/// <summary> /// Read the data from the stream into the buffer. /// </summary> /// /// <remarks> /// <para> /// The data for the zipentry will be decrypted and uncompressed, as /// necessary, before being copied into the buffer. /// </para> /// /// <para> /// You must set the <see cref="Password"/> property before calling /// <c>Read()</c> the first time for an encrypted entry. To determine if an /// entry is encrypted and requires a password, check the <see /// cref="ZipEntry.Encryption">ZipEntry.Encryption</see> property. /// </para> /// </remarks> /// /// <param name="buffer">The buffer to hold the data read from the stream.</param> /// <param name="offset">the offset within the buffer to copy the first byte read.</param> /// <param name="count">the number of bytes to read.</param> /// <returns>the number of bytes read, after decryption and decompression.</returns> public override int Read(byte[] buffer, int offset, int count) { if (_closed) { _exceptionPending = true; throw new System.InvalidOperationException("The stream has been closed."); } if (_needSetup) { SetupStream(); } if (_LeftToRead == 0) { return(0); } int len = (_LeftToRead > count) ? count : (int)_LeftToRead; int n = _crcStream.Read(buffer, offset, len); _LeftToRead -= n; if (_LeftToRead == 0) { int CrcResult = _crcStream.Crc; _currentEntry.VerifyCrcAfterExtract(CrcResult); _inputStream.Seek(_endOfEntry, SeekOrigin.Begin); // workitem 10178 SharedUtilities.Workaround_Ladybug318918(_inputStream); } return(n); }
/// <summary> /// Read the next entry from the zip file. /// </summary> /// /// <remarks> /// <para> /// Call this method just before calling <see cref="Read(byte[], int, int)"/>, /// to position the pointer in the zip file to the next entry that can be /// read. Subsequent calls to <c>Read()</c>, will decrypt and decompress the /// data in the zip file, until <c>Read()</c> returns 0. /// </para> /// /// <para> /// Each time you call <c>GetNextEntry()</c>, the pointer in the wrapped /// stream is moved to the next entry in the zip file. If you call <see /// cref="Seek(long, SeekOrigin)"/>, and thus re-position the pointer within /// the file, you will need to call <c>GetNextEntry()</c> again, to insure /// that the file pointer is positioned at the beginning of a zip entry. /// </para> /// /// <para> /// This method returns the <c>ZipEntry</c>. Using a stream approach, you will /// read the raw bytes for an entry in a zip file via calls to <c>Read()</c>. /// Alternatively, you can extract an entry into a file, or a stream, by /// calling <see cref="ZipEntry.Extract()"/>, or one of its siblings. /// </para> /// /// </remarks> /// /// <returns> /// The <c>ZipEntry</c> read. Returns null (or Nothing in VB) if there are no more /// entries in the zip file. /// </returns> /// public ZipEntry GetNextEntry() { if (_findRequired) { // find the next signature long d = SharedUtilities.FindSignature(_inputStream, ZipConstants.ZipEntrySignature); if (d == -1) { return(null); } // back up 4 bytes: ReadEntry assumes the file pointer is positioned before the entry signature _inputStream.Seek(-4, SeekOrigin.Current); // workitem 10178 SharedUtilities.Workaround_Ladybug318918(_inputStream); } // workitem 10923 else if (_firstEntry) { // we've already read one entry. // Seek to the end of it. _inputStream.Seek(_endOfEntry, SeekOrigin.Begin); SharedUtilities.Workaround_Ladybug318918(_inputStream); } _currentEntry = ZipEntry.ReadEntry(_container, !_firstEntry); // ReadEntry leaves the file position after all the entry // data and the optional bit-3 data descriptpr. This is // where the next entry would normally start. _endOfEntry = _inputStream.Position; _firstEntry = true; _needSetup = true; _findRequired = false; return(_currentEntry); }
