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mod_privilege/mod_privilege.lua @ 4282:281a864e7472

mod_pubsub_feeds: Don't skip publishing items after an existing one I encountered a feed which was backwards, such that older entries were considered first and then it would skip newer entries. This may however run into trouble if the feed contains more items than what's persisted in pubsub.
author Kim Alvefur <zash@zash.se>
date Mon, 30 Nov 2020 15:17:29 +0100
parent 3393:7454274ead2f
child 4937:3ddab718f717
line wrap: on
line source

-- XEP-0356 (Privileged Entity)
-- Copyright (C) 2015-2016 Jérôme Poisson
--
-- This module is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--
-- Some parts come from mod_remote_roster (module by Waqas Hussain and Kim Alvefur, see https://code.google.com/p/prosody-modules/)

-- TODO: manage external <presence/> (for "roster" presence permission) when the account with the roster is offline

local jid = require("util.jid")
local set = require("util.set")
local st = require("util.stanza")
local roster_manager = require("core.rostermanager")
local usermanager_user_exists = require "core.usermanager".user_exists;
local hosts = prosody.hosts
local full_sessions = prosody.full_sessions;

local priv_session = module:shared("/*/privilege/session")

if priv_session.connected_cb == nil then
	-- set used to have connected event listeners
	-- which allows a host to react on events from
	-- other hosts
	priv_session.connected_cb = set.new()
end
local connected_cb = priv_session.connected_cb

-- the folowing sets are used to forward presence stanza
-- the folowing sets are used to forward presence stanza
local presence_man_ent = set.new()
local presence_roster = set.new()

local _ALLOWED_ROSTER = set.new({'none', 'get', 'set', 'both'})
local _ROSTER_GET_PERM = set.new({'get', 'both'})
local _ROSTER_SET_PERM = set.new({'set', 'both'})
local _ALLOWED_MESSAGE = set.new({'none', 'outgoing'})
local _ALLOWED_PRESENCE = set.new({'none', 'managed_entity', 'roster'})
local _PRESENCE_MANAGED = set.new({'managed_entity', 'roster'})
local _TO_CHECK = {roster=_ALLOWED_ROSTER, message=_ALLOWED_MESSAGE, presence=_ALLOWED_PRESENCE}
local _PRIV_ENT_NS = 'urn:xmpp:privilege:1'
local _FORWARDED_NS = 'urn:xmpp:forward:0'
local _MODULE_HOST = module:get_host()


module:log("debug", "Loading privileged entity module ");


--> Permissions management <--

local privileges = module:get_option("privileged_entities", {})

local function get_session_privileges(session, host)
    if not session.privileges then return nil end
    return session.privileges[host]
end


local function advertise_perm(session, to_jid, perms)
	-- send <message/> stanza to advertise permissions
	-- as expained in § 4.2
	local message = st.message({from=module.host, to=to_jid})
					  :tag("privilege", {xmlns=_PRIV_ENT_NS})

	for _, perm in pairs({'roster', 'message', 'presence'}) do
		if perms[perm] then
			message:tag("perm", {access=perm, type=perms[perm]}):up()
		end
	end
	session.send(message)
end

local function set_presence_perm_set(to_jid, perms)
	-- fill the presence sets according to perms
	if _PRESENCE_MANAGED:contains(perms.presence) then
		presence_man_ent:add(to_jid)
	end
	if perms.presence == 'roster' then
		presence_roster:add(to_jid)
	end
end

local function advertise_presences(session, to_jid, perms)
	-- send presence status for already conencted entities
	-- as explained in § 7.1
	-- people in roster are probed only for active sessions
	-- TODO: manage roster load for inactive sessions
	if not perms.presence then return; end
	local to_probe = {}
	for _, user_session in pairs(full_sessions) do
		if user_session.presence and _PRESENCE_MANAGED:contains(perms.presence) then
			local presence = st.clone(user_session.presence)
			presence.attr.to = to_jid
			module:log("debug", "sending current presence for "..tostring(user_session.full_jid))
			session.send(presence)
		end
		if perms.presence == "roster" then
			-- we reset the cache to avoid to miss a presence that just changed
			priv_session.last_presence = nil

			if user_session.roster then
				local bare_jid = jid.bare(user_session.full_jid)
				for entity, item in pairs(user_session.roster) do
					if entity~=false and entity~="pending" and (item.subscription=="both" or item.subscription=="to") then
						local _, host = jid.split(entity)
						if not hosts[host] then -- we don't probe jid from hosts we manage
							-- using a table with entity as key avoid probing several time the same one
							to_probe[entity] = bare_jid
						end
					end
				end
			end
		end
	end

