From 37c2deb3ddcd473be9a55bbbd48b370b67a0384a Mon Sep 17 00:00:00 2001
From: href <href@random.sh>
Date: Tue, 12 May 2020 21:06:23 +0200
Subject: [PATCH] Expand and authorize streams in Streamer directly (backport
 from !2519)

---
 .../web/mastodon_api/websocket_handler.ex     |  69 +++---------
 lib/pleroma/web/streamer/state.ex             |  19 +---
 lib/pleroma/web/streamer/streamer.ex          |  65 +++++++++++
 test/integration/mastodon_websocket_test.exs  |  12 +-
 test/notification_test.exs                    |  11 +-
 test/web/streamer/streamer_test.exs           | 104 ++++++++++++++----
 6 files changed, 180 insertions(+), 100 deletions(-)

diff --git a/lib/pleroma/web/mastodon_api/websocket_handler.ex b/lib/pleroma/web/mastodon_api/websocket_handler.ex
index 5652a37c1..b1aebe014 100644
--- a/lib/pleroma/web/mastodon_api/websocket_handler.ex
+++ b/lib/pleroma/web/mastodon_api/websocket_handler.ex
@@ -12,29 +12,15 @@ defmodule Pleroma.Web.MastodonAPI.WebsocketHandler do
 
   @behaviour :cowboy_websocket
 
-  @streams [
-    "public",
-    "public:local",
-    "public:media",
-    "public:local:media",
-    "user",
-    "user:notification",
-    "direct",
-    "list",
-    "hashtag"
-  ]
-  @anonymous_streams ["public", "public:local", "hashtag"]
-
   # Handled by periodic keepalive in Pleroma.Web.Streamer.Ping.
   @timeout :infinity
 
   def init(%{qs: qs} = req, state) do
-    with params <- :cow_qs.parse_qs(qs),
+    with params <- Enum.into(:cow_qs.parse_qs(qs), %{}),
          sec_websocket <- :cowboy_req.header("sec-websocket-protocol", req, nil),
-         access_token <- List.keyfind(params, "access_token", 0),
-         {_, stream} <- List.keyfind(params, "stream", 0),
-         {:ok, user} <- allow_request(stream, [access_token, sec_websocket]),
-         topic when is_binary(topic) <- expand_topic(stream, params) do
+         access_token <- Map.get(params, "access_token"),
+         {:ok, user} <- authenticate_request(access_token, sec_websocket),
+         {:ok, topic} <- Streamer.get_topic(Map.get(params, "stream"), user, params) do
       req =
         if sec_websocket do
           :cowboy_req.set_resp_header("sec-websocket-protocol", sec_websocket, req)
@@ -44,14 +30,14 @@ defmodule Pleroma.Web.MastodonAPI.WebsocketHandler do
 
       {:cowboy_websocket, req, %{user: user, topic: topic}, %{idle_timeout: @timeout}}
     else
-      {:error, code} ->
-        Logger.debug("#{__MODULE__} denied connection: #{inspect(code)} - #{inspect(req)}")
-        {:ok, req} = :cowboy_req.reply(code, req)
+      {:error, :bad_topic} ->
+        Logger.debug("#{__MODULE__} bad topic #{inspect(req)}")
+        {:ok, req} = :cowboy_req.reply(404, req)
         {:ok, req, state}
 
-      error ->
-        Logger.debug("#{__MODULE__} denied connection: #{inspect(error)} - #{inspect(req)}")
-        {:ok, req} = :cowboy_req.reply(400, req)
+      {:error, :unauthorized} ->
+        Logger.debug("#{__MODULE__} authentication error: #{inspect(req)}")
+        {:ok, req} = :cowboy_req.reply(401, req)
         {:ok, req, state}
     end
   end
@@ -93,50 +79,23 @@ defmodule Pleroma.Web.MastodonAPI.WebsocketHandler do
   end
 
   # Public streams without authentication.
-  defp allow_request(stream, [nil, nil]) when stream in @anonymous_streams do
+  defp authenticate_request(nil, nil) do
     {:ok, nil}
   end
 
   # Authenticated streams.
-  defp allow_request(stream, [access_token, sec_websocket]) when stream in @streams do
-    token =
-      with {"access_token", token} <- access_token do
-        token
-      else
-        _ -> sec_websocket
-      end
+  defp authenticate_request(access_token, sec_websocket) do
+    token = access_token || sec_websocket
 
     with true <- is_bitstring(token),
          %Token{user_id: user_id} <- Repo.get_by(Token, token: token),
          user = %User{} <- User.get_cached_by_id(user_id) do
       {:ok, user}
     else
-      _ -> {:error, 403}
+      _ -> {:error, :unauthorized}
     end
   end
 
