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# -*- coding: binary -*-
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module Rex
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  module Proto
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    module Kerberos
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      module Model
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        # This class provides a representation of a KRB_AP_REQ definition, containing the Kerberos protocol version number,
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        # the message type KRB_AP_REQ, an options field to indicate any options in use, and the ticket and authenticator
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        # themselves
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        class ApReq < Element
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          # @!attribute pvno
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          #   @return [Integer] The protocol version number
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          attr_accessor :pvno
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          # @!attribute msg_type
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          #   @return [Integer] The type of the protocol message
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          attr_accessor :msg_type
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          # @!attribute options
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          #   @return [Integer] request options, affects processing
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          attr_accessor :options
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          # @!attribute ticket
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          #   @return [Rex::Proto::Kerberos::Model::Ticket] The ticket authenticating the client to the server
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          attr_accessor :ticket
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          # @!attribute authenticator
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          #   @return [Rex::Proto::Kerberos::Model::EncryptedData] This contains the authenticator, which includes the
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          #   client's choice of a subkey
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          attr_accessor :authenticator
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          # Rex::Proto::Kerberos::Model::ApReq decoding isn't supported
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          #
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          # @raise [NotImplementedError]
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          def decode(input)
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            raise ::NotImplementedError, 'AP-REQ decoding not supported'
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          end
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          # Encodes the Rex::Proto::Kerberos::Model::ApReq into an ASN.1 String
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          #
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          # @return [String]
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          def encode
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            to_asn1.to_der
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          end
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          # @return [OpenSSL::ASN1::ASN1Data] The ap_req ASN1Data
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          def to_asn1
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            elems = []
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            elems << OpenSSL::ASN1::ASN1Data.new([encode_pvno], 0, :CONTEXT_SPECIFIC)
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            elems << OpenSSL::ASN1::ASN1Data.new([encode_msg_type], 1, :CONTEXT_SPECIFIC)
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            elems << OpenSSL::ASN1::ASN1Data.new([encode_options], 2, :CONTEXT_SPECIFIC)
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            elems << OpenSSL::ASN1::ASN1Data.new([encode_ticket], 3, :CONTEXT_SPECIFIC)
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            elems << OpenSSL::ASN1::ASN1Data.new([encode_authenticator], 4, :CONTEXT_SPECIFIC)
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            seq = OpenSSL::ASN1::Sequence.new(elems)
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            seq_asn1 = OpenSSL::ASN1::ASN1Data.new([seq], AP_REQ, :APPLICATION)
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            seq_asn1
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          end
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          private
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          # Encodes the pvno field
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          #
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          # @return [OpenSSL::ASN1::Integer]
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          def encode_pvno
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            bn = OpenSSL::BN.new(pvno.to_s)
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            int = OpenSSL::ASN1::Integer.new(bn)
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            int
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          end
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          # Encodes the msg_type field
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          #
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          # @return [OpenSSL::ASN1::Integer]
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          def encode_msg_type
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            bn = OpenSSL::BN.new(msg_type.to_s)
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            int = OpenSSL::ASN1::Integer.new(bn)
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            int
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          end
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          # Encodes the options field
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          #
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          # @return [OpenSSL::ASN1::BitString]
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          def encode_options
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            OpenSSL::ASN1::BitString.new([options].pack('N'))
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          end
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          # Encodes the ticket field
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          #
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          # @return [String]
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          def encode_ticket
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            ticket.encode
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          end
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          # Encodes the authenticator field
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          #
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          # @return [String]
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          def encode_authenticator
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            authenticator.encode
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          end
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        end
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      end
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    end
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  end
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end
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