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#--
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# Copyright (c) 2009 Marc Dequènes (Duck) <Duck@DuckCorp.org>
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#
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# Permission is hereby granted, free of charge, to any person obtaining
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# a copy of this software and associated documentation files (the
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# "Software"), to deal in the Software without restriction, including
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# without limitation the rights to use, copy, modify, merge, publish,
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# distribute, sublicense, and/or sell copies of the Software, and to
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# permit persons to whom the Software is furnished to do so, subject to
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# the following conditions:
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#
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# The above copyright notice and this permission notice shall be
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# included in all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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#
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#++
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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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module GpgExtension
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def is_pgp_signed?
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content_type == "multipart/signed" and
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header['content-type'].params['protocol'] == "application/pgp-signature" and
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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
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header['content-type'].params['protocol'] == "application/pgp-encrypted" and
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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(crypters_id)
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crypters_id = [crypters_id] unless crypters_id.is_a? Array
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crypters = crypters_id.collect{|key_id| gpg_key(key_id, false) }
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GPGME.encrypt(crypters, 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_id = [signers_id] unless signers_id.is_a? Array
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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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def create_encrypted(crypters_id)
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clear_data = build_intermediate_mail()
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encrypted_data = clear_data.pgp_crypt(crypters_id)
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# build properly encrypted mail
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# (preserving headers from original mail)
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mail = TMail::Mail.new
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mail.copy_headers_from(self)
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mail.set_content_type("multipart", "encrypted", {'boundary' => TMail.new_boundary, "protocol" => "application/pgp-encrypted"})
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mail.transfer_encoding = "7bit"
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mail['content-disposition'] = nil
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mail.body = "This mail is a RFC3156 encrypted message.\n"
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mail.parts.clear
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# cryptographic info
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p_pgp = TMail::Mail.new
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p_pgp.set_content_type("application", "pgp-encrypted")
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p_pgp.transfer_encoding = "7bit"
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p_pgp.content_disposition = "inline"
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p_pgp.body = "Version: 1\n"
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mail.parts << p_pgp
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# encrypted message
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p_encrypted = TMail::Mail.new
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p_encrypted.set_content_type("application", "octet-stream")
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p_encrypted.transfer_encoding = "7bit"
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p_encrypted.content_disposition = "inline"
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p_encrypted.body = encrypted_data
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mail.parts << p_encrypted
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# store the calculated content, to be able to use parsing methods
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mail.write_back
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mail
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end
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def create_signed(signers_id)
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data = build_intermediate_mail()
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sign_data = data.pgp_sign(signers_id) do |uid_hint, passphrase_info, prev_was_bad|
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yield(uid_hint, passphrase_info, prev_was_bad)
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end
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# build properly signed mail
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# (preserving headers from original mail)
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mail = TMail::Mail.new
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mail.copy_headers_from(self)
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mail.set_content_type("multipart", "signed", {'boundary' => TMail.new_boundary, 'protocol' => "application/pgp-signature", 'micalg' => sign_data[:micalg]})
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mail.transfer_encoding = "7bit"
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mail['content-disposition'] = nil
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mail.body = "This mail is a RFC3156 signed message.\n"
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mail.parts.clear
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# signed message
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p_signed = data
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mail.parts << p_signed
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# signature
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p_signature = TMail::Mail.new
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p_signature.set_content_type("application", "pgp-signature")
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p_signature.transfer_encoding = "7bit"
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p_signature.content_disposition = "inline"
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p_signature.body = sign_data[:signature]
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mail.parts << p_signature
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# store the calculated content, to be able to use parsing methods
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mail.write_back
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mail
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end
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def create_signed_and_encrypted(signers_id, crypters_id)
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create_signed(signers_id) do |uid_hint, passphrase_info, prev_was_bad|
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yield(uid_hint, passphrase_info, prev_was_bad)
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end.create_encrypted(crypters_id)
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end
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def copy_headers_from(mail)
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mail.header.keys.each do |h|
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self[h] = mail[h].to_s
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end
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end
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protected
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def build_intermediate_mail
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# build a fake mail to get the generated content to be crypted/signed
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fake_mail = TMail::Mail.new
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fake_mail['content-type'] = self['content-type'].to_s
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fake_mail.transfer_encoding = self.transfer_encoding if self.transfer_encoding
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fake_mail.content_disposition = self.content_disposition if self.content_disposition
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if self.multipart?
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self.each_part {|p| fake_mail.parts << p }
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else
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fake_mail.quoted_body = self.quoted_body
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end
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# store the calculated content, to be able to use parsing methods
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fake_mail.write_back
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fake_mail
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end
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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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begin
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require 'gpgme' # >= 1.0.2 needed for :always_trust sign option
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TMail::Mail.send(:include, TMail::GpgExtension)
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rescue
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end
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