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mod_muc_eventsource/mod_muc_eventsource.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> |
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date | Sun, 22 Aug 2021 13:22:59 +0200 |
parent | 2897:39485b9bbdd6 |
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module:depends("http"); local nodeprep = require "util.encodings".stringprep.nodeprep; local jid_split = require "util.jid".split; local json = require "util.json"; local streams = {}; function client_closed(response) local node = response._eventsource_node; module:log("debug", "Destroying client for %q", node); streams[node][response] = nil; if next(streams[node]) == nil then streams[node] = nil; end end function serve_stream(event, node) local response = event.response; node = nodeprep(node); if node == nil then return 400; end module:log("debug", "Client subscribed to: %s", node); response.on_destroy = client_closed; response._eventsource_node = node; response.conn:write(table.concat({ "HTTP/1.1 200 OK"; "Content-Type: text/event-stream"; "Access-Control-Allow-Origin: *"; "Access-Control-Allow-Methods: GET"; "Access-Control-Max-Age: 7200"; ""; ""; }, "\r\n")); local clientlist = streams[node]; if not clientlist then clientlist = {}; streams[node] = clientlist; end clientlist[response] = response.conn; return true; end function handle_message(event) local room, stanza = event.room, event.stanza; local node = (jid_split(event.room.jid)); local clientlist = streams[node]; if not clientlist then module:log("debug", "No clients for %q", node); return; end -- Extract body from message local body = event.stanza:get_child_text("body"); if not body then return; end local nick = select(3, jid_split(stanza.attr.from)); -- Encode body and broadcast to eventsource subscribers local json_data = json.encode({ nick = nick; body = body; }); local data = "data: "..json_data:gsub("\n", "\ndata: \n").."\n\n"; for response, conn in pairs(clientlist) do conn:write(data); end end module:provides("http", { name = "eventsource"; route = { ["GET /*"] = serve_stream; }; }); module:hook("muc-broadcast-message", handle_message);