mobilizon.chapril.org-mobil.../lib/web/plugs/http_security_plug.ex

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# Portions of this file are derived from Pleroma:
# Pleroma: A lightweight social networking server
# Copyright © 2017-2021 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only
defmodule Mobilizon.Web.Plugs.HTTPSecurityPlug do
@moduledoc """
A plug to setup some HTTP security-related headers, like CSP
"""
alias Mobilizon.Config
import Plug.Conn
require Logger
def init(opts), do: opts
def call(conn, _options) do
if Config.get([:http_security, :enabled]) do
conn
|> merge_resp_headers(headers())
|> maybe_send_sts_header(Config.get([:http_security, :sts]))
else
conn
end
end
defp headers do
referrer_policy = Config.get([:http_security, :referrer_policy])
[
{"referrer-policy", referrer_policy},
{"content-security-policy", csp_string()}
]
end
@static_csp_rules [
"default-src 'none'",
"base-uri 'self'",
"manifest-src 'self'"
]
@csp_start [Enum.join(@static_csp_rules, ";") <> ";"]
defp csp_string do
scheme = Config.get([Pleroma.Web.Endpoint, :url])[:scheme]
static_url = Mobilizon.Web.Endpoint.static_url()
websocket_url = Mobilizon.Web.Endpoint.websocket_url()
img_src =
["img-src 'self' data: blob: "] ++ Config.get([:http_security, :csp_policy, :img_src])
media_src = ["media-src 'self' "] ++ Config.get([:http_security, :csp_policy, :media_src])
# Connect-src is available for any origin because of webfinger query to redirect to content
connect_src =
["connect-src 'self' * blob: ", static_url, ?\s, websocket_url] ++
Config.get([:http_security, :csp_policy, :connect_src])
script_src =
if Config.get(:env) == :dev do
"script-src 'self' 'unsafe-eval' 'unsafe-inline' "
else
"script-src 'self' 'unsafe-eval' 'sha256-4RS22DYeB7U14dra4KcQYxmwt5HkOInieXK1NUMBmQI=' "
end
script_src = [script_src] ++ Config.get([:http_security, :csp_policy, :script_src])
style_src =
["style-src 'self' 'unsafe-inline' "] ++
Config.get([:http_security, :csp_policy, :style_src])
font_src = ["font-src 'self' "] ++ Config.get([:http_security, :csp_policy, :font_src])
frame_src = if Config.get(:env) == :dev, do: "frame-src 'self' ", else: "frame-src 'none' "
frame_src = [frame_src] ++ Config.get([:http_security, :csp_policy, :frame_src])
frame_ancestors =
if Config.get(:env) == :dev, do: "frame-ancestors 'self' ", else: "frame-ancestors 'none' "
frame_ancestors =
[frame_ancestors] ++ Config.get([:http_security, :csp_policy, :frame_ancestors])
insecure = if scheme == "https", do: "upgrade-insecure-requests"
@csp_start
|> add_csp_param(script_src)
|> add_csp_param(style_src)
|> add_csp_param(connect_src)
|> add_csp_param(img_src)
|> add_csp_param(media_src)
|> add_csp_param(font_src)
|> add_csp_param(frame_src)
|> add_csp_param(frame_ancestors)
|> add_csp_param(insecure)
|> :erlang.iolist_to_binary()
end
defp add_csp_param(csp_iodata, nil), do: csp_iodata
defp add_csp_param(csp_iodata, param), do: [[param, ?;] | csp_iodata]
defp maybe_send_sts_header(conn, true) do
max_age_sts = Config.get([:http_security, :sts_max_age])
merge_resp_headers(conn, [
{"strict-transport-security", "max-age=#{max_age_sts}; includeSubDomains"}
])
end
defp maybe_send_sts_header(conn, _), do: conn
end