret; 188 size_t byte_length = ( ec->grp.pbits + 7 ) / 8; 189 unsigned char tmp[MBEDTLS_ECP_MAX_BYTES]; 190 191 ret = mbedtls_mpi_write_binary( &ec->d, tmp, byte_length ); 192 if( ret != 0 ) 193 goto exit; 194 ret = mbedtls_asn1_write_octet_string( p, start, tmp, byte_length ); 195 196 exit: 197 mbedtls_platform_zeroize( tmp, byte_length ); 198 return( ret ); 199 } 200 #endif /* MBEDTLS_ECP_C */ 201 202 int mbedtls_pk_write_pubkey( unsigned char **p, unsigned char *start, 203 const mbedtls_pk_context *key ) 204 { 205 int ret; 206 size_t len = 0; 207 208 PK_VALIDATE_RET( p != NULL ); 209 PK_VALIDATE_RET( *p != NULL ); 210 PK_VALIDATE_RET( start != NULL ); 211 PK_VALIDATE_RET( key != NULL ); 212 213 #if defined(MBEDTLS_RSA_C) 214 if( mbedtls_pk_get_type( key ) == MBEDTLS_PK_RSA ) 215 MBEDTLS_ASN1_CHK_ADD( len, pk_write_rsa_pubkey( p, start, mbedtls_pk_rsa( *key ) ) ); 216 else 217 #endif 218 #if defined(MBEDTLS_ECP_C) 219 if( mbedtls_pk_get_type( key ) == MBEDTLS_PK_ECKEY ) 220 MBEDTLS_ASN1_CHK_ADD( len, pk_write_ec_pubkey( p, start, mbedtls_pk_ec( *key ) ) ); 221 else 222 #endif 223 return( MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE ); 224 225 return( (int) len ); 226 } 227 228 int mbedtls_pk_write_pubkey_der( mbedtls_pk_context *key, unsigned char *buf, size_t size ) 229 { 230 int ret; 231 unsigned char *c; 232 size_t len = 0, par_len = 0, oid_len; 233 const char *oid; 234 235 PK_VALIDATE_RET( key != NULL ); 236 if( size == 0 ) 237 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); 238 PK_VALIDATE_RET( buf != NULL ); 239 240 c = buf + size; 241 242 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_pk_write_pubkey( &c, buf, key ) ); 243 244 if( c - buf < 1 ) 245 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); 246 247 /* 248 * SubjectPublicKeyInfo ::= SEQUENCE { 249 * algorithm AlgorithmIdentifier, 250 * subjectPublicKey BIT STRING } 251 */ 252 *--c = 0; 253 len += 1; 254 255 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) ); 256 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_BIT_STRING ) ); 257 258 if( ( ret = mbedtls_oid_get_oid_by_pk_alg( mbedtls_pk_get_type( key ), 259 &oid, &oid_len ) ) != 0 ) 260 { 261 return( ret ); 262 } 263 264 #if defined(MBEDTLS_ECP_C) 265 if( mbedtls_pk_get_type( key ) == MBEDTLS_PK_ECKEY ) 266 { 267 MBEDTLS_ASN1_CHK_ADD( par_len, pk_write_ec_param( &c, buf, mbedtls_pk_ec( *key ) ) ); 268 } 269 #endif 270 271 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_algorithm_identifier( &c, buf, oid, oid_len, 272 par_len ) ); 273 274 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) ); 275 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_CONSTRUCTED | 276 MBEDTLS_ASN1_SEQUENCE ) ); 277 278 return( (int) len ); 279 } 280 281 int mbedtls_pk_write_key_der( mbedtls_pk_context *key, unsigned char *buf, size_t size ) 282 { 283 int ret; 284 unsigned char *c; 285 size_t len = 0; 286 287 PK_VALIDATE_RET( key != NULL ); 288 if( size == 0 ) 289 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); 290 PK_VALIDATE_RET( buf != NULL ); 291 292 c = buf + size; 293 294 #if defined(MBEDTLS_RSA_C) 295 if( mbedtls_pk_get_type( key ) == MBEDTLS_PK_RSA ) 296 { 297 mbedtls_mpi T; /* Temporary holding the exported parameters */ 298 mbedtls_rsa_context *rsa = mbedtls_pk_rsa( *key ); 299 300 /* 301 * Export the parameters one after another to avoid simultaneous copies. 