/// <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)
{
ZipExtraData 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");
}
if ( localHeader || (size == uint.MaxValue) ) {
size = (ulong)extraData.ReadLong();
}
if ( localHeader || (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.");
}
}
if ( extraData.Find(10) ) {
// No room for any tags.
if ( extraData.ValueLength < 4 ) {
throw new ZipException("NTFS Extra data invalid");
}
extraData.ReadInt(); // Reserved
while ( extraData.UnreadCount >= 4 ) {
int ntfsTag = extraData.ReadShort();
int ntfsLength = extraData.ReadShort();
if ( ntfsTag == 1 ) {
if ( ntfsLength >= 24 ) {
long lastModification = extraData.ReadLong();
long lastAccess = extraData.ReadLong();
long createTime = extraData.ReadLong();
DateTime = System.DateTime.FromFileTime(lastModification);
}
break;
}
else {
// An unknown NTFS tag so simply skip it.
extraData.Skip(ntfsLength);
}
}
}
else if ( extraData.Find(0x5455) ) {
int length = extraData.ValueLength;
int flags = extraData.ReadByte();
// Can include other times but these are ignored. Length of data should
// actually be 1 + 4 * no of bits in flags.
if ( ((flags & 1) != 0) && (length >= 5) ) {
int iTime = extraData.ReadInt();
DateTime = (new System.DateTime ( 1970, 1, 1, 0, 0, 0 ).ToUniversalTime() +
new TimeSpan ( 0, 0, 0, iTime, 0 )).ToLocalTime();
}
}
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.");
}
ZipExtraData 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>
/// Finishes the stream. This will write the central directory at the
/// end of the zip file and flush the stream.
/// </summary>
/// <remarks>
/// This is automatically called when the stream is closed.
/// </remarks>
/// <exception cref="System.IO.IOException">
/// An I/O error occurs.
/// </exception>
/// <exception cref="ZipException">
/// Comment exceeds the maximum length<br/>
/// Entry name exceeds the maximum length
/// </exception>
public override void Finish()
{
if (entries == null) {
return;
}
if (curEntry != null) {
CloseEntry();
}
long numEntries = entries.Count;
long sizeEntries = 0;
foreach (ZipEntry entry in entries) {
WriteLeInt(ZipConstants.CentralHeaderSignature);
WriteLeShort(ZipConstants.VersionMadeBy);
WriteLeShort(entry.Version);
WriteLeShort(entry.Flags);
WriteLeShort((short)entry.CompressionMethodForHeader);
WriteLeInt((int)entry.DosTime);
WriteLeInt((int)entry.Crc);
if ( entry.IsZip64Forced() ||
(entry.CompressedSize >= uint.MaxValue) )
{
WriteLeInt(-1);
}
else {
WriteLeInt((int)entry.CompressedSize);
}
if ( entry.IsZip64Forced() ||
(entry.Size >= uint.MaxValue) )
{
WriteLeInt(-1);
}
else {
WriteLeInt((int)entry.Size);
}
byte[] name = ZipConstants.ConvertToArray(entry.Flags, entry.Name);
if (name.Length > 0xffff) {
throw new ZipException("Name too long.");
}
ZipExtraData ed = new ZipExtraData(entry.ExtraData);
if ( entry.CentralHeaderRequiresZip64 ) {
ed.StartNewEntry();
if ( entry.IsZip64Forced() ||
(entry.Size >= 0xffffffff) )
{
ed.AddLeLong(entry.Size);
}
if ( entry.IsZip64Forced() ||
(entry.CompressedSize >= 0xffffffff) )
{
ed.AddLeLong(entry.CompressedSize);
}
if ( entry.Offset >= 0xffffffff )
{
ed.AddLeLong(entry.Offset);
}
ed.AddNewEntry(1);
}
else {
ed.Delete(1);
}
#if !NET_1_1 && !NETCF_2_0
if (entry.AESKeySize > 0) {
AddExtraDataAES(entry, ed);
}
#endif
byte[] extra = ed.GetEntryData();
byte[] entryComment =
(entry.Comment != null) ?
