dll/3rdparty/mbedtls/pkwrite.c

   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 */