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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 |
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-- 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; };