Subversion Repositories Kolibri OS

Rev

Blame | Last modification | View Log | Download | RSS feed

  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.     {
  430.         mbedtls_platform_zeroize( ctx->buf, ctx->buflen );
  431.         mbedtls_free( ctx->buf );
  432.     }
  433.     mbedtls_free( ctx->info );
  434.  
  435.     mbedtls_platform_zeroize( ctx, sizeof( mbedtls_pem_context ) );
  436. }
  437. #endif /* MBEDTLS_PEM_PARSE_C */
  438.  
  439. #if defined(MBEDTLS_PEM_WRITE_C)
  440. int mbedtls_pem_write_buffer( const char *header, const char *footer,
  441.                       const unsigned char *der_data, size_t der_len,
  442.                       unsigned char *buf, size_t buf_len, size_t *olen )
  443. {
  444.     int ret;
  445.     unsigned char *encode_buf = NULL, *c, *p = buf;
  446.     size_t len = 0, use_len, add_len = 0;
  447.  
  448.     mbedtls_base64_encode( NULL, 0, &use_len, der_data, der_len );
  449.     add_len = strlen( header ) + strlen( footer ) + ( use_len / 64 ) + 1;
  450.  
  451.     if( use_len + add_len > buf_len )
  452.     {
  453.         *olen = use_len + add_len;
  454.         return( MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL );
  455.     }
  456.  
  457.     if( use_len != 0 &&
  458.         ( ( encode_buf = mbedtls_calloc( 1, use_len ) ) == NULL ) )
  459.         return( MBEDTLS_ERR_PEM_ALLOC_FAILED );
  460.  
  461.     if( ( ret = mbedtls_base64_encode( encode_buf, use_len, &use_len, der_data,
  462.                                der_len ) ) != 0 )
  463.     {
  464.         mbedtls_free( encode_buf );
  465.         return( ret );
  466.     }
  467.  
  468.     memcpy( p, header, strlen( header ) );
  469.     p += strlen( header );
  470.     c = encode_buf;
  471.  
  472.     while( use_len )
  473.     {
  474.         len = ( use_len > 64 ) ? 64 : use_len;
  475.         memcpy( p, c, len );
  476.         use_len -= len;
  477.         p += len;
  478.         c += len;
  479.         *p++ = '\n';
  480.     }
  481.  
  482.     memcpy( p, footer, strlen( footer ) );
  483.     p += strlen( footer );
  484.  
  485.     *p++ = '\0';
  486.     *olen = p - buf;
  487.  
  488.     mbedtls_free( encode_buf );
  489.     return( 0 );
  490. }
  491. #endif /* MBEDTLS_PEM_WRITE_C */
  492. #endif /* MBEDTLS_PEM_PARSE_C || MBEDTLS_PEM_WRITE_C */
  493.