-  # Not authenticated.
-  defp allow_request(stream, _) when stream in @streams, do: {:error, 403}
-
-  # No matching stream.
-  defp allow_request(_, _), do: {:error, 404}
-
-  defp expand_topic("hashtag", params) do
-    case List.keyfind(params, "tag", 0) do
-      {_, tag} -> "hashtag:#{tag}"
-      _ -> nil
-    end
-  end
-
-  defp expand_topic("list", params) do
-    case List.keyfind(params, "list", 0) do
-      {_, list} -> "list:#{list}"
-      _ -> nil
-    end
-  end
-
-  defp expand_topic(topic, _), do: topic
-
   defp streamer_socket(state) do
     %{transport_pid: self(), assigns: state}
   end
diff --git a/lib/pleroma/web/streamer/state.ex b/lib/pleroma/web/streamer/state.ex
index 999550b88..4eb462a1a 100644
--- a/lib/pleroma/web/streamer/state.ex
+++ b/lib/pleroma/web/streamer/state.ex
@@ -36,30 +36,28 @@ defmodule Pleroma.Web.Streamer.State do
   end
 
   def handle_call({:add, topic, socket}, _from, %{sockets: sockets} = state) do
-    internal_topic = internal_topic(topic, socket)
     stream_socket = StreamerSocket.from_socket(socket)
 
     sockets_for_topic =
       sockets
-      |> Map.get(internal_topic, [])
+      |> Map.get(topic, [])
       |> List.insert_at(0, stream_socket)
       |> Enum.uniq()
 
-    state = put_in(state, [:sockets, internal_topic], sockets_for_topic)
+    state = put_in(state, [:sockets, topic], sockets_for_topic)
     Logger.debug("Got new conn for #{topic}")
     {:reply, state, state}
   end
 
   def handle_call({:remove, topic, socket}, _from, %{sockets: sockets} = state) do
-    internal_topic = internal_topic(topic, socket)
     stream_socket = StreamerSocket.from_socket(socket)
 
     sockets_for_topic =
       sockets
-      |> Map.get(internal_topic, [])
+      |> Map.get(topic, [])
       |> List.delete(stream_socket)
 
-    state = Kernel.put_in(state, [:sockets, internal_topic], sockets_for_topic)
+    state = Kernel.put_in(state, [:sockets, topic], sockets_for_topic)
     {:reply, state, state}
   end
 
@@ -70,13 +68,4 @@ defmodule Pleroma.Web.Streamer.State do
   defp do_remove_socket(_env, topic, socket) do
     GenServer.call(__MODULE__, {:remove, topic, socket})
   end
-
-  defp internal_topic(topic, socket)
-       when topic in ~w[user user:notification direct] do
-    "#{topic}:#{socket.assigns[:user].id}"
-  end
-
-  defp internal_topic(topic, _) do
-    topic
-  end
 end
diff --git a/lib/pleroma/web/streamer/streamer.ex b/lib/pleroma/web/streamer/streamer.ex
index 814d5a729..1e5700b6a 100644
--- a/lib/pleroma/web/streamer/streamer.ex
+++ b/lib/pleroma/web/streamer/streamer.ex
@@ -5,10 +5,75 @@
 defmodule Pleroma.Web.Streamer do
   alias Pleroma.Web.Streamer.State
   alias Pleroma.Web.Streamer.Worker
+  alias Pleroma.User
 
   @timeout 60_000
   @mix_env Mix.env()
 
