-- 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_newcontext = ssl.newcontext;

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

local stat = require "lfs".attributes;

local x509 = require "util.x509";

local lfs = require "lfs";

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 now = os.time;

local next = next;

local pcall = pcall;

local prosody = prosody;

local pathutil = require"util.paths";

local resolve_path = pathutil.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(-14) == "/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_matching_key(cert_path)

	-- FIXME we shouldn't need to guess the key filename

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

		return cert_path:sub(1, -4) .. "key";

	elseif cert_path:sub(-14) == "/fullchain.pem" then

		return cert_path:sub(1, -14) .. "privkey.pem";

	end

end

local function index_certs(dir, files_by_name, depth_limit)

	files_by_name = files_by_name or {};

	depth_limit = depth_limit or 3;

	if depth_limit <= 0 then return files_by_name; end

	local ok, iter, v, i = pcall(lfs.dir, dir);

	if not ok then

		log("error", "Error indexing certificate directory %s: %s", dir, iter);

		-- Return an empty index, otherwise this just triggers a nil indexing

		-- error, plus this function would get called again.

		-- Reloading the config after correcting the problem calls this again so

		-- that's what should be done.

		return {}, iter;

	end

	for file in iter, v, i do

		local full = pathutil.join(dir, file);

		if lfs.attributes(full, "mode") == "directory" then

			if file:sub(1,1) ~= "." then

				index_certs(full, files_by_name, depth_limit-1);

			end

			-- TODO support more filename patterns?

		elseif full:match("%.crt$") or full:match("/fullchain%.pem$") then

			local f = io_open(full);

			if f then

				-- TODO look for chained certificates

				local firstline = f:read();

				if firstline == "-----BEGIN CERTIFICATE-----" then

					f:seek("set")

					local cert = ssl.loadcertificate(f:read("*a"))

					-- TODO if more than one cert is found for a name, the most recently

					-- issued one should be used.

					-- for now, just filter out expired certs

					-- TODO also check if there's a corresponding key

					if cert:validat(now()) then

						local names = x509.get_identities(cert);

						log("debug", "Found certificate %s with identities %q", full, names);

						for name, services in pairs(names) do

							-- TODO check services

							if files_by_name[name] then

								files_by_name[name][full] = services;

							else

								files_by_name[name] = { [full] = services; };

							end

						end

					end

				end

				f:close();

			end

		end

	end

	log("debug", "Certificate index: %q", files_by_name);

	-- | hostname | filename | service |

	return files_by_name;

end

local cert_index;

local function find_cert_in_index(index, host)

	if not host then return nil; end

	if not index then return nil; end

	local wildcard_host = host:gsub("^[^.]+%.", "*.");

	local certs = index[host] or index[wildcard_host];

	if certs then

		local cert_filename, services = next(certs);

		if services["*"] then

			log("debug", "Using cert %q from index", cert_filename);

			return {

				certificate = cert_filename,

				key = find_matching_key(cert_filename),

			}

		end

	end

	return nil

end

local function find_host_cert(host)

	if not host then return nil; end

	if not cert_index then

		cert_index = index_certs(resolve_path(config_path, global_certificates));

	end

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

end

local function find_service_cert(service, port)

	if not cert_index then

		cert_index = index_certs(resolve_path(config_path, global_certificates));

	end

	for _, certs in pairs(cert_index) do

		for cert_filename, services in pairs(certs) do

			if services[service] or services["*"] then

				log("debug", "Using cert %q from index", cert_filename);

				return {

					certificate = cert_filename,

					key = find_matching_key(cert_filename),

				}

			end

		end

	end

	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 = "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", -- Continue past certificate verification errors

		"lsec_ignore_purpose", -- Validate client certificates as if they were server certificates

	};

	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

	};

	dane = luasec_has.capabilities.dane and configmanager.get("*", "use_dane") and { "no_ee_namechecks" };

