view mod_net_dovecotauth/mod_net_dovecotauth.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 8e686bf63441
children
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-- mod_net_dovecotauth.lua
--
-- Protocol spec:
-- http://dovecot.org/doc/auth-protocol.txt
--
-- Example postfix config:
-- sudo postconf smtpd_sasl_path=inet:127.0.0.1:28484
-- sudo postconf smtpd_sasl_type=dovecot
-- sudo postconf smtpd_sasl_auth_enable=yes

module:set_global();

-- Imports
local new_sasl = require "core.usermanager".get_sasl_handler;
local user_exists = require "core.usermanager".user_exists;
local base64 = require"util.encodings".base64;
local dump = require"util.serialization".serialize;
local pposix = require "util.pposix";

-- Config
local default_vhost = module:get_option_string("dovecotauth_host", (next(hosts))); -- TODO Is there a better solution?
local allow_master = module:get_option_boolean("dovecotauth_allow_master", false);

-- Active sessions
local sessions = {};

-- Session methods
local new_session;
do
local sess = { };
local sess_mt = { __index = sess };

function new_session(conn)
	local s = { type = "?", conn = conn, buf = "", sasl = {} }
	function s:log(l, m, ...)
		return module:log(l, self.type..tonumber(tostring(self):match("%x+$"), 16)..": "..m, ...);
	end
	return setmetatable(s, sess_mt);
end

function sess:send(...)
	local data = table.concat({...}, "\t") .. "\n"
	-- self:log("debug", "SEND: %s", dump(ret));
	return self.conn:write(data);
end

local mech_params = {
	ANONYMOUS = "anonymous";
	PLAIN = "plaintext";
	["DIGEST-MD5"] = "mutual-auth";
	["SCRAM-SHA-1"] = "mutual-auth";
	["SCRAM-SHA-1-PLUS"] = "mutual-auth";
}

function sess:handshake()
	self:send("VERSION", 1, 1);
	self:send("SPID", pposix.getpid());
	self:send("CUID", tonumber(tostring(self):match"%x+$", 16));
	for mech in pairs(self.g_sasl:mechanisms()) do
		self:send("MECH", mech, mech_params[mech]);
	end
	self:send("DONE");
end

function sess:feed(data)
	-- TODO break this up a bit
	-- module:log("debug", "sess = %s", dump(self));
	local buf = self.buf;
	buf = buf .. data;
	local line, eol = buf:match("(.-)\r?\n()")
	while line and line ~= "" do
		buf = buf:sub(eol);
		self.buf = buf;
		local part = line:gmatch("[^\t]+");
		local command = part();
		if command == "VERSION" then
			local major = tonumber(part());
			local minor = tonumber(part());
			if major ~= 1 then
				self:log("warn", "Wrong version, expected 1.1, got %s.%s", tostring(major), tostring(minor));
				self.conn:close();
				break;
			end
		elseif command == "CPID" then
			self.type = "C";
			self.pid = part();
		elseif command == "SPID" and allow_master then
			self.type = "M";
			self.pid = part();
		elseif command == "AUTH" and self.type ~= "?" then
			-- C: "AUTH" TAB <id> TAB <mechanism> TAB service=<service> [TAB <parameters>]
			local id = part() -- <id>
			local sasl = self.sasl[id];
			local mech = part();
			if not sasl then
				-- TODO Should maybe initialize SASL handler after parsing the line?
				sasl = self.g_sasl:clean_clone();
				self.sasl[id] = sasl;
				if not sasl:select(mech) then
					self:send("FAIL", id, "reason=invalid-mechanism");
					self.sasl[id] = nil;
					sasl = false
				end
			end
			if sasl then
				local params = {}; -- Not used for anything yet
				for p in part do
					local k,v = p:match("^([^=]*)=(.*)$");
					if k == "resp" then
						self:log("debug", "params = %s", dump(params));
						v = base64.decode(v);
						local status, ret, err = sasl:process(v);
						self:log("debug", status);
						if status == "challenge" then
							self:send("CONT", id, base64.encode(ret));
						elseif status == "failure" then
							self.sasl[id] = nil;
							self:send("FAIL", id, "reason="..tostring(err));
						elseif status == "success" then
							self.sasl[id] = nil;
							self:send("OK", id, "user="..sasl.username, ret and "resp="..base64.encode(ret));
						end
						break; -- resp MUST be the last param
					else
						params[k or p] = v or true;
					end
				end
			end
		elseif command == "USER" and self.type == "M" then
			-- FIXME Should this be on a separate listener?
			local id = part();
			local user = part();
			if user and user_exists(user, default_vhost) then
				self:send("USER", id);
			else
				self:send("NOTFOUND", id);
			end
		else
			self:log("warn", "Unhandled command %s", tostring(command));
			self.conn:close();
			break;
		end
		line, eol = buf:match("(.-)\r?\n()")
	end
end

end

local listener = {}

function listener.onconnect(conn)
	local s = new_session(conn);
	sessions[conn] = s;
	local g_sasl = new_sasl(default_vhost, s);
	s.g_sasl = g_sasl;
	s:handshake();
end

function listener.onincoming(conn, data)
	local s = sessions[conn];
	-- s:log("debug", "RECV %s", dump(data));
	return s:feed(data);
end

function listener.ondisconnect(conn)
	sessions[conn] = nil;
end

function module.unload()
	for c in pairs(sessions) do
		c:close();
	end
end

module:provides("net", {
	default_port = 28484;
	listener = listener;
});