ZipConstants.ConvertToArray(entry.Flags, entry.Comment) :
new byte[0];
if (entryComment.Length > 0xffff) {
throw new ZipException("Comment too long.");
}
WriteLeShort(name.Length);
WriteLeShort(extra.Length);
WriteLeShort(entryComment.Length);
WriteLeShort(0); // disk number
WriteLeShort(0); // internal file attributes
// external file attributes
if (entry.ExternalFileAttributes != -1) {
WriteLeInt(entry.ExternalFileAttributes);
} else {
if (entry.IsDirectory) { // mark entry as directory (from nikolam.AT.perfectinfo.com)
WriteLeInt(16);
} else {
WriteLeInt(0);
}
}
if ( entry.Offset >= uint.MaxValue ) {
WriteLeInt(-1);
}
else {
WriteLeInt((int)entry.Offset);
}
if ( name.Length > 0 ) {
baseOutputStream_.Write(name, 0, name.Length);
}
if ( extra.Length > 0 ) {
baseOutputStream_.Write(extra, 0, extra.Length);
}
if ( entryComment.Length > 0 ) {
baseOutputStream_.Write(entryComment, 0, entryComment.Length);
}
sizeEntries += ZipConstants.CentralHeaderBaseSize + name.Length + extra.Length + entryComment.Length;
}
using ( ZipHelperStream zhs = new ZipHelperStream(baseOutputStream_) ) {
zhs.WriteEndOfCentralDirectory(numEntries, sizeEntries, offset, zipComment);
}
entries = null;
}
// For AES the method in the entry is 99, and the real compression method is in the extradata
//
private void ProcessAESExtraData(ZipExtraData extraData) {
#if !NET_1_1 && !NETCF_2_0
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");
#else
throw new ZipException("AES unsupported");
#endif
}
private static void AddExtraDataAES(ZipEntry entry, ZipExtraData extraData) {
// Vendor Version: AE-1 IS 1. AE-2 is 2. With AE-2 no CRC is required and 0 is stored.
const int VENDOR_VERSION = 2;
// Vendor ID is the two ASCII characters "AE".
const int VENDOR_ID = 0x4541; //not 6965;
extraData.StartNewEntry();
// Pack AES extra data field see http://www.winzip.com/aes_info.htm
//extraData.AddLeShort(7); // Data size (currently 7)
extraData.AddLeShort(VENDOR_VERSION); // 2 = AE-2
extraData.AddLeShort(VENDOR_ID); // "AE"
extraData.AddData(entry.AESEncryptionStrength); // 1 = 128, 2 = 192, 3 = 256
extraData.AddLeShort((int)entry.CompressionMethod); // The actual compression method used to compress the file
extraData.AddNewEntry(0x9901);
}
/// <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("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;
// 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;
}
}
if (Password != null) {
entry.IsCrypted = true;
if (entry.Crc < 0) {
// Need to append a data descriptor as the crc isnt available for use
// with encryption, the date is used instead. Setting the flag
// indicates this to the decompressor.
