Class: RubySMB::Gss::Provider::NTLM::Authenticator

Inherits:
Authenticator::Base
  • Object
show all
Defined in:
lib/ruby_smb/gss/provider/ntlm.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#server_challenge ⇒ Object

Returns the value of attribute server_challenge.



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# File 'lib/ruby_smb/gss/provider/ntlm.rb', line 189

def server_challenge
  @server_challenge
end

Instance Method Details

#process(request_buffer = nil) ⇒ Object 



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# File 'lib/ruby_smb/gss/provider/ntlm.rb', line 27

def process(request_buffer=nil)
  if request_buffer.nil?
    # this is only NTLMSSP (as opposed to SPNEGO + NTLMSSP)
    buffer = OpenSSL::ASN1::ASN1Data.new([
      Gss::OID_SPNEGO,
      OpenSSL::ASN1::ASN1Data.new([
        OpenSSL::ASN1::Sequence.new([
          OpenSSL::ASN1::ASN1Data.new([
            OpenSSL::ASN1::Sequence.new([
              Gss::OID_NTLMSSP
            ])
          ], 0, :CONTEXT_SPECIFIC),
          OpenSSL::ASN1::ASN1Data.new([
            OpenSSL::ASN1::ASN1Data.new([
              OpenSSL::ASN1::ASN1Data.new([
                OpenSSL::ASN1::GeneralString.new('not_defined_in_RFC4178@please_ignore')
              ], 0, :CONTEXT_SPECIFIC)
            ], 16, :UNIVERSAL)
          ], 3, :CONTEXT_SPECIFIC)
        ])
      ], 0, :CONTEXT_SPECIFIC)
    ], 0, :APPLICATION).to_der
    return Result.new(buffer, WindowsError::NTStatus::STATUS_SUCCESS)
  end

  begin
    gss_api = OpenSSL::ASN1.decode(request_buffer)
  rescue OpenSSL::ASN1::ASN1Error => e
    logger.error("Failed to parse the ASN1-encoded authentication request (#{e.message})")
    return
  end

  if gss_api&.tag == 0 && gss_api&.tag_class == :APPLICATION
    result = process_gss_type1(gss_api)
  elsif gss_api&.tag == 1 && gss_api&.tag_class == :CONTEXT_SPECIFIC
    result = process_gss_type3(gss_api)
  end

  result
end

#process_ntlm_type1(type1_msg) ⇒ Net::NTLM::Message::Type2

Process the NTLM type 1 message and build a type 2 response message.

Parameters:

  • type1_msg (Net::NTLM::Message::Type1) —

    the NTLM type 1 message received by the client that should be processed

Returns:

  • (Net::NTLM::Message::Type2) —

    the NTLM type 2 response message with which to reply to the client



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# File 'lib/ruby_smb/gss/provider/ntlm.rb', line 74

def process_ntlm_type1(type1_msg)
  type2_msg = Net::NTLM::Message::Type2.new.tap do |msg|
    msg.target_name = 'LOCALHOST'.encode('UTF-16LE').b
    msg.flag = 0
    %i{ KEY56 KEY128 KEY_EXCHANGE UNICODE TARGET_INFO VERSION_INFO }.each do |flag|
      msg.flag |= NTLM::NEGOTIATE_FLAGS.fetch(flag)
    end

    if type1_msg.flag & NTLM::NEGOTIATE_FLAGS[:EXTENDED_SECURITY] == NTLM::NEGOTIATE_FLAGS[:EXTENDED_SECURITY]
      msg.flag |= NTLM::NEGOTIATE_FLAGS[:EXTENDED_SECURITY]
    end

    @server_challenge = @provider.generate_server_challenge
    msg.challenge = @server_challenge.unpack1('Q<') # 64-bit unsigned, little endian (uint64_t)
    target_info = Net::NTLM::TargetInfo.new('')
    target_info.av_pairs.merge!({
      Net::NTLM::TargetInfo::MSV_AV_NB_DOMAIN_NAME => @provider.netbios_domain.encode('UTF-16LE').b,
      Net::NTLM::TargetInfo::MSV_AV_NB_COMPUTER_NAME => @provider.netbios_hostname.encode('UTF-16LE').b,
      Net::NTLM::TargetInfo::MSV_AV_DNS_DOMAIN_NAME => @provider.dns_domain.encode('UTF-16LE').b,
      Net::NTLM::TargetInfo::MSV_AV_DNS_COMPUTER_NAME => @provider.dns_hostname.encode('UTF-16LE').b,
      Net::NTLM::TargetInfo::MSV_AV_TIMESTAMP => [(Time.now.to_i + Net::NTLM::TIME_OFFSET) * Field::FileTime::NS_MULTIPLIER].pack('Q')
    })
    msg.target_info = target_info.to_s
    msg.enable(:target_info)
    msg.context = 0
    msg.enable(:context)
    msg.os_version = NTLM::OSVersion.new(major: 6, minor: 3).to_binary_s
    msg.enable(:os_version)
  end

  type2_msg
end

#process_ntlm_type3(type3_msg) ⇒ WindowsError::ErrorCode

Process the NTLM type 3 message and either accept or reject the authentication attempt.

