CHROOT - fix symbolic link that refers to a network share (#596)

Author: bagajjal

contrib/win32/openssh/OpenSSH-build.ps1

@@ -46,5 +46,4 @@ try
 finally
 {
     Pop-Location
-}
-
+}

contrib/win32/win32compat/fileio.c

@@ -427,6 +427,14 @@ file_in_chroot_jail(HANDLE handle) {
 	if (!final_path)
 		return 0;
 
+	const wchar_t* uncPrefix = L"UNC\\";
+	int isUNCPath = memcmp(final_path, uncPrefix, 2 * wcslen(uncPrefix));
+
+	if (0 == isUNCPath) {
+		debug3("symlink points to UNCPath");
+		return 1;
+	}
+
 	to_wlower_case(final_path);
 	if ((wcslen(final_path) < wcslen(chroot_pathw)) ||
 	    memcmp(final_path, chroot_pathw, 2 * wcslen(chroot_pathw)) != 0 ||