7016985: (launcher) implement safe secure dll loading

Reviewed-by: mchung

jdk/src/windows/bin/java_md.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -1212,11 +1212,22 @@ jclass FindBootStrapClass(JNIEnv *env, const char *classname)
    return findBootClass(env, classname);
 }
 
+typedef BOOL (WINAPI *pfn_SetDllDirectory)(LPCTSTR);
+
 void
 InitLauncher(boolean javaw)
 {
     INITCOMMONCONTROLSEX icx;
 
+    // Launcher links with kernel32
+    HMODULE hKernel32 = GetModuleHandle(TEXT("kernel32.dll"));
+    pfn_SetDllDirectory fn = (pfn_SetDllDirectory) GetProcAddress(hKernel32,
+                                 "SetDllDirectory");
+    if (fn != NULL) {
+        // Exclude CWD from Dll search path
+        fn("");
+    }
+
     /*
      * Required for javaw mode MessageBox output as well as for
      * HotSpot -XX:+ShowMessageBoxOnError in java mode, an empty