Fix compression method for encrypted empty files and directories when updating a ZipFile

Author: bwinsley

src/ICSharpCode.SharpZipLib/Zip/ZipFile.cs

@@ -398,9 +398,9 @@ private bool HaveKeys
 		/// <exception cref="ZipException">
 		/// The file doesn't contain a valid zip archive.
 		/// </exception>
-		public ZipFile(string name) : 
-			this(name, null) 
-		{ 
+		public ZipFile(string name) :
+			this(name, null)
+		{
 
 		}
 
@@ -534,10 +534,10 @@ public ZipFile(Stream stream) :
 		/// <exception cref="ArgumentNullException">
 		/// The <see cref="Stream">stream</see> argument is null.
 		/// </exception>
-		public ZipFile(Stream stream, bool leaveOpen) : 
-			this(stream, leaveOpen, null) 
-		{ 
-		
+		public ZipFile(Stream stream, bool leaveOpen) :
+			this(stream, leaveOpen, null)
+		{
+
 		}
 
 		/// <summary>
@@ -789,7 +789,8 @@ public Encoding ZipCryptoEncoding
 		/// <inheritdoc cref="Zip.StringCodec"/>
 		public StringCodec StringCodec
 		{
-			set {
+			set
+			{
 				_stringCodec = value;
 				if (!isNewArchive_)
 				{
@@ -1182,7 +1183,7 @@ private long TestLocalHeader(ZipEntry entry, HeaderTest tests)
 				bool testData = (tests & HeaderTest.Extract) != 0;
 
 				var entryAbsOffset = offsetOfFirstEntry + entry.Offset;
-				
+
 				baseStream_.Seek(entryAbsOffset, SeekOrigin.Begin);
 				var signature = (int)ReadLEUint();
 
@@ -1258,9 +1259,9 @@ private long TestLocalHeader(ZipEntry entry, HeaderTest tests)
 							throw new ZipException($"Version required to extract this entry not supported ({extractVersion})");
 						}
 
-						const GeneralBitFlags notSupportedFlags = GeneralBitFlags.Patched 
-																| GeneralBitFlags.StrongEncryption 
-																| GeneralBitFlags.EnhancedCompress 
+						const GeneralBitFlags notSupportedFlags = GeneralBitFlags.Patched
+																| GeneralBitFlags.StrongEncryption
+																| GeneralBitFlags.EnhancedCompress
 																| GeneralBitFlags.HeaderMasked;
 						if (localFlags.HasAny(notSupportedFlags))
 						{
@@ -1677,8 +1678,8 @@ public void CommitUpdate()
 				{
 					// Create an empty archive if none existed originally.
 					if (entries_.Length != 0) return;
-					byte[] theComment = (newComment_ != null) 
-						? newComment_.RawComment 
+					byte[] theComment = (newComment_ != null)
+						? newComment_.RawComment
 						: _stringCodec.ZipArchiveCommentEncoding.GetBytes(comment_);
 					ZipFormat.WriteEndOfCentralDirectory(baseStream_, 0, 0, 0, theComment);
 				}
@@ -2165,7 +2166,12 @@ private void WriteLocalEntryHeader(ZipUpdate update)
 						// No need to compress - no data.
 						entry.CompressedSize = entry.Size;
 						entry.Crc = 0;
-						entry.CompressionMethod = CompressionMethod.Stored;
+
+						// Crypted files should be deflated, even with no data (such as directories)
+						if (!HaveKeys)
+						{
+							entry.CompressionMethod = CompressionMethod.Stored;
+						}
 					}
 				}
 				else if (entry.CompressionMethod == CompressionMethod.Stored)
@@ -2583,15 +2589,15 @@ private void CopyBytes(ZipUpdate update, Stream destination, Stream source,
 		/// <returns>The descriptor size, zero if there isn't one.</returns>
 		private static int GetDescriptorSize(ZipUpdate update, bool includingSignature)
 		{
-			if (!((GeneralBitFlags)update.Entry.Flags).HasAny(GeneralBitFlags.Descriptor)) 
+			if (!((GeneralBitFlags)update.Entry.Flags).HasAny(GeneralBitFlags.Descriptor))
 				return 0;
-			
-			var descriptorWithSignature = update.Entry.LocalHeaderRequiresZip64 
-				? ZipConstants.Zip64DataDescriptorSize 
+
+			var descriptorWithSignature = update.Entry.LocalHeaderRequiresZip64
+				? ZipConstants.Zip64DataDescriptorSize
 				: ZipConstants.DataDescriptorSize;
 
-			return includingSignature 
-				? descriptorWithSignature 
+			return includingSignature
+				? descriptorWithSignature
 				: descriptorWithSignature - sizeof(int);
 		}
 
@@ -2878,7 +2884,7 @@ private void CopyEntryDirect(ZipFile workFile, ZipUpdate update, ref long destin
 
 			// Clumsy way of handling retrieving the original name and extra data length for now.
 			// TODO: Stop re-reading name and data length in CopyEntryDirect.
-			
+
 			uint nameLength = ReadLEUshort();
 			uint extraLength = ReadLEUshort();
 
@@ -3013,7 +3019,7 @@ private void UpdateCommentOnly()
 			}
 			finally
 			{
-				if(updateFile != baseStream_)
+				if (updateFile != baseStream_)
 					updateFile.Dispose();
 			}
 
@@ -3178,7 +3184,7 @@ private void RunUpdates()
 				}
 
 				byte[] theComment = newComment_?.RawComment ?? _stringCodec.ZipArchiveCommentEncoding.GetBytes(comment_);
-				ZipFormat.WriteEndOfCentralDirectory(workFile.baseStream_, updateCount_, 
+				ZipFormat.WriteEndOfCentralDirectory(workFile.baseStream_, updateCount_,
 					sizeEntries, centralDirOffset, theComment);
 
 				endOfStream = workFile.baseStream_.Position;
@@ -3520,7 +3526,7 @@ private ulong ReadLEUlong()
 		#endregion Reading
 
