defmodule Pleroma.Web.Salmon do @httpoison Application.get_env(:pleroma, :httpoison) use Bitwise alias Pleroma.Web.XML alias Pleroma.Web.OStatus.ActivityRepresenter alias Pleroma.User require Logger def decode(salmon) do doc = XML.parse_document(salmon) {:xmlObj, :string, data} = :xmerl_xpath.string('string(//me:data[1])', doc) {:xmlObj, :string, sig} = :xmerl_xpath.string('string(//me:sig[1])', doc) {:xmlObj, :string, alg} = :xmerl_xpath.string('string(//me:alg[1])', doc) {:xmlObj, :string, encoding} = :xmerl_xpath.string('string(//me:encoding[1])', doc) {:xmlObj, :string, type} = :xmerl_xpath.string('string(//me:data[1]/@type)', doc) {:ok, data} = Base.url_decode64(to_string(data), ignore: :whitespace) {:ok, sig} = Base.url_decode64(to_string(sig), ignore: :whitespace) alg = to_string(alg) encoding = to_string(encoding) type = to_string(type) [data, type, encoding, alg, sig] end def fetch_magic_key(salmon) do with [data, _, _, _, _] <- decode(salmon), doc <- XML.parse_document(data), uri when not is_nil(uri) <- XML.string_from_xpath("/entry/author[1]/uri", doc), {:ok, %{info: %{"magic_key" => magic_key}}} <- Pleroma.Web.OStatus.find_or_make_user(uri) do {:ok, magic_key} end end def decode_and_validate(magickey, salmon) do [data, type, encoding, alg, sig] = decode(salmon) signed_text = [data, type, encoding, alg] |> Enum.map(&Base.url_encode64/1) |> Enum.join(".") key = decode_key(magickey) verify = :public_key.verify(signed_text, :sha256, sig, key) if verify do {:ok, data} else :error end end def decode_key("RSA." <> magickey) do make_integer = fn(bin) -> list = :erlang.binary_to_list(bin) Enum.reduce(list, 0, fn (el, acc) -> (acc <<< 8) ||| el end) end [modulus, exponent] = magickey |> String.split(".") |> Enum.map(&Base.url_decode64!/1) |> Enum.map(make_integer) {:RSAPublicKey, modulus, exponent} end def encode_key({:RSAPublicKey, modulus, exponent}) do modulus_enc = :binary.encode_unsigned(modulus) |> Base.url_encode64 exponent_enc = :binary.encode_unsigned(exponent) |> Base.url_encode64 "RSA.#{modulus_enc}.#{exponent_enc}" end def generate_rsa_pem do port = Port.open({:spawn, "openssl genrsa"}, [:binary]) {:ok, pem} = receive do {^port, {:data, pem}} -> {:ok, pem} end Port.close(port) if Regex.match?(~r/RSA PRIVATE KEY/, pem) do {:ok, pem} else :error end end def keys_from_pem(pem) do [private_key_code] = :public_key.pem_decode(pem) private_key = :public_key.pem_entry_decode(private_key_code) {:RSAPrivateKey, _, modulus, exponent, _, _, _, _, _, _, _} = private_key public_key = {:RSAPublicKey, modulus, exponent} {:ok, private_key, public_key} end def encode(private_key, doc) do type = "application/atom+xml" encoding = "base64url" alg = "RSA-SHA256" signed_text = [doc, type, encoding, alg] |> Enum.map(&Base.url_encode64/1) |> Enum.join(".") signature = signed_text |> :public_key.sign(:sha256, private_key) |> to_string |> Base.url_encode64 doc_base64 = doc |> Base.url_encode64 # Don't need proper xml building, these strings are safe to leave unescaped salmon = """ #{doc_base64} #{encoding} #{alg} #{signature} """ {:ok, salmon} end def remote_users(%{data: %{"to" => to}}) do to |> Enum.map(fn(id) -> User.get_cached_by_ap_id(id) end) |> Enum.filter(fn(user) -> user && !user.local end) end defp send_to_user(%{info: %{"salmon" => salmon}}, feed, poster) do poster.(salmon, feed, [{"Content-Type", "application/magic-envelope+xml"}]) end defp send_to_user(_,_,_), do: nil def publish(user, activity, poster \\ &@httpoison.post/3) def publish(%{info: %{"keys" => keys}} = user, activity, poster) do feed = ActivityRepresenter.to_simple_form(activity, user, true) |> ActivityRepresenter.wrap_with_entry |> :xmerl.export_simple(:xmerl_xml) |> to_string if feed do {:ok, private, _} = keys_from_pem(keys) {:ok, feed} = encode(private, feed) remote_users(activity) |> Enum.each(fn(remote_user) -> Task.start(fn -> Logger.debug(fn -> "sending salmon to #{remote_user.ap_id}" end) send_to_user(remote_user, feed, poster) end) end) end end def publish(%{id: id}, _, _), do: Logger.debug(fn -> "Keys missing for user #{id}" end) end