view mod_external_services/mod_external_services.lua @ 5271:3a1df3adad0c

mod_http_oauth2: Allow user to decide which requested scopes to grant These should at the very least be shown to the user, so they can decide whether to grant them. Considered whether to filter the requested scopes down to actually understood scopes that would be granted, but decided that this was a bit complex for a first step, since role role selection and other kinds of scopes are mixed into the same field here.
author Kim Alvefur <zash@zash.se>
date Thu, 23 Mar 2023 16:28:08 +0100
parents ede9682c2022
children
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local dt = require "util.datetime";
local base64 = require "util.encodings".base64;
local hashes = require "util.hashes";
local st = require "util.stanza";
local jid = require "util.jid";
local array = require "util.array";
local set = require "util.set";

local default_host = module:get_option_string("external_service_host", module.host);
local default_port = module:get_option_number("external_service_port");
local default_secret = module:get_option_string("external_service_secret");
local default_ttl = module:get_option_number("external_service_ttl", 86400);

local configured_services = module:get_option_array("external_services", {});

local access = module:get_option_set("external_service_access", {});

-- https://tools.ietf.org/html/draft-uberti-behave-turn-rest-00
local function behave_turn_rest_credentials(srv, item, secret)
	local ttl = default_ttl;
	if type(item.ttl) == "number" then
		ttl = item.ttl;
	end
	local expires = srv.expires or os.time() + ttl;
	local username;
	if type(item.username) == "string" then
		username = string.format("%d:%s", expires, item.username);
	else
		username = string.format("%d", expires);
	end
	srv.username = username;
	srv.password = base64.encode(hashes.hmac_sha1(secret, srv.username));
end

local algorithms = {
	turn = behave_turn_rest_credentials;
}

-- filter config into well-defined service records
local function prepare(item)
	if type(item) ~= "table" then
		module:log("error", "Service definition is not a table: %q", item);
		return nil;
	end

	local srv = {
		type = nil;
		transport = nil;
		host = default_host;
		port = default_port;
		username = nil;
		password = nil;
		restricted = nil;
		expires = nil;
	};

	if type(item.type) == "string" then
		srv.type = item.type;
	else
		module:log("error", "Service missing mandatory 'type' field: %q", item);
		return nil;
	end
	if type(item.transport) == "string" then
		srv.transport = item.transport;
	end
	if type(item.host) == "string" then
		srv.host = item.host;
	end
	if type(item.port) == "number" then
		srv.port = item.port;
	end
	if type(item.username) == "string" then
		srv.username = item.username;
	end
	if type(item.password) == "string" then
		srv.password = item.password;
		srv.restricted = true;
	end
	if item.restricted == true then
		srv.restricted = true;
	end
	if type(item.expires) == "number" then
		srv.expires = item.expires;
	elseif type(item.ttl) == "number" then
		srv.expires = os.time() + item.ttl;
	end
	if (item.secret == true and default_secret) or type(item.secret) == "string" then
		local secret_cb = item.credentials_cb or algorithms[item.algorithm] or algorithms[srv.type];
		local secret = item.secret;
		if secret == true then
			secret = default_secret;
		end
		if secret_cb then
			secret_cb(srv, item, secret);
			srv.restricted = true;
		end
	end
	return srv;
end

function module.load()
	-- Trigger errors on startup
	local services = configured_services / prepare;
	if #services == 0 then
		module:log("warn", "No services configured or all had errors");
	end
end

-- Ensure only valid items are added in events
local services_mt = {
	__index = getmetatable(array()).__index;
	__newindex = function (self, i, v)
		rawset(self, i, assert(prepare(v), "Invalid service entry added"));
	end;
}

function get_services()
	local extras = module:get_host_items("external_service");
	local services = ( configured_services + extras ) / prepare;

	setmetatable(services, services_mt);

	return services;
end

function services_xml(services, name, namespace)
	local reply = st.stanza(name or "services", { xmlns = namespace or "urn:xmpp:extdisco:2" });

	for _, srv in ipairs(services) do
		reply:tag("service", {
				type = srv.type;
				transport = srv.transport;
				host = srv.host;
				port = srv.port and string.format("%d", srv.port) or nil;
				username = srv.username;
				password = srv.password;
				expires = srv.expires and dt.datetime(srv.expires) or nil;
				restricted = srv.restricted and "1" or nil;
			}):up();
	end

	return reply;
end

local function handle_services(event)
	local origin, stanza = event.origin, event.stanza;
	local action = stanza.tags[1];

	local user_bare = jid.bare(stanza.attr.from);
	local user_host = jid.host(user_bare);
	if not ((access:empty() and origin.type == "c2s") or access:contains(user_bare) or access:contains(user_host)) then
		origin.send(st.error_reply(stanza, "auth", "forbidden"));
		return true;
	end

	local services = get_services();

	local requested_type = action.attr.type;
	if requested_type then
		services:filter(function(item)
			return item.type == requested_type;
		end);
	end

	module:fire_event("external_service/services", {
			origin = origin;
			stanza = stanza;
			requested_type = requested_type;
			services = services;
		});

	local reply = st.reply(stanza):add_child(services_xml(services, action.name, action.attr.xmlns));

	origin.send(reply);
	return true;
end

local function handle_credentials(event)
	local origin, stanza = event.origin, event.stanza;
	local action = stanza.tags[1];

	if origin.type ~= "c2s" then
		origin.send(st.error_reply(stanza, "auth", "forbidden", "The 'port' and 'type' attributes are required."));
		return true;
	end

	local services = get_services();
	services:filter(function (item)
		return item.restricted;
	end)

	local requested_credentials = set.new();
	for service in action:childtags("service") do
		if not service.attr.type or not service.attr.host then
			origin.send(st.error_reply(stanza, "modify", "bad-request"));
			return true;
		end

		requested_credentials:add(string.format("%s:%s:%d", service.attr.type, service.attr.host,
			tonumber(service.attr.port) or 0));
	end

	module:fire_event("external_service/credentials", {
			origin = origin;
			stanza = stanza;
			requested_credentials = requested_credentials;
			services = services;
		});

	services:filter(function (srv)
		local port_key = string.format("%s:%s:%d", srv.type, srv.host, srv.port or 0);
		local portless_key = string.format("%s:%s:%d", srv.type, srv.host, 0);
		return requested_credentials:contains(port_key) or requested_credentials:contains(portless_key);
	end);

	local reply = st.reply(stanza):add_child(services_xml(services, action.name, action.attr.xmlns));

	origin.send(reply);
	return true;
end

-- XEP-0215 v0.7
module:add_feature("urn:xmpp:extdisco:2");
module:hook("iq-get/host/urn:xmpp:extdisco:2:services", handle_services);
module:hook("iq-get/host/urn:xmpp:extdisco:2:credentials", handle_credentials);

-- COMPAT XEP-0215 v0.6
-- Those still on the old version gets to deal with undefined attributes until they upgrade.
module:add_feature("urn:xmpp:extdisco:1");
module:hook("iq-get/host/urn:xmpp:extdisco:1:services", handle_services);
module:hook("iq-get/host/urn:xmpp:extdisco:1:credentials", handle_credentials);