Parameters:

  • type3_msg (Net::NTLM::Message::Type3) —

    the NTLM type 3 message received by the client that should be processed

Returns:

  • (WindowsError::ErrorCode) —

    an NT Status error code representing the operations outcome where STATUS_SUCCESS is a successful authentication attempt and anything else is a failure



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# File 'lib/ruby_smb/gss/provider/ntlm.rb', line 114

def process_ntlm_type3(type3_msg)
  if type3_msg.user == '' && type3_msg.domain == ''
    if @provider.allow_anonymous
      @session_key = "\x00".b * 16 # see MS-NLMP section 3.4
      return WindowsError::NTStatus::STATUS_SUCCESS
    end

    return WindowsError::NTStatus::STATUS_LOGON_FAILURE
  end

  dbg_string = "#{type3_msg.domain.encode(''.encoding)}\\#{type3_msg.user.encode(''.encoding)}"
  logger.debug("NTLM authentication request received for #{dbg_string}")
   = @provider.(
    type3_msg.user,
    domain: type3_msg.domain
  )
  if .nil?
    if @provider.allow_guests
      logger.info("NTLM authentication request succeeded for #{dbg_string} (guest)")
      @session_key = "\x00".b * 16 # see MS-NLMP section 3.4
      return WindowsError::NTStatus::STATUS_SUCCESS
    end

    logger.info("NTLM authentication request failed for #{dbg_string} (no account)")
    return WindowsError::NTStatus::STATUS_LOGON_FAILURE
  end

  matches = false
  case type3_msg.ntlm_version
  when :ntlmv1
    my_ntlm_response = Net::NTLM::ntlm_response(
      ntlm_hash: Net::NTLM::ntlm_hash(.password),
      challenge: @server_challenge
    )
    matches = my_ntlm_response == type3_msg.ntlm_response
  when :ntlmv2
    digest = OpenSSL::Digest::MD5.new
    their_nt_proof_str = type3_msg.ntlm_response[0...digest.digest_length]
    their_blob = type3_msg.ntlm_response[digest.digest_length..-1]

    ntlmv2_hash = Net::NTLM.ntlmv2_hash(
      Net::NTLM::EncodeUtil.encode_utf16le(.username),
      Net::NTLM::EncodeUtil.encode_utf16le(.password),
      type3_msg.domain.dup.force_encoding('ASCII-8BIT'),  # don't use the account domain because of the special '.' value
      {client_challenge: their_blob[16...24], unicode: true}
    )

    my_nt_proof_str = OpenSSL::HMAC.digest(OpenSSL::Digest::MD5.new, ntlmv2_hash, @server_challenge + their_blob)
    matches = my_nt_proof_str == their_nt_proof_str
    if matches
      user_session_key = OpenSSL::HMAC.digest(OpenSSL::Digest::MD5.new, ntlmv2_hash, my_nt_proof_str)
      if type3_msg.flag & NTLM::NEGOTIATE_FLAGS[:KEY_EXCHANGE] == NTLM::NEGOTIATE_FLAGS[:KEY_EXCHANGE] && type3_msg.session_key.length == 16
        rc4 = OpenSSL::Cipher.new('rc4')
        rc4.decrypt
        rc4.key = user_session_key
        @session_key = rc4.update type3_msg.session_key
        @session_key << rc4.final
      else
        @session_key = user_session_key
      end
    end
  else
    # the only other value Net::NTLM will return for this is ntlm_session
    raise NotImplementedError, "authentication via ntlm version #{type3_msg.ntlm_version} is not supported"
  end

  unless matches
    logger.info("NTLM authentication request failed for #{dbg_string} (bad password)")
    return WindowsError::NTStatus::STATUS_LOGON_FAILURE
  end

  logger.info("NTLM authentication request succeeded for #{dbg_string}")
  WindowsError::NTStatus::STATUS_SUCCESS
end

#reset! ⇒ Object 



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# File 'lib/ruby_smb/gss/provider/ntlm.rb', line 22

def reset!
  super
  @server_challenge = nil
end