302 */ 303 304 mbedtls_mpi_init( &T ); 305 306 /* Export QP */ 307 if( ( ret = mbedtls_rsa_export_crt( rsa, NULL, NULL, &T ) ) != 0 || 308 ( ret = mbedtls_asn1_write_mpi( &c, buf, &T ) ) < 0 ) 309 goto end_of_export; 310 len += ret; 311 312 /* Export DQ */ 313 if( ( ret = mbedtls_rsa_export_crt( rsa, NULL, &T, NULL ) ) != 0 || 314 ( ret = mbedtls_asn1_write_mpi( &c, buf, &T ) ) < 0 ) 315 goto end_of_export; 316 len += ret; 317 318 /* Export DP */ 319 if( ( ret = mbedtls_rsa_export_crt( rsa, &T, NULL, NULL ) ) != 0 || 320 ( ret = mbedtls_asn1_write_mpi( &c, buf, &T ) ) < 0 ) 321 goto end_of_export; 322 len += ret; 323 324 /* Export Q */ 325 if ( ( ret = mbedtls_rsa_export( rsa, NULL, NULL, 326 &T, NULL, NULL ) ) != 0 || 327 ( ret = mbedtls_asn1_write_mpi( &c, buf, &T ) ) < 0 ) 328 goto end_of_export; 329 len += ret; 330 331 /* Export P */ 332 if ( ( ret = mbedtls_rsa_export( rsa, NULL, &T, 333 NULL, NULL, NULL ) ) != 0 || 334 ( ret = mbedtls_asn1_write_mpi( &c, buf, &T ) ) < 0 ) 335 goto end_of_export; 336 len += ret; 337 338 /* Export D */ 339 if ( ( ret = mbedtls_rsa_export( rsa, NULL, NULL, 340 NULL, &T, NULL ) ) != 0 || 341 ( ret = mbedtls_asn1_write_mpi( &c, buf, &T ) ) < 0 ) 342 goto end_of_export; 343 len += ret; 344 345 /* Export E */ 346 if ( ( ret = mbedtls_rsa_export( rsa, NULL, NULL, 347 NULL, NULL, &T ) ) != 0 || 348 ( ret = mbedtls_asn1_write_mpi( &c, buf, &T ) ) < 0 ) 349 goto end_of_export; 350 len += ret; 351 352 /* Export N */ 353 if ( ( ret = mbedtls_rsa_export( rsa, &T, NULL, 354 NULL, NULL, NULL ) ) != 0 || 355 ( ret = mbedtls_asn1_write_mpi( &c, buf, &T ) ) < 0 ) 356 goto end_of_export; 357 len += ret; 358 359 end_of_export: 360 361 mbedtls_mpi_free( &T ); 362 if( ret < 0 ) 363 return( ret ); 364 365 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_int( &c, buf, 0 ) ); 366 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) ); 367 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, 368 buf, MBEDTLS_ASN1_CONSTRUCTED | 369 MBEDTLS_ASN1_SEQUENCE ) ); 370 } 371 else 372 #endif /* MBEDTLS_RSA_C */ 373 #if defined(MBEDTLS_ECP_C) 374 if( mbedtls_pk_get_type( key ) == MBEDTLS_PK_ECKEY ) 375 { 376 mbedtls_ecp_keypair *ec = mbedtls_pk_ec( *key ); 377 size_t pub_len = 0, par_len = 0; 378 379 /* 380 * RFC 5915, or SEC1 Appendix C.4 381 * 382 * ECPrivateKey ::= SEQUENCE { 383 * version INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1), 384 * privateKey OCTET STRING, 385 * parameters [0] ECParameters {{ NamedCurve }} OPTIONAL, 386 * publicKey [1] BIT STRING OPTIONAL 387 * } 388 */ 389 390 /* publicKey */ 391 MBEDTLS_ASN1_CHK_ADD( pub_len, pk_write_ec_pubkey( &c, buf, ec ) ); 392 393 if( c - buf < 1 ) 394 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); 395 *--c = 0; 396 pub_len += 1; 397 398 