	-- now we probe peoples for "roster" presence permission
	for probe_to, probe_from in pairs(to_probe) do
		module:log("debug", "probing presence for %s (on behalf of %s)", tostring(probe_to), tostring(probe_from))
		local probe = st.presence({from=probe_from, to=probe_to, type="probe"})
		prosody.core_route_stanza(nil, probe)
	end
end

local function on_auth(event)
	-- Check if entity is privileged according to configuration,
	-- and set session.privileges accordingly

	local session = event.session
	local bare_jid = jid.join(session.username, session.host)
    if not session.privileges then
        session.privileges = {}
    end

	local ent_priv = privileges[bare_jid]
	if ent_priv ~= nil then
		module:log("debug", "Entity is privileged")
		for perm_type, allowed_values in pairs(_TO_CHECK) do
			local value = ent_priv[perm_type]
			if value ~= nil then
				if not allowed_values:contains(value) then
					module:log('warn', 'Invalid value for '..perm_type..' privilege: ['..value..']')
					module:log('warn', 'Setting '..perm_type..' privilege to none')
					ent_priv[perm_type] = nil
				end
				if value == 'none' then
					ent_priv[perm_type] = nil
				end
			end
		end
		-- extra checks for presence permission
		if ent_priv.presence == 'roster' and not _ROSTER_GET_PERM:contains(ent_priv.roster) then
			module:log("warn", "Can't allow roster presence privilege without roster \"get\" privilege")
			module:log("warn", "Setting presence permission to none")
			ent_priv.presence = nil
		end

		if session.type == "component" then
			-- we send the message stanza only for component
			-- it will be sent at first <presence/> for other entities
			advertise_perm(session, bare_jid, ent_priv)
			set_presence_perm_set(bare_jid, ent_priv)
			advertise_presences(session, bare_jid, ent_priv)
		end
	end

	session.privileges[_MODULE_HOST] = ent_priv
end

local function on_presence(event)
	-- Permission are already checked at this point,
	-- we only advertise them to the entity
	local session = event.origin
    local session_privileges = get_session_privileges(session, _MODULE_HOST)
	if session_privileges then
		advertise_perm(session, session.full_jid, session_privileges)
		set_presence_perm_set(session.full_jid, session_privileges)
		advertise_presences(session, session.full_jid, session_privileges)
	end
end

local function on_component_auth(event)
	-- react to component-authenticated event from this host
	-- and call the on_auth methods from all other hosts
	-- needed for the component to get delegations advertising
	for callback in connected_cb:items() do
		callback(event)
	end
end

if module:get_host_type() ~= "component" then
    connected_cb:add(on_auth)
end
module:hook('authentication-success', on_auth)
module:hook('component-authenticated', on_component_auth)
module:hook('presence/initial', on_presence)


--> roster permission <--

-- get
module:hook("iq-get/bare/jabber:iq:roster:query", function(event)
	local session, stanza = event.origin, event.stanza;
	if not stanza.attr.to then
		-- we don't want stanzas addressed to /self
		return;
	end
    local node, host = jid.split(stanza.attr.to);
    local session_privileges = get_session_privileges(session, host)

	if session_privileges and _ROSTER_GET_PERM:contains(session_privileges.roster) then
		module:log("debug", "Roster get from allowed privileged entity received")
		-- following code is adapted from mod_remote_roster
		local roster = roster_manager.load_roster(node, host);

		local reply = st.reply(stanza):query("jabber:iq:roster");
		for entity_jid, item in pairs(roster) do
			if entity_jid and entity_jid ~= "pending" then
				reply:tag("item", {
					jid = entity_jid,
					subscription = item.subscription,
					ask = item.ask,
					name = item.name,
				});
				for group in pairs(item.groups) do
					reply:tag("group"):text(group):up();
				end
				reply:up(); -- move out from item
			end
		end
		-- end of code adapted from mod_remote_roster
		session.send(reply);
	else
	    module:log("warn", "Entity "..tostring(session.full_jid).." try to get roster without permission")
		session.send(st.error_reply(stanza, 'auth', 'forbidden'))
	end

	return true
end);