+  @public_streams ["public", "public:local", "public:media", "public:local:media"]
+  @user_streams ["user", "user:notification", "direct"]
+
+  @doc "Expands and authorizes a stream, and registers the process for streaming."
+  @spec get_topic_and_add_socket(stream :: String.t(), State.t(), Map.t() | nil) ::
+          {:ok, topic :: String.t()} | {:error, :bad_topic} | {:error, :unauthorized}
+  def get_topic_and_add_socket(stream, socket, params \\ %{}) do
+    user =
+      case socket do
+        %{assigns: %{user: user}} -> user
+        _ -> nil
+      end
+
+    case get_topic(stream, user, params) do
+      {:ok, topic} ->
+        add_socket(topic, socket)
+        {:ok, topic}
+
+      error ->
+        error
+    end
+  end
+
+  @doc "Expand and authorizes a stream"
+  @spec get_topic(stream :: String.t(), User.t() | nil, Map.t()) ::
+          {:ok, topic :: String.t()} | {:error, :bad_topic}
+  def get_topic(stream, user, params \\ %{})
+
+  # Allow all public steams.
+  def get_topic(stream, _, _) when stream in @public_streams do
+    {:ok, stream}
+  end
+
+  # Allow all hashtags streams.
+  def get_topic("hashtag", _, %{"tag" => tag}) do
+    {:ok, "hashtag:" <> tag}
+  end
+
+  # Expand user streams.
+  def get_topic(stream, %User{} = user, _) when stream in @user_streams do
+    {:ok, stream <> ":" <> to_string(user.id)}
+  end
+
+  def get_topic(stream, _, _) when stream in @user_streams do
+    {:error, :unauthorized}
+  end
+
+  # List streams.
+  def get_topic("list", %User{} = user, %{"list" => id}) do
+    if Pleroma.List.get(id, user) do
+      {:ok, "list:" <> to_string(id)}
+    else
+      {:error, :bad_topic}
+    end
+  end
+
+  def get_topic("list", _, _) do
+    {:error, :unauthorized}
+  end
+
+  def get_topic(_, _, _) do
+    {:error, :bad_topic}
+  end
+
   def add_socket(topic, socket) do
     State.add_socket(topic, socket)
   end
diff --git a/test/integration/mastodon_websocket_test.exs b/test/integration/mastodon_websocket_test.exs
index bd229c55f..39be5ad08 100644
--- a/test/integration/mastodon_websocket_test.exs
+++ b/test/integration/mastodon_websocket_test.exs
@@ -35,7 +35,7 @@ defmodule Pleroma.Integration.MastodonWebsocketTest do
 
   test "refuses invalid requests" do
     capture_log(fn ->
-      assert {:error, {400, _}} = start_socket()
+      assert {:error, {404, _}} = start_socket()
       assert {:error, {404, _}} = start_socket("?stream=ncjdk")
       Process.sleep(30)
     end)
@@ -43,8 +43,8 @@ defmodule Pleroma.Integration.MastodonWebsocketTest do
 
   test "requires authentication and a valid token for protected streams" do
     capture_log(fn ->
-      assert {:error, {403, _}} = start_socket("?stream=user&access_token=aaaaaaaaaaaa")
-      assert {:error, {403, _}} = start_socket("?stream=user")
+      assert {:error, {401, _}} = start_socket("?stream=user&access_token=aaaaaaaaaaaa")
+      assert {:error, {401, _}} = start_socket("?stream=user")
       Process.sleep(30)
     end)
   end
@@ -103,7 +103,7 @@ defmodule Pleroma.Integration.MastodonWebsocketTest do
       assert {:ok, _} = start_socket("?stream=user&access_token=#{token.token}")
 
       assert capture_log(fn ->
-               assert {:error, {403, "Forbidden"}} = start_socket("?stream=user")
+               assert {:error, {401, _}} = start_socket("?stream=user")
                Process.sleep(30)
              end) =~ ":badarg"
     end
@@ -112,7 +112,7 @@ defmodule Pleroma.Integration.MastodonWebsocketTest do
       assert {:ok, _} = start_socket("?stream=user:notification&access_token=#{token.token}")
 
       assert capture_log(fn ->
-               assert {:error, {403, "Forbidden"}} = start_socket("?stream=user:notification")
+               assert {:error, {401, _}} = start_socket("?stream=user:notification")
                Process.sleep(30)
              end) =~ ":badarg"
     end
@@ -121,7 +121,7 @@ defmodule Pleroma.Integration.MastodonWebsocketTest do
       assert {:ok, _} = start_socket("?stream=user", [{"Sec-WebSocket-Protocol", token.token}])
 
       assert capture_log(fn ->
-               assert {:error, {403, "Forbidden"}} =
+               assert {:error, {401, _}} =
                         start_socket("?stream=user", [{"Sec-WebSocket-Protocol", "I am a friend"}])
 