private void ReadExtraField() { _readExtraDepth++; // workitem 8098: ok (restore) long posn = this.ArchiveStream.Position; this.ArchiveStream.Seek(this._RelativeOffsetOfLocalHeader, SeekOrigin.Begin); // workitem 10178 SharedUtilities.Workaround_Ladybug318918(this.ArchiveStream); byte[] block = new byte[30]; this.ArchiveStream.Read(block, 0, block.Length); int i = 26; Int16 filenameLength = (short)(block[i++] + block[i++] * 256); Int16 extraFieldLength = (short)(block[i++] + block[i++] * 256); // workitem 8098: ok (relative) this.ArchiveStream.Seek(filenameLength, SeekOrigin.Current); // workitem 10178 SharedUtilities.Workaround_Ladybug318918(this.ArchiveStream); ProcessExtraField(this.ArchiveStream, extraFieldLength); // workitem 8098: ok (restore) this.ArchiveStream.Seek(posn, SeekOrigin.Begin); // workitem 10178 SharedUtilities.Workaround_Ladybug318918(this.ArchiveStream); _readExtraDepth--; }
public override long Seek(long offset, System.IO.SeekOrigin origin) { var x = _innerStream.Seek(offset, origin); // workitem 10178 SharedUtilities.Workaround_Ladybug318918(_innerStream); return(x); }
/// <summary> /// This method seeks in the underlying stream. /// </summary> /// /// <remarks> /// <para> /// Call this method if you want to seek around within the zip file for random access. /// </para> /// /// <para> /// Applications can intermix calls to <c>Seek()</c> with calls to <see /// cref="GetNextEntry()"/>. After a call to <c>Seek()</c>, /// <c>GetNextEntry()</c> will get the next <c>ZipEntry</c> that falls after /// the current position in the input stream. You're on your own for finding /// out just where to seek in the stream, to get to the various entries. /// </para> /// /// </remarks> /// /// <param name="offset">the offset point to seek to</param> /// <param name="origin">the reference point from which to seek</param> /// <returns>The new position</returns> public override long Seek(long offset, SeekOrigin origin) { _findRequired = true; var x = _inputStream.Seek(offset, origin); // workitem 10178 SharedUtilities.Workaround_Ladybug318918(_inputStream); return(x); }
/// <summary> /// Reads one <c>ZipEntry</c> from the given stream. The content for /// the entry does not get decompressed or decrypted. This method /// basically reads metadata, and seeks. /// </summary> /// <param name="zc">the ZipContainer this entry belongs to.</param> /// <param name="first"> /// true of this is the first entry being read from the stream. /// </param> /// <returns>the <c>ZipEntry</c> read from the stream.</returns> internal static ZipEntry ReadEntry(ZipContainer zc, bool first) { ZipFile zf = zc.ZipFile; Stream s = zc.ReadStream; System.Text.Encoding defaultEncoding = zc.AlternateEncoding; ZipEntry entry = new ZipEntry(); entry._Source = ZipEntrySource.ZipFile; entry._container = zc; entry._archiveStream = s; if (zf != null) { zf.OnReadEntry(true, null); } if (first) { HandlePK00Prefix(s); } // Read entry header, including any encryption header if (!ReadHeader(entry, defaultEncoding)) { return(null); } // Store the position in the stream for this entry // change for workitem 8098 entry.__FileDataPosition = entry.ArchiveStream.Position; // seek past the data without reading it. We will read on Extract() s.Seek(entry._CompressedFileDataSize + entry._LengthOfTrailer, SeekOrigin.Current); // workitem 10178 SharedUtilities.Workaround_Ladybug318918(s); // ReadHeader moves the file pointer to the end of the entry header, // as well as any encryption header. // CompressedFileDataSize includes: // the maybe compressed, maybe encrypted file data // the encryption trailer, if any // the bit 3 descriptor, if any // workitem 5306 // http://www.codeplex.com/DotNetZip/WorkItem/View.aspx?WorkItemId=5306 HandleUnexpectedDataDescriptor(entry); if (zf != null) { zf.OnReadBytes(entry); zf.OnReadEntry(false, entry); } return(entry); }
