%%%-------------------------------------------------------------------
%%% File : mod_delegation.erl
%%% Author : Anna Mukharram <amuhar3@gmail.com>
%%% Purpose : XEP-0355: Namespace Delegation
%%%
%%%
%%% 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(mod_delegation).
-author('amuhar3@gmail.com').
-protocol({xep, 355, '0.4.1', '16.09', "", ""}).
-behaviour(gen_server).
-behaviour(gen_mod).
%% API
-export([start/2, stop/1, reload/3, mod_opt_type/1, depends/2, mod_options/1]).
-export([mod_doc/0]).
%% gen_server callbacks
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
terminate/2, code_change/3]).
-export([component_connected/1, component_disconnected/2,
ejabberd_local/1, ejabberd_sm/1, decode_iq_subel/1,
disco_local_features/5, disco_sm_features/5,
disco_local_identity/5, disco_sm_identity/5]).
-include("logger.hrl").
-include_lib("xmpp/include/xmpp.hrl").
-include("translate.hrl").
-type route_type() :: ejabberd_sm | ejabberd_local.
-type delegations() :: #{{binary(), route_type()} => {binary(), disco_info()}}.
-record(state, {server_host = <<"">> :: binary()}).
%%%===================================================================
%%% API
%%%===================================================================
start(Host, Opts) ->
gen_mod:start_child(?MODULE, Host, Opts).
stop(Host) ->
gen_mod:stop_child(?MODULE, Host).
reload(_Host, _NewOpts, _OldOpts) ->
ok.
mod_opt_type(namespaces) ->
econf:and_then(
econf:map(
econf:binary(),
econf:options(
#{filtering => econf:list(econf:binary()),
access => econf:acl()})),
fun(L) ->
lists:map(
fun({NS, Opts}) ->
Attrs = proplists:get_value(filtering, Opts, []),
Access = proplists:get_value(access, Opts, none),
{NS, Attrs, Access}
end, L)
end).
-spec mod_options(binary()) -> [{namespaces,
[{binary(), [binary()], acl:acl()}]} |
{atom(), term()}].
mod_options(_Host) ->
[{namespaces, []}].
mod_doc() ->
#{desc =>
[?T("This module is an implementation of "
"https://xmpp.org/extensions/xep-0355.html"
"[XEP-0355: Namespace Delegation]. "
"Only admin mode has been implemented by now. "
"Namespace delegation allows external services to "
"handle IQ using specific namespace. This may be applied "
"for external PEP service."), "",
?T("WARNING: Security issue: Namespace delegation gives components "
"access to sensitive data, so permission should be granted "
"carefully, only if you trust the component."), "",
?T("NOTE: This module is complementary to _`mod_privilege`_ but can "
"also be used separately.")],
opts =>
[{namespaces,
#{value => "{Namespace: Options}",
desc =>
?T("If you want to delegate namespaces to a component, "
"specify them in this option, and associate them "
"to an access rule. The 'Options' are:")},
[{filtering,
#{value => ?T("Attributes"),
desc =>
?T("The list of attributes. Currently not used.")}},
{access,
#{value => ?T("AccessName"),
desc =>
?T("The option defines which components are allowed "
"for namespace delegation. The default value is 'none'.")}}]}],
example =>
[{?T("Make sure you do not delegate the same namespace to several "
"services at the same time. As in the example provided later, "
"to have the 'sat-pubsub.example.org' component perform "
"correctly disable the 'mod_pubsub' module."),
["access_rules:",
" external_pubsub:",
" allow: external_component",
" external_mam:",
" allow: external_component",
"",
"acl:",
" external_component:",
" server: sat-pubsub.example.org",
"",
"modules:",
" ...",
" mod_delegation:",
" namespaces:",
" urn:xmpp:mam:1:",
" access: external_mam",
" http://jabber.org/protocol/pubsub:",
" access: external_pubsub"]}]}.
depends(_, _) ->
[].
-spec decode_iq_subel(xmpp_element() | xmlel()) -> xmpp_element() | xmlel().
