From 4b859cae706af8e59671f8105be17a4436d7ba34 Mon Sep 17 00:00:00 2001
From: Pierre Ossman <ossman@cendio.se>
Date: Thu, 23 Feb 2023 07:19:09 +0100
Subject: [PATCH] Don't parse empty fence messages

We need to return here or we'll do an out-of-bounds access on the data
array.

(cherry picked from commit 7af69eb4a7a52d6baf4d09f79ccbec76bd1fcee1)
---
 common/rfb/VNCSConnectionST.cxx | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/common/rfb/VNCSConnectionST.cxx b/common/rfb/VNCSConnectionST.cxx
index 306bba1dc4..7587449525 100644
--- a/common/rfb/VNCSConnectionST.cxx
+++ b/common/rfb/VNCSConnectionST.cxx
@@ -706,8 +706,10 @@ void VNCSConnectionST::fence(uint32_t flags, unsigned len, const uint8_t data[])
     return;
   }
 
-  if (len < 1)
+  if (len < 1) {
     vlog.error("Fence response of unexpected size received");
+    return;
+  }
 
   type = data[0];