internal static void HandlePK00Prefix(Stream s) { // in some cases, the zip file begins with "PK00". This is a throwback and is rare, // but we handle it anyway. We do not change behavior based on it. uint datum = (uint)SharedUtilities.ReadInt(s); if (datum != ZipConstants.PackedToRemovableMedia) { s.Seek(-4, SeekOrigin.Current); // unread the block // workitem 10178 SharedUtilities.Workaround_Ladybug318918(s); } }
private static void HandleUnexpectedDataDescriptor(ZipEntry entry) { Stream s = entry.ArchiveStream; // In some cases, the "data descriptor" is present, without a signature, even when // bit 3 of the BitField is NOT SET. This is the CRC, followed // by the compressed length and the uncompressed length (4 bytes for each // of those three elements). Need to check that here. // uint datum = (uint)SharedUtilities.ReadInt(s); if (datum == entry._Crc32) { int sz = SharedUtilities.ReadInt(s); if (sz == entry._CompressedSize) { sz = SharedUtilities.ReadInt(s); if (sz == entry._UncompressedSize) { // ignore everything and discard it. } else { s.Seek(-12, SeekOrigin.Current); // unread the three blocks // workitem 10178 SharedUtilities.Workaround_Ladybug318918(s); } } else { s.Seek(-8, SeekOrigin.Current); // unread the two blocks // workitem 10178 SharedUtilities.Workaround_Ladybug318918(s); } } else { s.Seek(-4, SeekOrigin.Current); // unread the block // workitem 10178 SharedUtilities.Workaround_Ladybug318918(s); } }
/// <summary> /// Reads one entry from the zip directory structure in the zip file. /// </summary> /// /// <param name="zf"> /// The zipfile for which a directory entry will be read. From this param, the /// method gets the ReadStream and the expected text encoding /// (ProvisionalAlternateEncoding) which is used if the entry is not marked /// UTF-8. /// </param> /// /// <param name="previouslySeen"> /// a list of previously seen entry names; used to prevent duplicates. /// </param> /// /// <returns>the entry read from the archive.</returns> internal static ZipEntry ReadDirEntry(ZipFile zf, Dictionary <String, Object> previouslySeen) { System.IO.Stream s = zf.ReadStream; System.Text.Encoding expectedEncoding = (zf.AlternateEncodingUsage == ZipOption.Always) ? zf.AlternateEncoding : ZipFile.DefaultEncoding; int signature = SharedUtilities.ReadSignature(s); // return null if this is not a local file header signature if (IsNotValidZipDirEntrySig(signature)) { s.Seek(-4, System.IO.SeekOrigin.Current); // workitem 10178 SharedUtilities.Workaround_Ladybug318918(s); // Getting "not a ZipDirEntry signature" here is not always wrong or an // error. This can happen when walking through a zipfile. After the // last ZipDirEntry, we expect to read an // EndOfCentralDirectorySignature. When we get this is how we know // we've reached the end of the central directory. if (signature != ZipConstants.EndOfCentralDirectorySignature && signature != ZipConstants.Zip64EndOfCentralDirectoryRecordSignature && signature != ZipConstants.ZipEntrySignature // workitem 8299 ) { throw new BadReadException(String.Format(" Bad signature (0x{0:X8}) at position 0x{1:X8}", signature, s.Position)); } return(null); } int bytesRead = 42 + 4; byte[] block = new byte[42]; int n = s.Read(block, 0, block.Length); if (n != block.Length) { return(null); } int i = 0; ZipEntry zde = new ZipEntry(); zde.AlternateEncoding = expectedEncoding; zde._Source = ZipEntrySource.ZipFile; zde._container = new ZipContainer(zf); unchecked { zde._VersionMadeBy = (short)(block[i++] + block[i++] * 256); zde._VersionNeeded = (short)(block[i++] + block[i++] * 256); zde._BitField = (short)(block[i++] + block[i++] * 256); zde._CompressionMethod = (Int16)(block[i++] + block[i++] * 256); zde._TimeBlob = block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256; zde._LastModified = SharedUtilities.PackedToDateTime(zde._TimeBlob); zde._timestamp |= ZipEntryTimestamp.DOS; zde._Crc32 = block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256; zde._CompressedSize = (uint)(block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256); zde._UncompressedSize = (uint)(block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256); } // preserve zde._CompressionMethod_FromZipFile = zde._CompressionMethod; zde._filenameLength = (short)(block[i++] + block[i++] * 256); zde._extraFieldLength = (short)(block[i++] + block[i++] * 256); zde._commentLength = (short)(block[i++] + block[i++] * 256); zde._diskNumber = (UInt32)(block[i++] + block[i++] * 256); zde._InternalFileAttrs = (short)(block[i++] + block[i++] * 256); zde._ExternalFileAttrs = block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256; zde._RelativeOffsetOfLocalHeader = (uint)(block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256); // workitem 7801 zde.IsText = ((zde._InternalFileAttrs & 0x01) == 0x01); block = new byte[zde._filenameLength]; n = s.Read(block, 0, block.Length); bytesRead += n; if ((zde._BitField & 0x0800) == 0x0800) { // UTF-8 is in use zde._FileNameInArchive = SharedUtilities.Utf8StringFromBuffer(block); } else { zde._FileNameInArchive = SharedUtilities.StringFromBuffer(block, expectedEncoding); } // workitem 10330 // insure unique entry names while (previouslySeen.ContainsKey(zde._FileNameInArchive)) { zde._FileNameInArchive = CopyHelper.AppendCopyToFileName(zde._FileNameInArchive); zde._metadataChanged = true; } if (zde.AttributesIndicateDirectory) { zde.MarkAsDirectory(); // may append a slash to filename if nec. } // workitem 6898 else if (zde._FileNameInArchive.EndsWith("/")) { zde.MarkAsDirectory(); } zde._CompressedFileDataSize = zde._CompressedSize; if ((zde._BitField & 0x01) == 0x01) { // this may change after processing the Extra field zde._Encryption_FromZipFile = zde._Encryption = EncryptionAlgorithm.PkzipWeak; zde._sourceIsEncrypted = true; } if (zde._extraFieldLength > 0) { zde._InputUsesZip64 = (zde._CompressedSize == 0xFFFFFFFF || zde._UncompressedSize == 0xFFFFFFFF || zde._RelativeOffsetOfLocalHeader == 0xFFFFFFFF); // Console.WriteLine(" Input uses Z64?: {0}", zde._InputUsesZip64); bytesRead += zde.ProcessExtraField(s, zde._extraFieldLength); zde._CompressedFileDataSize = zde._CompressedSize; } // we've processed the extra field, so we know the encryption method is set now. if (zde._Encryption == EncryptionAlgorithm.PkzipWeak) { // the "encryption header" of 12 bytes precedes the file data zde._CompressedFileDataSize -= 12; } #if AESCRYPTO else if (zde.Encryption == EncryptionAlgorithm.WinZipAes128 || zde.Encryption == EncryptionAlgorithm.WinZipAes256) { zde._CompressedFileDataSize = zde.CompressedSize - (ZipEntry.GetLengthOfCryptoHeaderBytes(zde.Encryption) + 10); zde._LengthOfTrailer = 10; } #endif // tally the trailing descriptor if ((zde._BitField & 0x0008) == 0x0008) { // sig, CRC, Comp and Uncomp sizes if (zde._InputUsesZip64) { zde._LengthOfTrailer += 24; } else { zde._LengthOfTrailer += 16; } } // workitem 12744 zde.AlternateEncoding = ((zde._BitField & 0x0800) == 0x0800) ? System.Text.Encoding.UTF8 :expectedEncoding; zde.AlternateEncodingUsage = ZipOption.Always; if (zde._commentLength > 0) { block = new byte[zde._commentLength]; n = s.Read(block, 0, block.Length); bytesRead += n; if ((zde._BitField & 0x0800) == 0x0800) { // UTF-8 is in use zde._Comment = SharedUtilities.Utf8StringFromBuffer(block); } else { zde._Comment = SharedUtilities.StringFromBuffer(block, expectedEncoding); } } //zde._LengthOfDirEntry = bytesRead; return(zde); }
