text: /**
   * \file pkcs5.c
   *
   * \brief PKCS#5 functions
   *
   * \author Mathias Olsson <mathias@kompetensum.com>
   *
   *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
   *  SPDX-License-Identifier: Apache-2.0
   *
   *  Licensed under the Apache License, Version 2.0 (the "License"); you may
   *  not use this file except in compliance with the License.
   *  You may obtain a copy of the License at
   *
   *  http://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   *
   *  This file is part of mbed TLS (https://tls.mbed.org)
   */
  /*
   * PKCS#5 includes PBKDF2 and more
   *
   * http://tools.ietf.org/html/rfc2898 (Specification)
   * http://tools.ietf.org/html/rfc6070 (Test vectors)
   */
  
  #if !defined(MBEDTLS_CONFIG_FILE)
  #include "mbedtls/config.h"
  #else
  #include MBEDTLS_CONFIG_FILE
  #endif
  
  #if defined(MBEDTLS_PKCS5_C)
  
  #include "mbedtls/pkcs5.h"
  #include "mbedtls/asn1.h"
  #include "mbedtls/cipher.h"
  #include "mbedtls/oid.h"
  
  #include <string.h>
  
  #if defined(MBEDTLS_PLATFORM_C)
  #include "mbedtls/platform.h"
  #else
  #include <stdio.h>
  #define mbedtls_printf iot_printf
  #endif
  
  FLASH_FUNC static int pkcs5_parse_pbkdf2_params( const mbedtls_asn1_buf *params,
                                        mbedtls_asn1_buf *salt, int *iterations,
                                        int *keylen, mbedtls_md_type_t *md_type )
  {
      int ret;
      mbedtls_asn1_buf prf_alg_oid;
      unsigned char *p = params->p;
      const unsigned char *end = params->p + params->len;
  
      if( params->tag != ( MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) )
          return( MBEDTLS_ERR_PKCS5_INVALID_FORMAT +
                  MBEDTLS_ERR_ASN1_UNEXPECTED_TAG );
      /*
       *  PBKDF2-params ::= SEQUENCE {
       *    salt              OCTET STRING,
       *    iterationCount    INTEGER,
       *    keyLength         INTEGER OPTIONAL
       *    prf               AlgorithmIdentifier DEFAULT algid-hmacWithSHA1
       *  }
       *
       */
      if( ( ret = mbedtls_asn1_get_tag( &p, end, &salt->len, MBEDTLS_ASN1_OCTET_STRING ) ) != 0 )
          return( MBEDTLS_ERR_PKCS5_INVALID_FORMAT + ret );
  
      salt->p = p;
      p += salt->len;
  
      if( ( ret = mbedtls_asn1_get_int( &p, end, iterations ) ) != 0 )
          return( MBEDTLS_ERR_PKCS5_INVALID_FORMAT + ret );
  
      if( p == end )
          return( 0 );
  
      if( ( ret = mbedtls_asn1_get_int( &p, end, keylen ) ) != 0 )
      {
          if( ret != MBEDTLS_ERR_ASN1_UNEXPECTED_TAG )
              return( MBEDTLS_ERR_PKCS5_INVALID_FORMAT + ret );
      }
  
      if( p == end )
          return( 0 );
  
      if( ( ret = mbedtls_asn1_get_alg_null( &p, end, &prf_alg_oid ) ) != 0 )
          return( MBEDTLS_ERR_PKCS5_INVALID_FORMAT + ret );
  
      if( MBEDTLS_OID_CMP( MBEDTLS_OID_HMAC_SHA1, &prf_alg_oid ) != 0 )
          return( MBEDTLS_ERR_PKCS5_FEATURE_UNAVAILABLE );
  
