// For AES the method in the entry is 99, and the real compression method is in the extradata
//
private void ProcessAESExtraData(ZipExtraData extraData)
{
if (extraData.Find(0x9901))
{
// Set version and flag for Zipfile.CreateAndInitDecryptionStream
versionToExtract = ZipConstants.VERSION_AES; // Ver 5.1 = AES see "Version" getter
// Set StrongEncryption flag for ZipFile.CreateAndInitDecryptionStream
Flags = Flags | (int)GeneralBitFlags.StrongEncryption;
//
// Unpack AES extra data field see http://www.winzip.com/aes_info.htm
int length = extraData.ValueLength; // Data size currently 7
if (length < 7)
{
throw new ZipException("AES Extra Data Length " + length + " invalid.");
}
int ver = extraData.ReadShort(); // Version number (1=AE-1 2=AE-2)
int vendorId = extraData.ReadShort(); // 2-character vendor ID 0x4541 = "AE"
int encrStrength = extraData.ReadByte(); // encryption strength 1 = 128 2 = 192 3 = 256
int actualCompress = extraData.ReadShort(); // The actual compression method used to compress the file
_aesVer = ver;
_aesEncryptionStrength = encrStrength;
method = (CompressionMethod)actualCompress;
}
else
{
throw new ZipException("AES Extra Data missing");
}
}
/// <summary>
/// Process extra data fields updating the entry based on the contents.
/// </summary>
/// <param name="localHeader">True if the extra data fields should be handled
/// for a local header, rather than for a central header.
/// </param>
internal void ProcessExtraData(bool localHeader)
{
var extraData = new ZipExtraData(this.extra);
if (extraData.Find(0x0001))
{
// Version required to extract is ignored here as some archivers dont set it correctly
// in theory it should be version 45 or higher
// The recorded size will change but remember that this is zip64.
forceZip64_ = true;
if (extraData.ValueLength < 4)
{
throw new ZipException("Extra data extended Zip64 information length is invalid");
}
// (localHeader ||) was deleted, because actually there is no specific difference with reading sizes between local header & central directory
// https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT
// ...
// 4.4 Explanation of fields
// ...
// 4.4.8 compressed size: (4 bytes)
// 4.4.9 uncompressed size: (4 bytes)
//
// The size of the file compressed (4.4.8) and uncompressed,
// (4.4.9) respectively. When a decryption header is present it
// will be placed in front of the file data and the value of the
// compressed file size will include the bytes of the decryption
// header. If bit 3 of the general purpose bit flag is set,
// these fields are set to zero in the local header and the
// correct values are put in the data descriptor and
// in the central directory. If an archive is in ZIP64 format
// and the value in this field is 0xFFFFFFFF, the size will be
// in the corresponding 8 byte ZIP64 extended information
// extra field. When encrypting the central directory, if the
// local header is not in ZIP64 format and general purpose bit
// flag 13 is set indicating masking, the value stored for the
// uncompressed size in the Local Header will be zero.
//
// Othewise there is problem with minizip implementation
if (size == uint.MaxValue)
{
size = (ulong)extraData.ReadLong();
}
if (compressedSize == uint.MaxValue)
{
compressedSize = (ulong)extraData.ReadLong();
}
if (!localHeader && (offset == uint.MaxValue))
{
offset = extraData.ReadLong();
}
// Disk number on which file starts is ignored
}
else
{
if (
((versionToExtract & 0xff) >= ZipConstants.VersionZip64) &&
((size == uint.MaxValue) || (compressedSize == uint.MaxValue))
)
{
throw new ZipException("Zip64 Extended information required but is missing.");
}
}
DateTime = GetDateTime(extraData);
if (method == CompressionMethod.WinZipAES)
{
ProcessAESExtraData(extraData);
}
}
// Write the local file header
// TODO: ZipHelperStream.WriteLocalHeader is not yet used and needs checking for ZipFile and ZipOuptutStream usage
void WriteLocalHeader(ZipEntry entry, EntryPatchData patchData)
{
CompressionMethod method = entry.CompressionMethod;
bool headerInfoAvailable = true; // How to get this?
