File

net/http/errors.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 11225:8c17c08d100e
child 12974:ba409c67353b
line wrap: on
line source

-- This module returns a table that is suitable for use as a util.error registry,
-- and a function to return a util.error object given callback 'code' and 'body'
-- parameters.

local codes = require "net.http.codes";
local util_error = require "util.error";

local error_templates = {
	-- This code is used by us to report a client-side or connection error.
	-- Instead of using the code, use the supplied body text to get one of
	-- the more detailed errors below.
	[0] = {
		code = 0, type = "cancel", condition = "internal-server-error";
		text = "Connection or internal error";
	};

	-- These are net.http built-in errors, they are returned in
	-- the body parameter when code == 0
	["cancelled"] = {
		code = 0, type = "cancel", condition = "remote-server-timeout";
		text = "Request cancelled";
	};
	["connection-closed"] = {
		code = 0, type = "wait", condition = "remote-server-timeout";
		text = "Connection closed";
	};
	["certificate-chain-invalid"] = {
		code = 0, type = "cancel", condition = "remote-server-timeout";
		text = "Server certificate not trusted";
	};
	["certificate-verify-failed"] = {
		code = 0, type = "cancel", condition = "remote-server-timeout";
		text = "Server certificate invalid";
	};
	["connection failed"] = {
		code = 0, type = "cancel", condition = "remote-server-not-found";
		text = "Connection failed";
	};
	["invalid-url"] = {
		code = 0, type = "modify", condition = "bad-request";
		text = "Invalid URL";
	};
	["unable to resolve service"] = {
		code = 0, type = "cancel", condition = "remote-server-not-found";
		text = "DNS resolution failed";
	};

	-- This doesn't attempt to map every single HTTP code (not all have sane mappings),
	-- but all the common ones should be covered. XEP-0086 was used as reference for
	-- most of these.
	[400] = { type = "modify", condition = "bad-request" };
	[401] = { type = "auth", condition = "not-authorized" };
	[402] = { type = "auth", condition = "payment-required" };
	[403] = { type = "auth", condition = "forbidden" };
	[404] = { type = "cancel", condition = "item-not-found" };
	[405] = { type = "cancel", condition = "not-allowed" };
	[406] = { type = "modify", condition = "not-acceptable" };
	[407] = { type = "auth", condition = "registration-required" };
	[408] = { type = "wait", condition = "remote-server-timeout" };
	[409] = { type = "cancel", condition = "conflict" };
	[410] = { type = "cancel", condition = "gone" };
	[411] = { type = "modify", condition = "bad-request" };
	[412] = { type = "cancel", condition = "conflict" };
	[413] = { type = "modify", condition = "resource-constraint" };
	[414] = { type = "modify", condition = "resource-constraint" };
	[415] = { type = "cancel", condition = "feature-not-implemented" };
	[416] = { type = "modify", condition = "bad-request" };

	[422] = { type = "modify", condition = "bad-request" };
	[423] = { type = "wait", condition = "resource-constraint" };

	[429] = { type = "wait", condition = "resource-constraint" };
	[431] = { type = "modify", condition = "resource-constraint" };
	[451] = { type = "auth", condition = "forbidden" };

	[500] = { type = "wait", condition = "internal-server-error" };
	[501] = { type = "cancel", condition = "feature-not-implemented" };
	[502] = { type = "wait", condition = "remote-server-timeout" };
	[503] = { type = "cancel", condition = "service-unavailable" };
	[504] = { type = "wait", condition = "remote-server-timeout" };
	[507] = { type = "wait", condition = "resource-constraint" };
	[511] = { type = "auth", condition = "not-authorized" };
};

for k, v in pairs(codes) do
	if error_templates[k] then
		error_templates[k].code = k;
		error_templates[k].text = v;
	else
		error_templates[k] = { type = "cancel", condition = "undefined-condition", text = v, code = k };
	end
end

setmetatable(error_templates, {
	__index = function(_, k)
		if type(k) ~= "number" then
			return nil;
		end
		return {
			type = "cancel";
			condition = "undefined-condition";
			text = codes[k] or (k.." Unassigned");
			code = k;
		};
	end
});

local function new(code, body, context)
	if code == 0 then
		return util_error.new(body, context, error_templates);
	else
		return util_error.new(code, context, error_templates);
	end
end

return {
	registry = error_templates;
	new = new;
};