entry.Flags |= 8;
}
}
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 == 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 (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 = ZipConstants.ConvertToArray(entry.Flags, entry.Name);
if (name.Length > 0xFFFF) {
throw new ZipException("Entry name too long.");
}
ZipExtraData 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 !NET_1_1 && !NETCF_2_0
if (entry.AESKeySize > 0) {
AddExtraDataAES(entry, ed);
}
#endif
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;
if (entry.IsCrypted) {
#if !NET_1_1 && !NETCF_2_0
if (entry.AESKeySize > 0) {
WriteAESHeader(entry);
} else
#endif
{
if (entry.Crc < 0) { // so testing Zip will says its ok
WriteEncryptionHeader(entry.DosTime << 16);
} else {
WriteEncryptionHeader(entry.Crc);
}
}
}
}
int WriteCentralDirectoryHeader(ZipEntry entry)
{
if ( entry.CompressedSize < 0 ) {
throw new ZipException("Attempt to write central directory entry with unknown csize");
}
if ( entry.Size < 0 ) {
throw new ZipException("Attempt to write central directory entry with unknown size");
}
if ( entry.Crc < 0 ) {
throw new ZipException("Attempt to write central directory entry with unknown crc");
}
// Write the central file header
WriteLEInt(ZipConstants.CentralHeaderSignature);
// Version made by
WriteLEShort(ZipConstants.VersionMadeBy);
// Version required to extract
WriteLEShort(entry.Version);
WriteLEShort(entry.Flags);
unchecked {
WriteLEShort((byte)entry.CompressionMethod);
WriteLEInt((int)entry.DosTime);
WriteLEInt((int)entry.Crc);
}
if ( (entry.IsZip64Forced()) || (entry.CompressedSize >= 0xffffffff) ) {
WriteLEInt(-1);
}
else {
WriteLEInt((int)(entry.CompressedSize & 0xffffffff));
}
if ( (entry.IsZip64Forced()) || (entry.Size >= 0xffffffff) ) {
WriteLEInt(-1);
}
else {
WriteLEInt((int)entry.Size);
}
byte[] name = ZipConstants.ConvertToArray(entry.Flags, entry.Name);
if ( name.Length > 0xFFFF ) {
throw new ZipException("Entry name is too long.");
}
WriteLEShort(name.Length);
// Central header extra data is different to local header version so regenerate.
ZipExtraData ed = new ZipExtraData(entry.ExtraData);
if ( entry.CentralHeaderRequiresZip64 ) {
ed.StartNewEntry();
if ( (entry.Size >= 0xffffffff) || (useZip64_ == UseZip64.On) )
{
ed.AddLeLong(entry.Size);
}
if ( (entry.CompressedSize >= 0xffffffff) || (useZip64_ == UseZip64.On) )
{
ed.AddLeLong(entry.CompressedSize);
}
if ( entry.Offset >= 0xffffffff ) {
ed.AddLeLong(entry.Offset);
}
// Number of disk on which this file starts isnt supported and is never written here.
ed.AddNewEntry(1);
}
else {
// Should have already be done when local header was added.
ed.Delete(1);
}
byte[] centralExtraData = ed.GetEntryData();
WriteLEShort(centralExtraData.Length);
WriteLEShort(entry.Comment != null ? entry.Comment.Length : 0);
WriteLEShort(0); // disk number
WriteLEShort(0); // internal file attributes
// External file attributes...
if ( entry.ExternalFileAttributes != -1 ) {
WriteLEInt(entry.ExternalFileAttributes);
}
else {
if ( entry.IsDirectory ) {
WriteLEUint(16);
}
else {
WriteLEUint(0);
}
}
if ( entry.Offset >= 0xffffffff ) {
WriteLEUint(0xffffffff);
}
else {
WriteLEUint((uint)(int)entry.Offset);
}
if ( name.Length > 0 ) {
baseStream_.Write(name, 0, name.Length);
}
if ( centralExtraData.Length > 0 ) {
baseStream_.Write(centralExtraData, 0, centralExtraData.Length);
}
byte[] rawComment = (entry.Comment != null) ? Encoding.ASCII.GetBytes(entry.Comment) : new byte[0];
if ( rawComment.Length > 0 ) {
baseStream_.Write(rawComment, 0, rawComment.Length);
}
return ZipConstants.CentralHeaderBaseSize + name.Length + centralExtraData.Length + rawComment.Length;
}
void WriteLocalEntryHeader(ZipUpdate update)
{
ZipEntry entry = update.OutEntry;
// TODO: Local offset will require adjusting for multi-disk zip files.
entry.Offset = baseStream_.Position;
// TODO: Need to clear any entry flags that dont make sense or throw an exception here.