bool patchEntryHeader = false;
WriteLEInt(ZipConstants.LocalHeaderSignature);
WriteLEShort(entry.Version);
WriteLEShort(entry.Flags);
WriteLEShort((byte)method);
WriteLEInt((int)entry.DosTime);
if (headerInfoAvailable == true)
{
WriteLEInt((int)entry.Crc);
if (entry.LocalHeaderRequiresZip64)
{
WriteLEInt(-1);
WriteLEInt(-1);
}
else
{
WriteLEInt(entry.IsCrypted ? (int)entry.CompressedSize + ZipConstants.CryptoHeaderSize : (int)entry.CompressedSize);
WriteLEInt((int)entry.Size);
}
}
else
{
if (patchData != null)
{
patchData.CrcPatchOffset = stream_.Position;
}
WriteLEInt(0); // Crc
if (patchData != null)
{
patchData.SizePatchOffset = stream_.Position;
}
// For local header both sizes appear in Zip64 Extended Information
if (entry.LocalHeaderRequiresZip64 && patchEntryHeader)
{
WriteLEInt(-1);
WriteLEInt(-1);
}
else
{
WriteLEInt(0); // Compressed size
WriteLEInt(0); // Uncompressed size
}
}
byte[] name = ZipConstants.ConvertToArray(entry.Flags, entry.Name);
if (name.Length > 0xFFFF)
{
throw new ZipException("Entry name too long.");
}
var ed = new ZipExtraData(entry.ExtraData);
if (entry.LocalHeaderRequiresZip64 && (headerInfoAvailable || patchEntryHeader))
{
ed.StartNewEntry();
if (headerInfoAvailable)
{
ed.AddLeLong(entry.Size);
ed.AddLeLong(entry.CompressedSize);
}
else
{
ed.AddLeLong(-1);
ed.AddLeLong(-1);
}
ed.AddNewEntry(1);
if (!ed.Find(1))
{
throw new ZipException("Internal error cant find extra data");
}
if (patchData != null)
{
patchData.SizePatchOffset = ed.CurrentReadIndex;
}
}
else
{
ed.Delete(1);
}
byte[] extra = ed.GetEntryData();
WriteLEShort(name.Length);
WriteLEShort(extra.Length);
if (name.Length > 0)
{
stream_.Write(name, 0, name.Length);
}
if (entry.LocalHeaderRequiresZip64 && patchEntryHeader)
{
patchData.SizePatchOffset += stream_.Position;
}
if (extra.Length > 0)
{
stream_.Write(extra, 0, extra.Length);
}
}
/// <summary>
/// Starts a new Zip entry. It automatically closes the previous
/// entry if present.
/// All entry elements bar name are optional, but must be correct if present.
/// If the compression method is stored and the output is not patchable
/// the compression for that entry is automatically changed to deflate level 0
/// </summary>
/// <param name="entry">
/// the entry.
/// </param>
/// <exception cref="System.ArgumentNullException">
/// if entry passed is null.
/// </exception>
/// <exception cref="System.IO.IOException">
/// if an I/O error occured.
/// </exception>
/// <exception cref="System.InvalidOperationException">
/// if stream was finished
/// </exception>
/// <exception cref="ZipException">
/// Too many entries in the Zip file<br/>
/// Entry name is too long<br/>
/// Finish has already been called<br/>
/// </exception>
public void PutNextEntry(ZipEntry entry)
{
if (entry == null)
{
throw new ArgumentNullException(nameof(entry));
}
if (entries == null)
{
throw new InvalidOperationException("ZipOutputStream was finished");
}
if (curEntry != null)
{
CloseEntry();
}
if (entries.Count == int.MaxValue)
{
throw new ZipException("Too many entries for Zip file");
}
CompressionMethod method = entry.CompressionMethod;
int compressionLevel = defaultCompressionLevel;
// Clear flags that the library manages internally
entry.Flags &= (int)GeneralBitFlags.UnicodeText;
patchEntryHeader = false;
bool headerInfoAvailable;
// No need to compress - definitely no data.
if (entry.Size == 0)
{
entry.CompressedSize = entry.Size;
entry.Crc = 0;
method = CompressionMethod.Stored;
headerInfoAvailable = true;
}
else
{
headerInfoAvailable = (entry.Size >= 0) && entry.HasCrc && entry.CompressedSize >= 0;
// Switch to deflation if storing isnt possible.
