git.zerfleddert.de Git - proxmark3-svn/blob - common/mbedtls/pem.c

   1 /*
   2  *  Privacy Enhanced Mail (PEM) decoding
   3  *
   4  *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
   5  *  SPDX-License-Identifier: GPL-2.0
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License as published by
   9  *  the Free Software Foundation; either version 2 of the License, or
  10  *  (at your option) any later version.
  11  *
  12  *  This program is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *  GNU General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU General Public License along
  18  *  with this program; if not, write to the Free Software Foundation, Inc.,
  19  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  *  This file is part of mbed TLS (https://tls.mbed.org)
  22  */
  23
  24 #if !defined(MBEDTLS_CONFIG_FILE)
  25 #include "mbedtls/config.h"
  26 #else
  27 #include MBEDTLS_CONFIG_FILE
  28 #endif
  29
  30 #if defined(MBEDTLS_PEM_PARSE_C) || defined(MBEDTLS_PEM_WRITE_C)
  31
  32 #include "mbedtls/pem.h"
  33 #include "mbedtls/base64.h"
  34 #include "mbedtls/des.h"
  35 #include "mbedtls/aes.h"
  36 #include "mbedtls/md5.h"
  37 #include "mbedtls/cipher.h"
  38 #include "mbedtls/platform_util.h"
  39
  40 #include <string.h>
  41
  42 #if defined(MBEDTLS_PLATFORM_C)
  43 #include "mbedtls/platform.h"
  44 #else
  45 #include <stdlib.h>
  46 #define mbedtls_calloc    calloc
  47 #define mbedtls_free       free
  48 #endif
  49
  50 #if defined(MBEDTLS_PEM_PARSE_C)
  51 void mbedtls_pem_init( mbedtls_pem_context *ctx )
  52 {
  53     memset( ctx, 0, sizeof( mbedtls_pem_context ) );
  54 }
  55
  56 #if defined(MBEDTLS_MD5_C) && defined(MBEDTLS_CIPHER_MODE_CBC) &&         \
  57     ( defined(MBEDTLS_DES_C) || defined(MBEDTLS_AES_C) )
  58 /*
  59  * Read a 16-byte hex string and convert it to binary
  60  */
  61 static int pem_get_iv( const unsigned char *s, unsigned char *iv,
  62                        size_t iv_len )
  63 {
  64     size_t i, j, k;
  65
  66     memset( iv, 0, iv_len );
  67
  68     for( i = 0; i < iv_len * 2; i++, s++ )
  69     {
  70         if( *s >= '0' && *s <= '9' ) j = *s - '0'; else
  71         if( *s >= 'A' && *s <= 'F' ) j = *s - '7'; else
  72         if( *s >= 'a' && *s <= 'f' ) j = *s - 'W'; else
  73             return( MBEDTLS_ERR_PEM_INVALID_ENC_IV );
  74
  75         k = ( ( i & 1 ) != 0 ) ? j : j << 4;
  76
  77         iv[i >> 1] = (unsigned char)( iv[i >> 1] | k );
  78     }
  79
  80     return( 0 );
  81 }
  82
  83 static int pem_pbkdf1( unsigned char *key, size_t keylen,
  84                        unsigned char *iv,
  85                        const unsigned char *pwd, size_t pwdlen )
  86 {
  87     mbedtls_md5_context md5_ctx;
  88     unsigned char md5sum[16];
  89     size_t use_len;
  90     int ret;
  91
  92     mbedtls_md5_init( &md5_ctx );
  93
  94     /*
  95      * key[ 0..15] = MD5(pwd || IV)
  96      */
  97     if( ( ret = mbedtls_md5_starts_ret( &md5_ctx ) ) != 0 )
  98         goto exit;
  99     if( ( ret = mbedtls_md5_update_ret( &md5_ctx, pwd, pwdlen ) ) != 0 )
 100         goto exit;
 101     if( ( ret = mbedtls_md5_update_ret( &md5_ctx, iv,  8 ) ) != 0 )
 102         goto exit;
 103     if( ( ret = mbedtls_md5_finish_ret( &md5_ctx, md5sum ) ) != 0 )
 104         goto exit;
 105
 106     if( keylen <= 16 )
 107     {
 108         memcpy( key, md5sum, keylen );
 109         goto exit;
 110     }
 111
