From 84836642f94ffe5cb4df7406601bfd9990eac60b Mon Sep 17 00:00:00 2001
From: Ken Brown <kbrown@cornell.edu>
Date: Sat, 14 Nov 2020 09:02:43 -0500
Subject: [PATCH] Cygwin: path_conv::eq_worker: add NULL pointer checks

Don't call cstrdup on NULL pointers.

This fixes a crash that was observed when cloning an fhandler whose
path_conv member had freed its strings.
---
 winsup/cygwin/path.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/winsup/cygwin/path.h b/winsup/cygwin/path.h
index b94f13df8..0b3e72fc1 100644
--- a/winsup/cygwin/path.h
+++ b/winsup/cygwin/path.h
@@ -320,9 +320,11 @@ class path_conv
        contrast to statically allocated strings.  Calling device::dup()
        will duplicate the string if the source was allocated. */
     dev.dup ();
-    path = cstrdup (in_path);
+    if (in_path)
+      path = cstrdup (in_path);
     conv_handle.dup (pc.conv_handle);
-    posix_path = cstrdup(pc.posix_path);
+    if (pc.posix_path)
+      posix_path = cstrdup(pc.posix_path);
     if (pc.wide_path)
       {
 	wide_path = cwcsdup (uni_path.Buffer);