+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
# https://tools.ietf.org/html/draft-cavage-http-signatures-08
defmodule Pleroma.Web.HTTPSignatures do
+ alias Pleroma.User
+ alias Pleroma.Web.ActivityPub.ActivityPub
+ alias Pleroma.Web.ActivityPub.Utils
+
+ require Logger
+
def split_signature(sig) do
- default = %{"headers" => ["date"]}
-
- sig
- |> String.trim()
- |> String.split(",")
- |> Enum.reduce(default, fn(part, acc) ->
- [key | rest] = String.split(part, "=")
- value = Enum.join(rest, "=")
- Map.put(acc, key, String.trim(value, "\""))
- end)
+ default = %{"headers" => "date"}
+
+ sig =
+ sig
+ |> String.trim()
+ |> String.split(",")
+ |> Enum.reduce(default, fn part, acc ->
+ [key | rest] = String.split(part, "=")
+ value = Enum.join(rest, "=")
+ Map.put(acc, key, String.trim(value, "\""))
+ end)
+
+ Map.put(sig, "headers", String.split(sig["headers"], ~r/\s/))
end
def validate(headers, signature, public_key) do
sigstring = build_signing_string(headers, signature["headers"])
+ Logger.debug("Signature: #{signature["signature"]}")
+ Logger.debug("Sigstring: #{sigstring}")
{:ok, sig} = Base.decode64(signature["signature"])
- verify = :public_key.verify(sigstring, :sha256, sig, public_key)
+ :public_key.verify(sigstring, :sha256, sig, public_key)
+ end
+
+ def validate_conn(conn) do
+ # TODO: How to get the right key and see if it is actually valid for that request.
+ # For now, fetch the key for the actor.
+ with actor_id <- Utils.get_ap_id(conn.params["actor"]),
+ {:ok, public_key} <- User.get_public_key_for_ap_id(actor_id) do
+ if validate_conn(conn, public_key) do
+ true
+ else
+ Logger.debug("Could not validate, re-fetching user and trying one more time")
+ # Fetch user anew and try one more time
+ with actor_id <- Utils.get_ap_id(conn.params["actor"]),
+ {:ok, _user} <- ActivityPub.make_user_from_ap_id(actor_id),
+ {:ok, public_key} <- User.get_public_key_for_ap_id(actor_id) do
+ validate_conn(conn, public_key)
+ end
+ end
+ else
+ _e ->
+ Logger.debug("Could not public key!")
+ false
+ end
+ end
+
+ def validate_conn(conn, public_key) do
+ headers = Enum.into(conn.req_headers, %{})
+ signature = split_signature(headers["signature"])
+ validate(headers, signature, public_key)
end
def build_signing_string(headers, used_headers) do
used_headers
- |> Enum.map(fn (header) -> "#{header}: #{headers[header]}" end)
+ |> Enum.map(fn header -> "#{header}: #{headers[header]}" end)
|> Enum.join("\n")
end
+
+ def sign(user, headers) do
+ with {:ok, %{info: %{keys: keys}}} <- Pleroma.Web.WebFinger.ensure_keys_present(user),
+ {:ok, private_key, _} = Pleroma.Web.Salmon.keys_from_pem(keys) do
+ sigstring = build_signing_string(headers, Map.keys(headers))
+
+ signature =
+ :public_key.sign(sigstring, :sha256, private_key)
+ |> Base.encode64()
+
+ [
+ keyId: user.ap_id <> "#main-key",
+ algorithm: "rsa-sha256",
+ headers: Map.keys(headers) |> Enum.join(" "),
+ signature: signature
+ ]
+ |> Enum.map(fn {k, v} -> "#{k}=\"#{v}\"" end)
+ |> Enum.join(",")
+ end
+ end
end