if (update.Command != UpdateCommand.Copy) {
if (entry.CompressionMethod == CompressionMethod.Deflated) {
if (entry.Size == 0) {
// No need to compress - no data.
entry.CompressedSize = entry.Size;
entry.Crc = 0;
entry.CompressionMethod = CompressionMethod.Stored;
}
}
else if (entry.CompressionMethod == CompressionMethod.Stored) {
entry.Flags &= ~(int)GeneralBitFlags.Descriptor;
}
if (HaveKeys) {
entry.IsCrypted = true;
if (entry.Crc < 0) {
entry.Flags |= (int)GeneralBitFlags.Descriptor;
}
}
else {
entry.IsCrypted = false;
}
switch (useZip64_) {
case UseZip64.Dynamic:
if (entry.Size < 0) {
entry.ForceZip64();
}
break;
case UseZip64.On:
entry.ForceZip64();
break;
case UseZip64.Off:
// Do nothing. The entry itself may be using Zip64 independantly.
break;
}
}
// Write the local file header
WriteLEInt(ZipConstants.LocalHeaderSignature);
WriteLEShort(entry.Version);
WriteLEShort(entry.Flags);
WriteLEShort((byte)entry.CompressionMethod);
WriteLEInt(( int )entry.DosTime);
if ( !entry.HasCrc ) {
// Note patch address for updating CRC later.
update.CrcPatchOffset = baseStream_.Position;
WriteLEInt(( int )0);
}
else {
WriteLEInt(unchecked(( int )entry.Crc));
}
if (entry.LocalHeaderRequiresZip64) {
WriteLEInt(-1);
WriteLEInt(-1);
}
else {
if ( (entry.CompressedSize < 0) || (entry.Size < 0) ) {
update.SizePatchOffset = baseStream_.Position;
}
WriteLEInt(( int )entry.CompressedSize);
WriteLEInt(( int )entry.Size);
}
byte[] name = ZipConstants.ConvertToArray(entry.Flags, entry.Name);
if ( name.Length > 0xFFFF ) {
throw new ZipException("Entry name too long.");
}
ZipExtraData ed = new ZipExtraData(entry.ExtraData);
if ( entry.LocalHeaderRequiresZip64 ) {
ed.StartNewEntry();
// Local entry header always includes size and compressed size.
// NOTE the order of these fields is reversed when compared to the normal headers!
ed.AddLeLong(entry.Size);
ed.AddLeLong(entry.CompressedSize);
ed.AddNewEntry(1);
}
else {
ed.Delete(1);
}
entry.ExtraData = ed.GetEntryData();
WriteLEShort(name.Length);
WriteLEShort(entry.ExtraData.Length);
if ( name.Length > 0 ) {
baseStream_.Write(name, 0, name.Length);
}
if ( entry.LocalHeaderRequiresZip64 ) {
if ( !ed.Find(1) ) {
throw new ZipException("Internal error cannot find extra data");
}
update.SizePatchOffset = baseStream_.Position + ed.CurrentReadIndex;
}
if ( entry.ExtraData.Length > 0 ) {
baseStream_.Write(entry.ExtraData, 0, entry.ExtraData.Length);
}
}
/// <summary>
/// Test a local header against that provided from the central directory
/// </summary>
/// <param name="entry">
/// The entry to test against
/// </param>
/// <param name="tests">The type of <see cref="HeaderTest">tests</see> to carry out.</param>
/// <returns>The offset of the entries data in the file</returns>
long TestLocalHeader(ZipEntry entry, HeaderTest tests)
{
lock(baseStream_)
{
bool testHeader = (tests & HeaderTest.Header) != 0;
bool testData = (tests & HeaderTest.Extract) != 0;
baseStream_.Seek(offsetOfFirstEntry + entry.Offset, SeekOrigin.Begin);
if ((int)ReadLEUint() != ZipConstants.LocalHeaderSignature) {
throw new ZipException(string.Format("Wrong local header signature @{0:X}", offsetOfFirstEntry + entry.Offset));
}
short extractVersion = ( short )ReadLEUshort();
short localFlags = ( short )ReadLEUshort();
short compressionMethod = ( short )ReadLEUshort();
short fileTime = ( short )ReadLEUshort();
short fileDate = ( short )ReadLEUshort();
uint crcValue = ReadLEUint();
long compressedSize = ReadLEUint();
long size = ReadLEUint();
int storedNameLength = ReadLEUshort();
int extraDataLength = ReadLEUshort();
byte[] nameData = new byte[storedNameLength];
StreamUtils.ReadFully(baseStream_, nameData);
byte[] extraData = new byte[extraDataLength];
StreamUtils.ReadFully(baseStream_, extraData);
ZipExtraData localExtraData = new ZipExtraData(extraData);
// Extra data / zip64 checks
if (localExtraData.Find(1))
{
// 2010-03-04 Forum 10512: removed checks for version >= ZipConstants.VersionZip64
// and size or compressedSize = MaxValue, due to rogue creators.
