git.squeep.com Git - akkoma/blob - lib/pleroma/plugs/http_security_plug.ex

   1 # Pleroma: A lightweight social networking server
   2 # Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
   3 # SPDX-License-Identifier: AGPL-3.0-only
   4
   5 defmodule Pleroma.Plugs.HTTPSecurityPlug do
   6   alias Pleroma.Config
   7   import Plug.Conn
   8
   9   require Logger
  10
  11   def init(opts), do: opts
  12
  13   def call(conn, _options) do
  14     if Config.get([:http_security, :enabled]) do
  15       conn
  16       |> merge_resp_headers(headers())
  17       |> maybe_send_sts_header(Config.get([:http_security, :sts]))
  18     else
  19       conn
  20     end
  21   end
  22
  23   defp headers do
  24     referrer_policy = Config.get([:http_security, :referrer_policy])
  25     report_uri = Config.get([:http_security, :report_uri])
  26
  27     headers = [
  28       {"x-xss-protection", "1; mode=block"},
  29       {"x-permitted-cross-domain-policies", "none"},
  30       {"x-frame-options", "DENY"},
  31       {"x-content-type-options", "nosniff"},
  32       {"referrer-policy", referrer_policy},
  33       {"x-download-options", "noopen"},
  34       {"content-security-policy", csp_string()}
  35     ]
  36
  37     if report_uri do
  38       report_group = %{
  39         "group" => "csp-endpoint",
  40         "max-age" => 10_886_400,
  41         "endpoints" => [
  42           %{"url" => report_uri}
  43         ]
  44       }
  45
  46       [{"reply-to", Jason.encode!(report_group)} | headers]
  47     else
  48       headers
  49     end
  50   end
  51
  52   @csp_start [
  53                "default-src 'none'",
  54                "base-uri 'self'",
  55                "frame-ancestors 'none'",
  56                "style-src 'self' 'unsafe-inline'",
  57                "font-src 'self'",
  58                "manifest-src 'self'"
  59              ]
  60              |> Enum.join(";")
  61              |> Kernel.<>(";")
  62              |> List.wrap()
  63
  64   defp csp_string do
  65     scheme = Config.get([Pleroma.Web.Endpoint, :url])[:scheme]
  66     static_url = Pleroma.Web.Endpoint.static_url()
  67     websocket_url = Pleroma.Web.Endpoint.websocket_url()
  68     report_uri = Config.get([:http_security, :report_uri])
  69
  70     connect_src = ["connect-src 'self' ", static_url, ?\s, websocket_url]
  71
  72     connect_src =
  73       if Pleroma.Config.get(:env) == :dev do
  74         [connect_src," http://localhost:3035/"]
  75       else
  76         connect_src
  77       end
  78
  79     script_src =
  80       if Pleroma.Config.get(:env) == :dev do
  81         "script-src 'self' 'unsafe-eval'"
  82       else
  83         "script-src 'self'"
  84       end
  85
  86     report = if report_uri, do: ["report-uri ", report_uri, ";report-to csp-endpoint"]
  87     insecure = if scheme == "https", do: "upgrade-insecure-requests"
  88
  89     @csp_start
  90     |> add_csp_param("img-src 'self' data: blob: https:")
  91     |> add_csp_param("media-src 'self' https:")
  92     |> add_csp_param(connect_src)
  93     |> add_csp_param(script_src)
  94     |> add_csp_param(insecure)
  95     |> add_csp_param(report)
  96     |> :erlang.iolist_to_binary()
  97   end
  98
  99   defp add_csp_param(csp_iodata, nil), do: csp_iodata
 100
 101   defp add_csp_param(csp_iodata, param), do: [[param, ?;] | csp_iodata]
 102
 103   def warn_if_disabled do
 104     unless Config.get([:http_security, :enabled]) do
 105       Logger.warn("
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 139
 140 HTTP Security is disabled. Please re-enable it to prevent users from attacking
 141 your instance and your users via malicious posts:
 142
 143       config :pleroma, :http_security, enabled: true
 144       ")
 145     end
 146   end
 147
 148   defp maybe_send_sts_header(conn, true) do
 149     max_age_sts = Config.get([:http_security, :sts_max_age])
 150     max_age_ct = Config.get([:http_security, :ct_max_age])
 151
 152     merge_resp_headers(conn, [
 153       {"strict-transport-security", "max-age=#{max_age_sts}; includeSubDomains"},
 154       {"expect-ct", "enforce, max-age=#{max_age_ct}"}
 155     ])
 156   end
 157
 158   defp maybe_send_sts_header(conn, _), do: conn
 159 end