private static bool ReadHeader(ZipEntry ze, System.Text.Encoding defaultEncoding) { int bytesRead = 0; // change for workitem 8098 ze._RelativeOffsetOfLocalHeader = ze.ArchiveStream.Position; int signature = SharedUtilities.ReadEntrySignature(ze.ArchiveStream); bytesRead += 4; // Return false if this is not a local file header signature. if (ZipEntry.IsNotValidSig(signature)) { // Getting "not a ZipEntry signature" is not always wrong or an error. // This will happen after the last entry in a zipfile. In that case, we // expect to read : // a ZipDirEntry signature (if a non-empty zip file) or // a ZipConstants.EndOfCentralDirectorySignature. // // Anything else is a surprise. ze.ArchiveStream.Seek(-4, SeekOrigin.Current); // unread the signature // workitem 10178 SharedUtilities.Workaround_Ladybug318918(ze.ArchiveStream); if (ZipEntry.IsNotValidZipDirEntrySig(signature) && (signature != ZipConstants.EndOfCentralDirectorySignature)) { throw new BadReadException(String.Format(" Bad signature (0x{0:X8}) at position 0x{1:X8}", signature, ze.ArchiveStream.Position)); } return(false); } byte[] block = new byte[26]; int n = ze.ArchiveStream.Read(block, 0, block.Length); if (n != block.Length) { return(false); } bytesRead += n; int i = 0; ze._VersionNeeded = (Int16)(block[i++] + block[i++] * 256); ze._BitField = (Int16)(block[i++] + block[i++] * 256); ze._CompressionMethod_FromZipFile = ze._CompressionMethod = (Int16)(block[i++] + block[i++] * 256); ze._TimeBlob = block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256; // transform the time data into something usable (a DateTime) ze._LastModified = SharedUtilities.PackedToDateTime(ze._TimeBlob); ze._timestamp |= ZipEntryTimestamp.DOS; if ((ze._BitField & 0x01) == 0x01) { ze._Encryption_FromZipFile = ze._Encryption = EncryptionAlgorithm.PkzipWeak; // this *may* change after processing the Extra field ze._sourceIsEncrypted = true; } // NB: if ((ze._BitField & 0x0008) != 0x0008), then the Compressed, uncompressed and // CRC values are not true values; the true values will follow the entry data. // But, regardless of the status of bit 3 in the bitfield, the slots for // the three amigos may contain marker values for ZIP64. So we must read them. { ze._Crc32 = (Int32)(block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256); ze._CompressedSize = (uint)(block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256); ze._UncompressedSize = (uint)(block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256); if ((uint)ze._CompressedSize == 0xFFFFFFFF || (uint)ze._UncompressedSize == 0xFFFFFFFF) { ze._InputUsesZip64 = true; } } Int16 filenameLength = (short)(block[i++] + block[i++] * 256); Int16 extraFieldLength = (short)(block[i++] + block[i++] * 256); block = new byte[filenameLength]; n = ze.ArchiveStream.Read(block, 0, block.Length); bytesRead += n; // if the UTF8 bit is set for this entry, override the // encoding the application requested. if ((ze._BitField & 0x0800) == 0x0800) { // workitem 12744 ze.AlternateEncoding = System.Text.Encoding.UTF8; ze.AlternateEncodingUsage = ZipOption.Always; } // need to use this form of GetString() for .NET CF ze._FileNameInArchive = ze.AlternateEncoding.GetString(block, 0, block.Length); // workitem 6898 if (ze._FileNameInArchive.EndsWith("/")) { ze.MarkAsDirectory(); } bytesRead += ze.ProcessExtraField(ze.ArchiveStream, extraFieldLength); ze._LengthOfTrailer = 0; // workitem 6607 - don't read for directories // actually get the