 112     memcpy( key, md5sum, 16 );
 113
 114     /*
 115      * key[16..23] = MD5(key[ 0..15] || pwd || IV])
 116      */
 117     if( ( ret = mbedtls_md5_starts_ret( &md5_ctx ) ) != 0 )
 118         goto exit;
 119     if( ( ret = mbedtls_md5_update_ret( &md5_ctx, md5sum, 16 ) ) != 0 )
 120         goto exit;
 121     if( ( ret = mbedtls_md5_update_ret( &md5_ctx, pwd, pwdlen ) ) != 0 )
 122         goto exit;
 123     if( ( ret = mbedtls_md5_update_ret( &md5_ctx, iv, 8 ) ) != 0 )
 124         goto exit;
 125     if( ( ret = mbedtls_md5_finish_ret( &md5_ctx, md5sum ) ) != 0 )
 126         goto exit;
 127
 128     use_len = 16;
 129     if( keylen < 32 )
 130         use_len = keylen - 16;
 131
 132     memcpy( key + 16, md5sum, use_len );
 133
 134 exit:
 135     mbedtls_md5_free( &md5_ctx );
 136     mbedtls_platform_zeroize( md5sum, 16 );
 137
 138     return( ret );
 139 }
 140
 141 #if defined(MBEDTLS_DES_C)
 142 /*
 143  * Decrypt with DES-CBC, using PBKDF1 for key derivation
 144  */
 145 static int pem_des_decrypt( unsigned char des_iv[8],
 146                             unsigned char *buf, size_t buflen,
 147                             const unsigned char *pwd, size_t pwdlen )
 148 {
 149     mbedtls_des_context des_ctx;
 150     unsigned char des_key[8];
 151     int ret;
 152
 153     mbedtls_des_init( &des_ctx );
 154
 155     if( ( ret = pem_pbkdf1( des_key, 8, des_iv, pwd, pwdlen ) ) != 0 )
 156         goto exit;
 157
 158     if( ( ret = mbedtls_des_setkey_dec( &des_ctx, des_key ) ) != 0 )
 159         goto exit;
 160     ret = mbedtls_des_crypt_cbc( &des_ctx, MBEDTLS_DES_DECRYPT, buflen,
 161                      des_iv, buf, buf );
 162
 163 exit:
 164     mbedtls_des_free( &des_ctx );
 165     mbedtls_platform_zeroize( des_key, 8 );
 166
 167     return( ret );
 168 }
 169
 170 /*
 171  * Decrypt with 3DES-CBC, using PBKDF1 for key derivation
 172  */
 173 static int pem_des3_decrypt( unsigned char des3_iv[8],
 174                              unsigned char *buf, size_t buflen,
 175                              const unsigned char *pwd, size_t pwdlen )
 176 {
 177     mbedtls_des3_context des3_ctx;
 178     unsigned char des3_key[24];
 179     int ret;
 180
 181     mbedtls_des3_init( &des3_ctx );
 182
 183     if( ( ret = pem_pbkdf1( des3_key, 24, des3_iv, pwd, pwdlen ) ) != 0 )
 184         goto exit;
 185
 186     if( ( ret = mbedtls_des3_set3key_dec( &des3_ctx, des3_key ) ) != 0 )
 187         goto exit;
 188     ret = mbedtls_des3_crypt_cbc( &des3_ctx, MBEDTLS_DES_DECRYPT, buflen,
 189                      des3_iv, buf, buf );
 190
 191 exit:
 192     mbedtls_des3_free( &des3_ctx );
 193     mbedtls_platform_zeroize( des3_key, 24 );
 194
 195     return( ret );
 196 }
 197 #endif /* MBEDTLS_DES_C */
 198
 199 #if defined(MBEDTLS_AES_C)
 200 /*
 201  * Decrypt with AES-XXX-CBC, using PBKDF1 for key derivation
 202  */
 203 static int pem_aes_decrypt( unsigned char aes_iv[16], unsigned int keylen,
 204                             unsigned char *buf, size_t buflen,
 205                             const unsigned char *pwd, size_t pwdlen )
 206 {
 207     mbedtls_aes_context aes_ctx;
 208     unsigned char aes_key[32];
 209     int ret;
 210
 211     mbedtls_aes_init( &aes_ctx );
 212
 213     if( ( ret = pem_pbkdf1( aes_key, keylen, aes_iv, pwd, pwdlen ) ) != 0 )
 214         goto exit;
 215
 216     if( ( ret = mbedtls_aes_setkey_dec( &aes_ctx, aes_key, keylen * 8 ) ) != 0 )
 217         goto exit;