-- set
module:hook("iq-set/bare/jabber:iq:roster:query", function(event)
	local session, stanza = event.origin, event.stanza;
	if not stanza.attr.to then
		-- we don't want stanzas addressed to /self
		return;
	end
    local from_node, from_host = jid.split(stanza.attr.to);
    local session_privileges = get_session_privileges(session, from_host)

	if session_privileges and _ROSTER_SET_PERM:contains(session_privileges.roster) then
		module:log("debug", "Roster set from allowed privileged entity received")
		-- following code is adapted from mod_remote_roster
		if not(usermanager_user_exists(from_node, from_host)) then return; end
		local roster = roster_manager.load_roster(from_node, from_host);
		if not(roster) then return; end

		local query = stanza.tags[1];
		for _, item in ipairs(query.tags) do
			if item.name == "item"
				and item.attr.xmlns == "jabber:iq:roster" and item.attr.jid
					-- Protection against overwriting roster.pending, until we move it
				and item.attr.jid ~= "pending" then

				local item_jid = jid.prep(item.attr.jid);
				local _, host, resource = jid.split(item_jid);
				if not resource then
					if item_jid ~= stanza.attr.to then -- not self-item_jid
						if item.attr.subscription == "remove" then
							local r_item = roster[item_jid];
							if r_item then
								roster[item_jid] = nil;
								if roster_manager.save_roster(from_node, from_host, roster) then
									session.send(st.reply(stanza));
									roster_manager.roster_push(from_node, from_host, item_jid);
								else
									roster[item_jid] = item;
									session.send(st.error_reply(stanza, "wait", "internal-server-error", "Unable to save roster"));
								end
							else
								session.send(st.error_reply(stanza, "modify", "item-not-found"));
							end
						else
							local subscription = item.attr.subscription;
							if subscription ~= "both" and subscription ~= "to" and subscription ~= "from" and subscription ~= "none" then -- TODO error on invalid
								subscription = roster[item_jid] and roster[item_jid].subscription or "none";
							end
							local r_item = {name = item.attr.name, groups = {}};
							if r_item.name == "" then r_item.name = nil; end
							r_item.subscription = subscription;
							if subscription ~= "both" and subscription ~= "to" then
								r_item.ask = roster[item_jid] and roster[item_jid].ask;
							end
							for _, child in ipairs(item) do
								if child.name == "group" then
									local text = table.concat(child);
									if text and text ~= "" then
										r_item.groups[text] = true;
									end
								end
							end
							local olditem = roster[item_jid];
							roster[item_jid] = r_item;
							if roster_manager.save_roster(from_node, from_host, roster) then -- Ok, send success
								session.send(st.reply(stanza));
								-- and push change to all resources
								roster_manager.roster_push(from_node, from_host, item_jid);
							else -- Adding to roster failed
								roster[item_jid] = olditem;
								session.send(st.error_reply(stanza, "wait", "internal-server-error", "Unable to save roster"));
							end
						end
					else -- Trying to add self to roster
						session.send(st.error_reply(stanza, "cancel", "not-allowed"));
					end
				else -- Invalid JID added to roster
					module:log("warn", "resource: %s , host: %s", tostring(resource), tostring(host))
					session.send(st.error_reply(stanza, "modify", "bad-request")); -- FIXME what's the correct error?
				end
			else -- Roster set didn't include a single item, or its name wasn't  'item'
				session.send(st.error_reply(stanza, "modify", "bad-request"));
			end
		end -- for loop end
		-- end of code adapted from mod_remote_roster
	else -- The permission is not granted
	    module:log("warn", "Entity "..tostring(session.full_jid).." try to set roster without permission")
		session.send(st.error_reply(stanza, 'auth', 'forbidden'))
	end

	return true
end);