MBEDTLS_ASN1_CHK_ADD( pub_len, mbedtls_asn1_write_len( &c, buf, pub_len ) ); 399 MBEDTLS_ASN1_CHK_ADD( pub_len, mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_BIT_STRING ) ); 400 401 MBEDTLS_ASN1_CHK_ADD( pub_len, mbedtls_asn1_write_len( &c, buf, pub_len ) ); 402 MBEDTLS_ASN1_CHK_ADD( pub_len, mbedtls_asn1_write_tag( &c, buf, 403 MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | 1 ) ); 404 len += pub_len; 405 406 /* parameters */ 407 MBEDTLS_ASN1_CHK_ADD( par_len, pk_write_ec_param( &c, buf, ec ) ); 408 409 MBEDTLS_ASN1_CHK_ADD( par_len, mbedtls_asn1_write_len( &c, buf, par_len ) ); 410 MBEDTLS_ASN1_CHK_ADD( par_len, mbedtls_asn1_write_tag( &c, buf, 411 MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | 0 ) ); 412 len += par_len; 413 414 /* privateKey */ 415 MBEDTLS_ASN1_CHK_ADD( len, pk_write_ec_private( &c, buf, ec ) ); 416 417 /* version */ 418 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_int( &c, buf, 1 ) ); 419 420 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) ); 421 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_CONSTRUCTED | 422 MBEDTLS_ASN1_SEQUENCE ) ); 423 } 424 else 425 #endif /* MBEDTLS_ECP_C */ 426 return( MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE ); 427 428 return( (int) len ); 429 } 430 431 #if defined(MBEDTLS_PEM_WRITE_C) 432 433 #define PEM_BEGIN_PUBLIC_KEY "-----BEGIN PUBLIC KEY-----\n" 434 #define PEM_END_PUBLIC_KEY "-----END PUBLIC KEY-----\n" 435 436 #define PEM_BEGIN_PRIVATE_KEY_RSA "-----BEGIN RSA PRIVATE KEY-----\n" 437 #define PEM_END_PRIVATE_KEY_RSA "-----END RSA PRIVATE KEY-----\n" 438 #define PEM_BEGIN_PRIVATE_KEY_EC "-----BEGIN EC PRIVATE KEY-----\n" 439 #define PEM_END_PRIVATE_KEY_EC "-----END EC PRIVATE KEY-----\n" 440 441 /* 442 * Max sizes of key per types. Shown as tag + len (+ content). 443 */ 444 445 #if defined(MBEDTLS_RSA_C) 446 /* 447 * RSA public keys: 448 * SubjectPublicKeyInfo ::= SEQUENCE { 1 + 3 449 * algorithm AlgorithmIdentifier, 1 + 1 (sequence) 450 * + 1 + 1 + 9 (rsa oid) 451 * + 1 + 1 (params null) 452 * subjectPublicKey BIT STRING } 1 + 3 + (1 + below) 453 * RSAPublicKey ::= SEQUENCE { 1 + 3 454 * modulus INTEGER, -- n 1 + 3 + MPI_MAX + 1 455 * publicExponent INTEGER -- e 1 + 3 + MPI_MAX + 1 456 * } 457 */ 458 #define RSA_PUB_DER_MAX_BYTES ( 38 + 2 * MBEDTLS_MPI_MAX_SIZE ) 459 460 /* 461 * RSA private keys: 462 * RSAPrivateKey ::= SEQUENCE { 1 + 3 463 * version Version, 1 + 1 + 1 464 * modulus INTEGER, 1 + 3 + MPI_MAX + 1 465 * publicExponent INTEGER, 1 + 3 + MPI_MAX + 1 466 * privateExponent INTEGER, 1 + 3 + MPI_MAX + 1 467 * prime1 INTEGER, 1 + 3 + MPI_MAX / 2 + 1 468 * prime2 INTEGER, 1 + 3 + MPI_MAX / 2 + 1 469 * exponent1 INTEGER, 1 + 3 + MPI_MAX / 2 + 1 470 * exponent2 INTEGER, 1 + 3 + MPI_MAX / 2 + 1 471 * coefficient INTEGER, 1 + 3 + MPI_MAX / 2 + 1 472 * otherPrimeInfos OtherPrimeInfos OPTIONAL 0 (not supported) 473 * } 474 */ 475 #define MPI_MAX_SIZE_2 ( MBEDTLS_MPI_MAX_SIZE / 2 + \ 476 MBEDTLS_MPI_MAX_SIZE % 2 ) 477 #define RSA_PRV_DER_MAX_BYTES ( 47 + 3 * MBEDTLS_MPI_MAX_SIZE \ 478 + 5 * MPI_MAX_SIZE_2 ) 479 480 #else /* MBEDTLS_RSA_C */ 481 