1 files changed, 117 insertions, 0 deletions
diff --git a/net/tls_luasec.lua b/net/tls_luasec.lua
new file mode 100644
index 00000000..4e4e92ed
--- /dev/null
+++ b/net/tls_luasec.lua
@@ -0,0 +1,117 @@
+-- Prosody IM
+-- Copyright (C) 2021 Prosody folks
+--
+-- This project is MIT/X11 licensed. Please see the
+-- COPYING file in the source package for more information.
+--
+
+--[[
+This file provides a shim abstraction over LuaSec, consolidating some code
+which was previously spread between net.server backends, portmanager and
+certmanager.
+
+The goal is to provide a more or less well-defined API on top of LuaSec which
+abstracts away some of the things which are not needed and simplifies usage of
+commonly used things (such as SNI contexts). Eventually, network backends
+which do not rely on LuaSocket+LuaSec should be able to provide *this* API
+instead of having to mimic LuaSec.
+]]
+local ssl = require "ssl";
+local ssl_newcontext = ssl.newcontext;
+local ssl_context = ssl.context or require "ssl.context";
+local io_open = io.open;
+
+local context_api = {};
+local context_mt = {__index = context_api};
+
+function context_api:set_sni_host(host, cert, key)
+	local ctx, err = self._builder:clone():apply({
+		certificate = cert,
+		key = key,
+	}):build();
+	if not ctx then
+		return false, err
+	end
+
+	self._sni_contexts[host] = ctx._inner
+
+	return true, nil
+end
+
+function context_api:remove_sni_host(host)
+	self._sni_contexts[host] = nil
+end
+
+function context_api:wrap(sock)
+	local ok, conn, err = pcall(ssl.wrap, sock, self._inner);
+	if not ok then
+		return nil, err
+	end
+	return conn, nil
+end
+
+local function new_context(cfg, builder)
+	-- 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(cfg.dhparam) == "string" and cfg.dhparam:sub(1, 10) == "-----BEGIN" then
+		local dhparam = cfg.dhparam;
+		cfg.dhparam = function() return dhparam; end
+	elseif type(cfg.dhparam) == "string" then
+		local f, err = io_open(cfg.dhparam);
+		if not f then return nil, "Could not open DH parameters: "..err end
+		local dhparam = f:read("*a");
+		f:close();
+		cfg.dhparam = function() return dhparam; end
+	end
+
+	local inner, err = ssl_newcontext(cfg);
+	if not inner then
+		return nil, err
+	end
+
+	-- COMPAT Older LuaSec ignores the cipher list from the config, so we have to take care
+	-- of it ourselves (W/A for #x)
+	if inner and cfg.ciphers then
+		local success;
+		success, err = ssl_context.setcipher(inner, cfg.ciphers);
+		if not success then
+			return nil, err
+		end
+	end
+
+	return setmetatable({
+		_inner = inner,
+		_builder = builder,
+		_sni_contexts = {},
+	}, context_mt), nil
+end
+
+-- Feature detection / guessing
+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 {
+	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");
+	};
+};
+
+return {
+	features = luasec_has;
+	new_context = new_context,
+	load_certificate = ssl.loadcertificate;
+};