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require 'gpgme' # >= 1.0.2 needed for :always_trust sign option
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# Attempt to handle PGP/GPG features in a RFC3156-compliant way
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#
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# notes: These methods have been designed to be able to sign, crypt,
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# or sign+crypt with RFC 1847 Encapsulation. There is no
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# support (yet?) for the combined method described in chapter
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# 6.2 of RFC3156.
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module TMail
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class Mail
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def is_pgp_signed?
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content_type == "multipart/signed" and parts.size == 2 and
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parts[1].content_type == "application/pgp-signature"
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end
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def pgp_signature
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return nil unless is_pgp_signed?
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parts[1].decoded
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end
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def pgp_signed_part
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return nil unless is_pgp_signed?
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parts[0]
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end
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def verify_pgp_signature
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return nil unless is_pgp_signed?
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content = parts[0].to_rfc3156
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sig = pgp_signature()
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sigs_check = nil
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GPGME.verify(sig, content) do |signature|
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sigs_check ||= []
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sigs_check << signature
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end
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sigs_check
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end
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def is_pgp_encrypted?
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content_type == "multipart/encrypted" and parts.size == 2 and
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parts[0].content_type == "application/pgp-encrypted" and
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parts[1].content_type == "application/octet-stream"
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end
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def pgp_crypt_info
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return nil unless is_pgp_encrypted?
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a = parts[0].body.split("\n").collect{|l| l.chomp.split(": ") if l =~ /: / }.compact.flatten
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Hash[*a]
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end
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def pgp_encrypted_part
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return nil unless is_pgp_encrypted?
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parts[1].body
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end
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def pgp_decrypt(&passphrase_callback)
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return nil unless is_pgp_encrypted?
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protocol_version = pgp_crypt_info()["Version"].to_i
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raise NotImplementedError, "pgp-encrypted protocol version #{protocol_version} is not implemented" unless protocol_version == 1
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encrypted_data = pgp_encrypted_part()
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GPGME.decrypt(encrypted_data, {:passphrase_callback => method(:gpg_passphrase_callback_wrapper),
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:passphrase_callback_value => passphrase_callback, :textmode => true})
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end
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def pgp_crypt(fingerprint)
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GPGME.encrypt([gpg_key(fingerprint)], self.to_s, {:armor => true, :always_trust => true})
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end
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def pgp_sign(signers_id, &passphrase_callback)
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signers = signers_id.collect{|key_id| gpg_key(key_id, true) }
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# we don't use GPGME.sign(), because we need to get operation information to get the hash_algo and compute the micalg parameter
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gpg = GPGME::Ctx.new({:signers => signers, :passphrase_callback => method(:gpg_passphrase_callback_wrapper),
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:passphrase_callback_value => passphrase_callback, :armor => true})
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gpg.add_signer(*signers)
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sig_data = GPGME::Data.new
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gpg.sign(GPGME::Data.new(self.to_rfc3156), sig_data, GPGME::SIG_MODE_NORMAL)
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hash_algo = GPGME.gpgme_op_sign_result(gpg).signatures.first.hash_algo
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micalg = "pgp-" + GPGME.gpgme_hash_algo_name(hash_algo).downcase
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sig_data.seek(0, IO::SEEK_SET)
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{:signature => sig_data.read, :micalg => micalg}
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end
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def to_rfc3156
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# using RAW part, without any decoding
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# remove last EOL due to MIME protocol and properly convert all EOL to CRLF
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raw.chomp.gsub(/\r?\n/, "\r\n")
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end
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protected
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def gpg_key(fingerprint, secret = false)
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gpg = GPGME::Ctx.new
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gpg.get_key(fingerprint, secret)
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end
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def gpg_passphrase_callback_wrapper(hook, uid_hint, passphrase_info, prev_was_bad, fd)
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io = IO.for_fd(fd, 'w')
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io.puts hook.call(uid_hint, passphrase_info, prev_was_bad)
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io.flush
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end
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def raw
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@port.read_all
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end
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end
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end
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