view mod_firewall/definitions.lib.lua @ 4895:2542fd80cd15

mod_turn_external: Fix type of config option (thanks mirux) There was a separate boolean option to enable TLS before, but it was merged with the port number option and it seems the typed API interface got confused. Backport of trunk rev aa7a8aa64d3f
author Kim Alvefur <zash@zash.se>
date Tue, 15 Feb 2022 21:51:52 +0100
parents b88f05c878ac
children 0f943619e01a
line wrap: on
line source


-- Name arguments are unused here
-- luacheck: ignore 212

local definition_handlers = {};

local http = require "net.http";
local timer = require "util.timer";
local set = require"util.set";
local new_throttle = require "util.throttle".create;
local hashes = require "util.hashes";
local jid = require "util.jid";
local lfs = require "lfs";

local multirate_cache_size = module:get_option_number("firewall_multirate_cache_limit", 1000);

function definition_handlers.ZONE(zone_name, zone_members)
			local zone_member_list = {};
			for member in zone_members:gmatch("[^, ]+") do
				zone_member_list[#zone_member_list+1] = member;
			end
			return set.new(zone_member_list)._items;
end

-- Helper function used by RATE handler
local function evict_only_unthrottled(name, throttle)
	throttle:update();
	-- Check whether the throttle is at max balance (i.e. totally safe to forget about it)
	if throttle.balance < throttle.max then
		-- Not safe to forget
		return false;
	end
end

function definition_handlers.RATE(name, line)
			local rate = assert(tonumber(line:match("([%d.]+)")), "Unable to parse rate");
			local burst = tonumber(line:match("%(%s*burst%s+([%d.]+)%s*%)")) or 1;
			local max_throttles = tonumber(line:match("%(%s*entries%s+([%d]+)%s*%)")) or multirate_cache_size;
			local deny_when_full = not line:match("%(allow overflow%)");
			return {
				single = function ()
					return new_throttle(rate*burst, burst);
				end;

				multi = function ()
					local cache = require "util.cache".new(max_throttles, deny_when_full and evict_only_unthrottled or nil);
					return {
						poll_on = function (_, key, amount)
							assert(key, "no key");
							local throttle = cache:get(key);
							if not throttle then
								throttle = new_throttle(rate*burst, burst);
								if not cache:set(key, throttle) then
									module:log("warn", "Multirate '%s' has hit its maximum number of active throttles (%d), denying new events", name, max_throttles);
									return false;
								end
							end
							return throttle:poll(amount);
						end;
					}
				end;
			};
end

local list_backends = {
	-- %LIST name: memory (limit: number)
	memory = {
		init = function (self, type, opts)
			if opts.limit then
				local have_cache_lib, cache_lib = pcall(require, "util.cache");
				if not have_cache_lib then
					error("In-memory lists with a size limit require Prosody 0.10");
				end
				self.cache = cache_lib.new((assert(tonumber(opts.limit), "Invalid list limit")));
				if not self.cache.table then
					error("In-memory lists with a size limit require a newer version of Prosody 0.10");
				end
				self.items = self.cache:table();
			else
				self.items = {};
			end
		end;
		add = function (self, item)
			self.items[item] = true;
		end;
		remove = function (self, item)
			self.items[item] = nil;
		end;
		contains = function (self, item)
			return self.items[item] == true;
		end;
	};

	-- %LIST name: http://example.com/ (ttl: number, pattern: pat, hash: sha1)
	http = {
		init = function (self, url, opts)
			local poll_interval = assert(tonumber(opts.ttl or "3600"), "invalid ttl for <"..url.."> (expected number of seconds)");
			local pattern = opts.pattern or "([^\r\n]+)\r?\n";
			assert(pcall(string.match, "", pattern), "invalid pattern for <"..url..">");
			if opts.hash then
				assert(opts.hash:match("^%w+$") and type(hashes[opts.hash]) == "function", "invalid hash function: "..opts.hash);
				self.hash_function = hashes[opts.hash];
			end
			local etag;
			local failure_count = 0;
			local retry_intervals = { 60, 120, 300 };
			-- By default only check the certificate if net.http supports SNI
			local sni_supported = http.feature and http.features.sni;
			local insecure = false;
			if opts.checkcert == "never" then
				insecure = true;
			elseif (opts.checkcert == nil or opts.checkcert == "when-sni") and not sni_supported then
				insecure = false;
			end
			local function update_list()
				http.request(url, {
					insecure = insecure;
					headers = {
						["If-None-Match"] = etag;
					};
				}, function (body, code, response)
					local next_poll = poll_interval;
					if code == 200 and body then
						etag = response.headers.etag;
						local items = {};
						for entry in body:gmatch(pattern) do
							items[entry] = true;
						end
						self.items = items;
						module:log("debug", "Fetched updated list from <%s>", url);
					elseif code == 304 then
						module:log("debug", "List at <%s> is unchanged", url);
					elseif code == 0 or (code >= 400 and code <=599) then
						module:log("warn", "Failed to fetch list from <%s>: %d %s", url, code, tostring(body));
						failure_count = failure_count + 1;
						next_poll = retry_intervals[failure_count] or retry_intervals[#retry_intervals];
					end
					if next_poll > 0 then
						timer.add_task(next_poll+math.random(0, 60), update_list);
					end
				end);
			end
			update_list();
		end;
		add = function ()
		end;
		remove = function ()
		end;
		contains = function (self, item)
			if self.hash_function then
				item = self.hash_function(item);
			end
			return self.items and self.items[item] == true;
		end;
	};

