-- Prosody IM

-- Copyright (C) 2008-2010 Matthew Wild

-- Copyright (C) 2008-2010 Waqas Hussain

--

-- This project is MIT/X11 licensed. Please see the

-- COPYING file in the source package for more information.

--

local softreq = require"util.dependencies".softreq;

local ssl = softreq"ssl";

if not ssl then

	return {

		create_context = function ()

			return nil, "LuaSec (required for encryption) was not found";

		end;

		reload_ssl_config = function () end;

	}

end

local configmanager = require "core.configmanager";

local log = require "util.logger".init("certmanager");

local ssl_context = ssl.context or softreq"ssl.context";

local ssl_x509 = ssl.x509 or softreq"ssl.x509";

local ssl_newcontext = ssl.newcontext;

local new_config = require"util.sslconfig".new;

local stat = require "lfs".attributes;

local tonumber, tostring = tonumber, tostring;

local pairs = pairs;

local t_remove = table.remove;

local type = type;

local io_open = io.open;

local select = select;

local prosody = prosody;

local resolve_path = require"util.paths".resolve_relative_path;

local config_path = prosody.paths.config or ".";

local function test_option(option)

	return not not ssl_newcontext({mode="server",protocol="sslv23",options={ option }});

end

local luasec_major, luasec_minor = ssl._VERSION:match("^(%d+)%.(%d+)");

local luasec_version = tonumber(luasec_major) * 100 + tonumber(luasec_minor);

local luasec_has = ssl.config or softreq"ssl.config" or {

	algorithms = {

		ec = luasec_version >= 5;

	};

	capabilities = {

		curves_list = luasec_version >= 7;

	};

	options = {

		cipher_server_preference = test_option("cipher_server_preference");

		no_ticket = test_option("no_ticket");

		no_compression = test_option("no_compression");

		single_dh_use = test_option("single_dh_use");

		single_ecdh_use = test_option("single_ecdh_use");

		no_renegotiation = test_option("no_renegotiation");

	};

};

local _ENV = nil;

-- luacheck: std none

-- Global SSL options if not overridden per-host

local global_ssl_config = configmanager.get("*", "ssl");

local global_certificates = configmanager.get("*", "certificates") or "certs";

local crt_try = { "", "/%s.crt", "/%s/fullchain.pem", "/%s.pem", };

local key_try = { "", "/%s.key", "/%s/privkey.pem",   "/%s.pem", };

local function find_cert(user_certs, name)

	local certs = resolve_path(config_path, user_certs or global_certificates);

	log("debug", "Searching %s for a key and certificate for %s...", certs, name);

	for i = 1, #crt_try do

		local crt_path = certs .. crt_try[i]:format(name);

		local key_path = certs .. key_try[i]:format(name);

		if stat(crt_path, "mode") == "file" then

			if crt_path == key_path then

				if key_path:sub(-4) == ".crt" then

					key_path = key_path:sub(1, -4) .. "key";

				elseif key_path:sub(-13) == "fullchain.pem" then

					key_path = key_path:sub(1, -14) .. "privkey.pem";

				end

			end

			if stat(key_path, "mode") == "file" then

				log("debug", "Selecting certificate %s with key %s for %s", crt_path, key_path, name);

				return { certificate = crt_path, key = key_path };

			end

		end

	end

	log("debug", "No certificate/key found for %s", name);

end

local function find_host_cert(host)

	if not host then return nil; end

	return find_cert(configmanager.get(host, "certificate"), host) or find_host_cert(host:match("%.(.+)$"));

end

local function find_service_cert(service, port)

	local cert_config = configmanager.get("*", service.."_certificate");

	if type(cert_config) == "table" then

		cert_config = cert_config[port] or cert_config.default;

	end

	return find_cert(cert_config, service);

end

-- Built-in defaults

local core_defaults = {

	capath = "/etc/ssl/certs";

	depth = 9;

	protocol = "tlsv1+";

	verify = (ssl_x509 and { "peer", "client_once", }) or "none";

	options = {

		cipher_server_preference = luasec_has.options.cipher_server_preference;

		no_ticket = luasec_has.options.no_ticket;

		no_compression = luasec_has.options.no_compression and configmanager.get("*", "ssl_compression") ~= true;

		single_dh_use = luasec_has.options.single_dh_use;

		single_ecdh_use = luasec_has.options.single_ecdh_use;

		no_renegotiation = luasec_has.options.no_renegotiation;

	};

	verifyext = { "lsec_continue", "lsec_ignore_purpose" };

	curve = luasec_has.algorithms.ec and not luasec_has.capabilities.curves_list and "secp384r1";

	curveslist = {

		"X25519",

		"P-384",

		"P-256",

		"P-521",

	};

	ciphers = {      -- Enabled ciphers in order of preference:

		"HIGH+kEECDH", -- Ephemeral Elliptic curve Diffie-Hellman key exchange

		"HIGH+kEDH",   -- Ephemeral Diffie-Hellman key exchange, if a 'dhparam' file is set