%% Tell gen_iq_handler not to auto-decode IQ payload
decode_iq_subel(El) ->
El.
-spec component_connected(binary()) -> ok.
component_connected(Host) ->
lists:foreach(
fun(ServerHost) ->
Proc = gen_mod:get_module_proc(ServerHost, ?MODULE),
gen_server:cast(Proc, {component_connected, Host})
end, ejabberd_option:hosts()).
-spec component_disconnected(binary(), binary()) -> ok.
component_disconnected(Host, _Reason) ->
lists:foreach(
fun(ServerHost) ->
Proc = gen_mod:get_module_proc(ServerHost, ?MODULE),
gen_server:cast(Proc, {component_disconnected, Host})
end, ejabberd_option:hosts()).
-spec ejabberd_local(iq()) -> iq().
ejabberd_local(IQ) ->
process_iq(IQ, ejabberd_local).
-spec ejabberd_sm(iq()) -> iq().
ejabberd_sm(IQ) ->
process_iq(IQ, ejabberd_sm).
-spec disco_local_features(mod_disco:features_acc(), jid(), jid(),
binary(), binary()) -> mod_disco:features_acc().
disco_local_features(Acc, From, To, Node, Lang) ->
disco_features(Acc, From, To, Node, Lang, ejabberd_local).
-spec disco_sm_features(mod_disco:features_acc(), jid(), jid(),
binary(), binary()) -> mod_disco:features_acc().
disco_sm_features(Acc, From, To, Node, Lang) ->
disco_features(Acc, From, To, Node, Lang, ejabberd_sm).
-spec disco_local_identity([identity()], jid(), jid(), binary(), binary()) -> [identity()].
disco_local_identity(Acc, From, To, Node, Lang) ->
disco_identity(Acc, From, To, Node, Lang, ejabberd_local).
-spec disco_sm_identity([identity()], jid(), jid(), binary(), binary()) -> [identity()].
disco_sm_identity(Acc, From, To, Node, Lang) ->
disco_identity(Acc, From, To, Node, Lang, ejabberd_sm).
%%%===================================================================
%%% gen_server callbacks
%%%===================================================================
init([Host|_]) ->
process_flag(trap_exit, true),
catch ets:new(?MODULE,
[named_table, public,
{heir, erlang:group_leader(), none}]),
ejabberd_hooks:add(component_connected, ?MODULE,
component_connected, 50),
ejabberd_hooks:add(component_disconnected, ?MODULE,
component_disconnected, 50),
ejabberd_hooks:add(disco_local_features, Host, ?MODULE,
disco_local_features, 50),
ejabberd_hooks:add(disco_sm_features, Host, ?MODULE,
disco_sm_features, 50),
ejabberd_hooks:add(disco_local_identity, Host, ?MODULE,
disco_local_identity, 50),
ejabberd_hooks:add(disco_sm_identity, Host, ?MODULE,
disco_sm_identity, 50),
{ok, #state{server_host = Host}}.
handle_call(Request, From, State) ->
?WARNING_MSG("Unexpected call from ~p: ~p", [From, Request]),
{noreply, State}.
handle_cast({component_connected, Host}, State) ->
ServerHost = State#state.server_host,
To = jid:make(Host),
NSAttrsAccessList = mod_delegation_opt:namespaces(ServerHost),
lists:foreach(
fun({NS, _Attrs, Access}) ->
case acl:match_rule(ServerHost, Access, To) of
allow ->
send_disco_queries(ServerHost, Host, NS);
deny ->
?DEBUG("Denied delegation for ~ts on ~ts", [Host, NS])
end
end, NSAttrsAccessList),
{noreply, State};
handle_cast({component_disconnected, Host}, State) ->
ServerHost = State#state.server_host,
Delegations =
maps:filter(
fun({NS, Type}, {H, _}) when H == Host ->
?INFO_MSG("Remove delegation of namespace '~ts' "
"from external component '~ts'",
[NS, Host]),
gen_iq_handler:remove_iq_handler(Type, ServerHost, NS),
false;
(_, _) ->
true
end, get_delegations(ServerHost)),
set_delegations(ServerHost, Delegations),
{noreply, State};
handle_cast(Msg, State) ->
?WARNING_MSG("Unexpected cast: ~p", [Msg]),
{noreply, State}.
