File

tools/generate_format_spec.lua @ 12180:53e0ae770917

util.xml: Do not allow doctypes, comments or processing instructions Yes. This is as bad as it sounds. CVE pending. In Prosody itself, this only affects mod_websocket, which uses util.xml to parse the <open/> frame, thus allowing unauthenticated remote DoS using Billion Laughs. However, third-party modules using util.xml may also be affected by this. This commit installs handlers which disallow the use of doctype declarations and processing instructions without any escape hatch. It, by default, also introduces such a handler for comments, however, there is a way to enable comments nontheless. This is because util.xml is used to parse human-facing data, where comments are generally a desirable feature, and also because comments are generally harmless.
author Jonas Schäfer <jonas@wielicki.name>
date Mon, 10 Jan 2022 18:23:54 +0100
parent 12039:e0a8c5b1ab4f
line wrap: on
line source

local format = require"util.format".format;
local dump = require"util.serialization".new("oneline")
local types = {
	"nil";
	"boolean";
	"number";
	"string";
	"function";
	-- "userdata";
	"thread";
	"table";
};
local example_values = {
	["nil"] = { n = 1; nil };
	["boolean"] = { true; false };
	["number"] = { 97; -12345; 1.5; 73786976294838206464; math.huge; 2147483647 };
	["string"] = { "hello"; "foo \1\2\3 bar"; "nödåtgärd"; string.sub("nödåtgärd", 1, -4) };
	["function"] = { function() end };
	-- ["userdata"] = {};
	["thread"] = { coroutine.create(function() end) };
	["table"] = { {}, setmetatable({},{__tostring=function ()return "foo \1\2\3 bar"end}) };
};
local example_strings = setmetatable({
	["nil"] = { "nil" };
	["function"] = { "function() end" };
	["number"] = { "97"; "-12345"; "1.5"; "73786976294838206464"; "math.huge"; "2147483647" };
	["thread"] = { "coroutine.create(function() end)" };
	["table"] = { "{ }", "setmetatable({},{__tostring=function ()return \"foo \\1\\2\\3 bar\"end})" }
}, { __index = function() return {} end });
for _, lua_type in ipairs(types) do
	print(string.format("\t\tdescribe(\"%s\", function ()", lua_type));
	local examples = example_values[lua_type];
	for fmt in ("cdiouxXaAeEfgGqs"):gmatch(".") do
		print(string.format("\t\t\tdescribe(\"to %%%s\", function ()", fmt));
		print("\t\t\t\tit(\"works\", function ()");
		for i = 1, examples.n or #examples do
			local example = examples[i];
			if not tostring(example):match("%w+: 0[xX]%x+") then
				print(string.format("\t\t\t\t\tassert.equal(%q, format(%q, %s))", format("%" .. fmt, example), "%" .. fmt,
					example_strings[lua_type][i] or dump(example)));
			else
				print(string.format("\t\t\t\t\tassert.matches(\"[%s: 0[xX]%%x+]\", format(%q, %s))", lua_type, "%" .. fmt,
					example_strings[lua_type][i] or dump(example)));
			end
		end
		print("\t\t\t\tend);");
		print("\t\t\tend);");
		print()
	end
	print("\t\tend);");
	print()
end