		"HIGH",        -- Other "High strength" ciphers

		               -- Disabled cipher suites:

		"!PSK",        -- Pre-Shared Key - not used for XMPP

		"!SRP",        -- Secure Remote Password - not used for XMPP

		"!3DES",       -- 3DES - slow and of questionable security

		"!aNULL",      -- Ciphers that does not authenticate the connection

	};

}

if luasec_has.curves then

	for i = #core_defaults.curveslist, 1, -1 do

		if not luasec_has.curves[ core_defaults.curveslist[i] ] then

			t_remove(core_defaults.curveslist, i);

		end

	end

else

	core_defaults.curveslist = nil;

end

local path_options = { -- These we pass through resolve_path()

	key = true, certificate = true, cafile = true, capath = true, dhparam = true

}

if luasec_version < 5 and ssl_x509 then

	-- COMPAT mw/luasec-hg

	for i=1,#core_defaults.verifyext do -- Remove lsec_ prefix

		core_defaults.verify[#core_defaults.verify+1] = core_defaults.verifyext[i]:sub(6);

	end

end

local function create_context(host, mode, ...)

	local cfg = new_config();

	cfg:apply(core_defaults);

	local service_name, port = host:match("^(%S+) port (%d+)$");

	if service_name then

		cfg:apply(find_service_cert(service_name, tonumber(port)));

	else

		cfg:apply(find_host_cert(host));

	end

	cfg:apply({

		mode = mode,

		-- We can't read the password interactively when daemonized

		password = function() log("error", "Encrypted certificate for %s requires 'ssl' 'password' to be set in config", host); end;

	});

	cfg:apply(global_ssl_config);

	for i = select('#', ...), 1, -1 do

		cfg:apply(select(i, ...));

	end

	local user_ssl_config = cfg:final();

	if mode == "server" then

		if not user_ssl_config.certificate then return nil, "No certificate present in SSL/TLS configuration for "..host; end

		if not user_ssl_config.key then return nil, "No key present in SSL/TLS configuration for "..host; end

	end

	for option in pairs(path_options) do

		if type(user_ssl_config[option]) == "string" then

			user_ssl_config[option] = resolve_path(config_path, user_ssl_config[option]);

		else

			user_ssl_config[option] = nil;

		end

	end

	-- LuaSec expects dhparam to be a callback that takes two arguments.

	-- We ignore those because it is mostly used for having a separate

	-- set of params for EXPORT ciphers, which we don't have by default.

	if type(user_ssl_config.dhparam) == "string" then

		local f, err = io_open(user_ssl_config.dhparam);

		if not f then return nil, "Could not open DH parameters: "..err end

		local dhparam = f:read("*a");

		f:close();

		user_ssl_config.dhparam = function() return dhparam; end

	end

	local ctx, err = ssl_newcontext(user_ssl_config);

	-- COMPAT Older LuaSec ignores the cipher list from the config, so we have to take care

	-- of it ourselves (W/A for #x)

	if ctx and user_ssl_config.ciphers then

		local success;

		success, err = ssl_context.setcipher(ctx, user_ssl_config.ciphers);

		if not success then ctx = nil; end

	end

	if not ctx then

		err = err or "invalid ssl config"

		local file = err:match("^error loading (.-) %(");

		if file then

			local typ;

			if file == "private key" then

				typ = file;

				file = user_ssl_config.key or "your private key";

			elseif file == "certificate" then

				typ = file;

				file = user_ssl_config.certificate or "your certificate file";

			end

			local reason = err:match("%((.+)%)$") or "some reason";

			if reason == "Permission denied" then

				reason = "Check that the permissions allow Prosody to read this file.";

			elseif reason == "No such file or directory" then

				reason = "Check that the path is correct, and the file exists.";

			elseif reason == "system lib" then

				reason = "Previous error (see logs), or other system error.";

			elseif reason == "no start line" then

				reason = "Check that the file contains a "..(typ or file);

			elseif reason == "(null)" or not reason then

				reason = "Check that the file exists and the permissions are correct";

			else

				reason = "Reason: "..tostring(reason):lower();

			end

			log("error", "SSL/TLS: Failed to load '%s': %s (for %s)", file, reason, host);

		else

			log("error", "SSL/TLS: Error initialising for %s: %s", host, err);

		end

	end

	return ctx, err, user_ssl_config;

end

local function reload_ssl_config()

	global_ssl_config = configmanager.get("*", "ssl");

	global_certificates = configmanager.get("*", "certificates") or "certs";

	if luasec_has.options.no_compression then

		core_defaults.options.no_compression = configmanager.get("*", "ssl_compression") ~= true;

	end

end

prosody.events.add_handler("config-reloaded", reload_ssl_config);

return {

	create_context = create_context;

	reload_ssl_config = reload_ssl_config;

	find_cert = find_cert;

};