                Process.sleep(30)
diff --git a/test/notification_test.exs b/test/notification_test.exs
index e12418db3..d04754a9d 100644
--- a/test/notification_test.exs
+++ b/test/notification_test.exs
@@ -164,12 +164,13 @@ defmodule Pleroma.NotificationTest do
       user = insert(:user)
       task = Task.async(fn -> assert_receive {:text, _}, 4_000 end)
       task_user_notification = Task.async(fn -> assert_receive {:text, _}, 4_000 end)
-      Streamer.add_socket("user", %{transport_pid: task.pid, assigns: %{user: user}})
 
-      Streamer.add_socket(
-        "user:notification",
-        %{transport_pid: task_user_notification.pid, assigns: %{user: user}}
-      )
+      Streamer.get_topic_and_add_socket("user", %{transport_pid: task.pid, assigns: %{user: user}})
+
+      Streamer.get_topic_and_add_socket("user:notification", %{
+        transport_pid: task_user_notification.pid,
+        assigns: %{user: user}
+      })
 
       activity = insert(:note_activity)
 
diff --git a/test/web/streamer/streamer_test.exs b/test/web/streamer/streamer_test.exs
index 720f8fa44..cbd5ec462 100644
--- a/test/web/streamer/streamer_test.exs
+++ b/test/web/streamer/streamer_test.exs
@@ -17,11 +17,81 @@ defmodule Pleroma.Web.StreamerTest do
 
   @moduletag needs_streamer: true, capture_log: true
 
-  @streamer_timeout 150
+  @streamer_timeout 300
   @streamer_start_wait 10
 
   clear_config([:instance, :skip_thread_containment])
 
+  describe "get_topic without an user" do
+    test "allows public" do
+      assert {:ok, "public"} = Streamer.get_topic("public", nil)
+      assert {:ok, "public:local"} = Streamer.get_topic("public:local", nil)
+      assert {:ok, "public:media"} = Streamer.get_topic("public:media", nil)
+      assert {:ok, "public:local:media"} = Streamer.get_topic("public:local:media", nil)
+    end
+
+    test "allows hashtag streams" do
+      assert {:ok, "hashtag:cofe"} = Streamer.get_topic("hashtag", nil, %{"tag" => "cofe"})
+    end
+
+    test "disallows user streams" do
+      assert {:error, _} = Streamer.get_topic("user", nil)
+      assert {:error, _} = Streamer.get_topic("user:notification", nil)
+      assert {:error, _} = Streamer.get_topic("direct", nil)
+    end
+
+    test "disallows list streams" do
+      assert {:error, _} = Streamer.get_topic("list", nil, %{"list" => 42})
+    end
+  end
+
+  describe "get_topic with an user" do
+    setup do
+      user = insert(:user)
+      {:ok, %{user: user}}
+    end
+
+    test "allows public streams", %{user: user} do
+      assert {:ok, "public"} = Streamer.get_topic("public", user)
+      assert {:ok, "public:local"} = Streamer.get_topic("public:local", user)
+      assert {:ok, "public:media"} = Streamer.get_topic("public:media", user)
+      assert {:ok, "public:local:media"} = Streamer.get_topic("public:local:media", user)
+    end
+
+    test "allows user streams", %{user: user} do
+      expected_user_topic = "user:#{user.id}"
+      expected_notif_topic = "user:notification:#{user.id}"
+      expected_direct_topic = "direct:#{user.id}"
+      assert {:ok, ^expected_user_topic} = Streamer.get_topic("user", user)
+      assert {:ok, ^expected_notif_topic} = Streamer.get_topic("user:notification", user)
+      assert {:ok, ^expected_direct_topic} = Streamer.get_topic("direct", user)
+    end
+
+    test "allows hashtag streams", %{user: user} do
+      assert {:ok, "hashtag:cofe"} = Streamer.get_topic("hashtag", user, %{"tag" => "cofe"})
+    end
+
+    test "disallows registering to an user stream", %{user: user} do
+      another_user = insert(:user)
+      assert {:error, _} = Streamer.get_topic("user:#{another_user.id}", user)
+      assert {:error, _} = Streamer.get_topic("user:notification:#{another_user.id}", user)
+      assert {:error, _} = Streamer.get_topic("direct:#{another_user.id}", user)
+    end
+
+    test "allows list stream that are owned by the user", %{user: user} do
+      {:ok, list} = List.create("Test", user)
+      assert {:error, _} = Streamer.get_topic("list:#{list.id}", user)
+      assert {:ok, _} = Streamer.get_topic("list", user, %{"list" => list.id})
+    end
+
+    test "disallows list stream that are not owned by the user", %{user: user} do
+      another_user = insert(:user)
+      {:ok, list} = List.create("Test", another_user)
+      assert {:error, _} = Streamer.get_topic("list:#{list.id}", user)
+      assert {:error, _} = Streamer.get_topic("list", user, %{"list" => list.id})
+    end
+  end
+
   describe "user streams" do
     setup do
       user = insert(:user)
@@ -35,7 +105,7 @@ defmodule Pleroma.Web.StreamerTest do
           assert_receive {:text, _}, @streamer_timeout
         end)
 