if (method == CompressionMethod.Stored)
{
if (!headerInfoAvailable)
{
if (!CanPatchEntries)
{
// Can't patch entries so storing is not possible.
method = CompressionMethod.Deflated;
compressionLevel = 0;
}
}
else // entry.size must be > 0
{
entry.CompressedSize = entry.Size;
headerInfoAvailable = entry.HasCrc;
}
}
}
if (headerInfoAvailable == false)
{
if (CanPatchEntries == false)
{
// Only way to record size and compressed size is to append a data descriptor
// after compressed data.
// Stored entries of this form have already been converted to deflating.
entry.Flags |= 8;
}
else
{
patchEntryHeader = true;
}
}
entry.Offset = offset;
entry.CompressionMethod = (CompressionMethod)method;
curMethod = method;
sizePatchPos = -1;
if ((useZip64_ == UseZip64.On) || ((entry.Size < 0) && (useZip64_ == UseZip64.Dynamic)))
{
entry.ForceZip64();
}
// Write the local file header
WriteLeInt(ZipConstants.LocalHeaderSignature);
WriteLeShort(entry.Version);
WriteLeShort(entry.Flags);
WriteLeShort((byte)entry.CompressionMethodForHeader);
WriteLeInt((int)entry.DosTime);
// TODO: Refactor header writing. Its done in several places.
if (headerInfoAvailable)
{
WriteLeInt((int)entry.Crc);
if (entry.LocalHeaderRequiresZip64)
{
WriteLeInt(-1);
WriteLeInt(-1);
}
else
{
WriteLeInt(entry.IsCrypted ? (int)entry.CompressedSize + ZipConstants.CryptoHeaderSize : (int)entry.CompressedSize);
WriteLeInt((int)entry.Size);
}
}
else
{
if (patchEntryHeader)
{
crcPatchPos = BaseOutputStream.Position;
}
WriteLeInt(0); // Crc
if (patchEntryHeader)
{
sizePatchPos = BaseOutputStream.Position;
}
// For local header both sizes appear in Zip64 Extended Information
if (entry.LocalHeaderRequiresZip64 || patchEntryHeader)
{
WriteLeInt(-1);
WriteLeInt(-1);
}
else
{
WriteLeInt(0); // Compressed size
WriteLeInt(0); // Uncompressed size
}
}
byte[] name = ZipStrings.ConvertToArray(entry.Flags, entry.Name);
if (name.Length > 0xFFFF)
{
throw new ZipException("Entry name too long.");
}
var ed = new ZipExtraData(entry.ExtraData);
if (entry.LocalHeaderRequiresZip64)
{
ed.StartNewEntry();
if (headerInfoAvailable)
{
ed.AddLeLong(entry.Size);
ed.AddLeLong(entry.CompressedSize);
}
else
{
ed.AddLeLong(-1);
ed.AddLeLong(-1);
}
ed.AddNewEntry(1);
if (!ed.Find(1))
{
throw new ZipException("Internal error cant find extra data");
}
if (patchEntryHeader)
{
sizePatchPos = ed.CurrentReadIndex;
}
}
else
{
ed.Delete(1);
}
if (entry.AESKeySize > 0)
{
AddExtraDataAES(entry, ed);
}
byte[] extra = ed.GetEntryData();
WriteLeShort(name.Length);
WriteLeShort(extra.Length);
if (name.Length > 0)
{
BaseOutputStream.Write(name, 0, name.Length);
}
if (entry.LocalHeaderRequiresZip64 && patchEntryHeader)
{
sizePatchPos += BaseOutputStream.Position;
}
if (extra.Length > 0)
{
BaseOutputStream.Write(extra, 0, extra.Length);
}
offset += ZipConstants.LocalHeaderBaseSize + name.Length + extra.Length;
// Fix offsetOfCentraldir for AES
if (entry.AESKeySize > 0)
{
offset += entry.AESOverheadSize;
}
// Activate the entry.
curEntry = entry;
crc.Reset();
if (method == CompressionMethod.Deflated)
{
Deflater.Reset();
Deflater.SetLevel(compressionLevel);
}
size = 0;
}