Mercurial > prosody-modules
view mod_warn_legacy_tls/mod_warn_legacy_tls.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 | 406b32b50457 |
children |
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local st = require"util.stanza"; local host = module.host; local deprecated_protocols = module:get_option_set("legacy_tls_versions", { "SSLv3", "TLSv1", "TLSv1.1" }); local warning_message = module:get_option_string("legacy_tls_warning", "Your connection is encrypted using the %s protocol, which has known problems and will be disabled soon. Please upgrade your client."); module:hook("resource-bind", function (event) local session = event.session; module:log("debug", "mod_%s sees that %s logged in", module.name, session.username); local ok, protocol = pcall(function(session) return session.conn:socket():info"protocol"; end, session); if not ok then module:log("debug", "Could not determine TLS version: %s", protocol); elseif deprecated_protocols:contains(protocol) then session.log("warn", "Uses %s", protocol); module:add_timer(15, function () if session.type == "c2s" and session.resource then session.send(st.message({ from = host, type = "headline", to = session.full_jid }, warning_message:format(protocol))); end end); else module:log("debug", "Using acceptable TLS version: %s", protocol); end end);