//This function reads all the EOCD stuff it needs to find the offset to the start of the central directory
//This offset gets put in _centralDirectoryStart and the number of this disk gets put in _numberOfThisDisk
//Also does some verification that this isn't a split/spanned archive
//Also checks that offset to CD isn't out of bounds
private void ReadEndOfCentralDirectory()
{
try
{
//this seeks to the start of the end of central directory record
_archiveStream.Seek(-ZipEndOfCentralDirectoryBlock.SizeOfBlockWithoutSignature, SeekOrigin.End);
if (!ZipHelper.SeekBackwardsToSignature(_archiveStream, ZipEndOfCentralDirectoryBlock.SignatureConstant))
{
throw new InvalidDataException(SR.EOCDNotFound);
}
Int64 eocdStart = _archiveStream.Position;
//read the EOCD
ZipEndOfCentralDirectoryBlock eocd;
Boolean eocdProper = ZipEndOfCentralDirectoryBlock.TryReadBlock(_archiveReader, out eocd);
Debug.Assert(eocdProper); //we just found this using the signature finder, so it should be okay
if (eocd.NumberOfThisDisk != eocd.NumberOfTheDiskWithTheStartOfTheCentralDirectory)
{
throw new InvalidDataException(SR.SplitSpanned);
}
_numberOfThisDisk = eocd.NumberOfThisDisk;
_centralDirectoryStart = eocd.OffsetOfStartOfCentralDirectoryWithRespectToTheStartingDiskNumber;
if (eocd.NumberOfEntriesInTheCentralDirectory != eocd.NumberOfEntriesInTheCentralDirectoryOnThisDisk)
{
throw new InvalidDataException(SR.SplitSpanned);
}
_expectedNumberOfEntries = eocd.NumberOfEntriesInTheCentralDirectory;
//only bother saving the comment if we are in update mode
if (_mode == ZipArchiveMode.Update)
{
_archiveComment = eocd.ArchiveComment;
}
//only bother looking for zip64 EOCD stuff if we suspect it is needed because some value is FFFFFFFFF
//because these are the only two values we need, we only worry about these
//if we don't find the zip64 EOCD, we just give up and try to use the original values
if (eocd.NumberOfThisDisk == ZipHelper.Mask16Bit ||
eocd.OffsetOfStartOfCentralDirectoryWithRespectToTheStartingDiskNumber == ZipHelper.Mask32Bit ||
eocd.NumberOfEntriesInTheCentralDirectory == ZipHelper.Mask16Bit)
{
//we need to look for zip 64 EOCD stuff
//seek to the zip 64 EOCD locator
_archiveStream.Seek(eocdStart - Zip64EndOfCentralDirectoryLocator.SizeOfBlockWithoutSignature, SeekOrigin.Begin);
//if we don't find it, assume it doesn't exist and use data from normal eocd
if (ZipHelper.SeekBackwardsToSignature(_archiveStream, Zip64EndOfCentralDirectoryLocator.SignatureConstant))
{
//use locator to get to Zip64EOCD
Zip64EndOfCentralDirectoryLocator locator;
Boolean zip64eocdLocatorProper = Zip64EndOfCentralDirectoryLocator.TryReadBlock(_archiveReader, out locator);
Debug.Assert(zip64eocdLocatorProper); //we just found this using the signature finder, so it should be okay
if (locator.OffsetOfZip64EOCD > (UInt64)Int64.MaxValue)
{
throw new InvalidDataException(SR.FieldTooBigOffsetToZip64EOCD);
}
Int64 zip64EOCDOffset = (Int64)locator.OffsetOfZip64EOCD;
_archiveStream.Seek(zip64EOCDOffset, SeekOrigin.Begin);
//read Zip64EOCD
Zip64EndOfCentralDirectoryRecord record;
if (!Zip64EndOfCentralDirectoryRecord.TryReadBlock(_archiveReader, out record))
{
throw new InvalidDataException(SR.Zip64EOCDNotWhereExpected);
}
_numberOfThisDisk = record.NumberOfThisDisk;
if (record.NumberOfEntriesTotal > (UInt64)Int64.MaxValue)
{
throw new InvalidDataException(SR.FieldTooBigNumEntries);
}
if (record.OffsetOfCentralDirectory > (UInt64)Int64.MaxValue)
{
throw new InvalidDataException(SR.FieldTooBigOffsetToCD);
}
if (record.NumberOfEntriesTotal != record.NumberOfEntriesOnThisDisk)
{
throw new InvalidDataException(SR.SplitSpanned);
}
_expectedNumberOfEntries = (Int64)record.NumberOfEntriesTotal;
_centralDirectoryStart = (Int64)record.OffsetOfCentralDirectory;
}
}
if (_centralDirectoryStart > _archiveStream.Length)
{
throw new InvalidDataException(SR.FieldTooBigOffsetToCD);
}
}
catch (EndOfStreamException ex)
{
throw new InvalidDataException(SR.CDCorrupt, ex);
}
catch (IOException ex)
{
throw new InvalidDataException(SR.CDCorrupt, ex);
}
}
// Tries to find the Zip64 End of Central Directory Locator, then the Zip64 End of Central Directory, assuming the
// End of Central Directory block has already been found, as well as the location in the stream where the EOCD starts.
