mobilizon/lib/service/auth/ldap_authenticator.ex

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# Portions of this file are derived from Pleroma:
# Pleroma: A lightweight social networking server
# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only
defmodule Mobilizon.Service.Auth.LDAPAuthenticator do
@moduledoc """
Authenticate Mobilizon users through LDAP accounts
"""
alias Mobilizon.Service.Auth.{Authenticator, MobilizonAuthenticator}
alias Mobilizon.Users
alias Mobilizon.Users.User
require Logger
import Authenticator,
only: [fetch_user: 1]
@behaviour Authenticator
@base MobilizonAuthenticator
@connection_timeout 10_000
@search_timeout 10_000
@impl Authenticator
def login(email, password) do
with {:ldap, true} <- {:ldap, Mobilizon.Config.get([:ldap, :enabled])},
%User{} = user <- ldap_user(email, password) do
{:ok, user}
else
{:error, {:ldap_connection_error, _}} ->
# When LDAP is unavailable, try default authenticator
@base.login(email, password)
{:ldap, _} ->
@base.login(email, password)
error ->
error
end
end
@impl Authenticator
def can_change_email?(%User{provider: provider}), do: provider != "ldap"
@impl Authenticator
def can_change_password?(%User{provider: provider}), do: provider != "ldap"
@impl Authenticator
def provider_name, do: "ldap"
defp ldap_user(email, password) do
ldap = Mobilizon.Config.get(:ldap, [])
host = Keyword.get(ldap, :host, "localhost")
port = Keyword.get(ldap, :port, 389)
ssl = Keyword.get(ldap, :ssl, false)
sslopts = Keyword.get(ldap, :sslopts, [])
options =
[{:port, port}, {:ssl, ssl}, {:timeout, @connection_timeout}] ++
if sslopts != [], do: [{:sslopts, sslopts}], else: []
case :eldap.open([to_charlist(host)], options) do
{:ok, connection} ->
try do
ensure_eventual_tls(connection, ldap)
base = Keyword.get(ldap, :base)
uid_field = Keyword.get(ldap, :uid, "cn")
group = Keyword.get(ldap, :group, false)
# We first need to find the LDAP UID/CN for this specif email
with uid when is_binary(uid) <-
search_user(connection, ldap, base, uid_field, email, group),
# Then we can verify the user's password
:ok <- bind_user(connection, base, uid_field, uid, password) do
case fetch_user(email) do
%User{disabled: false} = user ->
user
%User{disabled: true} = _user ->
{:error, :disabled_user}
_ ->
register_user(email)
end
else
{:error, err}
when err in [:ldap_search_email_not_found, :ldap_search_missing_attributes] ->
{:ldap, err}
{:error, error} ->
{:error, error}
error ->
{:error, error}
end
after
:eldap.close(connection)
end
{:error, error} ->
Logger.error("Could not open LDAP connection: #{inspect(error)}")
{:error, {:ldap_connection_error, error}}
end
end
# Bind user with full DN
@spec bind_user(any(), String.t(), String.t(), {:full, String.t()}, String.t()) ::
User.t() | any()
defp bind_user(connection, _base, _uid, {:full, field}, password) do
Logger.debug("Binding to LDAP with \"#{field}\"")
:eldap.simple_bind(connection, field, password)
end
# Bind user with only uid field on top of base
@spec bind_user(any(), String.t(), String.t(), String.t(), String.t()) ::
User.t() | any()
defp bind_user(connection, base, uid, field, password) do
bind = "#{uid}=#{field},#{base}"
Logger.debug("Binding to LDAP with \"#{bind}\"")
:eldap.simple_bind(connection, bind, password)
end
@spec search_user(
any(),
Keyword.t(),
String.t(),
String.t(),
String.t(),
String.t() | boolean()
) ::
String.t() | {:error, :ldap_registration_missing_attributes} | any()
defp search_user(connection, ldap, base, uid, email, group) do
# We may need to bind before performing the search
res =
if Keyword.get(ldap, :require_bind_for_search, true) do
admin_field = Keyword.get(ldap, :bind_uid)
admin_password = Keyword.get(ldap, :bind_password)
bind_user(connection, base, uid, admin_field, admin_password)
else
:ok
end
if res == :ok do
do_search_user(connection, base, uid, email, group)
else
res
end
end
# Search an user by uid to find their CN
@spec do_search_user(any(), String.t(), String.t(), String.t(), String.t() | boolean()) ::
String.t() | {:error, :ldap_registration_missing_attributes} | any()
defp do_search_user(connection, base, uid, email, group) do
with {:ok, {:eldap_search_result, [{:eldap_entry, _, attributes}], _}} <-
:eldap.search(connection, [
{:base, to_charlist(base)},
{:filter, search_filter(email, group)},
{:scope, :eldap.wholeSubtree()},
{:attributes, [to_charlist(uid)]},
{:timeout, @search_timeout}
]),
{:uid, {_, [uid]}} <- {:uid, List.keyfind(attributes, to_charlist(uid), 0)} do
:erlang.list_to_binary(uid)
else
{:ok, {:eldap_search_result, [], []}} ->
Logger.info("Unable to find user with email #{email}")
{:error, :ldap_search_email_not_found}
{:cn, err} ->
Logger.error("Could not find LDAP attribute CN: #{inspect(err)}")
{:error, :ldap_search_missing_attributes}
error ->
error
end
end
@spec search_filter(String.t(), boolean()) :: any()
defp search_filter(email, false) do
:eldap.equalityMatch('mail', to_charlist(email))
end
# If we need to filter for group memberships as well
@spec search_filter(String.t(), String.t()) :: any()
defp search_filter(email, group) when is_binary(group) do
:eldap.and([
:eldap.equalityMatch('mail', to_charlist(email)),
:eldap.equalityMatch('memberOf', to_charlist(group))
])
end
@spec register_user(String.t()) :: User.t() | any()
defp register_user(email) do
case Users.create_external(email, "ldap") do
{:ok, %User{} = user} ->
user
error ->
error
end
end
@spec ensure_eventual_tls(any(), Keyword.t()) :: :ok
defp ensure_eventual_tls(connection, ldap) do
if Keyword.get(ldap, :tls, false) do
:application.ensure_all_started(:ssl)
case :eldap.start_tls(
connection,
Keyword.get(ldap, :tlsopts, []),
@connection_timeout
) do
:ok ->
:ok
error ->
Logger.error("Could not start TLS: #{inspect(error)}")
end
end
:ok
end
end