Mercurial > prosody-modules
view mod_auto156/mod_auto156.lua @ 4651:8231774f5bfd
mod_cloud_notify_encrypted: Ensure body substring remains valid UTF-8
The `body:sub()` call risks splitting the string in the middle of a
multi-byte UTF-8 sequence. This should have been caught by util.stanza
validation, but that would have caused some havoc, at the very least causing
the notification to not be sent.
There have been no reports of this happening. Likely because this module
isn't widely deployed among users with languages that use many longer UTF-8
sequences.
The util.encodings.utf8.valid() function is O(n) where only the last
sequence really needs to be checked, but it's in C and expected to be fast.
author | Kim Alvefur <zash@zash.se> |
---|---|
date | Sun, 22 Aug 2021 13:22:59 +0200 |
parents | 5d494dba9c02 |
children |
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-- Synthesize XEP-0156 JSON from DNS local array = require "util.array"; local encodings = require "util.encodings"; local json = require "util.json"; local promise = require "util.promise"; local dns = require"net.adns".resolver(); local function check_dns(domain) return dns:lookup_promise("_xmppconnect." .. domain, "TXT"); end local function check_domain(domain) return promise.resolve(domain):next(encodings.stringprep.nameprep):next(encodings.idna.to_ascii):next( function(domain_A) if not domain_A then return promise.reject(400); else return domain_A; end end):next(check_dns):next(function(txt) local uris = array(); for _, cm in ipairs(txt) do local kind, uri = tostring(cm.txt):match("^_xmpp%-client%-(%w+)=([hpstw]+s?://.*)"); if kind then uris:push({rel = "urn:xmpp:alt-connections:" .. kind, href = uri}); end end if #uris == 0 then return promise.reject(404); end return {links=uris}; end); end module:depends("http"); module:provides("http", { route = { ["GET /*"] = function(_, domain) return check_domain(domain):next(function(altmethods) return {headers = {content_type = "application/json"}, body = json.encode(altmethods)}; end); end, }, }); function module.command(args) local async = require "util.async"; for _, domain in ipairs(args) do print(assert(async.wait_for(check_domain(domain):next(json.encode)))); end end