Fixed #72339 Integer Overflow in _gd2GetHeader() resulting in heap ov…

…erflow

ext/gd/libgd/gd_gd2.c

@@ -138,11 +138,18 @@ static int _gd2GetHeader(gdIOCtxPtr in, int *sx, int *sy, int *cs, int *vers, in
 	if (gd2_compressed(*fmt)) {
 		nc = (*ncx) * (*ncy);
 		GD2_DBG(php_gd_error("Reading %d chunk index entries", nc));
+		if (overflow2(sidx, nc)) {
+			goto fail1;
+		}
 		sidx = sizeof(t_chunk_info) * nc;
 		if (sidx <= 0) {
 			goto fail1;
 		}
 		cidx = gdCalloc(sidx, 1);
+		if (cidx == NULL) {
+			goto fail1;
+		}
+
 		for (i = 0; i < nc; i++) {
 			if (gdGetInt(&cidx[i].offset, in) != 1) {
 				gdFree(cidx);

ext/gd/tests/bug72339.phpt

@@ -0,0 +1,11 @@
+--TEST--
+Bug #72339 Integer Overflow in _gd2GetHeader() resulting in heap overflow 
+--SKIPIF--
+<?php if (!function_exists("imagecreatefromgd2")) print "skip"; ?>
+--FILE--
+<?php imagecreatefromgd2(dirname(__FILE__) . DIRECTORY_SEPARATOR . "bug72339.gd"); ?>
+--EXPECTF--	
+Warning: imagecreatefromgd2(): gd warning: product of memory allocation multiplication would exceed INT_MAX, failing operation gracefully
+ in %sbug72339.php on line %d
+
+Warning: imagecreatefromgd2(): '%sbug72339.gd' is not a valid GD2 file in %sbug72339.php on line %d