Revision 5425b3f0
Added by Marc Dequènes almost 16 years ago
- ID 5425b3f0470e93a44529f3100be771616135b530
| lib/cyborghood/mail.rb | ||
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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 Order
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attr_accessor :ok, :message, :system_message, :user, :commands, :references
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attr_writer = :warn_sender
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def initialize(ok, message = nil, system_message = nil)
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@ok = ok
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@message = message
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@system_message = system_message
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end
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def warn_sender
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# send reply message if user is identified or in selected situations
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# (@warn_sender acts as an override)
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@warn_sender || @user
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end
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end
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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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attr_accessor :user
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def initialize(msg = nil)
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@config = Config.instance
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| ... | ... | |
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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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return Order.new(false, "Replay detected.")
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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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# don't parse commands if user is not identified
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return parse_plain if self.user
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Order.new(false, "Mail not RFC3156 compliant.")
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end
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def create_reply
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| ... | ... | |
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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.user = self.user
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reply
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end
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| ... | ... | |
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relay.set_disposition("inline")
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reply.quoted_printable_body = msg
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reply.sign
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reply.crypt(reply.user.keyFingerPrint) unless reply.user.nil?
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reply
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end
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| ... | ... | |
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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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def parse_plain
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command_txt = nil
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if multipart?
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if parts[0].content_type == "text/plain"
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command_txt = self.parts[0].body
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refs = self.parts.collect{|p| p.dup }
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end
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else
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command_txt = self.body if self.content_type == "text/plain"
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refs = []
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end
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unless command_txt
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order = Order.new(false, "Mail does not contain a proper text part for commands.")
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order.user = self.user
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return order
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end
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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 = Order.new(true)
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order.user = self.user
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order.commands = commands
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order.refs = refs
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end
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def parse_signed
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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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return Order.new(false, "mail not formatted correctly (signed part)") 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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return Order.new(false, "Mail content tampered or badly signed: " + sig_check.to_s) unless 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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order = Order.new(false, "Mail is from an unknown person.")
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order.warn_sender = true
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return order
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end
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logger.info "Mail is from user #{user.uid} (#{user.cn})"
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self.user = user
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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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unless drift.abs < MAX_DRIFT_TIME
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if drift > 0
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order = Order.new(false, "The signature was made too long ago (check your system clock)." +
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" Rejected message to avoid replay attacks.")
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order.user = self.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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# mark message to prevent later replay of the message
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mark_processed(sig_check.timestamp)
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order = Order.new(false, "The signature was made in the future (check your system clock)." +
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" Rejected message to avoid replay attacks.")
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order.user = self.user
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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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return order
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end
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order.to_ostruct
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signed_content = pgp_signed_part()
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# create a fake mail and chain parsing operations
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plain_mail = self.class.new(signed_content)
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plain_mail.user = self.user
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# propagate message_id to be able to mark messages (replay protection)
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plein_mail.message_id = @mail.message_id
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return plain_mail.parse
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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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| ... | ... | |
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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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clear_mail.user = self.user
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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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| ... | ... | |
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end
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end
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order.to_ostruct
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Order.new(false, "Mail not formatted correctly (encrypted part).")
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end
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def mark_dir
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| postman | ||
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when :ignorable
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end
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end
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if order.nil?
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logger.info "Mail is invalid, ignoring..."
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msg.delete
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next
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elsif not order.ok
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logger.info "Sending reply for rejected message (#{order.msg})"
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mail_reply = mail.create_simple_reject_reply("A message (ID: #{mail.message_id}) apparently from you was rejected for the following reason:\n #{order.msg}")
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mail_reply.crypt(order.user.keyFingerPrint) unless order.user.nil?
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mail_reply.deliver
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result_tag = order.ok ? "SUCCESS" : "FAILURE"
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logger.info "Processing result: #{result_tag} (#{order.message})"
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logger.info "Extra processing information: " + order.system_message if order.system_message
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unless order.ok
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if order.warn_sender
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logger.info "Sending reply for rejected message"
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mail_reply = mail.create_simple_reject_reply("A message (ID: #{mail.message_id}), apparently from you," +
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" was rejected for the following reason:\n #{order.message}")
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mail_reply.deliver
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end
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msg.delete
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next
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end
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| ... | ... | |
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# create transcript
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logger.debug "Preparing reply"
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reply_txt = "Hello #{order.user.cn},\n\nFollows the transcript of your commands:\n"
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reply_txt = "Hello #{order.user.cn},\n\n"
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reply_txt += order.message + "\n\n" if order.message
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reply_txt += "Follows the transcript of your commands:\n"
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reply_attachments = []
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result_list.each do |result|
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reply_txt << "> #{result.cmd}\n"
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Also available in: Unified diff
[evol] separate signed mail processing from commands extracting, and improved order