prevent invalid color index (palette only), may lead to crash

Author: pierrejoye

ext/gd/libgd/gd.c

@@ -1769,6 +1769,12 @@ void gdImageFillToBorder (gdImagePtr im, int x, int y, int border, int color)
 		return;
 	}
 
+	if (!im->trueColor) {
+		if ((color > (im->colorsTotal - 1)) || (border > (im->colorsTotal - 1)) || (color < 0)) {
+			return;
+		}
+	}
+
 	restoreAlphaBlending = im->alphaBlendingFlag;
 	im->alphaBlendingFlag = 0;
 

ext/gd/tests/github_bug_215.phpt

@@ -0,0 +1,43 @@
+--TEST-- 
+Github #215 (imagefilltoborder stack overflow when invalid pallete index used)
+--SKIPIF-- 
+<?php  
+if (!extension_loaded("gd")) die("skip GD not present"); 
+?> 
+--FILE--
+<?php
+$image = imagecreate( 10, 10 ); 
+$bgd = imagecolorallocate( $image, 0, 0, 0 );
+$border = imagecolorallocate( $image, 255, 0, 0 );
+$fillcolor = imagecolorallocate( $image, 255, 0, 0 );
+
+/* Use unallocated color index */
+imagefilltoborder( $image, 0,0, $border+10, $fillcolor);
+echo "#1 passes\n";
+
+/* Use negative color index */
+imagefilltoborder( $image, 0,0, -$border,  $fillcolor);
+echo "#2 passes\n";
+
+
+/* Use unallocated color index */
+imagefilltoborder( $image, 0,0, $border, $fillcolor+10);
+echo "#3 passes\n";
+
+/* Use negative color index */
+imagefilltoborder( $image, 0,0, $border, -$fillcolor);
+echo "#4 passes\n";
+
+
+/* Use negative color index */
+imagefilltoborder( $image, 0,0, $border+10, $fillcolor+10);
+echo "#5 passes";
+
+
+?> 
+--EXPECT-- 
+#1 passes
+#2 passes
+#3 passes
+#4 passes
+#5 passes