defmodule MatrixServer.Event do use Ecto.Schema import Ecto.Query alias MatrixServer.{Repo, Room, Event, Account, EncodableMap, KeyServer} @primary_key {:event_id, :string, []} schema "events" do field :type, :string field :origin_server_ts, :utc_datetime_usec field :state_key, :string field :sender, :string field :content, :map field :prev_events, {:array, :string} field :auth_events, {:array, :string} field :unsigned, :map field :signatures, {:map, {:map, :string}} field :hashes, {:map, :string} belongs_to :room, Room, type: :string end def new(%Room{id: room_id}, %Account{localpart: localpart}) do %Event{ room_id: room_id, sender: MatrixServer.get_mxid(localpart), origin_server_ts: DateTime.utc_now(), prev_events: [], auth_events: [] } end def create_room( room, %Account{localpart: localpart} = creator, room_version ) do mxid = MatrixServer.get_mxid(localpart) %Event{ new(room, creator) | type: "m.room.create", state_key: "", content: %{ "creator" => mxid, "room_version" => room_version || MatrixServer.default_room_version() } } end def join(room, %Account{localpart: localpart} = sender, auth_events) do mxid = MatrixServer.get_mxid(localpart) %Event{ new(room, sender) | type: "m.room.member", state_key: mxid, content: %{ "membership" => "join" }, auth_events: Enum.map(auth_events, & &1.event_id) } end def power_levels( room, %Account{localpart: localpart} = sender, auth_events ) do mxid = MatrixServer.get_mxid(localpart) %Event{ new(room, sender) | type: "m.room.power_levels", state_key: "", content: %{ "ban" => 50, "events" => %{}, "events_default" => 0, "invite" => 50, "kick" => 50, "redact" => 50, "state_default" => 50, "users" => %{ mxid => 50 }, "users_default" => 0, "notifications" => %{ "room" => 50 } }, auth_events: Enum.map(auth_events, & &1.event_id) } end def name(room, sender, name, auth_events) do %Event{ new(room, sender) | type: "m.room.name", state_key: "", content: %{ "name" => name }, auth_events: Enum.map(auth_events, & &1.event_id) } end def topic(room, sender, topic, auth_events) do %Event{ new(room, sender) | type: "m.room.topic", state_key: "", content: %{ "topic" => topic }, auth_events: Enum.map(auth_events, & &1.event_id) } end def join_rules(room, sender, join_rule, auth_events) do %Event{ new(room, sender) | type: "m.room.join_rules", state_key: "", content: %{ "join_rule" => join_rule }, auth_events: Enum.map(auth_events, & &1.event_id) } end def history_visibility(room, sender, history_visibility, auth_events) do %Event{ new(room, sender) | type: "m.room.history_visibility", state_key: "", content: %{ "history_visibility" => history_visibility }, auth_events: Enum.map(auth_events, & &1.event_id) } end def guest_access(room, sender, guest_access, auth_events) do %Event{ new(room, sender) | type: "m.room.guest_access", state_key: "", content: %{ "guest_access" => guest_access }, auth_events: Enum.map(auth_events, & &1.event_id) } end def is_control_event(%Event{type: "m.room.power_levels", state_key: ""}), do: true def is_control_event(%Event{type: "m.room.join_rules", state_key: ""}), do: true def is_control_event(%Event{ type: "m.room.member", state_key: state_key, sender: sender, content: %{membership: membership} }) when sender != state_key and membership in ["leave", "ban"], do: true def is_control_event(_), do: false def is_state_event(%Event{state_key: state_key}), do: state_key != nil # Perform validations that can be done before state resolution. # For example checking the domain of the sender. # We assume that required keys, as well as in the content, is already validated. # Rule 1.4 is left to changeset validation. def prevalidate(%Event{ type: "m.room.create", prev_events: prev_events, auth_events: auth_events, room_id: room_id, sender: sender }) do # TODO: error check on domains? # TODO: rule 1.3 # Check rules: 1.1, 1.2 prev_events == [] and auth_events == [] and MatrixServer.get_domain(sender) == MatrixServer.get_domain(room_id) end def prevalidate(%Event{auth_events: auth_event_ids, prev_events: prev_event_ids} = event) do prev_events = Event |> where([e], e.event_id in ^prev_event_ids) |> Repo.all() auth_events = Event |> where([e], e.event_id in ^auth_event_ids) |> Repo.all() state_pairs = Enum.map(auth_events, &{&1.type, &1.state_key}) # Check rules: 2.1, 2.2, 3 length(auth_events) == length(auth_event_ids) and length(prev_events) == length(prev_event_ids) and not MatrixServer.has_duplicates?