      *md_type = MBEDTLS_MD_SHA1;
  
      if( p != end )
          return( MBEDTLS_ERR_PKCS5_INVALID_FORMAT +
                  MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
  
      return( 0 );
  }
  
  FLASH_FUNC int mbedtls_pkcs5_pbes2( const mbedtls_asn1_buf *pbe_params, int mode,
                   const unsigned char *pwd,  size_t pwdlen,
                   const unsigned char *data, size_t datalen,
                   unsigned char *output )
  {
      int ret, iterations = 0, keylen = 0;
      unsigned char *p, *end;
      mbedtls_asn1_buf kdf_alg_oid, enc_scheme_oid, kdf_alg_params, enc_scheme_params;
      mbedtls_asn1_buf salt;
      mbedtls_md_type_t md_type = MBEDTLS_MD_SHA1;
      unsigned char key[32], iv[32];
      size_t olen = 0;
      const mbedtls_md_info_t *md_info;
      const mbedtls_cipher_info_t *cipher_info;
      mbedtls_md_context_t md_ctx;
      mbedtls_cipher_type_t cipher_alg;
      mbedtls_cipher_context_t cipher_ctx;
  
      p = pbe_params->p;
      end = p + pbe_params->len;
  
      /*
       *  PBES2-params ::= SEQUENCE {
       *    keyDerivationFunc AlgorithmIdentifier {{PBES2-KDFs}},
       *    encryptionScheme AlgorithmIdentifier {{PBES2-Encs}}
       *  }
       */
      if( pbe_params->tag != ( MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) )
          return( MBEDTLS_ERR_PKCS5_INVALID_FORMAT +
                  MBEDTLS_ERR_ASN1_UNEXPECTED_TAG );
  
      if( ( ret = mbedtls_asn1_get_alg( &p, end, &kdf_alg_oid, &kdf_alg_params ) ) != 0 )
          return( MBEDTLS_ERR_PKCS5_INVALID_FORMAT + ret );
  
      // Only PBKDF2 supported at the moment
      //
      if( MBEDTLS_OID_CMP( MBEDTLS_OID_PKCS5_PBKDF2, &kdf_alg_oid ) != 0 )
          return( MBEDTLS_ERR_PKCS5_FEATURE_UNAVAILABLE );
  
      if( ( ret = pkcs5_parse_pbkdf2_params( &kdf_alg_params,
                                             &salt, &iterations, &keylen,
                                             &md_type ) ) != 0 )
      {
          return( ret );
      }
  
      md_info = mbedtls_md_info_from_type( md_type );
      if( md_info == NULL )
          return( MBEDTLS_ERR_PKCS5_FEATURE_UNAVAILABLE );
  
      if( ( ret = mbedtls_asn1_get_alg( &p, end, &enc_scheme_oid,
                                &enc_scheme_params ) ) != 0 )
      {
          return( MBEDTLS_ERR_PKCS5_INVALID_FORMAT + ret );
      }
  
      if( mbedtls_oid_get_cipher_alg( &enc_scheme_oid, &cipher_alg ) != 0 )
          return( MBEDTLS_ERR_PKCS5_FEATURE_UNAVAILABLE );
  
      cipher_info = mbedtls_cipher_info_from_type( cipher_alg );
      if( cipher_info == NULL )
          return( MBEDTLS_ERR_PKCS5_FEATURE_UNAVAILABLE );
  
      /*
       * The value of keylen from pkcs5_parse_pbkdf2_params() is ignored
       * since it is optional and we don't know if it was set or not
       */
      keylen = cipher_info->key_bitlen / 8;
  
      if( enc_scheme_params.tag != MBEDTLS_ASN1_OCTET_STRING ||
          enc_scheme_params.len != cipher_info->iv_size )
      {
          return( MBEDTLS_ERR_PKCS5_INVALID_FORMAT );
      }
  
      mbedtls_md_init( &md_ctx );
      mbedtls_cipher_init( &cipher_ctx );
  
      memcpy( iv, enc_scheme_params.p, enc_scheme_params.len );
  
      if( ( ret = mbedtls_md_setup( &md_ctx, md_info, 1 ) ) != 0 )
          goto exit;
  