-      Streamer.add_socket(
+      Streamer.get_topic_and_add_socket(
         "user",
         %{transport_pid: task.pid, assigns: %{user: user}}
       )
@@ -50,7 +120,7 @@ defmodule Pleroma.Web.StreamerTest do
           assert_receive {:text, _}, @streamer_timeout
         end)
 
-      Streamer.add_socket(
+      Streamer.get_topic_and_add_socket(
         "user:notification",
         %{transport_pid: task.pid, assigns: %{user: user}}
       )
@@ -70,7 +140,7 @@ defmodule Pleroma.Web.StreamerTest do
 
       task = Task.async(fn -> refute_receive {:text, _}, @streamer_timeout end)
 
-      Streamer.add_socket(
+      Streamer.get_topic_and_add_socket(
         "user:notification",
         %{transport_pid: task.pid, assigns: %{user: user}}
       )
@@ -90,7 +160,7 @@ defmodule Pleroma.Web.StreamerTest do
 
       task = Task.async(fn -> refute_receive {:text, _}, @streamer_timeout end)
 
-      Streamer.add_socket(
+      Streamer.get_topic_and_add_socket(
         "user:notification",
         %{transport_pid: task.pid, assigns: %{user: user}}
       )
@@ -110,7 +180,7 @@ defmodule Pleroma.Web.StreamerTest do
 
       task = Task.async(fn -> refute_receive {:text, _}, @streamer_timeout end)
 
-      Streamer.add_socket(
+      Streamer.get_topic_and_add_socket(
         "user:notification",
         %{transport_pid: task.pid, assigns: %{user: user}}
       )
@@ -127,7 +197,7 @@ defmodule Pleroma.Web.StreamerTest do
 
       Process.sleep(@streamer_start_wait)
 
-      Streamer.add_socket(
+      Streamer.get_topic_and_add_socket(
         "user:notification",
         %{transport_pid: task.pid, assigns: %{user: user}}
       )
@@ -415,14 +485,10 @@ defmodule Pleroma.Web.StreamerTest do
         assert_receive {:text, _}, 1_000
       end)
 
-    fake_socket = %StreamerSocket{
-      transport_pid: task.pid,
-      user: user_a
-    }
-
-    Streamer.add_socket(
-      "list:#{list.id}",
-      fake_socket
+    Streamer.get_topic_and_add_socket(
+      "list",
+      %{transport_pid: task.pid, assigns: %{user: user_a}},
+      %{"list" => list.id}
     )
 
     Worker.handle_call({:stream, "list", activity}, self(), %{})
@@ -497,7 +563,7 @@ defmodule Pleroma.Web.StreamerTest do
 
     task = Task.async(fn -> refute_receive {:text, _}, @streamer_timeout end)
 
-    Streamer.add_socket(
+    Streamer.get_topic_and_add_socket(
       "user",
       %{transport_pid: task.pid, assigns: %{user: user2}}
     )
@@ -527,7 +593,7 @@ defmodule Pleroma.Web.StreamerTest do
           assert last_status["pleroma"]["direct_conversation_id"] == participation.id
         end)
 
-      Streamer.add_socket(
+      Streamer.get_topic_and_add_socket(
         "direct",
         %{transport_pid: task.pid, assigns: %{user: user}}
       )
@@ -561,7 +627,7 @@ defmodule Pleroma.Web.StreamerTest do
 
       Process.sleep(@streamer_start_wait)
 
-      Streamer.add_socket(
+      Streamer.get_topic_and_add_socket(
         "direct",
         %{transport_pid: task.pid, assigns: %{user: user}}
       )
@@ -604,7 +670,7 @@ defmodule Pleroma.Web.StreamerTest do
 
       Process.sleep(@streamer_start_wait)
 
-      Streamer.add_socket(
+      Streamer.get_topic_and_add_socket(
         "direct",
         %{transport_pid: task.pid, assigns: %{user: user}}
       )