Merge branch '1668-prometheus-access-restrictions' into 'develop'

[#1668] App metrics endpoint (Prometheus) access restrictions

Closes #1668

See merge request pleroma/pleroma!3093

2 files changed, 53 insertions, 6 deletions

diff --git a/lib/pleroma/helpers/inet_helper.ex b/lib/pleroma/helpers/inet_helper.ex
new file mode 100644
index 000000000..126f82381
--- /dev/null
+++ b/lib/pleroma/helpers/inet_helper.ex
@@ -0,0 +1,19 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Helpers.InetHelper do
+  def parse_address(ip) when is_tuple(ip) do
+    {:ok, ip}
+  end
+
+  def parse_address(ip) when is_binary(ip) do
+    ip
+    |> String.to_charlist()
+    |> parse_address()
+  end
+
+  def parse_address(ip) do
+    :inet.parse_address(ip)
+  end
+end
diff --git a/lib/pleroma/web/endpoint.ex b/lib/pleroma/web/endpoint.ex
index d0e01f3d9..f26542e88 100644
--- a/lib/pleroma/web/endpoint.ex
+++ b/lib/pleroma/web/endpoint.ex
@@ -7,6 +7,8 @@ defmodule Pleroma.Web.Endpoint do
 
   require Pleroma.Constants
 
+  alias Pleroma.Config
+
   socket("/socket", Pleroma.Web.UserSocket)
 
   plug(Plug.Telemetry, event_prefix: [:phoenix, :endpoint])
@@ -88,19 +90,19 @@ defmodule Pleroma.Web.Endpoint do
   plug(Plug.Parsers,
     parsers: [
       :urlencoded,
-      {:multipart, length: {Pleroma.Config, :get, [[:instance, :upload_limit]]}},
+      {:multipart, length: {Config, :get, [[:instance, :upload_limit]]}},
       :json
     ],
     pass: ["*/*"],
     json_decoder: Jason,
-    length: Pleroma.Config.get([:instance, :upload_limit]),
+    length: Config.get([:instance, :upload_limit]),
     body_reader: {Pleroma.Web.Plugs.DigestPlug, :read_body, []}
   )
 
   plug(Plug.MethodOverride)
   plug(Plug.Head)
 
-  secure_cookies = Pleroma.Config.get([__MODULE__, :secure_cookie_flag])
+  secure_cookies = Config.get([__MODULE__, :secure_cookie_flag])
 
   cookie_name =
     if secure_cookies,
@@ -108,7 +110,7 @@ defmodule Pleroma.Web.Endpoint do
       else: "pleroma_key"
 
   extra =
-    Pleroma.Config.get([__MODULE__, :extra_cookie_attrs])
+    Config.get([__MODULE__, :extra_cookie_attrs])
     |> Enum.join(";")
 
   # The session will be stored in the cookie and signed,
@@ -118,7 +120,7 @@ defmodule Pleroma.Web.Endpoint do
     Plug.Session,
     store: :cookie,
     key: cookie_name,
-    signing_salt: Pleroma.Config.get([__MODULE__, :signing_salt], "CqaoopA2"),
+    signing_salt: Config.get([__MODULE__, :signing_salt], "CqaoopA2"),
     http_only: true,
     secure: secure_cookies,
     extra: extra
@@ -138,8 +140,34 @@ defmodule Pleroma.Web.Endpoint do
     use Prometheus.PlugExporter
   end
 
+  defmodule MetricsExporterCaller do
+    @behaviour Plug
+
+    def init(opts), do: opts
+
+    def call(conn, opts) do
+      prometheus_config = Application.get_env(:prometheus, MetricsExporter, [])
+      ip_whitelist = List.wrap(prometheus_config[:ip_whitelist])
+
+      cond do
+        !prometheus_config[:enabled] ->
+          conn
+
+        ip_whitelist != [] and
+            !Enum.find(ip_whitelist, fn ip ->
+              Pleroma.Helpers.InetHelper.parse_address(ip) == {:ok, conn.remote_ip}
+            end) ->
+          conn
+
+        true ->
+          MetricsExporter.call(conn, opts)
+      end
+    end
+  end
+
   plug(PipelineInstrumenter)
-  plug(MetricsExporter)
+
+  plug(MetricsExporterCaller)
 
   plug(Pleroma.Web.Router)