Mercurial > prosody-modules
view mod_muc_limits/mod_muc_limits.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 | 2b10e51d85a6 |
children | 731ba9400c10 |
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local mod_muc = module:depends"muc"; local rooms = rawget(mod_muc, "rooms"); -- Old MUC API local jid_split, jid_bare = require "util.jid".split, require "util.jid".bare; local st = require "util.stanza"; local new_throttle = require "util.throttle".create; local t_insert, t_concat = table.insert, table.concat; local xmlns_muc = "http://jabber.org/protocol/muc"; local period = math.max(module:get_option_number("muc_event_rate", 0.5), 0); local burst = math.max(module:get_option_number("muc_burst_factor", 6), 1); local max_nick_length = module:get_option_number("muc_max_nick_length", 23); -- Default chosen through scientific methods local join_only = module:get_option_boolean("muc_limit_joins_only", false); local dropped_count = 0; local dropped_jids; local function log_dropped() module:log("warn", "Dropped %d stanzas from %d JIDs: %s", dropped_count, #dropped_jids, t_concat(dropped_jids, ", ")); dropped_count = 0; dropped_jids = nil; end local function handle_stanza(event) local origin, stanza = event.origin, event.stanza; if stanza.name == "presence" and stanza.attr.type == "unavailable" then -- Don't limit room leaving return; end local dest_room, dest_host, dest_nick = jid_split(stanza.attr.to); local room = event.room or rooms[dest_room.."@"..dest_host]; if not room then return; end local from_jid = stanza.attr.from; if room:get_affiliation(jid_bare(from_jid)) then module:log("debug", "Skipping stanza from affiliated user..."); return; elseif dest_nick and max_nick_length and stanza.name == "presence" and not room._occupants[stanza.attr.to] and #dest_nick > max_nick_length then module:log("debug", "Forbidding long (%d bytes) nick in %s", #dest_nick, dest_room) origin.send(st.error_reply(stanza, "modify", "policy-violation", "Your nick name is too long, please use a shorter one") :up():tag("x", { xmlns = xmlns_muc })); return true; end local throttle = room.throttle; if not room.throttle then throttle = new_throttle(period*burst, burst); room.throttle = throttle; end if not throttle:poll(1) then module:log("debug", "Dropping stanza for %s@%s from %s, over rate limit", dest_room, dest_host, from_jid); if not dropped_jids then dropped_jids = { [from_jid] = true, from_jid }; module:add_timer(5, log_dropped); elseif not dropped_jids[from_jid] then dropped_jids[from_jid] = true; t_insert(dropped_jids, from_jid); end dropped_count = dropped_count + 1; if stanza.attr.type == "error" then -- We don't want to bounce errors return true; end local reply = st.error_reply(stanza, "wait", "policy-violation", "The room is currently overactive, please try again later"); local body = stanza:get_child_text("body"); if body then reply:up():tag("body"):text(body):up(); end local x = stanza:get_child("x", xmlns_muc); if x then reply:add_child(st.clone(x)); end origin.send(reply); return true; end end if rooms then function module.unload() for room_jid, room in pairs(rooms) do --luacheck: ignore 213/room_jid room.throttle = nil; end end module:hook("presence/full", handle_stanza, 501); if not join_only then module:hook("message/bare", handle_stanza, 501); module:hook("message/full", handle_stanza, 501); module:hook("presence/bare", handle_stanza, 501); end else module:hook("muc-occupant-pre-join", handle_stanza); if not join_only then module:hook("muc-occupant-pre-change", handle_stanza); module:hook("muc-occupant-groupchat", handle_stanza); end end