--> message permission <--

local function clean_xmlns(node)
	-- Recursively remove "jabber:client" attribute from node.
	-- In Prosody internal routing, xmlns should not be set.
	-- Keeping xmlns would lead to issues like mod_smacks ignoring the outgoing stanza,
	-- so we remove all xmlns attributes with a value of "jabber:client"
	if node.attr.xmlns == 'jabber:client' then
		for childnode in node:childtags() do
			clean_xmlns(childnode);
		end
		node.attr.xmlns = nil;
	end
end

module:hook("message/host", function(event)
	local session, stanza = event.origin, event.stanza;
	local privilege_elt = stanza:get_child('privilege', _PRIV_ENT_NS)
	if privilege_elt==nil then return; end
    local _, to_host = jid.split(stanza.attr.to)
    local session_privileges = get_session_privileges(session, to_host)

	if session_privileges and session_privileges.message=="outgoing" then
		if #privilege_elt.tags==1 and privilege_elt.tags[1].name == "forwarded"
			and privilege_elt.tags[1].attr.xmlns==_FORWARDED_NS then
			local message_elt = privilege_elt.tags[1]:get_child('message', 'jabber:client')
			if message_elt ~= nil then
				local _, from_host, from_resource = jid.split(message_elt.attr.from)
				if from_resource == nil and hosts[from_host] then -- we only accept bare jids from one of the server hosts
					clean_xmlns(message_elt);  -- needed do to proper routing
					-- at this point everything should be alright, we can send the message
					prosody.core_route_stanza(nil, message_elt)
				else -- trying to send a message from a forbidden entity
	    			module:log("warn", "Entity "..tostring(session.full_jid).." try to send a message from "..tostring(message_elt.attr.from))
					session.send(st.error_reply(stanza, 'auth', 'forbidden'))
				end
			else -- incorrect message child
				session.send(st.error_reply(stanza, "modify", "bad-request", "invalid forwarded <message/> element"));
			end
		else -- incorrect forwarded child
			session.send(st.error_reply(stanza, "modify", "bad-request", "invalid <forwarded/> element"));
		end;
	else -- The permission is not granted
	    module:log("warn", "Entity "..tostring(session.full_jid).." try to send message without permission")
		session.send(st.error_reply(stanza, 'auth', 'forbidden'))
	end

	return true
end);


--> presence permission <--

local function same_tags(tag1, tag2)
	-- check if two tags are equivalent

    if tag1.name ~= tag2.name then return false; end

	if #tag1 ~= #tag2 then return false; end

	for name, value in pairs(tag1.attr) do
		if tag2.attr[name] ~= value then return false; end
	end

	for i=1,#tag1 do
		if type(tag1[i]) == "string" then
			if tag1[i] ~= tag2[i] then return false; end
		else
			if not same_tags(tag1[i], tag2[i]) then return false; end
		end
	end

	return true
end

local function same_presences(presence1, presence2)
	-- check that 2 <presence/> stanzas are equivalent (except for "to" attribute)
	-- /!\ if the id change but everything else is equivalent, this method return false
	-- this behaviour may change in the future
	if presence1.attr.from ~= presence2.attr.from or presence1.attr.id ~= presence2.attr.id
		or presence1.attr.type ~= presence2.attr.type then
		return false
	end

	if presence1.attr.id and presence1.attr.id == presence2.attr.id then return true; end

	if #presence1 ~= #presence2 then return false; end

	for i=1,#presence1 do
		if type(presence1[i]) == "string" then
			if presence1[i] ~= presence2[i] then return false; end
		else
			if not same_tags(presence1[i], presence2[i]) then return false; end
		end
	end

	return true
end

local function forward_presence(presence, to_jid)
	local presence_fwd = st.clone(presence)
	presence_fwd.attr.to = to_jid
	module:log("debug", "presence forwarded to "..to_jid..": "..tostring(presence_fwd))
	module:send(presence_fwd)
	-- cache used to avoid to send several times the same stanza
	priv_session.last_presence = presence
end

module:hook("presence/bare", function(event)
	if presence_man_ent:empty() and presence_roster:empty() then return; end

	local stanza = event.stanza
	if stanza.attr.type == nil or stanza.attr.type == "unavailable" then
		if not stanza.attr.to then
			for entity in presence_man_ent:items() do
				if stanza.attr.from ~= entity then forward_presence(stanza, entity); end
			end
		else -- directed presence
			-- we ignore directed presences from our own host, as we already have them
			local _, from_host = jid.split(stanza.attr.from)
			if hosts[from_host] then return; end

			-- we don't send several time the same presence, as recommended in §7 #2
			if priv_session.last_presence and same_presences(priv_session.last_presence, stanza) then
			   return
			end

			for entity in presence_roster:items() do
				if stanza.attr.from ~= entity then forward_presence(stanza, entity); end
			end
		end
	end
end, 150)