mobilizon.chapril.org-mobil.../lib/web/plugs/http_signatures.ex
Thomas Citharel 3a753312c1
Validate Date header in HTTPSignatures
Signed-off-by: Thomas Citharel <tcit@tcit.fr>
2020-02-14 09:22:17 +01:00

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# Portions of this file are derived from Pleroma:
# Copyright © 2017-2018 Pleroma Authors <https://pleroma.social>
# SPDX-License-Identifier: AGPL-3.0-only
# Upstream: https://git.pleroma.social/pleroma/pleroma/blob/develop/lib/pleroma/plugs/http_signature.ex
defmodule Mobilizon.Web.Plugs.HTTPSignatures do
@moduledoc """
Plug to check HTTP Signatures on every incoming request
"""
import Plug.Conn
require Logger
def init(options) do
options
end
def call(%{assigns: %{valid_signature: true}} = conn, _opts) do
conn
end
def call(conn, _opts) do
case get_req_header(conn, "signature") do
[signature | _] ->
if signature do
# set (request-target) header to the appropriate value
# we also replace the digest header with the one we computed
conn =
conn
|> put_req_header(
"(request-target)",
String.downcase("#{conn.method}") <> " #{conn.request_path}"
)
conn =
if conn.assigns[:digest] do
conn
|> put_req_header("digest", conn.assigns[:digest])
else
conn
end
signature_valid = HTTPSignatures.validate_conn(conn)
Logger.debug("Is signature valid ? #{inspect(signature_valid)}")
date_valid = date_valid?(conn)
assign(conn, :valid_signature, signature_valid && date_valid)
else
Logger.debug("No signature header!")
conn
end
_ ->
conn
end
end
@spec date_valid?(Plug.Conn.t()) :: boolean()
defp date_valid?(conn) do
with [date | _] <- get_req_header(conn, "date") || [""],
{:ok, date} <- Timex.parse(date, "{WDshort}, {0D} {Mshort} {YYYY} {h24}:{m}:{s} GMT") do
Timex.diff(date, DateTime.utc_now(), :hours) <= 12 &&
Timex.diff(date, DateTime.utc_now(), :hours) >= -12
else
_ -> false
end
end
end