	-- %LIST: file:/path/to/file
	file = {
		init = function (self, file_spec, opts)
			local n, items = 0, {};
			self.items = items;
			local filename = file_spec:gsub("^file:", "");
			if opts.missing == "ignore" and not lfs.attributes(filename, "mode") then
				module:log("debug", "Ignoring missing list file: %s", filename);
				return;
			end
			local file, err = io.open(filename);
			if not file then
				module:log("warn", "Failed to open list from %s: %s", filename, err);
				return;
			else
				for line in file:lines() do
					if not items[line] then
						n = n + 1;
						items[line] = true;
					end
				end
			end
			module:log("debug", "Loaded %d items from %s", n, filename);
		end;
		add = function (self, item)
			self.items[item] = true;
		end;
		remove = function (self, item)
			self.items[item] = nil;
		end;
		contains = function (self, item)
			return self.items and self.items[item] == true;
		end;
	};

	-- %LIST: pubsub:pubsub.example.com/node
	-- TODO or the actual URI scheme? Bit overkill maybe?
	-- TODO Publish items back to the service?
	-- Step 1: Receiving pubsub events and storing them in the list
	-- We'll start by using only the item id.
	-- TODO Invent some custom schema for this? Needed for just a set of strings?
	pubsubitemid = {
		init = function(self, pubsub_spec, opts)
			local service_addr, node = pubsub_spec:match("^([^/]*)/(.*)");
			module:depends("pubsub_subscription");
			module:add_item("pubsub-subscription", {
					service = service_addr;
					node = node;
					on_subscribed = function ()
						self.items = {};
					end;
					on_item = function (event)
						self:add(event.item.attr.id);
					end;
					on_retract = function (event)
						self:remove(event.item.attr.id);
					end;
					on_purge = function ()
						self.items = {};
					end;
					on_unsubscribed = function ()
						self.items = nil;
					end;
					on_delete= function ()
						self.items = nil;
					end;
				});
			-- TODO Initial fetch? Or should mod_pubsub_subscription do this?
		end;
		add = function (self, item)
			if self.items then
				self.items[item] = true;
			end
		end;
		remove = function (self, item)
			if self.items then
				self.items[item] = nil;
			end
		end;
		contains = function (self, item)
			return self.items and self.items[item] == true;
		end;
	};
};
list_backends.https = list_backends.http;

local normalize_functions = {
	upper = string.upper, lower = string.lower;
	md5 = hashes.md5, sha1 = hashes.sha1, sha256 = hashes.sha256;
	prep = jid.prep, bare = jid.bare;
};

local function wrap_list_method(list_method, filter)
	return function (self, item)
		return list_method(self, filter(item));
	end
end

local function create_list(list_backend, list_def, opts)
	if not list_backends[list_backend] then
		error("Unknown list type '"..list_backend.."'", 0);
	end
	local list = setmetatable({}, { __index = list_backends[list_backend] });
	if list.init then
		list:init(list_def, opts);
	end
	if opts.filter then
		local filters = {};
		for func_name in opts.filter:gmatch("[%w_]+") do
			if func_name == "log" then
				table.insert(filters, function (s)
					--print("&&&&&", s);
					module:log("debug", "Checking list <%s> for: %s", list_def, s);
					return s;
				end);
			else
				assert(normalize_functions[func_name], "Unknown list filter: "..func_name);
				table.insert(filters, normalize_functions[func_name]);
			end
		end

		local filter;
		local n = #filters;
		if n == 1 then
			filter = filters[1];
		else
			function filter(s)
				for i = 1, n do
					s = filters[i](s or "");
				end
				return s;
			end
		end

		list.add = wrap_list_method(list.add, filter);
		list.remove = wrap_list_method(list.remove, filter);
		list.contains = wrap_list_method(list.contains, filter);
	end
	return list;
end

--[[
%LIST spammers: memory (source: /etc/spammers.txt)

%LIST spammers: memory (source: /etc/spammers.txt)


%LIST spammers: http://example.com/blacklist.txt
]]

function definition_handlers.LIST(list_name, list_definition)
	local list_backend = list_definition:match("^%w+");
	local opts = {};
	local opt_string = list_definition:match("^%S+%s+%((.+)%)");
	if opt_string then
		for opt_k, opt_v in opt_string:gmatch("(%w+): ?([^,]+)") do
			opts[opt_k] = opt_v;
		end
	end
	return create_list(list_backend, list_definition:match("^%S+"), opts);
end

function definition_handlers.PATTERN(name, pattern)
	local ok, err = pcall(string.match, "", pattern);
	if not ok then
		error("Invalid pattern '"..name.."': "..err);
	end
	return pattern;
end

function definition_handlers.SEARCH(name, pattern)
	return pattern;
end

return definition_handlers;