size = localExtraData.ReadLong();
compressedSize = localExtraData.ReadLong();
if ((localFlags & (int)GeneralBitFlags.Descriptor) != 0)
{
// These may be valid if patched later
if ( (size != -1) && (size != entry.Size)) {
throw new ZipException("Size invalid for descriptor");
}
if ((compressedSize != -1) && (compressedSize != entry.CompressedSize)) {
throw new ZipException("Compressed size invalid for descriptor");
}
}
}
else
{
// No zip64 extra data but entry requires it.
if ((extractVersion >= ZipConstants.VersionZip64) &&
(((uint)size == uint.MaxValue) || ((uint)compressedSize == uint.MaxValue)))
{
throw new ZipException("Required Zip64 extended information missing");
}
}
if ( testData ) {
if ( entry.IsFile ) {
if ( !entry.IsCompressionMethodSupported() ) {
throw new ZipException("Compression method not supported");
}
if ( (extractVersion > ZipConstants.VersionMadeBy)
|| ((extractVersion > 20) && (extractVersion < ZipConstants.VersionZip64)) ) {
throw new ZipException(string.Format("Version required to extract this entry not supported ({0})", extractVersion));
}
if ( (localFlags & ( int )(GeneralBitFlags.Patched | GeneralBitFlags.StrongEncryption | GeneralBitFlags.EnhancedCompress | GeneralBitFlags.HeaderMasked)) != 0 ) {
throw new ZipException("The library does not support the zip version required to extract this entry");
}
}
}
if (testHeader)
{
if ((extractVersion <= 63) && // Ignore later versions as we dont know about them..
(extractVersion != 10) &&
(extractVersion != 11) &&
(extractVersion != 20) &&
(extractVersion != 21) &&
(extractVersion != 25) &&
(extractVersion != 27) &&
(extractVersion != 45) &&
(extractVersion != 46) &&
(extractVersion != 50) &&
(extractVersion != 51) &&
(extractVersion != 52) &&
(extractVersion != 61) &&
(extractVersion != 62) &&
(extractVersion != 63)
)
{
throw new ZipException(string.Format("Version required to extract this entry is invalid ({0})", extractVersion));
}
// Local entry flags dont have reserved bit set on.
if ((localFlags & (int)(GeneralBitFlags.ReservedPKware4 | GeneralBitFlags.ReservedPkware14 | GeneralBitFlags.ReservedPkware15)) != 0)
{
throw new ZipException("Reserved bit flags cannot be set.");
}
// Encryption requires extract version >= 20
if (((localFlags & (int)GeneralBitFlags.Encrypted) != 0) && (extractVersion < 20))
{
throw new ZipException(string.Format("Version required to extract this entry is too low for encryption ({0})", extractVersion));
}
// Strong encryption requires encryption flag to be set and extract version >= 50.
