Class: Redwood::CryptoManager

Inherits:
Object
  • Object
show all
Includes:
Singleton
Defined in:
lib/sup/crypto.rb

Defined Under Namespace

Classes: Error

Constant Summary collapse

OUTGOING_MESSAGE_OPERATIONS = 
OrderedHash.new(
  [:sign, "Sign"],
  [:sign_and_encrypt, "Sign and encrypt"],
  [:encrypt, "Encrypt only"]
)

Instance Method Summary collapse

Methods included from Singleton

included

Constructor Details

#initialize ⇒ CryptoManager

Returns a new instance of CryptoManager.



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# File 'lib/sup/crypto.rb', line 25

def initialize
  @mutex = Mutex.new

  bin = `which gpg`.chomp
  @cmd = case bin
  when /\S/
    debug "crypto: detected gpg binary in #{bin}"
    "#{bin} --quiet --batch --no-verbose --logger-fd 1 --use-agent"
  else
    debug "crypto: no gpg binary detected"
    nil
  end
end

Instance Method Details

#decrypt(payload, armor = false) ⇒ Object

returns decrypted_message, status, desc, lines



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# File 'lib/sup/crypto.rb', line 142

def decrypt payload, armor=false # a RubyMail::Message object
  return unknown_status(cant_find_binary) unless @cmd

  payload_fn = Tempfile.new(["redwood.payload", ".asc"])
  payload_fn.write payload.to_s
  payload_fn.close

  output_fn = Tempfile.new "redwood.output"
  output_fn.close

  message = run_gpg "--output #{output_fn.path} --skip-verify --yes --decrypt #{payload_fn.path}", :interactive => true

  unless $?.success?
    info "Error while running gpg: #{message}"
    return Chunk::CryptoNotice.new(:invalid, "This message could not be decrypted", message.split("\n"))
  end

  output = IO.read output_fn.path
  output.force_encoding Encoding::ASCII_8BIT if output.respond_to? :force_encoding

  ## check for a valid signature in an extra run because gpg aborts if the
  ## signature cannot be verified (but it is still able to decrypt)
  sigoutput = run_gpg "#{payload_fn.path}"
  sig = self.verified_ok? sigoutput, $?

  if armor
    msg = RMail::Message.new
    # Look for Charset, they are put before the base64 crypted part
    charsets = payload.body.split("\n").grep(/^Charset:/)
    if !charsets.empty? and charsets[0] =~ /^Charset: (.+)$/
      output = Iconv.easy_decode($encoding, $1, output)
    end
    msg.body = output
  else
    # It appears that some clients use Windows new lines - CRLF - but RMail
    # splits the body and header on "\n\n". So to allow the parse below to 
    # succeed, we will convert the newlines to what RMail expects
    output = output.gsub(/\r\n/, "\n")
    # This is gross. This decrypted payload could very well be a multipart
    # element itself, as opposed to a simple payload. For example, a
    # multipart/signed element, like those generated by Mutt when encrypting
    # and signing a message (instead of just clearsigning the body).
    # Supposedly, decrypted_payload being a multipart element ought to work
    # out nicely because Message::multipart_encrypted_to_chunks() runs the
    # decrypted message through message_to_chunks() again to get any
    # children. However, it does not work as intended because these inner
    # payloads need not carry a MIME-Version header, yet they are fed to
    # RMail as a top-level message, for which the MIME-Version header is
    # required. This causes for the part not to be detected as multipart,
    # hence being shown as an attachment. If we detect this is happening,
    # we force the decrypted payload to be interpreted as MIME.
    msg = RMail::Parser.read output
    if msg.header.content_type =~ %r{^multipart/} && !msg.multipart?
      output = "MIME-Version: 1.0\n" + output
      output.force_encoding Encoding::ASCII_8BIT if output.respond_to? :force_encoding
      msg = RMail::Parser.read output
    end
  end
  notice = Chunk::CryptoNotice.new :valid, "This message has been decrypted for display"
  [notice, sig, msg]
end

