Diff

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/plugins/mod_mimicking.lua	Wed Sep 30 09:50:33 2020 +0100
@@ -0,0 +1,85 @@
+-- Prosody IM
+-- Copyright (C) 2012 Florian Zeitz
+-- Copyright (C) 2019 Kim Alvefur
+--
+-- This project is MIT/X11 licensed. Please see the
+-- COPYING file in the source package for more information.
+--
+
+local encodings = require "util.encodings";
+assert(encodings.confusable, "This module requires that Prosody be built with ICU");
+local skeleton = encodings.confusable.skeleton;
+
+local usage = require "util.prosodyctl".show_usage;
+local usermanager = require "core.usermanager";
+local storagemanager = require "core.storagemanager";
+
+local skeletons
+function module.load()
+	if module.host ~= "*" then
+		skeletons = module:open_store("skeletons");
+	end
+end
+
+module:hook("user-registered", function(user)
+	local skel = skeleton(user.username);
+	local ok, err = skeletons:set(skel, { username = user.username });
+	if not ok then
+		module:log("error", "Unable to store mimicry data (%q => %q): %s", user.username, skel, err);
+	end
+end);
+
+module:hook("user-deleted", function(user)
+	local skel = skeleton(user.username);
+	local ok, err = skeletons:set(skel, nil);
+	if not ok and err then
+		module:log("error", "Unable to clear mimicry data (%q): %s", skel, err);
+	end
+end);
+
+module:hook("user-registering", function(user)
+	local existing, err = skeletons:get(skeleton(user.username));
+	if existing then
+		module:log("debug", "Attempt to register username '%s' which could be confused with '%s'", user.username, existing.username);
+		user.allowed = false;
+	elseif err then
+		module:log("error", "Unable to check if new username '%s' can be confused with any existing user: %s", err);
+	end
+end);
+
+function module.command(arg)
+	if (arg[1] ~= "bootstrap" or not arg[2]) then
+		usage("mod_mimicking bootstrap <host>", "Initialize username mimicry database");
+		return;
+	end
+
+	local host = arg[2];
+
+	local host_session = prosody.hosts[host];
+	if not host_session then
+		return "No such host";
+	end
+
+	storagemanager.initialize_host(host);
+	usermanager.initialize_host(host);
+
+	skeletons = storagemanager.open(host, "skeletons");
+
+	local count = 0;
+	for user in usermanager.users(host) do
+		local skel = skeleton(user);
+		local existing, err = skeletons:get(skel);
+		if existing and existing.username ~= user then
+			module:log("warn", "Existing usernames '%s' and '%s' are confusable", existing.username, user);
+		elseif err then
+			module:log("error", "Error checking for existing mimicry data (%q = %q): %s", user, skel, err);
+		end
+		local ok, err = skeletons:set(skel, { username = user });
+		if ok then
+			count = count + 1;
+		elseif err then
+			module:log("error", "Unable to store mimicry data (%q => %q): %s", user, skel, err);
+		end
+	end
+	module:log("info", "%d usernames indexed", count);
+end