private void TryReadZip64EndOfCentralDirectory(ZipEndOfCentralDirectoryBlock eocd, long eocdStart)
{
// Only bother looking for the Zip64-EOCD stuff if we suspect it is needed because some value is FFFFFFFFF
// because these are the only two values we need, we only worry about these
// if we don't find the Zip64-EOCD, we just give up and try to use the original values
if (eocd.NumberOfThisDisk == ZipHelper.Mask16Bit ||
eocd.OffsetOfStartOfCentralDirectoryWithRespectToTheStartingDiskNumber == ZipHelper.Mask32Bit ||
eocd.NumberOfEntriesInTheCentralDirectory == ZipHelper.Mask16Bit)
{
// Read Zip64 End of Central Directory Locator
// This seeks forwards almost to the beginning of the Zip64-EOCDL, one byte after where the signature would be located
_archiveStream.Seek(eocdStart - Zip64EndOfCentralDirectoryLocator.SizeOfBlockWithoutSignature, SeekOrigin.Begin);
// Exactly the previous 4 bytes should contain the Zip64-EOCDL signature
// if we don't find it, assume it doesn't exist and use data from normal EOCD
if (ZipHelper.SeekBackwardsToSignature(_archiveStream,
Zip64EndOfCentralDirectoryLocator.SignatureConstant,
Zip64EndOfCentralDirectoryLocator.SignatureSize))
{
Debug.Assert(_archiveReader != null);
// use locator to get to Zip64-EOCD
Zip64EndOfCentralDirectoryLocator locator;
bool zip64eocdLocatorProper = Zip64EndOfCentralDirectoryLocator.TryReadBlock(_archiveReader, out locator);
Debug.Assert(zip64eocdLocatorProper); // we just found this using the signature finder, so it should be okay
if (locator.OffsetOfZip64EOCD > long.MaxValue)
{
throw new InvalidDataException(SR.FieldTooBigOffsetToZip64EOCD);
}
long zip64EOCDOffset = (long)locator.OffsetOfZip64EOCD;
_archiveStream.Seek(zip64EOCDOffset, SeekOrigin.Begin);
// Read Zip64 End of Central Directory Record
Zip64EndOfCentralDirectoryRecord record;
if (!Zip64EndOfCentralDirectoryRecord.TryReadBlock(_archiveReader, out record))
{
throw new InvalidDataException(SR.Zip64EOCDNotWhereExpected);
}
_numberOfThisDisk = record.NumberOfThisDisk;
if (record.NumberOfEntriesTotal > long.MaxValue)
{
throw new InvalidDataException(SR.FieldTooBigNumEntries);
}
if (record.OffsetOfCentralDirectory > long.MaxValue)
{
throw new InvalidDataException(SR.FieldTooBigOffsetToCD);
}
if (record.NumberOfEntriesTotal != record.NumberOfEntriesOnThisDisk)
{
throw new InvalidDataException(SR.SplitSpanned);
}
_expectedNumberOfEntries = (long)record.NumberOfEntriesTotal;
_centralDirectoryStart = (long)record.OffsetOfCentralDirectory;
}
}
}
// This function reads all the EOCD stuff it needs to find the offset to the start of the central directory
// This offset gets put in _centralDirectoryStart and the number of this disk gets put in _numberOfThisDisk
// Also does some verification that this isn't a split/spanned archive
// Also checks that offset to CD isn't out of bounds
private void ReadEndOfCentralDirectory()
{
try
{
// This seeks backwards almost to the beginning of the EOCD, one byte after where the signature would be
// located if the EOCD had the minimum possible size (no file zip comment)
_archiveStream.Seek(-ZipEndOfCentralDirectoryBlock.SizeOfBlockWithoutSignature, SeekOrigin.End);
