From 610362f8c979b2d1aeb98a8d9dfee94fcbad8ec8 Mon Sep 17 00:00:00 2001
From: Lephe <sebastien.michelland@protonmail.com>
Date: Sat, 13 Jun 2020 19:13:01 +0200
Subject: [PATCH] render-cg: fix potential VRAM overflow in gint_dhline()

A missing coordinate check in gint_dhline() would allow lines entirely
out of bounds of the screen to write pixels outside of their expected
range, often wrapping up to the next line, but possibly overflowing from
VRAM.
---
 src/render-cg/dline.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/render-cg/dline.c b/src/render-cg/dline.c
index c056c0e..ddc531d 100644
--- a/src/render-cg/dline.c
+++ b/src/render-cg/dline.c
@@ -7,6 +7,7 @@ void gint_dhline(int x1, int x2, int y, uint16_t color)
 	/* Order and bounds */
 	if((uint)y >= 224) return;
 	if(x1 > x2) swap(x1, x2);
+	if(x1 >= 396 || x2 < 0) return;
 	if(x1 < 0) x1 = 0;
 	if(x2 >= 396) x2 = 395;