}

local mozilla_ssl_configs = {

	-- https://wiki.mozilla.org/Security/Server_Side_TLS

	-- Version 5.6 as of 2021-12-26

	modern = {

		protocol = "tlsv1_3";

		options = { cipher_server_preference = false };

		ciphers = "DEFAULT"; -- TLS 1.3 uses 'ciphersuites' rather than these

		curveslist = { "X25519"; "prime256v1"; "secp384r1" };

		ciphersuites = { "TLS_AES_128_GCM_SHA256"; "TLS_AES_256_GCM_SHA384"; "TLS_CHACHA20_POLY1305_SHA256" };

	};

	intermediate = {

		protocol = "tlsv1_2+";

		dhparam = nil; -- ffdhe2048.txt

		options = { cipher_server_preference = false };

		ciphers = {

			"ECDHE-ECDSA-AES128-GCM-SHA256";

			"ECDHE-RSA-AES128-GCM-SHA256";

			"ECDHE-ECDSA-AES256-GCM-SHA384";

			"ECDHE-RSA-AES256-GCM-SHA384";

			"ECDHE-ECDSA-CHACHA20-POLY1305";

			"ECDHE-RSA-CHACHA20-POLY1305";

			"DHE-RSA-AES128-GCM-SHA256";

			"DHE-RSA-AES256-GCM-SHA384";

		};

		curveslist = { "X25519"; "prime256v1"; "secp384r1" };

		ciphersuites = { "TLS_AES_128_GCM_SHA256"; "TLS_AES_256_GCM_SHA384"; "TLS_CHACHA20_POLY1305_SHA256" };

	};

	old = {

		protocol = "tlsv1+";

		dhparam = nil; -- openssl dhparam 1024

		options = { cipher_server_preference = true };

		ciphers = {

			"ECDHE-ECDSA-AES128-GCM-SHA256";

			"ECDHE-RSA-AES128-GCM-SHA256";

			"ECDHE-ECDSA-AES256-GCM-SHA384";

			"ECDHE-RSA-AES256-GCM-SHA384";

			"ECDHE-ECDSA-CHACHA20-POLY1305";

			"ECDHE-RSA-CHACHA20-POLY1305";

			"DHE-RSA-AES128-GCM-SHA256";

			"DHE-RSA-AES256-GCM-SHA384";

			"DHE-RSA-CHACHA20-POLY1305";

			"ECDHE-ECDSA-AES128-SHA256";

			"ECDHE-RSA-AES128-SHA256";

			"ECDHE-ECDSA-AES128-SHA";

			"ECDHE-RSA-AES128-SHA";

			"ECDHE-ECDSA-AES256-SHA384";

			"ECDHE-RSA-AES256-SHA384";

			"ECDHE-ECDSA-AES256-SHA";

			"ECDHE-RSA-AES256-SHA";

			"DHE-RSA-AES128-SHA256";

			"DHE-RSA-AES256-SHA256";

			"AES128-GCM-SHA256";

			"AES256-GCM-SHA384";

			"AES128-SHA256";

			"AES256-SHA256";

			"AES128-SHA";

			"AES256-SHA";

			"DES-CBC3-SHA";

		};

		curveslist = { "X25519"; "prime256v1"; "secp384r1" };

		ciphersuites = { "TLS_AES_128_GCM_SHA256"; "TLS_AES_256_GCM_SHA384"; "TLS_CHACHA20_POLY1305_SHA256" };

	};

};

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

}

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

	local cfg = new_config();

	cfg:apply(core_defaults);

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

	-- port 0 is used with client-only things that normally don't need certificates, e.g. https

	if service_name and port ~= "0" then

		log("debug", "Automatically locating certs for service %s on port %s", service_name, port);

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

	else

		log("debug", "Automatically locating certs for host %s", host);

		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;

	});

	local preset = configmanager.get("*", "tls_preset") or "intermediate";

	if preset ~= "legacy" then

		cfg:apply(mozilla_ssl_configs[preset]);

	end

	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

			log("info", "No certificate present in SSL/TLS configuration for %s. SNI will be required.", host);

		end

		if user_ssl_config.certificate and 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