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#--
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# CyborgHood, a distributed system management software.
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# Copyright (c) 2009 Marc Dequènes (Duck) <Duck@DuckCorp.org>
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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#++
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# add Rails load path for Debian, until rails framework is split properly
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DEB_RAILS_PATH = "/usr/share/rails" unless Object.constants.include?("DEB_RAILS_PATH")
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Dir.new(DEB_RAILS_PATH).each do |file|
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next if file =~ /^\./
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path = File.join(DEB_RAILS_PATH, file, "lib")
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$: << path if File.directory?(path)
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end
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require 'cyborghood/base'
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require 'delegate'
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require 'tmail'
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require 'tmail_gpg'
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require 'action_mailer/quoting'
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require 'action_mailer/utils'
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require 'net/smtp'
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require 'fileutils'
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require 'digest/md5'
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# This class handles RFC3156 signed messages, validates them, and extract orders properly.
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# Encrypted content are not implemented yet.
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module CyborgHood
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class Mail < Delegator
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include ActionMailer::Quoting
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include ActionMailer::Utils
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MAX_DRIFT_TIME = 600
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def initialize(msg = nil)
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@config = Config.instance
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if msg.nil?
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@mail = TMail::Mail.new
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set_custom_headers
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else
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# unquote headers and transform into TMail object
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@mail = TMail::Mail.parse(TMail::Unquoter.unquote_and_convert_to(msg, "UTF-8"))
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end
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end
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def __getobj__
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@mail
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end
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def parse
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if is_marked?
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logger.info "Replay detected"
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return nil
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end
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return parse_signed() if is_pgp_signed?
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return parse_encrypted() if is_pgp_encrypted?
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{:ok => false, :msg => "mail not RFC3156 compliant"}.to_ostruct
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end
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def create_reply
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tmail_reply = @mail.create_reply
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tmail_reply.from_addrs = TMail::Address.parse(@config.mail.from_address || self.to.first)
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reply = self.class.new(tmail_reply.to_s)
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reply.set_custom_headers
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reply
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end
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def set_custom_headers
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@mail['Organization'] = @config.mail.organization
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end
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def check_headers
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@mail.header.keys.each do |h|
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@mail[h] = quote_address_if_necessary(@mail[h].to_s, "utf-8")
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end
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end
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def deliver
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check_headers
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smtp_server = @config.mail.smtp_server || "localhost"
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smtp_port = @config.mail.smtp_port || 25
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smtp_from = @mail.from_addrs.collect{|a| a.address}.join(", ")
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smtp_to = @mail.to_addrs.collect{|a| a.address}
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Net::SMTP.start(smtp_server, smtp_port) do |smtp|
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#p @mail.to_s
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smtp.send_message(@mail.to_s, smtp_from, smtp_to)
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end
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end
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def to_s
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@mail.to_s
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end
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def crypt(fingerprint)
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@mail = @mail.create_encrypted(fingerprint)
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end
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def sign
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# we don't check the uid, as their is only one signer
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@mail = @mail.create_signed(@config.mail.key_id) do |uid_hint, passphrase_info, prev_was_bad|
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@config.mail.key_passphrase
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end
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end
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def sign_and_crypt(fingerprint)
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# not using sign_and_crypt(), to avoid repeating code
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sign()
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crypt(fingerprint)
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end
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def quoted_printable_body=(txt)
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@mail.transfer_encoding = "quoted-printable"
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@mail.body = [normalize_new_lines(txt)].pack("M*")
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end
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private
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def parse_signed
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order = {:ok => false, :msg => "mail not formatted correctly"}
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sigs_check = verify_pgp_signature()
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return order.to_ostruct if sigs_check.nil? or sigs_check.size != 1
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sig_check = sigs_check.first
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if sig_check.status == 0
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logger.info "Mail content was properly signed by key #{sig_check.fingerprint}"
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user = Person.find_by_fingerprint(sig_check.fingerprint)
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if user.nil?
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logger.info "Mail is from an unknown person"
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order[:msg] = "unknown user"
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else
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logger.info "Mail is from user #{user.uid} (#{user.cn})"
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drift = Time.new.to_i - sig_check.timestamp.to_i
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logger.debug "Signature drift time: #{drift}"
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if drift.abs < MAX_DRIFT_TIME
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signed_content = pgp_signed_part()
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if signed_content.multipart?
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if signed_content.parts[0].content_type == "text/plain"
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command_txt = signed_content.parts[0].body
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refs = signed_content.parts.collect{|p| p.dup }
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end
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else
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command_txt = signed_content.body if signed_content.content_type == "text/plain"
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refs = []
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end
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if command_txt
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commands = []
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command_txt.each_line do |line|
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line.chomp!
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sline = line.strip
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# skip empty lines and comments
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next if sline == "" or sline[0, 1] == "#"
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# stop processing when detecting message signature
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break if line == "-- "
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commands << sline
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end
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logger.debug "Mail OK"
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mark_processed(sig_check.timestamp)
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order = {:ok => true, :user => user, :commands => commands, :refs => refs}
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else
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order[:user] = user
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logger.info "Mail does not contain a proper MIME part for commands"
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end
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else
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if drift > 0
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logger.info "Mail rejected as it may be a replay (signature timestamp is too old)"
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order = {:ok => false, :user => user, :msg => "The signature was made too long ago (perhaps your system clock is not up-to-date). Rejected message to avoid replay attacks."}
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else
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# mark message to prevent later replay of the message
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mark_processed(sig_check.timestamp)
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logger.info "Mail rejected as it is coming from the future (and may allow later replay)"
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order = {:ok => false, :user => user, :msg => "The signature was made in the future (perhaps your system clock is not up-to-date). Rejected message to avoid replay attacks."}
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end
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end
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end
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else
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logger.info "Mail content tampered or badly signed: " + sig_check.to_s
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return nil
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end
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order.to_ostruct
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end
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def parse_encrypted
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order = {:ok => false, :msg => "mail not formatted correctly"}
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catch :notforme do
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begin
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# block is not passed to delegate (limitation ?)
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clear_message = @mail.pgp_decrypt do |uid_hint, passphrase_info, prev_was_bad|
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logger.info "Mail crypted for #{uid_hint}"
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# check if requesting passphrase for the expected key
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key_id = passphrase_info.split(" ")[1]
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throw :notforme if key_id != @config.mail.key_id[-(key_id.size)..-1]
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# sending key
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@config.mail.key_passphrase
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end
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# create a fake mail and chain parsing operations
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clear_mail = self.class.new(clear_message)
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# propagate message_id to be able to mark messages (replay protection)
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clear_mail.message_id = @mail.message_id
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return clear_mail.parse
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rescue GPGME::Error, NotImplementedError => e
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raise CyberError.new(:unrecoverable, "protocol/mail", e.message)
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end
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end
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order.to_ostruct
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end
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def mark_dir
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File.join(@config.work_dir, "marks")
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end
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def mark_filename
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File.join(mark_dir(), Digest::MD5.hexdigest(self.message_id))
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end
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def mark_processed(time)
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FileUtils.mkdir_p(mark_dir())
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File.open(mark_filename(), "w") do |fp|
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fp.write self.message_id
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end
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File.utime(Time.now.to_i, time.to_i, mark_filename())
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end
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def is_marked?
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File.exists?(mark_filename())
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end
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end
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end
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