      if( ( ret = mbedtls_pkcs5_pbkdf2_hmac( &md_ctx, pwd, pwdlen, salt.p, salt.len,
                                     iterations, keylen, key ) ) != 0 )
      {
          goto exit;
      }
  
      if( ( ret = mbedtls_cipher_setup( &cipher_ctx, cipher_info ) ) != 0 )
          goto exit;
  
      if( ( ret = mbedtls_cipher_setkey( &cipher_ctx, key, 8 * keylen, (mbedtls_operation_t) mode ) ) != 0 )
          goto exit;
  
      if( ( ret = mbedtls_cipher_crypt( &cipher_ctx, iv, enc_scheme_params.len,
                                data, datalen, output, &olen ) ) != 0 )
          ret = MBEDTLS_ERR_PKCS5_PASSWORD_MISMATCH;
  
  exit:
      mbedtls_md_free( &md_ctx );
      mbedtls_cipher_free( &cipher_ctx );
  
      return( ret );
  }
  
  FLASH_FUNC int mbedtls_pkcs5_pbkdf2_hmac( mbedtls_md_context_t *ctx, const unsigned char *password,
                         size_t plen, const unsigned char *salt, size_t slen,
                         unsigned int iteration_count,
                         uint32_t key_length, unsigned char *output )
  {
      int ret, j;
      unsigned int i;
      unsigned char md1[MBEDTLS_MD_MAX_SIZE];
      unsigned char work[MBEDTLS_MD_MAX_SIZE];
      unsigned char md_size = mbedtls_md_get_size( ctx->md_info );
      size_t use_len;
      unsigned char *out_p = output;
      unsigned char counter[4];
  
      memset( counter, 0, 4 );
      counter[3] = 1;
  
      if( iteration_count > 0xFFFFFFFF )
          return( MBEDTLS_ERR_PKCS5_BAD_INPUT_DATA );
  
      while( key_length )
      {
          // U1 ends up in work
          //
          if( ( ret = mbedtls_md_hmac_starts( ctx, password, plen ) ) != 0 )
              return( ret );
  
          if( ( ret = mbedtls_md_hmac_update( ctx, salt, slen ) ) != 0 )
              return( ret );
  
          if( ( ret = mbedtls_md_hmac_update( ctx, counter, 4 ) ) != 0 )
              return( ret );
  
          if( ( ret = mbedtls_md_hmac_finish( ctx, work ) ) != 0 )
              return( ret );
  
          memcpy( md1, work, md_size );
  
          for( i = 1; i < iteration_count; i++ )
          {
              // U2 ends up in md1
              //
              if( ( ret = mbedtls_md_hmac_starts( ctx, password, plen ) ) != 0 )
                  return( ret );
  
              if( ( ret = mbedtls_md_hmac_update( ctx, md1, md_size ) ) != 0 )
                  return( ret );
  
              if( ( ret = mbedtls_md_hmac_finish( ctx, md1 ) ) != 0 )
                  return( ret );
  
              // U1 xor U2
              //
              for( j = 0; j < md_size; j++ )
                  work[j] ^= md1[j];
          }
  
          use_len = ( key_length < md_size ) ? key_length : md_size;
          memcpy( out_p, work, use_len );
  
          key_length -= (uint32_t) use_len;
          out_p += use_len;
  
          for( i = 4; i > 0; i-- )
              if( ++counter[i - 1] != 0 )
                  break;
      }
  
      return( 0 );
  }
  
  #if defined(MBEDTLS_SELF_TEST)
  