// If the EOCD has the minimum possible size (no zip file comment), then exactly the previous 4 bytes will contain the signature
// But if the EOCD has max possible size, the signature should be found somewhere in the previous 64K + 4 bytes
if (!ZipHelper.SeekBackwardsToSignature(_archiveStream,
ZipEndOfCentralDirectoryBlock.SignatureConstant,
ZipEndOfCentralDirectoryBlock.ZipFileCommentMaxLength + ZipEndOfCentralDirectoryBlock.SignatureSize))
{
throw new InvalidDataException(SR.EOCDNotFound);
}
long eocdStart = _archiveStream.Position;
// read the EOCD
ZipEndOfCentralDirectoryBlock eocd;
bool eocdProper = ZipEndOfCentralDirectoryBlock.TryReadBlock(_archiveReader, out eocd);
Debug.Assert(eocdProper); // we just found this using the signature finder, so it should be okay
if (eocd.NumberOfThisDisk != eocd.NumberOfTheDiskWithTheStartOfTheCentralDirectory)
{
throw new InvalidDataException(SR.SplitSpanned);
}
_numberOfThisDisk = eocd.NumberOfThisDisk;
_centralDirectoryStart = eocd.OffsetOfStartOfCentralDirectoryWithRespectToTheStartingDiskNumber;
if (eocd.NumberOfEntriesInTheCentralDirectory != eocd.NumberOfEntriesInTheCentralDirectoryOnThisDisk)
{
throw new InvalidDataException(SR.SplitSpanned);
}
_expectedNumberOfEntries = eocd.NumberOfEntriesInTheCentralDirectory;
// only bother saving the comment if we are in update mode
if (_mode == ZipArchiveMode.Update)
{
_archiveComment = eocd.ArchiveComment;
}
TryReadZip64EndOfCentralDirectory(eocd, eocdStart);
if (_centralDirectoryStart > _archiveStream.Length)
{
throw new InvalidDataException(SR.FieldTooBigOffsetToCD);
}
}
catch (EndOfStreamException ex)
{
throw new InvalidDataException(SR.CDCorrupt, ex);
}
catch (IOException ex)
{
throw new InvalidDataException(SR.CDCorrupt, ex);
}
}
// return value is true if we allocated an extra field for 64 bit headers, un/compressed size
private bool WriteLocalFileHeader(bool isEmptyFile)
{
BinaryWriter writer = new BinaryWriter(_archive.ArchiveStream);
// _entryname only gets set when we read in or call moveTo. MoveTo does a check, and
// reading in should not be able to produce an entryname longer than ushort.MaxValue
Debug.Assert(_storedEntryNameBytes.Length <= ushort.MaxValue);
// decide if we need the Zip64 extra field:
Zip64ExtraField zip64ExtraField = new Zip64ExtraField();
bool zip64Used = false;
uint compressedSizeTruncated, uncompressedSizeTruncated;
// if we already know that we have an empty file don't worry about anything, just do a straight shot of the header
if (isEmptyFile)
{
CompressionMethod = CompressionMethodValues.Stored;
compressedSizeTruncated = 0;
uncompressedSizeTruncated = 0;
Debug.Assert(_compressedSize == 0);
Debug.Assert(_uncompressedSize == 0);
Debug.Assert(_crc32 == 0);
}
else
{
// if we have a non-seekable stream, don't worry about sizes at all, and just set the right bit
// if we are using the data descriptor, then sizes and crc should be set to 0 in the header
if (_archive.Mode == ZipArchiveMode.Create && _archive.ArchiveStream.CanSeek == false && !isEmptyFile)
{
_generalPurposeBitFlag |= BitFlagValues.DataDescriptor;
zip64Used = false;
compressedSizeTruncated = 0;
uncompressedSizeTruncated = 0;
// the crc should not have been set if we are in create mode, but clear it just to be sure
Debug.Assert(_crc32 == 0);
