/// <summary>
/// Perform the initial read on an entry which may include
/// reading encryption headers and setting up inflation.
/// </summary>
/// <param name="destination">The destination to fill with data read.</param>
/// <param name="offset">The offset to start reading at.</param>
/// <param name="count">The maximum number of bytes to read.</param>
/// <returns>The actual number of bytes read.</returns>
int InitialRead(byte[] destination, int offset, int count)
{
if ( !CanDecompressEntry ) {
throw new ZipException("Library cannot extract this entry. Version required is (" + entry.Version.ToString() + ")");
}
// Handle encryption if required.
if (entry.IsCrypted) {
#if COMPACT_FRAMEWORK_V10
throw new ZipException("Encyptiong not supported for Compact Framework 1.0");
#else
if (password == null) {
throw new ZipException("No password set.");
}
// Generate and set crypto transform...
PkzipClassicManaged managed = new PkzipClassicManaged();
byte[] key = PkzipClassic.GenerateKeys(Encoding.ASCII.GetBytes(password));
inputBuffer.CryptoTransform = managed.CreateDecryptor(key, null);
byte[] cryptbuffer = new byte[ZipConstants.CryptoHeaderSize];
inputBuffer.ReadClearTextBuffer(cryptbuffer, 0, ZipConstants.CryptoHeaderSize);
if (cryptbuffer[ZipConstants.CryptoHeaderSize - 1] != entry.CryptoCheckValue) {
throw new ZipException("Invalid password");
}
if (csize >= ZipConstants.CryptoHeaderSize) {
csize -= ZipConstants.CryptoHeaderSize;
}
#endif
} else {
#if !COMPACT_FRAMEWORK_V10
inputBuffer.CryptoTransform = null;
#endif
}
if ( (method == (int)CompressionMethod.Deflated) && (inputBuffer.Available > 0) ) {
inputBuffer.SetInflaterInput(inf);
}
internalReader = new ReaderDelegate(BodyRead);
return BodyRead(destination, offset, count);
}
private int InitialRead(byte[] destination, int offset, int count)
{
if (!CanDecompressEntry)
{
throw new ZipException("Library cannot extract this entry. Version required is ("
+ _entry.Version + ")");
}
if (_entry.IsCrypted)
{
if (_password == null)
{
throw new ZipException("No password set.");
}
var managed = new PkzipClassicManaged();
var rgbKey = PkzipClassic.GenerateKeys(ZipConstants.ConvertToArray(_password));
InputBuffer.CryptoTransform = managed.CreateDecryptor(rgbKey, null);
var outBuffer = new byte[12];
InputBuffer.ReadClearTextBuffer(outBuffer, 0, 12);
if (outBuffer[11] != _entry.CryptoCheckValue)
{
throw new ZipException("Invalid password");
}
if (Csize < 12L)
{
if ((_entry.Flags & 8) == 0)
{
throw new ZipException($"Entry compressed size {Csize} too small for encryption");
}
}
else
{
Csize -= 12L;
}
}
else
{
InputBuffer.CryptoTransform = null;
}
if ((Csize > 0L) || ((_flags & 8) != 0))
{
if ((_method == 8) && (InputBuffer.Available > 0))
{
InputBuffer.SetInflaterInput(Inf);
}
_internalReader = BodyRead;
return BodyRead(destination, offset, count);
}
_internalReader = ReadingNotAvailable;
return 0;
}
Stream CreateAndInitDecryptionStream(Stream baseStream, ZipEntry entry)
{
CryptoStream result = null;
if ( (entry.Version < ZipConstants.VersionStrongEncryption)
|| (entry.Flags & (int)GeneralBitFlags.StrongEncryption) == 0) {
PkzipClassicManaged classicManaged = new PkzipClassicManaged();
OnKeysRequired(entry.Name);
if (HaveKeys == false) {
throw new ZipException("No password available for encrypted stream");
}
result = new CryptoStream(baseStream, classicManaged.CreateDecryptor(key, null), CryptoStreamMode.Read);
CheckClassicPassword(result, entry);
}
else {
throw new ZipException("Decryption method not supported");
}
return result;
}
private Stream CreateAndInitDecryptionStream(Stream baseStream, ZipEntry entry)
{
if ((entry.Version < 50) || ((entry.Flags & 0x40) == 0))
{
var managed = new PkzipClassicManaged();
OnKeysRequired(entry.Name);
if (!HaveKeys)
{
throw new ZipException("No password available for encrypted stream");
}
var classicCryptoStream
= new CryptoStream(baseStream, managed.CreateDecryptor(_key, null), CryptoStreamMode.Read);
CheckClassicPassword(classicCryptoStream, entry);
return classicCryptoStream;
}
if (entry.Version != 0x33)
{
throw new ZipException("Decryption method not supported");
}
OnKeysRequired(entry.Name);
if (!HaveKeys)
{
throw new ZipException("No password available for AES encrypted stream");
}
var aEsSaltLen = entry.AesSaltLen;
var buffer = new byte[aEsSaltLen];
var num2 = baseStream.Read(buffer, 0, aEsSaltLen);
if (num2 != aEsSaltLen)
{
throw new ZipException(string.Concat(new object[] { "AES Salt expected ", aEsSaltLen, " got ", num2 }));
}
var buffer2 = new byte[2];
baseStream.Read(buffer2, 0, 2);
var blockSize = entry.AesKeySize / 8;
var transform = new ZipAESTransform(_rawPassword, buffer, blockSize, false);
var pwdVerifier = transform.PwdVerifier;
if ((pwdVerifier[0] != buffer2[0]) || (pwdVerifier[1] != buffer2[1]))
{
throw new Exception("Invalid password for AES");
}
return new ZipAESStream(baseStream, transform, CryptoStreamMode.Read);
}