Fix prev events not being hashed and signed during room creation.

lib/matrix_server/room_server.ex

@@ -74,16 +74,10 @@ defmodule MatrixServer.RoomServer do
     # TODO: power_level_content_override, initial_state, invite, invite_3pid
     room = Repo.one!(from r in Room, where: r.id == ^room_id)
 
-    case create_room_events(room, account, input) do
-      events when is_list(events) ->
-        case Repo.transaction(create_room_insert_events(room, events)) do
-          {:ok, state_set} -> {:reply, {:ok, room_id}, %{state | state_set: state_set}}
-          {:error, reason} -> {:reply, {:error, reason}, state}
-          _ -> {:reply, {:error, :unknown}, state}
-        end
-
-      :error ->
-        {:reply, {:error, :event_creation}, state}
+    case Repo.transaction(create_room_insert_events(room, account, input)) do
+      {:ok, state_set} -> {:reply, {:ok, room_id}, %{state | state_set: state_set}}
+      {:error, reason} -> {:reply, {:error, reason}, state}
+      _ -> {:reply, {:error, :unknown}, state}
     end
   end
 
@@ -100,51 +94,54 @@ defmodule MatrixServer.RoomServer do
     {:reply, result, state}
   end
 
-  defp create_room_events(room, account, %CreateRoom{
+  defp create_room_insert_events(room, account, %CreateRoom{
          room_version: room_version,
+         preset: preset,
          name: name,
-         topic: topic,
-         preset: preset
+         topic: topic
        }) do
-    with {:ok, create_room} <- Event.create_room(room, account, room_version),
-         {:ok, join_creator} <- Event.join(room, account, [create_room]),
-         {:ok, pls} <- Event.power_levels(room, account, [create_room, join_creator]),
-         auth_events <- [create_room, join_creator, pls],
-         {:ok, preset_events} <- room_creation_preset(account, preset, room, auth_events),
-         {:ok, name_event} <-
-           if(name, do: Event.name(room, account, name, auth_events), else: {:ok, nil}),
-         {:ok, topic_event} <-
-           if(topic, do: Event.topic(room, account, topic, auth_events), else: {:ok, nil}) do
-      events = [create_room, join_creator, pls] ++ preset_events ++ [name_event, topic_event]
-
-      Enum.reject(events, &Kernel.is_nil/1)
-    else
-      _ -> :error
-    end
-  end
-
-  defp create_room_insert_events(room, events) do
     fn ->
-      result =
-        Enum.reduce_while(events, {%{}, room}, fn event, {state_set, room} ->
-          case verify_and_insert_event(event, state_set, room) do
-            {:ok, state_set, room} -> {:cont, {state_set, room}}
-            {:error, reason} -> {:halt, {:error, reason}}
-          end
-        end)
+      state_set = %{}
 
-      case result do
-        {:error, reason} ->
-          Repo.rollback(reason)
+      with create_room <- Event.create_room(room, account, room_version),
+           {:ok, state_set, create_room, room} <-
+             verify_and_insert_event(create_room, state_set, room),
+           join_creator <- Event.join(room, account, [create_room]),
+           {:ok, state_set, join_creator, room} <-
+             verify_and_insert_event(join_creator, state_set, room),
+           pls <- Event.power_levels(room, account, [create_room, join_creator]),
+           {:ok, state_set, pls, room} <- verify_and_insert_event(pls, state_set, room) do
+        auth_events = [create_room, join_creator, pls]
+        preset_events = room_creation_preset(account, preset, room, auth_events)
+        name_event = if name, do: Event.name(room, account, name, auth_events)
+        topic_event = if topic, do: Event.topic(room, account, topic, auth_events)
 
-        {state_set, room} ->
-          serialized_state_set =
-            Enum.map(state_set, fn {{type, state_key}, event} ->
-              [type, state_key, event.event_id]
-            end)
+        remaining_events =
+          Enum.reject(preset_events ++ [name_event, topic_event], &Kernel.is_nil/1)
 
