git.squeep.com Git - akkoma/blob - lib/pleroma/web/http_signatures/http_signatures.ex

   1 # https://tools.ietf.org/html/draft-cavage-http-signatures-08
   2 defmodule Pleroma.Web.HTTPSignatures do
   3   def split_signature(sig) do
   4     default = %{"headers" => "date"}
   5
   6     sig = sig
   7     |> String.trim()
   8     |> String.split(",")
   9     |> Enum.reduce(default, fn(part, acc) ->
  10       [key | rest] = String.split(part, "=")
  11       value = Enum.join(rest, "=")
  12       Map.put(acc, key, String.trim(value, "\""))
  13     end)
  14
  15     Map.put(sig, "headers", String.split(sig["headers"], ~r/\s/))
  16   end
  17
  18   def validate(headers, signature, public_key) do
  19     sigstring = build_signing_string(headers, signature["headers"])
  20     {:ok, sig} = Base.decode64(signature["signature"])
  21     verify = :public_key.verify(sigstring, :sha256, sig, public_key)
  22   end
  23
  24   def validate_conn(conn, public_key) do
  25     headers = Enum.into(conn.req_headers, %{})
  26     signature = split_signature(headers["signature"])
  27     validate(headers, signature, public_key)
  28   end
  29
  30   def build_signing_string(headers, used_headers) do
  31     used_headers
  32     |> Enum.map(fn (header) -> "#{header}: #{headers[header]}" end)
  33     |> Enum.join("\n")
  34   end
  35 end