view mod_register_dnsbl/mod_register_dnsbl.lua @ 5265:f845c218e52c

mod_http_oauth2: Allow revoking a token without OAuth client credentials If you have a valid token, and you're not supposed to have it, revoking it seems the most responsible thing to do with it, so it should be allowed, while if you are supposed to have it, you should also be allowed to revoke it.
author Kim Alvefur <zash@zash.se>
date Tue, 21 Mar 2023 22:02:38 +0100
parents 82482e7e92cb
children
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local adns = require "net.adns";
local async = require "util.async";
local inet_pton = require "util.net".pton;
local to_hex = require "util.hex".to;

local rbl = module:get_option_string("registration_rbl");

local function reverse(ip, suffix)
	local n, err = inet_pton(ip);
	if not n then return n, err end
	if #n == 4 then
		local a,b,c,d = n:byte(1,4);
		return ("%d.%d.%d.%d.%s"):format(d,c,b,a, suffix);
	elseif #n == 16 then
		return to_hex(n):reverse():gsub("%x", "%1.") .. suffix;
	end
end

module:hook("user-registering", function (event)
	local session, ip = event.session, event.ip;
	local log = (session and session.log) or module._log;
	if not ip then
		log("debug", "Unable to check DNSBL when IP is unknown");
		return;
	end
	local rbl_ip, err = reverse(ip, rbl);
	if not rbl_ip then
		log("debug", "Unable to check DNSBL for ip %s: %s", ip, err);
		return;
	end

	local wait, done = async.waiter();
	adns.lookup(function (reply)
		if reply and reply[1] and reply[1].a then
			log("debug", "DNSBL response: %s IN A %s", rbl_ip, reply[1].a);
			log("info", "Blocking %s from registering %s (dnsbl hit)", ip, event.username);
			event.allowed = false;
			event.reason = "Blocked by DNSBL";
		end
		done();
	end, rbl_ip);
	wait();
end);