Fixed bug #70183 null pointer deref (segfault) in zend_eval_const_expr

Author: hughdavenport

Zend/tests/bug70183.phpt

@@ -0,0 +1,8 @@
+--TEST--
+Bug #70183 (null pointer deref (segfault) in zend_eval_const_expr)
+--FILE--
+<?php
+[[][]]
+?>
+--EXPECTF--
+Fatal error: Cannot use [] for reading in %sbug70183.php on line %d

Zend/zend_compile.c

@@ -7374,7 +7374,7 @@ void zend_eval_const_expr(zend_ast **ast_ptr) /* {{{ */
 
 			zend_eval_const_expr(&ast->child[0]);
 			zend_eval_const_expr(&ast->child[1]);
-			if (ast->child[0]->kind != ZEND_AST_ZVAL || ast->child[1]->kind != ZEND_AST_ZVAL) {
+			if (!ast->child[0] || !ast->child[1] || ast->child[0]->kind != ZEND_AST_ZVAL || ast->child[1]->kind != ZEND_AST_ZVAL) {
 				return;
 			}