 218     ret = mbedtls_aes_crypt_cbc( &aes_ctx, MBEDTLS_AES_DECRYPT, buflen,
 219                      aes_iv, buf, buf );
 220
 221 exit:
 222     mbedtls_aes_free( &aes_ctx );
 223     mbedtls_platform_zeroize( aes_key, keylen );
 224
 225     return( ret );
 226 }
 227 #endif /* MBEDTLS_AES_C */
 228
 229 #endif /* MBEDTLS_MD5_C && MBEDTLS_CIPHER_MODE_CBC &&
 230           ( MBEDTLS_AES_C || MBEDTLS_DES_C ) */
 231
 232 int mbedtls_pem_read_buffer( mbedtls_pem_context *ctx, const char *header, const char *footer,
 233                      const unsigned char *data, const unsigned char *pwd,
 234                      size_t pwdlen, size_t *use_len )
 235 {
 236     int ret, enc;
 237     size_t len;
 238     unsigned char *buf;
 239     const unsigned char *s1, *s2, *end;
 240 #if defined(MBEDTLS_MD5_C) && defined(MBEDTLS_CIPHER_MODE_CBC) &&         \
 241     ( defined(MBEDTLS_DES_C) || defined(MBEDTLS_AES_C) )
 242     unsigned char pem_iv[16];
 243     mbedtls_cipher_type_t enc_alg = MBEDTLS_CIPHER_NONE;
 244 #else
 245     ((void) pwd);
 246     ((void) pwdlen);
 247 #endif /* MBEDTLS_MD5_C && MBEDTLS_CIPHER_MODE_CBC &&
 248           ( MBEDTLS_AES_C || MBEDTLS_DES_C ) */
 249
 250     if( ctx == NULL )
 251         return( MBEDTLS_ERR_PEM_BAD_INPUT_DATA );
 252
 253     s1 = (unsigned char *) strstr( (const char *) data, header );
 254
 255     if( s1 == NULL )
 256         return( MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT );
 257
 258     s2 = (unsigned char *) strstr( (const char *) data, footer );
 259
 260     if( s2 == NULL || s2 <= s1 )
 261         return( MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT );
 262
 263     s1 += strlen( header );
 264     if( *s1 == ' '  ) s1++;
 265     if( *s1 == '\r' ) s1++;
 266     if( *s1 == '\n' ) s1++;
 267     else return( MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT );
 268
 269     end = s2;
 270     end += strlen( footer );
 271     if( *end == ' '  ) end++;
 272     if( *end == '\r' ) end++;
 273     if( *end == '\n' ) end++;
 274     *use_len = end - data;
 275
 276     enc = 0;
 277
 278     if( s2 - s1 >= 22 && memcmp( s1, "Proc-Type: 4,ENCRYPTED", 22 ) == 0 )
 279     {
 280 #if defined(MBEDTLS_MD5_C) && defined(MBEDTLS_CIPHER_MODE_CBC) &&         \
 281     ( defined(MBEDTLS_DES_C) || defined(MBEDTLS_AES_C) )
 282         enc++;
 283
 284         s1 += 22;
 285         if( *s1 == '\r' ) s1++;
 286         if( *s1 == '\n' ) s1++;
 287         else return( MBEDTLS_ERR_PEM_INVALID_DATA );
 288
 289
 290 #if defined(MBEDTLS_DES_C)
 291         if( s2 - s1 >= 23 && memcmp( s1, "DEK-Info: DES-EDE3-CBC,", 23 ) == 0 )
 292         {
 293             enc_alg = MBEDTLS_CIPHER_DES_EDE3_CBC;
 294
 295             s1 += 23;
 296             if( s2 - s1 < 16 || pem_get_iv( s1, pem_iv, 8 ) != 0 )
 297                 return( MBEDTLS_ERR_PEM_INVALID_ENC_IV );
 298
 299             s1 += 16;
 300         }
 301         else if( s2 - s1 >= 18 && memcmp( s1, "DEK-Info: DES-CBC,", 18 ) == 0 )
 302         {
 303             enc_alg = MBEDTLS_CIPHER_DES_CBC;
 304
 305             s1 += 18;
 306             if( s2 - s1 < 16 || pem_get_iv( s1, pem_iv, 8) != 0 )
 307                 return( MBEDTLS_ERR_PEM_INVALID_ENC_IV );
 308
 309             s1 += 16;
 310         }
 311 #endif /* MBEDTLS_DES_C */
 312
 313 #if defined(MBEDTLS_AES_C)
 314         if( s2 - s1 >= 14 && memcmp( s1, "DEK-Info: AES-", 14 ) == 0 )
 315         {