}
else // if we are not in streaming mode, we have to decide if we want to write zip64 headers
{
if (SizesTooLarge()
#if DEBUG_FORCE_ZIP64
|| (_archive._forceZip64 && _archive.Mode == ZipArchiveMode.Update)
#endif
)
{
zip64Used = true;
compressedSizeTruncated = ZipHelper.Mask32Bit;
uncompressedSizeTruncated = ZipHelper.Mask32Bit;
// prepare Zip64 extra field object. If we have one of the sizes, the other must go in there
zip64ExtraField.CompressedSize = _compressedSize;
zip64ExtraField.UncompressedSize = _uncompressedSize;
VersionToExtractAtLeast(ZipVersionNeededValues.Zip64);
}
else
{
zip64Used = false;
compressedSizeTruncated = (uint)_compressedSize;
uncompressedSizeTruncated = (uint)_uncompressedSize;
}
}
}
// save offset
_offsetOfLocalHeader = writer.BaseStream.Position;
// calculate extra field. if zip64 stuff + original extraField aren't going to fit, dump the original extraField, because this is more important
int bigExtraFieldLength = (zip64Used ? zip64ExtraField.TotalSize : 0)
+ (_lhUnknownExtraFields != null ? ZipGenericExtraField.TotalSize(_lhUnknownExtraFields) : 0);
ushort extraFieldLength;
if (bigExtraFieldLength > ushort.MaxValue)
{
extraFieldLength = (ushort)(zip64Used ? zip64ExtraField.TotalSize : 0);
_lhUnknownExtraFields = null;
}
else
{
extraFieldLength = (ushort)bigExtraFieldLength;
}
// write header
writer.Write(ZipLocalFileHeader.SignatureConstant);
writer.Write((ushort)_versionToExtract);
writer.Write((ushort)_generalPurposeBitFlag);
writer.Write((ushort)CompressionMethod);
writer.Write(ZipHelper.DateTimeToDosTime(_lastModified.DateTime)); // uint
writer.Write(_crc32); // uint
writer.Write(compressedSizeTruncated); // uint
writer.Write(uncompressedSizeTruncated); // uint
writer.Write((ushort)_storedEntryNameBytes.Length);
writer.Write(extraFieldLength); // ushort
writer.Write(_storedEntryNameBytes);
if (zip64Used)
{
zip64ExtraField.WriteBlock(_archive.ArchiveStream);
}
if (_lhUnknownExtraFields != null)
{
ZipGenericExtraField.WriteAllBlocks(_lhUnknownExtraFields, _archive.ArchiveStream);
}
return(zip64Used);
}
// should only throw an exception in extremely exceptional cases because it is called from dispose
internal void WriteCentralDirectoryFileHeader()
{
// This part is simple, because we should definitely know the sizes by this time
BinaryWriter writer = new BinaryWriter(_archive.ArchiveStream);
// _entryname only gets set when we read in or call moveTo. MoveTo does a check, and
// reading in should not be able to produce an entryname longer than ushort.MaxValue
Debug.Assert(_storedEntryNameBytes.Length <= ushort.MaxValue);
// decide if we need the Zip64 extra field:
Zip64ExtraField zip64ExtraField = new Zip64ExtraField();
uint compressedSizeTruncated, uncompressedSizeTruncated, offsetOfLocalHeaderTruncated;
bool zip64Needed = false;
if (SizesTooLarge()
#if DEBUG_FORCE_ZIP64
|| _archive._forceZip64
#endif
)
{
zip64Needed = true;
compressedSizeTruncated = ZipHelper.Mask32Bit;
uncompressedSizeTruncated = ZipHelper.Mask32Bit;
// If we have one of the sizes, the other must go in there as speced for LH, but not necessarily for CH, but we do it anyways
zip64ExtraField.CompressedSize = _compressedSize;