482 #define RSA_PUB_DER_MAX_BYTES 0 483 #define RSA_PRV_DER_MAX_BYTES 0 484 485 #endif /* MBEDTLS_RSA_C */ 486 487 #if defined(MBEDTLS_ECP_C) 488 /* 489 * EC public keys: 490 * SubjectPublicKeyInfo ::= SEQUENCE { 1 + 2 491 * algorithm AlgorithmIdentifier, 1 + 1 (sequence) 492 * + 1 + 1 + 7 (ec oid) 493 * + 1 + 1 + 9 (namedCurve oid) 494 * subjectPublicKey BIT STRING 1 + 2 + 1 [1] 495 * + 1 (point format) [1] 496 * + 2 * ECP_MAX (coords) [1] 497 * } 498 */ 499 #define ECP_PUB_DER_MAX_BYTES ( 30 + 2 * MBEDTLS_ECP_MAX_BYTES ) 500 501 /* 502 * EC private keys: 503 * ECPrivateKey ::= SEQUENCE { 1 + 2 504 * version INTEGER , 1 + 1 + 1 505 * privateKey OCTET STRING, 1 + 1 + ECP_MAX 506 * parameters [0] ECParameters OPTIONAL, 1 + 1 + (1 + 1 + 9) 507 * publicKey [1] BIT STRING OPTIONAL 1 + 2 + [1] above 508 * } 509 */ 510 #define ECP_PRV_DER_MAX_BYTES ( 29 + 3 * MBEDTLS_ECP_MAX_BYTES ) 511 512 #else /* MBEDTLS_ECP_C */ 513 514 #define ECP_PUB_DER_MAX_BYTES 0 515 #define ECP_PRV_DER_MAX_BYTES 0 516 517 #endif /* MBEDTLS_ECP_C */ 518 519 #define PUB_DER_MAX_BYTES ( RSA_PUB_DER_MAX_BYTES > ECP_PUB_DER_MAX_BYTES ? \ 520 RSA_PUB_DER_MAX_BYTES : ECP_PUB_DER_MAX_BYTES ) 521 #define PRV_DER_MAX_BYTES ( RSA_PRV_DER_MAX_BYTES > ECP_PRV_DER_MAX_BYTES ? \ 522 RSA_PRV_DER_MAX_BYTES : ECP_PRV_DER_MAX_BYTES ) 523 524 int mbedtls_pk_write_pubkey_pem( mbedtls_pk_context *key, unsigned char *buf, size_t size ) 525 { 526 int ret; 527 unsigned char output_buf[PUB_DER_MAX_BYTES]; 528 size_t olen = 0; 529 530 PK_VALIDATE_RET( key != NULL ); 531 PK_VALIDATE_RET( buf != NULL || size == 0 ); 532 533 if( ( ret = mbedtls_pk_write_pubkey_der( key, output_buf, 534 sizeof(output_buf) ) ) < 0 ) 535 { 536 return( ret ); 537 } 538 539 if( ( ret = mbedtls_pem_write_buffer( PEM_BEGIN_PUBLIC_KEY, PEM_END_PUBLIC_KEY, 540 output_buf + sizeof(output_buf) - ret, 541 ret, buf, size, &olen ) ) != 0 ) 542 { 543 return( ret ); 544 } 545 546 return( 0 ); 547 } 548 549 int mbedtls_pk_write_key_pem( mbedtls_pk_context *key, unsigned char *buf, size_t size ) 550 { 551 int ret; 552 unsigned char output_buf[PRV_DER_MAX_BYTES]; 553 const char *begin, *end; 554 size_t olen = 0; 555 556 PK_VALIDATE_RET( key != NULL ); 557 PK_VALIDATE_RET( buf != NULL || size == 0 ); 558 559 if( ( ret = mbedtls_pk_write_key_der( key, output_buf, sizeof(output_buf) ) ) < 0 ) 560 return( ret ); 561 562 #if defined(MBEDTLS_RSA_C) 563 if( mbedtls_pk_get_type( key ) == MBEDTLS_PK_RSA ) 564 { 565 begin = PEM_BEGIN_PRIVATE_KEY_RSA; 566 end = PEM_END_PRIVATE_KEY_RSA; 567 } 568 else 569 #endif 570 #if defined(MBEDTLS_ECP_C) 571 if( mbedtls_pk_get_type( key ) == MBEDTLS_PK_ECKEY ) 572 { 573 begin = PEM_BEGIN_PRIVATE_KEY_EC; 574 end = PEM_END_PRIVATE_KEY_EC; 575 } 576 else 577 #endif 578 return( MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE ); 579 580 if( ( ret = mbedtls_pem_write_buffer( begin, end, 581 output_buf + sizeof(output_buf) - ret, 582 ret, buf, size, &olen ) ) != 0 ) 583 { 584 return( ret ); 585 } 586 587 return( 0 ); 588 } 589 #endif /* MBEDTLS_PEM_WRITE_C */ 590 591 #endif /* MBEDTLS_PK_WRITE_C */ 592