handle_info({iq_reply, ResIQ, {disco_info, Type, Host, NS}}, State) ->
case ResIQ of
#iq{type = result, sub_els = [SubEl]} ->
try xmpp:decode(SubEl) of
#disco_info{} = Info ->
ServerHost = State#state.server_host,
process_disco_info(ServerHost, Type, Host, NS, Info)
catch _:{xmpp_codec, _} ->
ok
end;
_ ->
ok
end,
{noreply, State};
handle_info({iq_reply, ResIQ, #iq{} = IQ}, State) ->
process_iq_result(IQ, ResIQ),
{noreply, State};
handle_info(Info, State) ->
?WARNING_MSG("Unexpected info: ~p", [Info]),
{noreply, State}.
terminate(_Reason, State) ->
ServerHost = State#state.server_host,
case gen_mod:is_loaded_elsewhere(ServerHost, ?MODULE) of
false ->
ejabberd_hooks:delete(component_connected, ?MODULE,
component_connected, 50),
ejabberd_hooks:delete(component_disconnected, ?MODULE,
component_disconnected, 50);
true ->
ok
end,
ejabberd_hooks:delete(disco_local_features, ServerHost, ?MODULE,
disco_local_features, 50),
ejabberd_hooks:delete(disco_sm_features, ServerHost, ?MODULE,
disco_sm_features, 50),
ejabberd_hooks:delete(disco_local_identity, ServerHost, ?MODULE,
disco_local_identity, 50),
ejabberd_hooks:delete(disco_sm_identity, ServerHost, ?MODULE,
disco_sm_identity, 50),
lists:foreach(
fun({NS, Type}) ->
gen_iq_handler:remove_iq_handler(Type, ServerHost, NS)
end, maps:keys(get_delegations(ServerHost))),
ets:delete(?MODULE, ServerHost).
code_change(_OldVsn, State, _Extra) ->
{ok, State}.
%%%===================================================================
%%% Internal functions
%%%===================================================================
-spec get_delegations(binary()) -> delegations().
get_delegations(Host) ->
try ets:lookup_element(?MODULE, Host, 2)
catch _:badarg -> #{}
end.
-spec set_delegations(binary(), delegations()) -> true.
set_delegations(ServerHost, Delegations) ->
case maps:size(Delegations) of
0 -> ets:delete(?MODULE, ServerHost);
_ -> ets:insert(?MODULE, {ServerHost, Delegations})
end.
-spec process_iq(iq(), route_type()) -> ignore | iq().
process_iq(#iq{to = To, lang = Lang, sub_els = [SubEl]} = IQ, Type) ->
LServer = To#jid.lserver,
NS = xmpp:get_ns(SubEl),
Delegations = get_delegations(LServer),
case maps:find({NS, Type}, Delegations) of
{ok, {Host, _}} ->
Delegation = #delegation{
forwarded = #forwarded{sub_els = [IQ]}},
NewFrom = jid:make(LServer),
NewTo = jid:make(Host),
ejabberd_router:route_iq(
#iq{type = set,
from = NewFrom,
to = NewTo,
sub_els = [Delegation]},
IQ, gen_mod:get_module_proc(LServer, ?MODULE)),
ignore;
error ->
Txt = ?T("Failed to map delegated namespace to external component"),
xmpp:make_error(IQ, xmpp:err_internal_server_error(Txt, Lang))
end.