zip64ExtraField.UncompressedSize = _uncompressedSize;
}
else
{
compressedSizeTruncated = (uint)_compressedSize;
uncompressedSizeTruncated = (uint)_uncompressedSize;
}
if (_offsetOfLocalHeader > uint.MaxValue
#if DEBUG_FORCE_ZIP64
|| _archive._forceZip64
#endif
)
{
zip64Needed = true;
offsetOfLocalHeaderTruncated = ZipHelper.Mask32Bit;
// If we have one of the sizes, the other must go in there as speced for LH, but not necessarily for CH, but we do it anyways
zip64ExtraField.LocalHeaderOffset = _offsetOfLocalHeader;
}
else
{
offsetOfLocalHeaderTruncated = (uint)_offsetOfLocalHeader;
}
if (zip64Needed)
{
VersionToExtractAtLeast(ZipVersionNeededValues.Zip64);
}
// determine if we can fit zip64 extra field and original extra fields all in
int bigExtraFieldLength = (zip64Needed ? zip64ExtraField.TotalSize : 0)
+ (_cdUnknownExtraFields != null ? ZipGenericExtraField.TotalSize(_cdUnknownExtraFields) : 0);
ushort extraFieldLength;
if (bigExtraFieldLength > ushort.MaxValue)
{
extraFieldLength = (ushort)(zip64Needed ? zip64ExtraField.TotalSize : 0);
_cdUnknownExtraFields = null;
}
else
{
extraFieldLength = (ushort)bigExtraFieldLength;
}
writer.Write(ZipCentralDirectoryFileHeader.SignatureConstant); // Central directory file header signature (4 bytes)
writer.Write((byte)_versionMadeBySpecification); // Version made by Specification (version) (1 byte)
writer.Write((byte)CurrentZipPlatform); // Version made by Compatibility (type) (1 byte)
writer.Write((ushort)_versionToExtract); // Minimum version needed to extract (2 bytes)
writer.Write((ushort)_generalPurposeBitFlag); // General Purpose bit flag (2 bytes)
writer.Write((ushort)CompressionMethod); // The Compression method (2 bytes)
writer.Write(ZipHelper.DateTimeToDosTime(_lastModified.DateTime)); // File last modification time and date (4 bytes)
writer.Write(_crc32); // CRC-32 (4 bytes)
writer.Write(compressedSizeTruncated); // Compressed Size (4 bytes)
writer.Write(uncompressedSizeTruncated); // Uncompressed Size (4 bytes)
writer.Write((ushort)_storedEntryNameBytes.Length); // File Name Length (2 bytes)
writer.Write(extraFieldLength); // Extra Field Length (2 bytes)
// This should hold because of how we read it originally in ZipCentralDirectoryFileHeader:
Debug.Assert((_fileComment == null) || (_fileComment.Length <= ushort.MaxValue));
writer.Write(_fileComment != null ? (ushort)_fileComment.Length : (ushort)0); // file comment length
writer.Write((ushort)0); // disk number start
writer.Write((ushort)0); // internal file attributes
writer.Write(_externalFileAttr); // external file attributes
writer.Write(offsetOfLocalHeaderTruncated); // offset of local header
writer.Write(_storedEntryNameBytes);
// write extra fields
if (zip64Needed)
{
zip64ExtraField.WriteBlock(_archive.ArchiveStream);
}
if (_cdUnknownExtraFields != null)
{
ZipGenericExtraField.WriteAllBlocks(_cdUnknownExtraFields, _archive.ArchiveStream);
}
if (_fileComment != null)
{
writer.Write(_fileComment);
}
}
private void ReadEndOfCentralDirectory()
{
ZipEndOfCentralDirectoryBlock zipEndOfCentralDirectoryBlock;
Zip64EndOfCentralDirectoryLocator zip64EndOfCentralDirectoryLocator;
Zip64EndOfCentralDirectoryRecord zip64EndOfCentralDirectoryRecord;
try
{
this._archiveStream.Seek((long)-18, SeekOrigin.End);
