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PR #475: Fix updating zips with descriptor entries
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- Unit tests for using ZipFile to update file entries that have descriptors
- Fix size calculation in GetDescriptorSize
- Handle optional descriptor signature when updating
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@piksel
piksel committed Nov 21, 2020
1 parent ddc545b commit 933c41c
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Showing 2 changed files with 154 additions and 42 deletions.
113 changes: 71 additions & 42 deletions src/ICSharpCode.SharpZipLib/Zip/ZipFile.cs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1003,16 +1003,19 @@ public bool TestArchive(bool testData, TestStrategy strategy, ZipTestResultHandl
if (this[entryIndex].Crc != data.Crc)
{
status.AddError();
resultHandler?.Invoke(status, "Descriptor CRC mismatch");
}

if (this[entryIndex].CompressedSize != data.CompressedSize)
{
status.AddError();
resultHandler?.Invoke(status, "Descriptor compressed size mismatch");
}

if (this[entryIndex].Size != data.Size)
{
status.AddError();
resultHandler?.Invoke(status, "Descriptor size mismatch");
}
}
}
Expand Down Expand Up @@ -1921,11 +1924,9 @@ public void Modify(ZipEntry original, ZipEntry updated)
if ( original == null ) {
throw new ArgumentNullException("original");
}
if ( updated == null ) {
throw new ArgumentNullException("updated");
}
CheckUpdating();
contentsEdited_ = true;
updates_.Add(new ZipUpdate(original, updated));
Expand Down Expand Up @@ -2386,26 +2387,37 @@ private byte[] GetBuffer()

private void CopyDescriptorBytes(ZipUpdate update, Stream dest, Stream source)
{
int bytesToCopy = GetDescriptorSize(update);
// Don't include the signature size to allow copy without seeking
var bytesToCopy = GetDescriptorSize(update, false);

// Don't touch the source stream if no descriptor is present
if (bytesToCopy == 0) return;

if (bytesToCopy > 0)
var buffer = GetBuffer();

// Copy the first 4 bytes of the descriptor
source.Read(buffer, 0, sizeof(int));
dest.Write(buffer, 0, sizeof(int));

if (BitConverter.ToUInt32(buffer, 0) != ZipConstants.DataDescriptorSignature)
{
byte[] buffer = GetBuffer();
// The initial bytes wasn't the descriptor, reduce the pending byte count
bytesToCopy -= buffer.Length;
}

while (bytesToCopy > 0)
{
int readSize = Math.Min(buffer.Length, bytesToCopy);
while (bytesToCopy > 0)
{
int readSize = Math.Min(buffer.Length, bytesToCopy);

int bytesRead = source.Read(buffer, 0, readSize);
if (bytesRead > 0)
{
dest.Write(buffer, 0, bytesRead);
bytesToCopy -= bytesRead;
}
else
{
throw new ZipException("Unxpected end of stream");
}
int bytesRead = source.Read(buffer, 0, readSize);
if (bytesRead > 0)
{
dest.Write(buffer, 0, bytesRead);
bytesToCopy -= bytesRead;
}
else
{
throw new ZipException("Unxpected end of stream");
}
}
}
Expand Down Expand Up @@ -2464,32 +2476,37 @@ private void CopyBytes(ZipUpdate update, Stream destination, Stream source,
/// Get the size of the source descriptor for a <see cref="ZipUpdate"/>.
/// </summary>
/// <param name="update">The update to get the size for.</param>
/// <returns>The descriptor size, zero if there isnt one.</returns>
private int GetDescriptorSize(ZipUpdate update)
/// <param name="includingSignature">Whether to include the signature size</param>
/// <returns>The descriptor size, zero if there isn't one.</returns>
private int GetDescriptorSize(ZipUpdate update, bool includingSignature)
{
int result = 0;
if ((update.Entry.Flags & (int)GeneralBitFlags.Descriptor) != 0)
{
result = ZipConstants.DataDescriptorSize - 4;
if (update.Entry.LocalHeaderRequiresZip64)
{
result = ZipConstants.Zip64DataDescriptorSize - 4;
}
}
return result;
if (!((GeneralBitFlags)update.Entry.Flags).HasFlag(GeneralBitFlags.Descriptor))
return 0;

var descriptorWithSignature = update.Entry.LocalHeaderRequiresZip64
? ZipConstants.Zip64DataDescriptorSize
: ZipConstants.DataDescriptorSize;

return includingSignature
? descriptorWithSignature
: descriptorWithSignature - sizeof(int);
}

private void CopyDescriptorBytesDirect(ZipUpdate update, Stream stream, ref long destinationPosition, long sourcePosition)
{
int bytesToCopy = GetDescriptorSize(update);
var buffer = GetBuffer(); ;

stream.Position = sourcePosition;
stream.Read(buffer, 0, sizeof(int));
var sourceHasSignature = BitConverter.ToUInt32(buffer, 0) == ZipConstants.DataDescriptorSignature;

var bytesToCopy = GetDescriptorSize(update, sourceHasSignature);

while (bytesToCopy > 0)
{
var readSize = (int)bytesToCopy;
byte[] buffer = GetBuffer();

stream.Position = sourcePosition;
int bytesRead = stream.Read(buffer, 0, readSize);

var bytesRead = stream.Read(buffer, 0, bytesToCopy);
if (bytesRead > 0)
{
stream.Position = destinationPosition;
Expand All @@ -2500,7 +2517,7 @@ private void CopyDescriptorBytesDirect(ZipUpdate update, Stream stream, ref long
}
else
{
throw new ZipException("Unxpected end of stream");
throw new ZipException("Unexpected end of stream");
}
}
}
Expand Down Expand Up @@ -2757,6 +2774,7 @@ 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();