if ((localFlags & (int)GeneralBitFlags.StrongEncryption) != 0)
{
if ((localFlags & (int)GeneralBitFlags.Encrypted) == 0)
{
throw new ZipException("Strong encryption flag set but encryption flag is not set");
}
if (extractVersion < 50)
{
throw new ZipException(string.Format("Version required to extract this entry is too low for encryption ({0})", extractVersion));
}
}
// Patched entries require extract version >= 27
if (((localFlags & (int)GeneralBitFlags.Patched) != 0) && (extractVersion < 27))
{
throw new ZipException(string.Format("Patched data requires higher version than ({0})", extractVersion));
}
// Central header flags match local entry flags.
if (localFlags != entry.Flags)
{
throw new ZipException("Central header/local header flags mismatch");
}
// Central header compression method matches local entry
if (entry.CompressionMethod != (CompressionMethod)compressionMethod)
{
throw new ZipException("Central header/local header compression method mismatch");
}
if (entry.Version != extractVersion)
{
throw new ZipException("Extract version mismatch");
}
// Strong encryption and extract version match
if ((localFlags & (int)GeneralBitFlags.StrongEncryption) != 0)
{
if (extractVersion < 62)
{
throw new ZipException("Strong encryption flag set but version not high enough");
}
}
if ((localFlags & (int)GeneralBitFlags.HeaderMasked) != 0)
{
if ((fileTime != 0) || (fileDate != 0))
{
throw new ZipException("Header masked set but date/time values non-zero");
}
}
if ((localFlags & (int)GeneralBitFlags.Descriptor) == 0)
{
if (crcValue != (uint)entry.Crc)
{
throw new ZipException("Central header/local header crc mismatch");
}
}
// Crc valid for empty entry.
// This will also apply to streamed entries where size isnt known and the header cant be patched
if ((size == 0) && (compressedSize == 0))
{
if (crcValue != 0)
{
throw new ZipException("Invalid CRC for empty entry");
}
}
// TODO: make test more correct... can't compare lengths as was done originally as this can fail for MBCS strings
// Assuming a code page at this point is not valid? Best is to store the name length in the ZipEntry probably
if (entry.Name.Length > storedNameLength)
{
throw new ZipException("File name length mismatch");
}
// Name data has already been read convert it and compare.
string localName = ZipConstants.ConvertToStringExt(localFlags, nameData);
// Central directory and local entry name match
if (localName != entry.Name)
{
throw new ZipException("Central header and local header file name mismatch");
}
// Directories have zero actual size but can have compressed size
if (entry.IsDirectory)
{
if (size > 0)
{
throw new ZipException("Directory cannot have size");
}
// There may be other cases where the compressed size can be greater than this?
// If so until details are known we will be strict.
if (entry.IsCrypted)
{
if (compressedSize > ZipConstants.CryptoHeaderSize + 2)
{
throw new ZipException("Directory compressed size invalid");
}
}
else if (compressedSize > 2)
{
// When not compressed the directory size can validly be 2 bytes
// if the true size wasnt known when data was originally being written.
// NOTE: Versions of the library 0.85.4 and earlier always added 2 bytes
throw new ZipException("Directory compressed size invalid");
}
}
if (!ZipNameTransform.IsValidName(localName, true))
{
throw new ZipException("Name is invalid");
}
}
// Tests that apply to both data and header.
// Size can be verified only if it is known in the local header.
// it will always be known in the central header.
if (((localFlags & (int)GeneralBitFlags.Descriptor) == 0) ||
((size > 0) || (compressedSize > 0))) {
if (size != entry.Size) {
throw new ZipException(
string.Format("Size mismatch between central header({0}) and local header({1})",
entry.Size, size));
}
if (compressedSize != entry.CompressedSize &&
compressedSize != 0xFFFFFFFF && compressedSize != -1) {
throw new ZipException(
string.Format("Compressed size mismatch between central header({0}) and local header({1})",
entry.CompressedSize, compressedSize));
}
}
int extraLength = storedNameLength + extraDataLength;
return offsetOfFirstEntry + entry.Offset + ZipConstants.LocalHeaderBaseSize + extraLength;
}
}
