# Pleroma: A lightweight social networking server # Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/> # SPDX-License-Identifier: AGPL-3.0-only defmodule Pleroma.MFA.TOTP do @moduledoc """ This module represents functions to create secrets for TOTP Application as well as validate them with a time based token. """ alias Pleroma.Config @config_ns [:instance, :multi_factor_authentication, :totp] @doc """ https://github.com/google/google-authenticator/wiki/Key-Uri-Format """ def provisioning_uri(secret, label, opts \\ []) do query = %{ secret: secret, issuer: Keyword.get(opts, :issuer, default_issuer()), digits: Keyword.get(opts, :digits, default_digits()), period: Keyword.get(opts, :period, default_period()) } |> Enum.filter(fn {_, v} -> not is_nil(v) end) |> Enum.into(%{}) |> URI.encode_query() %URI{scheme: "otpauth", host: "totp", path: "/" <> label, query: query} |> URI.to_string() end defp default_period, do: Config.get(@config_ns ++ [:period]) defp default_digits, do: Config.get(@config_ns ++ [:digits]) defp default_issuer, do: Config.get(@config_ns ++ [:issuer], Config.get([:instance, :name])) @doc "Creates a random Base 32 encoded string" def generate_secret do Base.encode32(:crypto.strong_rand_bytes(10)) end @doc "Generates a valid token based on a secret" def generate_token(secret) do :pot.totp(secret) end @doc """ Validates a given token based on a secret. optional parameters: `token_length` default `6` `interval_length` default `30` `window` default 0 Returns {:ok, :pass} if the token is valid and {:error, :invalid_token} if it is not. """ @spec validate_token(String.t(), String.t()) :: {:ok, :pass} | {:error, :invalid_token | :invalid_secret_and_token} def validate_token(secret, token) when is_binary(secret) and is_binary(token) do opts = [ token_length: default_digits(), interval_length: default_period() ] validate_token(secret, token, opts) end def validate_token(_, _), do: {:error, :invalid_secret_and_token} @doc "See `validate_token/2`" @spec validate_token(String.t(), String.t(), Keyword.t()) :: {:ok, :pass} | {:error, :invalid_token | :invalid_secret_and_token} def validate_token(secret, token, options) when is_binary(secret) and is_binary(token) do case :pot.valid_totp(token, secret, options) do true -> {:ok, :pass} false -> {:error, :invalid_token} end end def validate_token(_, _, _), do: {:error, :invalid_secret_and_token} end