From dca5da02a04571d0baa28712846539b7588d7d8f Mon Sep 17 00:00:00 2001
From: Geoffrey McRae <geoff@hostfission.com>
Date: Wed, 20 Oct 2021 13:34:16 +1100
Subject: [PATCH] [client] egl: fix undefined behaviour with zero size array

---
 client/renderers/EGL/desktop_rects.c | 6 ++++++
 common/src/rects.c                   | 3 +++
 2 files changed, 9 insertions(+)

diff --git a/client/renderers/EGL/desktop_rects.c b/client/renderers/EGL/desktop_rects.c
index 5c0edf51..8d97e5ce 100644
--- a/client/renderers/EGL/desktop_rects.c
+++ b/client/renderers/EGL/desktop_rects.c
@@ -107,6 +107,12 @@ inline static void rectToVertices(GLfloat * vertex, const FrameDamageRect * rect
 void egl_desktopRectsUpdate(EGL_DesktopRects * rects, const struct DamageRects * data,
     int width, int height)
 {
+  if (data && data->count == 0)
+  {
+    rects->count = 0;
+    return;
+  }
+
   GLfloat vertices[(!data || data->count < 0 ? 1 : data->count) * 8];
   if (!data || data->count < 0)
   {
diff --git a/common/src/rects.c b/common/src/rects.c
index c6b93699..80257ee6 100644
--- a/common/src/rects.c
+++ b/common/src/rects.c
@@ -211,6 +211,9 @@ inline static bool rectIntersects(const FrameDamageRect * r1, const FrameDamageR
 
 int rectsMergeOverlapping(FrameDamageRect * rects, int count)
 {
+  if (count == 0)
+    return 0;
+
   bool removed[count];
   bool changed;