compressed size and CRC if necessary if (!ze._FileNameInArchive.EndsWith("/") && (ze._BitField & 0x0008) == 0x0008) { // This descriptor exists only if bit 3 of the general // purpose bit flag is set (see below). It is byte aligned // and immediately follows the last byte of compressed data, // as well as any encryption trailer, as with AES. // This descriptor is used only when it was not possible to // seek in the output .ZIP file, e.g., when the output .ZIP file // was standard output or a non-seekable device. For ZIP64(tm) format // archives, the compressed and uncompressed sizes are 8 bytes each. // workitem 8098: ok (restore) long posn = ze.ArchiveStream.Position; // Here, we're going to loop until we find a ZipEntryDataDescriptorSignature and // a consistent data record after that. To be consistent, the data record must // indicate the length of the entry data. bool wantMore = true; long SizeOfDataRead = 0; int tries = 0; while (wantMore) { tries++; // We call the FindSignature shared routine to find the specified signature // in the already-opened zip archive, starting from the current cursor // position in that filestream. If we cannot find the signature, then the // routine returns -1, and the ReadHeader() method returns false, // indicating we cannot read a legal entry header. If we have found it, // then the FindSignature() method returns the number of bytes in the // stream we had to seek forward, to find the sig. We need this to // determine if the zip entry is valid, later. if (ze._container.ZipFile != null) { ze._container.ZipFile.OnReadBytes(ze); } long d = SharedUtilities.FindSignature(ze.ArchiveStream, ZipConstants.ZipEntryDataDescriptorSignature); if (d == -1) { return(false); } // total size of data read (through all loops of this). SizeOfDataRead += d; if (ze._InputUsesZip64) { // read 1x 4-byte (CRC) and 2x 8-bytes (Compressed Size, Uncompressed Size) block = new byte[20]; n = ze.ArchiveStream.Read(block, 0, block.Length); if (n != 20) { return(false); } // do not increment bytesRead - it is for entry header only. // the data we have just read is a footer (falls after the file data) //bytesRead += n; i = 0; ze._Crc32 = (Int32)(block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256); ze._CompressedSize = BitConverter.ToInt64(block, i); i += 8; ze._UncompressedSize = BitConverter.ToInt64(block, i); i += 8; ze._LengthOfTrailer += 24; // bytes including sig, CRC, Comp and Uncomp sizes } else { // read 3x 4-byte fields (CRC, Compressed Size, Uncompressed Size) block = new byte[12]; n = ze.ArchiveStream.Read(block, 0, block.Length); if (n != 12) { return(false); } // do not increment bytesRead - it is for entry header only. // the data we have just read is a footer (falls after the file data) //bytesRead += n; i = 0; ze._Crc32 = (Int32)(block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256); ze._CompressedSize = (uint)(block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256); ze._UncompressedSize = (uint)(block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256); ze._LengthOfTrailer += 16; // bytes including sig, CRC, Comp and Uncomp sizes } wantMore = (SizeOfDataRead != ze._CompressedSize); if (wantMore) { // Seek back to un-read the last 12 bytes - maybe THEY contain // the ZipEntryDataDescriptorSignature. // (12 bytes for the CRC, Comp and Uncomp size.) ze.ArchiveStream.Seek(-12, SeekOrigin.Current); // workitem 10178 SharedUtilities.Workaround_Ladybug318918(ze.ArchiveStream); // Adjust the size to account for the false signature read in // FindSignature(). SizeOfDataRead += 4; } } // seek back to previous position, to prepare to read file data // workitem 8098: ok (restore) ze.ArchiveStream.Seek(posn, SeekOrigin.Begin); // workitem 10178 SharedUtilities.Workaround_Ladybug318918(ze.ArchiveStream); } ze._CompressedFileDataSize = ze._CompressedSize; // bit 0 set indicates that some kind of encryption is in use if ((ze._BitField & 0x01) == 0x01) { #if AESCRYPTO if (ze.Encryption == EncryptionAlgorithm.WinZipAes128 || ze.Encryption == EncryptionAlgorithm.WinZipAes256) { int bits = ZipEntry.GetKeyStrengthInBits(ze._Encryption_FromZipFile); // read in the WinZip AES metadata: salt + PV. 18 bytes for AES256. 