-          Repo.update!(change(room, state: serialized_state_set))
-          state_set
+        result =
+          Enum.reduce_while(remaining_events, {state_set, room}, fn event, {state_set, room} ->
+            case verify_and_insert_event(event, state_set, room) do
+              {:ok, state_set, _event, room} -> {:cont, {state_set, room}}
+              {:error, reason} -> {:halt, {:error, reason}}
+            end
+          end)
+
+        case result do
+          {:error, reason} ->
+            Repo.rollback(reason)
+
+          {state_set, room} ->
+            serialized_state_set =
+              Enum.map(state_set, fn {{type, state_key}, event} ->
+                [type, state_key, event.event_id]
+              end)
+
+            Repo.update!(change(room, state: serialized_state_set))
+            state_set
+        end
+      else
+        _ -> Repo.rollback(:event_creation)
       end
     end
   end
@@ -169,11 +166,11 @@ defmodule MatrixServer.RoomServer do
         "public_chat" -> {"public", "shared", "forbidden"}
       end
 
-    with {:ok, join_rules} <- Event.join_rules(room, account, join_rule, auth_events),
-         {:ok, his_vis} <- Event.history_visibility(room, account, his_vis, auth_events),
-         {:ok, guest_access} <- Event.guest_access(room, account, guest_access, auth_events) do
-      {:ok, [join_rules, his_vis, guest_access]}
-    end
+    [
+      Event.join_rules(room, account, join_rule, auth_events),
+      Event.history_visibility(room, account, his_vis, auth_events),
+      Event.guest_access(room, account, guest_access, auth_events)
+    ]
   end
 
   defp verify_and_insert_event(
@@ -181,6 +178,7 @@ defmodule MatrixServer.RoomServer do
          current_state_set,
          %Room{forward_extremities: forward_extremities} = room
        ) do
+    # TODO: Correct error values.
     # Check the following things:
     # 1. TODO: Is a valid event, otherwise it is dropped.
     # 2. TODO: Passes signature checks, otherwise it is dropped.
@@ -190,7 +188,8 @@ defmodule MatrixServer.RoomServer do
     # 6. Passes authorization rules based on the current state of the room, otherwise it is "soft failed".
     event = %Event{event | prev_events: forward_extremities}
 
-    with true <- Event.prevalidate(event),
+    with {:ok, event} <- Event.post_process(event),
+         true <- Event.prevalidate(event),
          true <- Authorization.authorized_by_auth_events?(event),
          state_set <- StateResolution.resolve(event, false),
          true <- Authorization.authorized?(event, state_set),
@@ -198,7 +197,7 @@ defmodule MatrixServer.RoomServer do
       room = Room.update_forward_extremities(event, room)
       event = Repo.insert!(event)
       state_set = StateResolution.resolve_forward_extremities(event)
-      {:ok, state_set, room}
+      {:ok, state_set, event, room}
     else
       _ -> {:error, :authorization}
     end

lib/matrix_server/schema/event.ex

@@ -14,11 +14,10 @@ defmodule MatrixServer.Event do
     field :content, :map
     field :prev_events, {:array, :string}
     field :auth_events, {:array, :string}
-    # TODO: make these database fields eventually?
-    field :signing_keys, :map, virtual: true, default: %{}
-    field :unsigned, :map, virtual: true, default: %{}
-    field :signatures, :map, virtual: true, default: %{}
-    field :hashes, :map, virtual: true, default: %{}
+    field :unsigned, :map
+    field :signatures, {:map, {:map, :string}}
+    field :hashes, {:map, :string}
+
     belongs_to :room, Room, type: :string
   end
 
@@ -35,12 +34,11 @@ defmodule MatrixServer.Event do
   def create_room(
         room,
         %Account{localpart: localpart} = creator,
-        room_version,
-        generate_id \\ true
+        room_version
       ) do
     mxid = MatrixServer.get_mxid(localpart)
 
-    event = %Event{
+    %Event{
       new(room, creator)
       | type: "m.room.create",
         state_key: "",
@@ -49,14 +47,12 @@ defmodule MatrixServer.Event do
           "room_version" => room_version || MatrixServer.default_room_version()
         }
     }
-
-    if generate_id, do: set_event_id(event), else: event
   end
 
-  def join(room, %Account{localpart: localpart} = sender, auth_events, generate_id \\ true) do
+  def join(room, %Account{localpart: localpart} = sender, auth_events) do
     mxid = MatrixServer.get_mxid(localpart)
 
-    event = %Event{
+    %Event{
       new(room, sender)
       | type: "m.room.member",
         state_key: mxid,
@@ -65,19 +61,16 @@ defmodule MatrixServer.Event do
         },
         auth_events: Enum.map(auth_events, & &1.event_id)
     }
-
-    if generate_id, do: set_event_id(event), else: event
   end
 
   def power_levels(
         room,
         %Account{localpart: localpart} = sender,
-        auth_events,
-        generate_id \\ true
+        auth_events
       ) do
     mxid = MatrixServer.get_mxid(localpart)
 