#encrypt(from, to, payload, sign = false) ⇒ Object 



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# File 'lib/sup/crypto.rb', line 64

def encrypt from, to, payload, sign=false
  payload_fn = Tempfile.new "redwood.payload"
  payload_fn.write format_payload(payload)
  payload_fn.close

  encrypted_fn = Tempfile.new "redwood.encrypted"; encrypted_fn.close

  recipient_opts = (to + [ from ] ).map { |r| "--recipient '<#{r}>'" }.join(" ")
  sign_opts = ""
  sign_opts = "--sign --digest-algo sha256 " + gen_sign_user_opts(from) if sign
  message = run_gpg "--output #{encrypted_fn.path} --yes --armor --encrypt --textmode #{sign_opts} #{recipient_opts} #{payload_fn.path}", :interactive => true
  unless $?.success?
    info "Error while running gpg: #{message}"
    raise Error, "GPG command failed. See log for details."
  end

  encrypted_payload = RMail::Message.new
  encrypted_payload.header["Content-Type"] = "application/octet-stream"
  encrypted_payload.header["Content-Disposition"] = 'inline; filename="msg.asc"'
  encrypted_payload.body = IO.read(encrypted_fn.path)

  control = RMail::Message.new
  control.header["Content-Type"] = "application/pgp-encrypted"
  control.header["Content-Disposition"] = "attachment"
  control.body = "Version: 1\n"

  envelope = RMail::Message.new
  envelope.header["Content-Type"] = 'multipart/encrypted; protocol=application/pgp-encrypted'

  envelope.add_part control
  envelope.add_part encrypted_payload
  envelope
end

#have_crypto? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/sup/crypto.rb', line 39

def have_crypto?; !@cmd.nil? end

#sign(from, to, payload) ⇒ Object 



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# File 'lib/sup/crypto.rb', line 41

def sign from, to, payload
  payload_fn = Tempfile.new "redwood.payload"
  payload_fn.write format_payload(payload)
  payload_fn.close

  sig_fn = Tempfile.new "redwood.signature"; sig_fn.close

  sign_user_opts = gen_sign_user_opts from
  message = run_gpg "--output #{sig_fn.path} --yes --armor --detach-sign --textmode --digest-algo sha256 #{sign_user_opts} #{payload_fn.path}", :interactive => true
  unless $?.success?
    info "Error while running gpg: #{message}"
    raise Error, "GPG command failed. See log for details."
  end

  envelope = RMail::Message.new
  envelope.header["Content-Type"] = 'multipart/signed; protocol=application/pgp-signature; micalg=pgp-sha256'

  envelope.add_part payload
  signature = RMail::Message.make_attachment IO.read(sig_fn.path), "application/pgp-signature", nil, "signature.asc"
  envelope.add_part signature
  envelope
end

#sign_and_encrypt(from, to, payload) ⇒ Object 



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# File 'lib/sup/crypto.rb', line 98

def sign_and_encrypt from, to, payload
  encrypt from, to, payload, true
end

#verified_ok?(output, rc) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/sup/crypto.rb', line 102

def verified_ok? output, rc
  output_lines = output.split(/\n/)

  if output =~ /^gpg: (.* signature from .*$)/
    if rc == 0
      Chunk::CryptoNotice.new :valid, $1, output_lines
    else
      Chunk::CryptoNotice.new :invalid, $1, output_lines
    end
  elsif output_lines.length == 0 && rc == 0
    # the message wasn't signed
    Chunk::CryptoNotice.new :valid, "Encrypted message wasn't signed", output_lines
  else
    unknown_status output_lines
  end
end

#verify(payload, signature, detached = true) ⇒ Object

both RubyMail::Message objects



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# File 'lib/sup/crypto.rb', line 119

def verify payload, signature, detached=true # both RubyMail::Message objects
  return unknown_status(cant_find_binary) unless @cmd

  if detached
    payload_fn = Tempfile.new "redwood.payload"
    payload_fn.write format_payload(payload)
    payload_fn.close
  end

  signature_fn = Tempfile.new "redwood.signature"
  signature_fn.write signature.decode
  signature_fn.close

  if detached
    output = run_gpg "--verify #{signature_fn.path} #{payload_fn.path}"
  else
    output = run_gpg "--verify #{signature_fn.path}"
  end

  self.verified_ok? output, $?
end