 		// NOTE this returns the offset of the first byte after the signature.
-		private long LocateBlockWithSignature(int signature, long endLocation, int minimumBlockSize, int maximumVariableData) 
+		private long LocateBlockWithSignature(int signature, long endLocation, int minimumBlockSize, int maximumVariableData)
 			=> ZipFormat.LocateBlockWithSignature(baseStream_, signature, endLocation, minimumBlockSize, maximumVariableData);
 
 		/// <summary>
@@ -3578,14 +3584,14 @@ private void ReadEntries()
 			}
 
 			bool isZip64 = false;
-			
+
 			// Check if zip64 header information is required.
 			bool requireZip64 = thisDiskNumber == 0xffff ||
-			                    startCentralDirDisk == 0xffff ||
-			                    entriesForThisDisk == 0xffff ||
-			                    entriesForWholeCentralDir == 0xffff ||
-			                    centralDirSize == 0xffffffff ||
-			                    offsetOfCentralDir == 0xffffffff;
+								startCentralDirDisk == 0xffff ||
+								entriesForThisDisk == 0xffff ||
+								entriesForWholeCentralDir == 0xffff ||
+								centralDirSize == 0xffffffff ||
+								offsetOfCentralDir == 0xffffffff;
 
 			// #357 - always check for the existence of the Zip64 central directory.
 			// #403 - Take account of the fixed size of the locator when searching.
@@ -3676,7 +3682,7 @@ private void ReadEntries()
 				int extraLen = ReadLEUshort();
 				int commentLen = ReadLEUshort();
 
-				
+
 				// ReSharper disable once UnusedVariable, Currently unused but needs to be read to offset the stream
 				int diskStartNo = ReadLEUshort();
 				// ReSharper disable once UnusedVariable, Currently unused but needs to be read to offset the stream
@@ -3773,9 +3779,9 @@ private Stream CreateAndInitDecryptionStream(Stream baseStream, ZipEntry entry)
 					int saltLen = entry.AESSaltLen;
 					byte[] saltBytes = new byte[saltLen];
 					int saltIn = StreamUtils.ReadRequestedBytes(baseStream, saltBytes, offset: 0, saltLen);
-					
+
 					if (saltIn != saltLen) throw new ZipException($"AES Salt expected {saltLen} git {saltIn}");
-					
+
 					byte[] pwdVerifyRead = new byte[2];
 					StreamUtils.ReadFully(baseStream, pwdVerifyRead);
 					int blockSize = entry.AESKeySize / 8;   // bits to bytes
@@ -3819,7 +3825,7 @@ private Stream CreateAndInitDecryptionStream(Stream baseStream, ZipEntry entry)
 		private Stream CreateAndInitEncryptionStream(Stream baseStream, ZipEntry entry)
 		{
 			if (entry.Version >= ZipConstants.VersionStrongEncryption &&
-			    entry.HasFlag(GeneralBitFlags.StrongEncryption)) return null;
+				entry.HasFlag(GeneralBitFlags.StrongEncryption)) return null;
 
 			var classicManaged = new PkzipClassicManaged();
 

test/ICSharpCode.SharpZipLib.Tests/Zip/GeneralHandling.cs

@@ -832,5 +832,53 @@ public void PasswordCheckingWithDateInExtraData()
 				Assert.AreEqual(checkTime.DateTime, uno.DateTime);
 			}
 		}
+
+		[Test]
+		[Category("Zip")]
+		[Category("Encryption")]
+		public void ReadingEncryptedZipWithDirectories()
+		{
+			var ms = new MemoryStream();
+			using (ZipOutputStream outStream = new ZipOutputStream(ms))
+			{
+				outStream.IsStreamOwner = false;
+				outStream.Password = "testPassword123";
+				outStream.SetLevel(5);
+
+				var entry = new ZipEntry("Folder/");
+				outStream.PutNextEntry(entry);
+
+				entry = new ZipEntry("Folder/File.txt");
+				outStream.PutNextEntry(entry);
+				byte[] fileData = Encoding.UTF8.GetBytes("This is some test data");
+				outStream.Write(fileData, 0, fileData.Length);
+			}
+
+			ms.Seek(0, SeekOrigin.Begin);
+			using (ZipFile zipFile = new ZipFile(ms))
+			{
+				zipFile.BeginUpdate();
+				zipFile.IsStreamOwner = false;
+				zipFile.Password = "testPassword123";
+				zipFile.AddDirectory("Folder2/");
+				zipFile.Add(new MemoryDataSource(Encoding.UTF8.GetBytes("Test content")), "Folder2/File2.txt");
+				zipFile.CommitUpdate();
+			}
+
+			ms.Seek(0, SeekOrigin.Begin);
+			using (var inStream = new ZipInputStream(ms))
+			{
+				inStream.IsStreamOwner = false;
+				inStream.Password = "testPassword123";
+				ZipEntry fileEntry = inStream.GetNextEntry();
+				Assert.AreEqual("Folder/", fileEntry.Name);
+				fileEntry = inStream.GetNextEntry();
+				Assert.AreEqual("Folder/File.txt", fileEntry.Name);
+				fileEntry = inStream.GetNextEntry();
+				Assert.AreEqual("Folder2/", fileEntry.Name);
+				fileEntry = inStream.GetNextEntry();
+				Assert.AreEqual("Folder2/File2.txt", fileEntry.Name);
+			}
+		}
 	}
 }