(state_pairs) and valid_auth_events?(event, auth_events) and Enum.find_value(state_pairs, &(&1 == {"m.room.create", ""})) and do_prevalidate(event, auth_events, prev_events) end # Rule 4.1 is left to changeset validation. defp do_prevalidate(%Event{type: "m.room.aliases", sender: sender, state_key: state_key}, _, _) do # Check rule: 4.2 MatrixServer.get_domain(sender) == MatrixServer.get_domain(state_key) end # Rule 5.1 is left to changeset validation. # Rules 5.2.3, 5.2.4, 5.2.5 is left to state resolution. # Check rule: 5.2.1 defp do_prevalidate( %Event{type: "m.room.member", content: %{"membership" => "join"}, sender: sender}, _, [%Event{type: "m.room.create", state_key: sender}] ), do: true # Check rule: 5.2.2 defp do_prevalidate( %Event{ type: "m.room.member", content: %{"membership" => "join"}, sender: sender, state_key: state_key }, _, _ ) when sender != state_key, do: false # All other rules will be checked during state resolution. defp do_prevalidate(_, _, _), do: true defp valid_auth_events?( %Event{type: type, sender: sender, state_key: state_key, content: content}, auth_events ) do Enum.all?(auth_events, fn %Event{type: "m.room.create", state_key: ""} -> true %Event{type: "m.room.power_levels", state_key: ""} -> true %Event{type: "m.room.member", state_key: ^sender} -> true %Event{type: auth_type, state_key: auth_state_key} -> if type == "m.room.member" do %{"membership" => membership} = content (auth_type == "m.room.member" and auth_state_key == state_key) or (membership in ["join", "invite"] and auth_type == "m.room.join_rules" and auth_state_key == "") or (membership == "invite" and auth_type == "m.room.third_party_invite" and auth_state_key == "") else false end end) end defp calculate_content_hash(event) do m = event |> MatrixServer.to_serializable_map() |> Map.drop([:unsigned, :signature, :hashes]) |> EncodableMap.from_map() with {:ok, json} <- Jason.encode(m) do {:ok, :crypto.hash(:sha256, json)} end end defp redact(%Event{type: type, content: content} = event) do redacted_event = event |> MatrixServer.to_serializable_map() |> Map.take([ :event_id, :type, :room_id, :sender, :state_key, :content, :hashes, :signatures, :depth, :prev_events, :prev_state, :auth_events, :origin, :origin_server_ts, :membership ]) %{redacted_event | content: redact_content(type, content)} end defp redact_content("m.room.member", content), do: Map.take(content, ["membership"]) defp redact_content("m.room.create", content), do: Map.take(content, ["creator"]) defp redact_content("m.room.join_rules", content), do: Map.take(content, ["join_rule"]) defp redact_content("m.room.aliases", content), do: Map.take(content, ["aliases"]) defp redact_content("m.room.history_visibility", content), do: Map.take(content, ["history_visibility"]) defp redact_content("m.room.power_levels", content), do: Map.take(content, [ "ban", "events", "events_default", "kick", "redact", "state_default", "users", "users_default" ]) defp redact_content(_, _), do: %{} # Adds content hash, adds signature and calculates event id. def post_process(event) do with {:ok, content_hash} <- calculate_content_hash(event) do encoded_hash = MatrixServer.encode_unpadded_base64(content_hash) event = %Event{event | hashes: %{"sha256" => encoded_hash}} with {:ok, sig, key_id} <- KeyServer.sign_object(redact(event)) do event = %Event{event | signatures: %{MatrixServer.server_name() => %{key_id => sig}}} with {:ok, event} <- set_event_id(event) do {:ok, event} end end end end def set_event_id(event) do with {:ok, event_id} <- generate_event_id(event) do {:ok, %Event{event | event_id: event_id}} end end defp generate_event_id(event) do with {:ok, hash} <- calculate_reference_hash(event) do {:ok, "$" <> MatrixServer.encode_url_safe_base64(hash)} end end defp calculate_reference_hash(event) do redacted_event = event |> redact() |> Map.drop([:unsigned, :signature, :age_ts]) with {:ok, json} <- MatrixServer.encode_canonical_json(redacted_event) do {:ok, :crypto.hash(:sha256, json)} end end end