 316             if( s2 - s1 < 22 )
 317                 return( MBEDTLS_ERR_PEM_UNKNOWN_ENC_ALG );
 318             else if( memcmp( s1, "DEK-Info: AES-128-CBC,", 22 ) == 0 )
 319                 enc_alg = MBEDTLS_CIPHER_AES_128_CBC;
 320             else if( memcmp( s1, "DEK-Info: AES-192-CBC,", 22 ) == 0 )
 321                 enc_alg = MBEDTLS_CIPHER_AES_192_CBC;
 322             else if( memcmp( s1, "DEK-Info: AES-256-CBC,", 22 ) == 0 )
 323                 enc_alg = MBEDTLS_CIPHER_AES_256_CBC;
 324             else
 325                 return( MBEDTLS_ERR_PEM_UNKNOWN_ENC_ALG );
 326
 327             s1 += 22;
 328             if( s2 - s1 < 32 || pem_get_iv( s1, pem_iv, 16 ) != 0 )
 329                 return( MBEDTLS_ERR_PEM_INVALID_ENC_IV );
 330
 331             s1 += 32;
 332         }
 333 #endif /* MBEDTLS_AES_C */
 334
 335         if( enc_alg == MBEDTLS_CIPHER_NONE )
 336             return( MBEDTLS_ERR_PEM_UNKNOWN_ENC_ALG );
 337
 338         if( *s1 == '\r' ) s1++;
 339         if( *s1 == '\n' ) s1++;
 340         else return( MBEDTLS_ERR_PEM_INVALID_DATA );
 341 #else
 342         return( MBEDTLS_ERR_PEM_FEATURE_UNAVAILABLE );
 343 #endif /* MBEDTLS_MD5_C && MBEDTLS_CIPHER_MODE_CBC &&
 344           ( MBEDTLS_AES_C || MBEDTLS_DES_C ) */
 345     }
 346
 347     if( s1 >= s2 )
 348         return( MBEDTLS_ERR_PEM_INVALID_DATA );
 349
 350     ret = mbedtls_base64_decode( NULL, 0, &len, s1, s2 - s1 );
 351
 352     if( ret == MBEDTLS_ERR_BASE64_INVALID_CHARACTER )
 353         return( MBEDTLS_ERR_PEM_INVALID_DATA + ret );
 354
 355     if( ( buf = mbedtls_calloc( 1, len ) ) == NULL )
 356         return( MBEDTLS_ERR_PEM_ALLOC_FAILED );
 357
 358     if( ( ret = mbedtls_base64_decode( buf, len, &len, s1, s2 - s1 ) ) != 0 )
 359     {
 360         mbedtls_platform_zeroize( buf, len );
 361         mbedtls_free( buf );
 362         return( MBEDTLS_ERR_PEM_INVALID_DATA + ret );
 363     }
 364
 365     if( enc != 0 )
 366     {
 367 #if defined(MBEDTLS_MD5_C) && defined(MBEDTLS_CIPHER_MODE_CBC) &&         \
 368     ( defined(MBEDTLS_DES_C) || defined(MBEDTLS_AES_C) )
 369         if( pwd == NULL )
 370         {
 371             mbedtls_platform_zeroize( buf, len );
 372             mbedtls_free( buf );
 373             return( MBEDTLS_ERR_PEM_PASSWORD_REQUIRED );
 374         }
 375
 376         ret = 0;
 377
 378 #if defined(MBEDTLS_DES_C)
 379         if( enc_alg == MBEDTLS_CIPHER_DES_EDE3_CBC )
 380             ret = pem_des3_decrypt( pem_iv, buf, len, pwd, pwdlen );
 381         else if( enc_alg == MBEDTLS_CIPHER_DES_CBC )
 382             ret = pem_des_decrypt( pem_iv, buf, len, pwd, pwdlen );
 383 #endif /* MBEDTLS_DES_C */
 384
 385 #if defined(MBEDTLS_AES_C)
 386         if( enc_alg == MBEDTLS_CIPHER_AES_128_CBC )
 387             ret = pem_aes_decrypt( pem_iv, 16, buf, len, pwd, pwdlen );
 388         else if( enc_alg == MBEDTLS_CIPHER_AES_192_CBC )
 389             ret = pem_aes_decrypt( pem_iv, 24, buf, len, pwd, pwdlen );
 390         else if( enc_alg == MBEDTLS_CIPHER_AES_256_CBC )
 391             ret = pem_aes_decrypt( pem_iv, 32, buf, len, pwd, pwdlen );
 392 #endif /* MBEDTLS_AES_C */
 393
 394         if( ret != 0 )
 395         {
 396             mbedtls_free( buf );
 397             return( ret );
 398         }
 399
 400         /*
 401          * The result will be ASN.1 starting with a SEQUENCE tag, with 1 to 3
 402          * length bytes (allow 4 to be sure) in all known use cases.