-spec process_iq_result(iq(), iq()) -> ok.
process_iq_result(#iq{from = From, to = To, id = ID, lang = Lang} = IQ,
#iq{type = result} = ResIQ) ->
try
CodecOpts = ejabberd_config:codec_options(),
#delegation{forwarded = #forwarded{sub_els = [SubEl]}} =
xmpp:get_subtag(ResIQ, #delegation{}),
case xmpp:decode(SubEl, ?NS_CLIENT, CodecOpts) of
#iq{from = To, to = From, type = Type, id = ID} = Reply
when Type == error; Type == result ->
ejabberd_router:route(Reply)
end
catch _:_ ->
?ERROR_MSG("Got iq-result with invalid delegated "
"payload:~n~ts", [xmpp:pp(ResIQ)]),
Txt = ?T("External component failure"),
Err = xmpp:err_internal_server_error(Txt, Lang),
ejabberd_router:route_error(IQ, Err)
end;
process_iq_result(#iq{from = From, to = To}, #iq{type = error} = ResIQ) ->
Err = xmpp:set_from_to(ResIQ, To, From),
ejabberd_router:route(Err);
process_iq_result(#iq{lang = Lang} = IQ, timeout) ->
Txt = ?T("External component timeout"),
Err = xmpp:err_internal_server_error(Txt, Lang),
ejabberd_router:route_error(IQ, Err).
-spec process_disco_info(binary(), route_type(),
binary(), binary(), disco_info()) -> ok.
process_disco_info(ServerHost, Type, Host, NS, Info) ->
From = jid:make(ServerHost),
To = jid:make(Host),
Delegations = get_delegations(ServerHost),
case maps:find({NS, Type}, Delegations) of
error ->
Msg = #message{from = From, to = To,
sub_els = [#delegation{delegated = [#delegated{ns = NS}]}]},
Delegations1 = maps:put({NS, Type}, {Host, Info}, Delegations),
gen_iq_handler:add_iq_handler(Type, ServerHost, NS, ?MODULE, Type),
ejabberd_router:route(Msg),
set_delegations(ServerHost, Delegations1),
?INFO_MSG("Namespace '~ts' is delegated to external component '~ts'",
[NS, Host]);
{ok, {AnotherHost, _}} ->
?WARNING_MSG("Failed to delegate namespace '~ts' to "
"external component '~ts' because it's already "
"delegated to '~ts'",
[NS, Host, AnotherHost])
end.
-spec send_disco_queries(binary(), binary(), binary()) -> ok.
send_disco_queries(LServer, Host, NS) ->
From = jid:make(LServer),
To = jid:make(Host),
lists:foreach(
fun({Type, Node}) ->
ejabberd_router:route_iq(
#iq{type = get, from = From, to = To,
sub_els = [#disco_info{node = Node}]},
{disco_info, Type, Host, NS},
gen_mod:get_module_proc(LServer, ?MODULE))
end, [{ejabberd_local, <<(?NS_DELEGATION)/binary, "::", NS/binary>>},
{ejabberd_sm, <<(?NS_DELEGATION)/binary, ":bare:", NS/binary>>}]).
-spec disco_features(mod_disco:features_acc(), jid(), jid(), binary(), binary(),
route_type()) -> mod_disco:features_acc().
disco_features(Acc, _From, To, <<"">>, _Lang, Type) ->
Delegations = get_delegations(To#jid.lserver),
Features = my_features(Type) ++
lists:flatmap(
fun({{_, T}, {_, Info}}) when T == Type ->
Info#disco_info.features;
(_) ->
[]
end, maps:to_list(Delegations)),
case Acc of
empty when Features /= [] -> {result, Features};
{result, Fs} -> {result, Fs ++ Features};
_ -> Acc
end;
disco_features(Acc, _, _, _, _, _) ->
Acc.
-spec disco_identity([identity()], jid(), jid(), binary(), binary(),
route_type()) -> [identity()].
disco_identity(Acc, _From, To, <<"">>, _Lang, Type) ->
Delegations = get_delegations(To#jid.lserver),
Identities = lists:flatmap(
fun({{_, T}, {_, Info}}) when T == Type ->
Info#disco_info.identities;
(_) ->
[]
end, maps:to_list(Delegations)),
Acc ++ Identities;
disco_identity(Acc, _From, _To, _Node, _Lang, _Type) ->
Acc.
my_features(ejabberd_local) -> [?NS_DELEGATION];
my_features(ejabberd_sm) -> [].
