commit 0308e1f010cd8650840fa0ceee3b342229982420
from: Xiao-Yong <jinxiaoyong@gmail.com>
via: Russ Cox <rsc@golang.org>
date: Fri Apr 05 18:44:47 2019 UTC

devdraw: fix cocoa metal _flushmemscreen for invalid rectangles (#240)

It is possible to receive multiple screen resize events, and resizeimg
would be called for different sizes, before _flushmemscreen actually
gets called with rectangle sizes different from the most recent
resizeimg call.  The size mismatch would trigger illegal memory
access inside _flushmemscreen.

This commit protects _flushmemscreen by returning early if the requested
rectangle is outside of the current texture rectangle.

commit - 4d3c36cce4d70dfd88bd5e782e86141775577d30
commit + 0308e1f010cd8650840fa0ceee3b342229982420
blob - 21123f16323dd43bbb1c6629b598265ff2691e56
blob + 78110302b1f40714d758eeaa023d4a5012fe01e0
--- src/cmd/devdraw/cocoa-screen-metal.m
+++ src/cmd/devdraw/cocoa-screen-metal.m
@@ -987,6 +987,10 @@ void
 _flushmemscreen(Rectangle r)
 {
 	LOG(@"_flushmemscreen(%d,%d,%d,%d)", r.min.x, r.min.y, Dx(r), Dy(r));
+	if(!rectinrect(r, Rect(0, 0, texture.width, texture.height))){
+		LOG(@"Rectangle is out of bounds, return.");
+		return;
+	}
 
 	@autoreleasepool{
 		[texture