-    event = %Event{
+    %Event{
       new(room, sender)
       | type: "m.room.power_levels",
         state_key: "",
@@ -99,12 +92,10 @@ defmodule MatrixServer.Event do
         },
         auth_events: Enum.map(auth_events, & &1.event_id)
     }
-
-    if generate_id, do: set_event_id(event), else: event
   end
 
-  def name(room, sender, name, auth_events, generate_id \\ true) do
-    event = %Event{
+  def name(room, sender, name, auth_events) do
+    %Event{
       new(room, sender)
       | type: "m.room.name",
         state_key: "",
@@ -113,12 +104,10 @@ defmodule MatrixServer.Event do
         },
         auth_events: Enum.map(auth_events, & &1.event_id)
     }
-
-    if generate_id, do: set_event_id(event), else: event
   end
 
-  def topic(room, sender, topic, auth_events, generate_id \\ true) do
-    event = %Event{
+  def topic(room, sender, topic, auth_events) do
+    %Event{
       new(room, sender)
       | type: "m.room.topic",
         state_key: "",
@@ -127,12 +116,10 @@ defmodule MatrixServer.Event do
         },
         auth_events: Enum.map(auth_events, & &1.event_id)
     }
-
-    if generate_id, do: set_event_id(event), else: event
   end
 
-  def join_rules(room, sender, join_rule, auth_events, generate_id \\ true) do
-    event = %Event{
+  def join_rules(room, sender, join_rule, auth_events) do
+    %Event{
       new(room, sender)
       | type: "m.room.join_rules",
         state_key: "",
@@ -141,12 +128,10 @@ defmodule MatrixServer.Event do
         },
         auth_events: Enum.map(auth_events, & &1.event_id)
     }
-
-    if generate_id, do: set_event_id(event), else: event
   end
 
-  def history_visibility(room, sender, history_visibility, auth_events, generate_id \\ true) do
-    event = %Event{
+  def history_visibility(room, sender, history_visibility, auth_events) do
+    %Event{
       new(room, sender)
       | type: "m.room.history_visibility",
         state_key: "",
@@ -155,12 +140,10 @@ defmodule MatrixServer.Event do
         },
         auth_events: Enum.map(auth_events, & &1.event_id)
     }
-
-    if generate_id, do: set_event_id(event), else: event
   end
 
-  def guest_access(room, sender, guest_access, auth_events, generate_id \\ true) do
-    event = %Event{
+  def guest_access(room, sender, guest_access, auth_events) do
+    %Event{
       new(room, sender)
       | type: "m.room.guest_access",
         state_key: "",
@@ -169,8 +152,6 @@ defmodule MatrixServer.Event do
         },
         auth_events: Enum.map(auth_events, & &1.event_id)
     }
-
-    if generate_id, do: set_event_id(event), else: event
   end
 
   def is_control_event(%Event{type: "m.room.power_levels", state_key: ""}), do: true
@@ -294,28 +275,15 @@ defmodule MatrixServer.Event do
     end)
   end
 
-  def sign(event) do
-    content_hash =
-      event
-      |> calculate_content_hash()
-      |> MatrixServer.encode_unpadded_base64()
-
-    event
-    |> Map.put(:hashes, %{"sha256" => content_hash})
-    |> redact()
-    |> KeyServer.sign_object()
-  end
-
   defp calculate_content_hash(event) do
     m =
       event
       |> MatrixServer.to_serializable_map()
       |> Map.drop([:unsigned, :signature, :hashes])
       |> EncodableMap.from_map()
-      |> Jason.encode()
 
     with {:ok, json} <- Jason.encode(m) do
-      :crypto.hash(:sha256, json)
+      {:ok, :crypto.hash(:sha256, json)}
     end
   end
 
@@ -367,6 +335,22 @@ defmodule MatrixServer.Event do
 
   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}}

priv/repo/migrations/20210818133912_add_fields_to_events.exs

@@ -0,0 +1,11 @@
+defmodule MatrixServer.Repo.Migrations.AddFieldsToEvents do
+  use Ecto.Migration
+
+  def change do
+    alter table(:events) do
+      add :unsigned, :map, default: %{}, null: true
+      add :hashes, :map, null: false
+      add :signatures, :map, null: false
+    end
+  end
+end