From bc129a26a8553a073ed16c1253a12801c16fc96b Mon Sep 17 00:00:00 2001
From: jfreegman <jfreegman@gmail.com>
Date: Sat, 2 Apr 2022 10:44:39 -0400
Subject: [PATCH] Fix possible buffer overread

---
 toxcore/group_announce.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/toxcore/group_announce.c b/toxcore/group_announce.c
index 50867fce746..903d906d3e7 100644
--- a/toxcore/group_announce.c
+++ b/toxcore/group_announce.c
@@ -191,6 +191,10 @@ static int gca_unpack_announce(const Logger *log, const uint8_t *data, uint16_t
     }
 
     if (announce->ip_port_is_set) {
+        if (length == 0) {
+            return -1;
+        }
+
         const int ip_port_length = unpack_ip_port(&announce->ip_port, data + offset, length - offset, false);
 
         if (ip_port_length == -1) {