From 25135bbd16bd852379f63923bc3edfdc63a3145f Mon Sep 17 00:00:00 2001
From: JC Brand <jc@opkode.com>
Date: Fri, 2 Oct 2020 16:12:47 +0200
Subject: MUC: Reject probes from non-occupants

Also test for self-probes
---
 plugins/muc/muc.lib.lua              | 33 +++++++++++-------
 spec/scansion/muc_presence_probe.scs | 65 +++++++++++++++++++++++++++++++++++-
 2 files changed, 85 insertions(+), 13 deletions(-)

diff --git a/plugins/muc/muc.lib.lua b/plugins/muc/muc.lib.lua
index 5bbc28f1..d1449af1 100644
--- a/plugins/muc/muc.lib.lua
+++ b/plugins/muc/muc.lib.lua
@@ -595,6 +595,26 @@ function room_mt:build_unavailable_presence(from_muc_jid, to_jid)
 	return event.stanza;
 end
 
+function room_mt:respond_to_probe(origin, stanza, probing_occupant)
+	if probing_occupant == nil then
+		origin.send(st.error_reply(stanza, "cancel", "not-acceptable", "You are not currently connected to this chat", self.jid));
+		return;
+	end
+
+	local from_muc_jid = stanza.attr.to;
+	local probed_occupant = self:get_occupant_by_nick(from_muc_jid);
+	if probed_occupant == nil then
+		local to_jid = stanza.attr.from;
+		local pr = self:build_unavailable_presence(from_muc_jid, to_jid);
+		if pr then
+			self:route_stanza(pr);
+		end
+		return;
+	end
+	local x = st.stanza("x", {xmlns = "http://jabber.org/protocol/muc#user"});
+	self:publicise_occupant_status(probed_occupant, x, nil, nil, nil, nil, false, probing_occupant);
+end
+
 
 function room_mt:handle_normal_presence(origin, stanza)
 	local type = stanza.attr.type;
@@ -616,18 +636,7 @@ function room_mt:handle_normal_presence(origin, stanza)
 		if orig_occupant == nil then return true; end -- Unavailable from someone not in the room
 		-- dest_occupant = nil
 	elseif type == "probe" then
-		local occupant = self:get_occupant_by_nick(stanza.attr.to);
-		if occupant == nil then
-			local from_muc_jid = stanza.attr.to;
-			local to_jid = real_jid;
-			local pr = self:build_unavailable_presence(from_muc_jid, to_jid);
-			if pr then
-				self:route_stanza(pr);
-			end
-			return true;
-		end
-		local x = st.stanza("x", {xmlns = "http://jabber.org/protocol/muc#user"});
-		self:publicise_occupant_status(occupant, x, nil, nil, nil, nil, false, orig_occupant);
+		self:respond_to_probe(origin, stanza, orig_occupant)
 		return true;
 	elseif orig_occupant and orig_occupant.nick == stanza.attr.to then -- Just a presence update
 		log("debug", "presence update for %s from session %s", orig_occupant.nick, real_jid);
diff --git a/spec/scansion/muc_presence_probe.scs b/spec/scansion/muc_presence_probe.scs
index ffd61dba..1fb5d9f5 100644
--- a/spec/scansion/muc_presence_probe.scs
+++ b/spec/scansion/muc_presence_probe.scs
@@ -16,6 +16,8 @@
 
 Romeo connects
 
+# Romeo joins the MUC
+
 Romeo sends:
 	<presence to="room@conference.localhost/Romeo">
 		<x xmlns="http://jabber.org/protocol/muc"/>
@@ -52,9 +54,52 @@ Romeo receives:
 	<iq id="config1" from="room@conference.localhost" type="result">
 	</iq>
 
-# Juliet connects, and joins the room
+# Romeo probes himself
+
+Romeo sends:
+	<presence to="room@conference.localhost/Romeo" type="probe">
+		<x xmlns="http://jabber.org/protocol/muc"/>
+	</presence>
+
+Romeo receives:
+	<presence from='room@conference.localhost/Romeo'>
+		<x xmlns='http://jabber.org/protocol/muc#user'>
+			<item jid="${Romeo's full JID}" affiliation='owner' role='moderator'/>
+		</x>
+	</presence>
+
+# Juliet tries to probe Romeo before joining the room
+
 Juliet connects
 
+Juliet sends:
+	<presence to="room@conference.localhost/Romeo" type="probe">
+		<x xmlns="http://jabber.org/protocol/muc"/>
+	</presence>
+
+Juliet receives:
+	<presence from="room@conference.localhost/Romeo" type="error">
+		<error type="cancel">
+			<not-acceptable xmlns="urn:ietf:params:xml:ns:xmpp-stanzas"/>
+		</error>
+	</presence>
+
+# Juliet tries to probe Mercutio (who's not in the MUC) before joining the room
+
+Juliet sends:
+	<presence to="room@conference.localhost/Mercutio" type="probe">
+		<x xmlns="http://jabber.org/protocol/muc"/>
+	</presence>
+
+Juliet receives:
+	<presence from="room@conference.localhost/Mercutio" type="error">
+		<error type="cancel">
+			<not-acceptable xmlns="urn:ietf:params:xml:ns:xmpp-stanzas"/>
+		</error>
+	</presence>
+
+# Juliet joins the room
+
 Juliet sends:
 	<presence to="room@conference.localhost/Juliet">
 		<x xmlns="http://jabber.org/protocol/muc"/>
@@ -80,6 +125,24 @@ Romeo receives:
 		</x>
 	</presence>
 
+
+# Mercutio tries to probe himself in a MUC before joining
+
+Mercutio connects
+
+Mercutio sends:
+	<presence to="room@conference.localhost/Mercutio" type="probe">
+		<x xmlns="http://jabber.org/protocol/muc"/>
+	</presence>
+
+Mercutio receives:
+	<presence from="room@conference.localhost/Mercutio" type="error">
+		<error type="cancel">
+			<not-acceptable xmlns="urn:ietf:params:xml:ns:xmpp-stanzas"/>
+		</error>
+	</presence>
+
+
 # Romeo makes Mercutio a member and registers his nickname
 
 Romeo sends:
-- 
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