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mod_post_msg/mod_post_msg.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 |
parent | 2989:926aaaeb0d21 |
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module:depends"http" local jid_split = require "util.jid".split; local jid_prep = require "util.jid".prep; local msg = require "util.stanza".message; local test_password = require "core.usermanager".test_password; local b64_decode = require "util.encodings".base64.decode; local formdecode = require "net.http".formdecode; local xml = require"util.xml"; local json = require "util.json"; local function require_valid_user(f) return function(event, path) local request = event.request; local response = event.response; local headers = request.headers; if not headers.authorization then response.headers.www_authenticate = ("Basic realm=%q"):format(module.host.."/"..module.name); return 401 end local from_jid, password = b64_decode(headers.authorization:match"[^ ]*$"):match"([^:]*):(.*)"; from_jid = jid_prep(from_jid); if from_jid and password then local user, host = jid_split(from_jid); local ok, err = test_password(user, host, password); if ok and user and host then module:log("debug", "Authed as %s", from_jid); return f(event, path, from_jid); elseif err then module:log("debug", "User failed authentication: %s", err); end end return 401 end end local function handle_post(event, path, authed_user) local request = event.request; local response = event.response; local headers = request.headers; local body_type = headers.content_type; local to = jid_prep(path); local message; if body_type == "text/plain" then if to and request.body then message = msg({ to = to, from = authed_user, type = "chat"},request.body); end elseif body_type == "application/x-www-form-urlencoded" then local post_body = formdecode(request.body); message = msg({ to = post_body.to or to, from = authed_user, type = post_body.type or "chat"}, post_body.body); if post_body.html then local html, err = xml.parse([[<body xmlns="http://www.w3.org/1999/xhtml">]]..post_body.html..[[</body>]]); if not html then module:log("warn", "mod_post_msg: invalid XML: %s", err); return 400; end message:tag("html", {xmlns="http://jabber.org/protocol/xhtml-im"}):add_child(html):up(); end elseif body_type == "application/json" then local post_body = json.decode(request.body); if not post_body then return 400; end message = msg({ to = post_body.to or to, from = authed_user, type = post_body.type or "chat"}, post_body.body); else return 415; end if message and message.attr.to then module:log("debug", "Sending %s", tostring(message)); module:send(message); return 201; end return 422; end module:provides("http", { default_path = "/msg"; route = { ["POST /*"] = require_valid_user(handle_post); OPTIONS = function(e) local headers = e.response.headers; headers.allow = "POST"; headers.accept = "application/x-www-form-urlencoded, text/plain"; return 200; end; } });