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mod_cache_c2s_caps/mod_cache_c2s_caps.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 | 4320:8fc16174fec6 |
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local st_iq = require "util.stanza".iq; local uuid_gen = require "util.uuid".generate; local calculate_hash = require "util.caps".calculate_hash; -- Map of jid..node, to avoid querying the same client multiple times for the same value. local in_flight_iqs = {} -- Some clients (*ahem* poezio…) don’t include the @node in their result iq. local iq_node_map = {} assert(module.send_iq, "This module is not compatible with this version of Prosody."); local function iq_result_handler(event) local origin, stanza = event.origin, event.stanza; local query = stanza:get_child("query", "http://jabber.org/protocol/disco#info"); if not query then origin.log("debug", "Wrong iq payload in disco#info result: %s", stanza); origin.caps_cache = nil; return; end local from = stanza.attr.from; local id = stanza.attr.id; local node_string = query.attr.node; local node_query = iq_node_map[from..id]; if node_string == nil then node_string = node_query; query.attr.node = node_query; end iq_node_map[from..id] = nil; if node_string ~= node_query then origin.log("debug", "Wrong node for our disco#info query, expected %s, received %s", node_string, node_query); origin.caps_cache = nil; return; end local node, ver = node_query:match("([^#]+)#([^#]+)"); local hash = calculate_hash(query) if ver ~= hash then origin.log("debug", "Wrong hash for disco#info: %s ~= %s", ver, hash); origin.caps_cache = nil; return; end origin.caps_cache = query; origin.log("info", "Stored caps %s", ver); module:fire_event("c2s-capabilities-changed", { origin = origin }); return true; end local function iq_error_handler(err) local origin = err.context.origin; if origin ~= nil then origin.caps_cache = nil; module:fire_event("c2s-capabilities-changed", { origin = origin }); end end local function presence_stanza_handler(event) local origin, stanza = event.origin, event.stanza; local from = stanza.attr.from; if stanza.attr.to ~= nil then return; end local caps = stanza:get_child("c", "http://jabber.org/protocol/caps"); if caps == nil then origin.log("debug", "Presence from %s without caps received, skipping", from); return; end local hash = caps.attr.hash; local node = caps.attr.node; local ver = caps.attr.ver; if not hash or not node or not ver then return; end if hash ~= "sha-1" then origin.log("warn", "Presence from %s with non-SHA-1 caps : %s", from, hash); return; end local node_query = node.."#"..ver; if (origin.caps_cache and origin.caps_cache.attr.node == node_query) or in_flight_iqs[from..node_query] ~= nil then origin.log("debug", "Already requested these caps, skipping"); return; end origin.log("debug", "Presence from %s with SHA-1 caps %s, querying disco#info", from, node_query); local id = uuid_gen(); iq_node_map[from..id] = node_query local iq = st_iq({ type = "get", from = module.host, to = from, id = id }) :tag("query", { xmlns = "http://jabber.org/protocol/disco#info", node = node_query }); in_flight_iqs[from..node_query] = true; module:send_iq(iq, origin) :next(iq_result_handler, iq_error_handler) :finally(function () in_flight_iqs[from..node_query] = nil; end) end -- Handle only non-directed presences for now. module:hook("pre-presence/bare", presence_stanza_handler);