  #if !defined(MBEDTLS_SHA1_C)
  FLASH_FUNC int mbedtls_pkcs5_self_test( int verbose )
  {
      if( verbose != 0 )
          mbedtls_printf( "  PBKDF2 (SHA1): skipped\n\n" );
  
      return( 0 );
  }
  #else
  
  #define MAX_TESTS   6
  
  static const size_t plen[MAX_TESTS] =
      { 8, 8, 8, 24, 9 };
  
  static const unsigned char password[MAX_TESTS][32] =
  {
      "password",
      "password",
      "password",
      "passwordPASSWORDpassword",
      "pass\0word",
  };
  
  static const size_t slen[MAX_TESTS] =
      { 4, 4, 4, 36, 5 };
  
  static const unsigned char salt[MAX_TESTS][40] =
  {
      "salt",
      "salt",
      "salt",
      "saltSALTsaltSALTsaltSALTsaltSALTsalt",
      "sa\0lt",
  };
  
  static const uint32_t it_cnt[MAX_TESTS] =
      { 1, 2, 4096, 4096, 4096 };
  
  static const uint32_t key_len[MAX_TESTS] =
      { 20, 20, 20, 25, 16 };
  
  static const unsigned char result_key[MAX_TESTS][32] =
  {
      { 0x0c, 0x60, 0xc8, 0x0f, 0x96, 0x1f, 0x0e, 0x71,
        0xf3, 0xa9, 0xb5, 0x24, 0xaf, 0x60, 0x12, 0x06,
        0x2f, 0xe0, 0x37, 0xa6 },
      { 0xea, 0x6c, 0x01, 0x4d, 0xc7, 0x2d, 0x6f, 0x8c,
        0xcd, 0x1e, 0xd9, 0x2a, 0xce, 0x1d, 0x41, 0xf0,
        0xd8, 0xde, 0x89, 0x57 },
      { 0x4b, 0x00, 0x79, 0x01, 0xb7, 0x65, 0x48, 0x9a,
        0xbe, 0xad, 0x49, 0xd9, 0x26, 0xf7, 0x21, 0xd0,
        0x65, 0xa4, 0x29, 0xc1 },
      { 0x3d, 0x2e, 0xec, 0x4f, 0xe4, 0x1c, 0x84, 0x9b,
        0x80, 0xc8, 0xd8, 0x36, 0x62, 0xc0, 0xe4, 0x4a,
        0x8b, 0x29, 0x1a, 0x96, 0x4c, 0xf2, 0xf0, 0x70,
        0x38 },
      { 0x56, 0xfa, 0x6a, 0xa7, 0x55, 0x48, 0x09, 0x9d,
        0xcc, 0x37, 0xd7, 0xf0, 0x34, 0x25, 0xe0, 0xc3 },
  };
  
  FLASH_FUNC int mbedtls_pkcs5_self_test( int verbose )
  {
      mbedtls_md_context_t sha1_ctx;
      const mbedtls_md_info_t *info_sha1;
      int ret, i;
      unsigned char key[64];
  
      mbedtls_md_init( &sha1_ctx );
  
      info_sha1 = mbedtls_md_info_from_type( MBEDTLS_MD_SHA1 );
      if( info_sha1 == NULL )
      {
          ret = 1;
          goto exit;
      }
  
      if( ( ret = mbedtls_md_setup( &sha1_ctx, info_sha1, 1 ) ) != 0 )
      {
          ret = 1;
          goto exit;
      }
  
      for( i = 0; i < MAX_TESTS; i++ )
      {
          if( verbose != 0 )
              mbedtls_printf( "  PBKDF2 (SHA1) #%d: ", i );
  
          ret = mbedtls_pkcs5_pbkdf2_hmac( &sha1_ctx, password[i], plen[i], salt[i],
                                    slen[i], it_cnt[i], key_len[i], key );
          if( ret != 0 ||
              memcmp( result_key[i], key, key_len[i] ) != 0 )
          {
              if( verbose != 0 )
                  mbedtls_printf( "failed\n" );
  
              ret = 1;
              goto exit;
          }
  
          if( verbose != 0 )
              mbedtls_printf( "passed\n" );
      }
  
      if( verbose != 0 )
          mbedtls_printf( "\n" );
  
  exit:
      mbedtls_md_free( &sha1_ctx );
  
      return( ret );
  }
  #endif /* MBEDTLS_SHA1_C */
  
  #endif /* MBEDTLS_SELF_TEST */
  
  #endif /* MBEDTLS_PKCS5_C */
  