From cad2eef7afc2cb5df9daf35a1abe59dc9a4db860 Mon Sep 17 00:00:00 2001
From: John Livingston <git@john-livingston.fr>
Date: Thu, 27 Jun 2024 15:14:49 +0200
Subject: [PATCH] Fix terms: broadcasted messages should not be stored by
 mod_muc_mam.

---
 .../mod_muc_peertubelivechat_terms.lua                    | 8 ++++++++
 support/documentation/content/en/technical/terms.md       | 4 ++++
 2 files changed, 12 insertions(+)

diff --git a/prosody-modules/mod_muc_peertubelivechat_terms/mod_muc_peertubelivechat_terms.lua b/prosody-modules/mod_muc_peertubelivechat_terms/mod_muc_peertubelivechat_terms.lua
index 11daf5eb..cdb6ebf7 100644
--- a/prosody-modules/mod_muc_peertubelivechat_terms/mod_muc_peertubelivechat_terms.lua
+++ b/prosody-modules/mod_muc_peertubelivechat_terms/mod_muc_peertubelivechat_terms.lua
@@ -116,3 +116,11 @@ module:hook("muc-occupant-groupchat", function(event)
     return child;
   end);
 end, 100);
+
+-- don't save terms messages in history
+module:hook("muc-message-is-historic", function(event)
+  local stanza = event.stanza;
+  if (stanza:get_child("x-livechat-terms")) then
+    return false, "hint";
+  end
+end, 1);
diff --git a/support/documentation/content/en/technical/terms.md b/support/documentation/content/en/technical/terms.md
index eecd4365..9c23217c 100644
--- a/support/documentation/content/en/technical/terms.md
+++ b/support/documentation/content/en/technical/terms.md
@@ -49,6 +49,10 @@ This also ensure clients will not drop the message because there is no occupant
 
 When muc terms are updated, the new terms will be broadcasted.
 
+To avoid anyone spoofing terms & conditions, incoming message stanza are filtered, and any `x-livechat-terms` tag will be removed.
+
+Message history is disabled for message containing the `x-livechat-terms`, so that messages broadcasted when the terms change are not stored by muc_mam modume ("Message Archiving Management").
+
 ## Frontend
 
 For standard XMPP clients, terms will be shown as delayed messages.