 403          *
 404          * Use that as a heuristic to try to detect password mismatches.
 405          */
 406         if( len <= 2 || buf[0] != 0x30 || buf[1] > 0x83 )
 407         {
 408             mbedtls_platform_zeroize( buf, len );
 409             mbedtls_free( buf );
 410             return( MBEDTLS_ERR_PEM_PASSWORD_MISMATCH );
 411         }
 412 #else
 413         mbedtls_platform_zeroize( buf, len );
 414         mbedtls_free( buf );
 415         return( MBEDTLS_ERR_PEM_FEATURE_UNAVAILABLE );
 416 #endif /* MBEDTLS_MD5_C && MBEDTLS_CIPHER_MODE_CBC &&
 417           ( MBEDTLS_AES_C || MBEDTLS_DES_C ) */
 418     }
 419
 420     ctx->buf = buf;
 421     ctx->buflen = len;
 422
 423     return( 0 );
 424 }
 425
 426 void mbedtls_pem_free( mbedtls_pem_context *ctx )
 427 {
 428     if( ctx->buf != NULL )
 429         mbedtls_platform_zeroize( ctx->buf, ctx->buflen );
 430     mbedtls_free( ctx->buf );
 431     mbedtls_free( ctx->info );
 432
 433     mbedtls_platform_zeroize( ctx, sizeof( mbedtls_pem_context ) );
 434 }
 435 #endif /* MBEDTLS_PEM_PARSE_C */
 436
 437 #if defined(MBEDTLS_PEM_WRITE_C)
 438 int mbedtls_pem_write_buffer( const char *header, const char *footer,
 439                       const unsigned char *der_data, size_t der_len,
 440                       unsigned char *buf, size_t buf_len, size_t *olen )
 441 {
 442     int ret;
 443     unsigned char *encode_buf = NULL, *c, *p = buf;
 444     size_t len = 0, use_len, add_len = 0;
 445
 446     mbedtls_base64_encode( NULL, 0, &use_len, der_data, der_len );
 447     add_len = strlen( header ) + strlen( footer ) + ( use_len / 64 ) + 1;
 448
 449     if( use_len + add_len > buf_len )
 450     {
 451         *olen = use_len + add_len;
 452         return( MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL );
 453     }
 454
 455     if( use_len != 0 &&
 456         ( ( encode_buf = mbedtls_calloc( 1, use_len ) ) == NULL ) )
 457         return( MBEDTLS_ERR_PEM_ALLOC_FAILED );
 458
 459     if( ( ret = mbedtls_base64_encode( encode_buf, use_len, &use_len, der_data,
 460                                der_len ) ) != 0 )
 461     {
 462         mbedtls_free( encode_buf );
 463         return( ret );
 464     }
 465
 466     memcpy( p, header, strlen( header ) );
 467     p += strlen( header );
 468     c = encode_buf;
 469
 470     while( use_len )
 471     {
 472         len = ( use_len > 64 ) ? 64 : use_len;
 473         memcpy( p, c, len );
 474         use_len -= len;
 475         p += len;
 476         c += len;
 477         *p++ = '\n';
 478     }
 479
 480     memcpy( p, footer, strlen( footer ) );
 481     p += strlen( footer );
 482
 483     *p++ = '\0';
 484     *olen = p - buf;
 485
 486     mbedtls_free( encode_buf );
 487     return( 0 );
 488 }
 489 #endif /* MBEDTLS_PEM_WRITE_C */
 490 #endif /* MBEDTLS_PEM_PARSE_C || MBEDTLS_PEM_WRITE_C */