%%%----------------------------------------------------------------------
%%% File : ejabberd_auth_jwt.erl
%%% Author : Mickael Remond <mremond@process-one.net>
%%% Purpose : Authentication using JWT tokens
%%% Created : 16 Mar 2019 by Mickael Remond <mremond@process-one.net>
%%%
%%%
%%% ejabberd, Copyright (C) 2002-2022 ProcessOne
%%%
%%% This program is free software; you can redistribute it and/or
%%% modify it under the terms of the GNU General Public License as
%%% published by the Free Software Foundation; either version 2 of the
%%% License, or (at your option) any later version.
%%%
%%% This program is distributed in the hope that it will be useful,
%%% but WITHOUT ANY WARRANTY; without even the implied warranty of
%%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
%%% General Public License for more details.
%%%
%%% You should have received a copy of the GNU General Public License along
%%% with this program; if not, write to the Free Software Foundation, Inc.,
%%% 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
%%%
%%%----------------------------------------------------------------------
-module(ejabberd_auth_jwt).
-author('mremond@process-one.net').
-behaviour(ejabberd_auth).
-export([start/1, stop/1, check_password/4,
store_type/1, plain_password_required/1,
user_exists/2, use_cache/1
]).
%% 'ejabberd_hooks' callback:
-export([check_decoded_jwt/5]).
-include_lib("xmpp/include/xmpp.hrl").
-include("logger.hrl").
%%%----------------------------------------------------------------------
%%% API
%%%----------------------------------------------------------------------
start(Host) ->
%% We add our default JWT verifier with hook priority 100.
%% So if you need to check or verify your custom JWT before the
%% default verifier, It's better to use this hook with priority
%% little than 100 and return bool() or {stop, bool()} in your own
%% callback function.
ejabberd_hooks:add(check_decoded_jwt, Host, ?MODULE, check_decoded_jwt, 100),
case ejabberd_option:jwt_key(Host) of
undefined ->
?ERROR_MSG("Option jwt_key is not configured for ~ts: "
"JWT authentication won't work", [Host]);
_ ->
ok
end.
stop(Host) ->
ejabberd_hooks:delete(check_decoded_jwt, Host, ?MODULE, check_decoded_jwt, 100).
plain_password_required(_Host) -> true.
store_type(_Host) -> external.
-spec check_password(binary(), binary(), binary(), binary()) -> {ets_cache:tag(), boolean() | {stop, boolean()}}.
check_password(User, AuthzId, Server, Token) ->
%% MREMOND: Should we move the AuthzId check at a higher level in
%% the call stack?
if AuthzId /= <<>> andalso AuthzId /= User ->
{nocache, false};
true ->
if Token == <<"">> -> {nocache, false};
true ->
Res = check_jwt_token(User, Server, Token),
Rule = ejabberd_option:jwt_auth_only_rule(Server),
case acl:match_rule(Server, Rule,
jid:make(User, Server, <<"">>)) of
deny ->
{nocache, Res};
allow ->
{nocache, {stop, Res}}
end
end
end.
user_exists(User, Host) ->
%% Checking that the user has an active session
%% If the session was negociated by the JWT auth method then we define that the user exists
%% Any other cases will return that the user doesn't exist
{nocache, case ejabberd_sm:get_user_info(User, Host) of
[{_, Info}] -> proplists:get_value(auth_module, Info) == ejabberd_auth_jwt;
_ -> false
end}.
use_cache(_) ->
false.
%%%----------------------------------------------------------------------
%%% 'ejabberd_hooks' callback
%%%----------------------------------------------------------------------
check_decoded_jwt(true, Fields, _Signature, Server, User) ->
JidField = ejabberd_option:jwt_jid_field(Server),
case maps:find(JidField, Fields) of
{ok, SJid} when is_binary(SJid) ->
try
JID = jid:decode(SJid),
JID#jid.luser == User andalso JID#jid.lserver == Server
catch error:{bad_jid, _} ->
false
end;
_ -> % error | {ok, _UnknownType}
false
end;
check_decoded_jwt(Acc, _, _, _, _) ->
Acc.
%%%----------------------------------------------------------------------
%%% Internal functions
%%%----------------------------------------------------------------------
check_jwt_token(User, Server, Token) ->
JWK = ejabberd_option:jwt_key(Server),
try jose_jwt:verify(JWK, Token) of
{true, {jose_jwt, Fields}, Signature} ->
Now = erlang:system_time(second),
?DEBUG("jwt verify at system timestamp ~p: ~p - ~p~n", [Now, Fields, Signature]),
case maps:find(<<"exp">>, Fields) of
error ->
%% No expiry in token => We consider token invalid:
false;
{ok, Exp} ->
if
Exp > Now ->
ejabberd_hooks:run_fold(
check_decoded_jwt,
Server,
true,
[Fields, Signature, Server, User]
);
true ->
%% return false, if token has expired
false
end
end;
{false, _, _} ->
false
catch
A:B ->
?DEBUG("jose_jwt:verify failed ~n for account ~p@~p~n "
" JWK and token: ~p~n with error: ~p",
[User, Server, {JWK, Token}, {A, B}]),
false
end.