if (!ZipHelper.SeekBackwardsToSignature(this._archiveStream, 101010256))
{
throw new InvalidDataException(Messages.EOCDNotFound);
}
long position = this._archiveStream.Position;
ZipEndOfCentralDirectoryBlock.TryReadBlock(this._archiveReader, out zipEndOfCentralDirectoryBlock);
if (zipEndOfCentralDirectoryBlock.NumberOfThisDisk != zipEndOfCentralDirectoryBlock.NumberOfTheDiskWithTheStartOfTheCentralDirectory)
{
throw new InvalidDataException(Messages.SplitSpanned);
}
this._numberOfThisDisk = zipEndOfCentralDirectoryBlock.NumberOfThisDisk;
this._centralDirectoryStart = (long)zipEndOfCentralDirectoryBlock.OffsetOfStartOfCentralDirectoryWithRespectToTheStartingDiskNumber;
if (zipEndOfCentralDirectoryBlock.NumberOfEntriesInTheCentralDirectory != zipEndOfCentralDirectoryBlock.NumberOfEntriesInTheCentralDirectoryOnThisDisk)
{
throw new InvalidDataException(Messages.SplitSpanned);
}
this._expectedNumberOfEntries = (long)zipEndOfCentralDirectoryBlock.NumberOfEntriesInTheCentralDirectory;
if (this._mode == ZipArchiveMode.Update)
{
this._archiveComment = zipEndOfCentralDirectoryBlock.ArchiveComment;
}
if (zipEndOfCentralDirectoryBlock.NumberOfThisDisk == 65535 || zipEndOfCentralDirectoryBlock.OffsetOfStartOfCentralDirectoryWithRespectToTheStartingDiskNumber == -1 || zipEndOfCentralDirectoryBlock.NumberOfEntriesInTheCentralDirectory == 65535)
{
this._archiveStream.Seek(position - (long)16, SeekOrigin.Begin);
if (ZipHelper.SeekBackwardsToSignature(this._archiveStream, 117853008))
{
Zip64EndOfCentralDirectoryLocator.TryReadBlock(this._archiveReader, out zip64EndOfCentralDirectoryLocator);
if (zip64EndOfCentralDirectoryLocator.OffsetOfZip64EOCD > 9223372036854775807L)
{
throw new InvalidDataException(Messages.FieldTooBigOffsetToZip64EOCD);
}
long offsetOfZip64EOCD = (long)zip64EndOfCentralDirectoryLocator.OffsetOfZip64EOCD;
this._archiveStream.Seek(offsetOfZip64EOCD, SeekOrigin.Begin);
if (!Zip64EndOfCentralDirectoryRecord.TryReadBlock(this._archiveReader, out zip64EndOfCentralDirectoryRecord))
{
throw new InvalidDataException(Messages.Zip64EOCDNotWhereExpected);
}
this._numberOfThisDisk = zip64EndOfCentralDirectoryRecord.NumberOfThisDisk;
if (zip64EndOfCentralDirectoryRecord.NumberOfEntriesTotal > 9223372036854775807L)
{
throw new InvalidDataException(Messages.FieldTooBigNumEntries);
}
if (zip64EndOfCentralDirectoryRecord.OffsetOfCentralDirectory > 9223372036854775807L)
{
throw new InvalidDataException(Messages.FieldTooBigOffsetToCD);
}
if (zip64EndOfCentralDirectoryRecord.NumberOfEntriesTotal != zip64EndOfCentralDirectoryRecord.NumberOfEntriesOnThisDisk)
{
throw new InvalidDataException(Messages.SplitSpanned);
}
this._expectedNumberOfEntries = (long)zip64EndOfCentralDirectoryRecord.NumberOfEntriesTotal;
this._centralDirectoryStart = (long)zip64EndOfCentralDirectoryRecord.OffsetOfCentralDirectory;
}
}
if (this._centralDirectoryStart > this._archiveStream.Length)
{
throw new InvalidDataException(Messages.FieldTooBigOffsetToCD);
}
}
catch (EndOfStreamException endOfStreamException)
{
throw new InvalidDataException(Messages.CDCorrupt, endOfStreamException);
}
catch (IOException oException)
{
throw new InvalidDataException(Messages.CDCorrupt, oException);
}
}