Expand All @@ -2765,14 +2783,25 @@ private void CopyEntryDirect(ZipFile workFile, ZipUpdate update, ref long destin
if (skipOver)
{
if (update.OffsetBasedSize != -1)
{
destinationPosition += update.OffsetBasedSize;
}
else
// TODO: Find out why this calculation comes up 4 bytes short on some entries in ODT (Office Document Text) archives.
// WinZip produces a warning on these entries:
// "caution: value of lrec.csize (compressed size) changed from ..."
destinationPosition +=
(sourcePosition - entryDataOffset) + NameLengthOffset + // Header size
update.Entry.CompressedSize + GetDescriptorSize(update);
{
// Skip entry header
destinationPosition += (sourcePosition - entryDataOffset) + NameLengthOffset;

// Skip entry compressed data
destinationPosition += update.Entry.CompressedSize;

// Seek to end of entry to check for descriptor signature
baseStream_.Seek(destinationPosition, SeekOrigin.Begin);

var descriptorHasSignature = ReadLEUint() == ZipConstants.DataDescriptorSignature;

// Skip descriptor and it's signature (if present)
destinationPosition += GetDescriptorSize(update, descriptorHasSignature);
}
}
else
{
Expand Down
83 changes: 83 additions & 0 deletions test/ICSharpCode.SharpZipLib.Tests/Zip/ZipFileHandling.cs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1755,5 +1755,88 @@ public void ShouldReadAESBZip2ZipCreatedBy7Zip()
}
}
}

/// <summary>
/// Test for https://github.com/icsharpcode/SharpZipLib/issues/147, when deleting items in a zip
/// </summary>
/// <param name="useZip64">Whether Zip64 should be used in the test archive</param>
[TestCase(UseZip64.On)]
[TestCase(UseZip64.Off)]
[Category("Zip")]
public void TestDescriptorUpdateOnDelete(UseZip64 useZip64)
{
MemoryStream msw = new MemoryStreamWithoutSeek();
using (ZipOutputStream outStream = new ZipOutputStream(msw))
{
outStream.UseZip64 = useZip64;
outStream.IsStreamOwner = false;
outStream.PutNextEntry(new ZipEntry("StripedMarlin"));
outStream.WriteByte(89);

outStream.PutNextEntry(new ZipEntry("StripedMarlin2"));
outStream.WriteByte(91);
}

var zipData = msw.ToArray();
Assert.IsTrue(ZipTesting.TestArchive(zipData));

using (var memoryStream = new MemoryStream(zipData))
{
using (var zipFile = new ZipFile(memoryStream, leaveOpen: true))
{
zipFile.BeginUpdate();
zipFile.Delete("StripedMarlin");
zipFile.CommitUpdate();
}

memoryStream.Position = 0;

using (var zipFile = new ZipFile(memoryStream, leaveOpen: true))
{
Assert.That(zipFile.TestArchive(true), Is.True);
}
}
}

/// <summary>
/// Test for https://github.com/icsharpcode/SharpZipLib/issues/147, when adding items to a zip
/// </summary>
/// <param name="useZip64">Whether Zip64 should be used in the test archive</param>
[TestCase(UseZip64.On)]
[TestCase(UseZip64.Off)]
[Category("Zip")]
public void TestDescriptorUpdateOnAdd(UseZip64 useZip64)
{
MemoryStream msw = new MemoryStreamWithoutSeek();
using (ZipOutputStream outStream = new ZipOutputStream(msw))
{
outStream.UseZip64 = useZip64;
outStream.IsStreamOwner = false;
outStream.PutNextEntry(new ZipEntry("StripedMarlin"));
outStream.WriteByte(89);
}

var zipData = msw.ToArray();
Assert.IsTrue(ZipTesting.TestArchive(zipData));

using (var memoryStream = new MemoryStream())
{
memoryStream.Write(zipData, 0, zipData.Length);

using (var zipFile = new ZipFile(memoryStream, leaveOpen: true))
{
zipFile.BeginUpdate();
zipFile.Add(new StringMemoryDataSource("stripey"), "Zebra");
zipFile.CommitUpdate();
}

memoryStream.Position = 0;

using (var zipFile = new ZipFile(memoryStream, leaveOpen: true))
{
Assert.That(zipFile.TestArchive(true), Is.True);
}
}
}
}
}

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