1 # https://tools.ietf.org/html/draft-cavage-http-signatures-08
2 defmodule Pleroma.Web.HTTPSignatures do
5 def split_signature(sig) do
6 default = %{"headers" => "date"}
11 |> Enum.reduce(default, fn(part, acc) ->
12 [key | rest] = String.split(part, "=")
13 value = Enum.join(rest, "=")
14 Map.put(acc, key, String.trim(value, "\""))
17 Map.put(sig, "headers", String.split(sig["headers"], ~r/\s/))
20 def validate(headers, signature, public_key) do
21 sigstring = build_signing_string(headers, signature["headers"])
22 {:ok, sig} = Base.decode64(signature["signature"])
23 :public_key.verify(sigstring, :sha256, sig, public_key)
26 def validate_conn(conn) do
27 # TODO: How to get the right key and see if it is actually valid for that request.
28 # For now, fetch the key for the actor.
29 with actor_id <- conn.params["actor"],
30 {:ok, public_key} <- User.get_public_key_for_ap_id(actor_id) do
31 validate_conn(conn, public_key)
37 def validate_conn(conn, public_key) do
38 headers = Enum.into(conn.req_headers, %{})
39 signature = split_signature(headers["signature"])
40 validate(headers, signature, public_key)
43 def build_signing_string(headers, used_headers) do
45 |> Enum.map(fn (header) -> "#{header}: #{headers[header]}" end)