From 4875a4502288e7a0e4b73a93ba0eda5998a696f8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?nils=20m=C3=A5s=C3=A9n?= <nils@piksel.se>
Date: Sat, 8 May 2021 15:35:24 +0200
Subject: [PATCH] fix: add dir separator to base dir if missing

---
 src/ICSharpCode.SharpZipLib/Zip/WindowsNameTransform.cs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/ICSharpCode.SharpZipLib/Zip/WindowsNameTransform.cs b/src/ICSharpCode.SharpZipLib/Zip/WindowsNameTransform.cs
index 4958df41b..43aa61403 100644
--- a/src/ICSharpCode.SharpZipLib/Zip/WindowsNameTransform.cs
+++ b/src/ICSharpCode.SharpZipLib/Zip/WindowsNameTransform.cs
@@ -134,7 +134,12 @@ public string TransformFile(string name)
 				{
 					name = Path.Combine(_baseDirectory, name);
 
-					var pathBase = Path.GetFullPath(_baseDirectory) + Path.DirectorySeparatorChar;
+					// Ensure base directory ends with directory separator ('/' or '\' depending on OS)
+					var pathBase = Path.GetFullPath(_baseDirectory);
+					if (pathBase[pathBase.Length - 1] != Path.DirectorySeparatorChar)
+					{
+						pathBase += Path.DirectorySeparatorChar;
+					}
 
 					if (!_allowParentTraversal && !Path.GetFullPath(name).StartsWith(pathBase, StringComparison.InvariantCultureIgnoreCase))
 					{