10 bytes for AES128. ze._aesCrypto_forExtract = WinZipAesCrypto.ReadFromStream(null, bits, ze.ArchiveStream); bytesRead += ze._aesCrypto_forExtract.SizeOfEncryptionMetadata - 10; // MAC (follows crypto bytes) // according to WinZip, the CompressedSize includes the AES Crypto framing data. ze._CompressedFileDataSize -= ze._aesCrypto_forExtract.SizeOfEncryptionMetadata; ze._LengthOfTrailer += 10; // MAC } else #endif { // read in the header data for "weak" encryption ze._WeakEncryptionHeader = new byte[12]; bytesRead += ZipEntry.ReadWeakEncryptionHeader(ze._archiveStream, ze._WeakEncryptionHeader); // decrease the filedata size by 12 bytes ze._CompressedFileDataSize -= 12; } } // Remember the size of the blob for this entry. // We also have the starting position in the stream for this entry. ze._LengthOfHeader = bytesRead; ze._TotalEntrySize = ze._LengthOfHeader + ze._CompressedFileDataSize + ze._LengthOfTrailer; // We've read in the regular entry header, the extra field, and any // encryption header. The pointer in the file is now at the start of the // filedata, which is potentially compressed and encrypted. Just ahead in // the file, there are _CompressedFileDataSize bytes of data, followed by // potentially a non-zero length trailer, consisting of optionally, some // encryption stuff (10 byte MAC for AES), and the bit-3 trailer (16 or 24 // bytes). return(true); }
public long TruncateBackward(uint diskNumber, long offset) { // Console.WriteLine("***ZSS.Trunc to disk {0}", diskNumber); // Console.WriteLine("***ZSS.Trunc: current disk {0}", CurrentSegment); if (diskNumber >= 99) { throw new ArgumentOutOfRangeException("diskNumber"); } if (rwMode != RwMode.Write) { _exceptionPending = true; throw new ZipException("bad state."); } // Seek back in the segmented stream to a (maybe) prior segment. // Check if it is the same segment. If it is, very simple. if (diskNumber == CurrentSegment) { var x = _innerStream.Seek(offset, SeekOrigin.Begin); // workitem 10178 SharedUtilities.Workaround_Ladybug318918(_innerStream); return(x); } // Seeking back to a prior segment. // The current segment and any intervening segments must be removed. // First, close the current segment, and then remove it. if (_innerStream != null) { #if NETCF _innerStream.Close(); #else _innerStream.Dispose(); #endif if (File.Exists(_currentTempName)) { File.Delete(_currentTempName); } } // Now, remove intervening segments. for (uint j = CurrentSegment - 1; j > diskNumber; j--) { string s = _NameForSegment(j); // Console.WriteLine("***ZSS.Trunc: removing file {0}", s); if (File.Exists(s)) { File.Delete(s); } } // now, open the desired segment. It must exist. CurrentSegment = diskNumber; // get a new temp file, try 3 times: for (int i = 0; i < 3; i++) { try { _currentTempName = SharedUtilities.InternalGetTempFileName(); // move the .z0x file back to a temp name File.Move(CurrentName, _currentTempName); break; // workitem 12403 } catch (IOException) { if (i == 2) { throw; } } } // open it _innerStream = new FileStream(_currentTempName, FileMode.Open); var r = _innerStream.Seek(offset, SeekOrigin.Begin); // workitem 10178 SharedUtilities.Workaround_Ladybug318918(_innerStream); return(r); }