/// <summary>
/// Test an archive for integrity/validity
/// </summary>
/// <param name="testData">Perform low level data Crc check</param>
/// <param name="strategy">The <see cref="TestStrategy"></see> to apply.</param>
/// <param name="resultHandler">The <see cref="ZipTestResultHandler"></see> handler to call during testing.</param>
/// <returns>true if all tests pass, false otherwise</returns>
/// <exception cref="ObjectDisposedException">The object has already been closed.</exception>
public bool TestArchive(bool testData, TestStrategy strategy, ZipTestResultHandler resultHandler)
{
if (isDisposed_) {
throw new ObjectDisposedException("ZipFile");
}
TestStatus status = new TestStatus(this);
if ( resultHandler != null ) {
resultHandler(status, null);
}
HeaderTest test = testData ? (HeaderTest.Header | HeaderTest.Extract) : HeaderTest.Header;
bool testing = true;
try {
int entryIndex = 0;
while ( testing && (entryIndex < Count) ) {
if ( resultHandler != null ) {
status.SetEntry(this[entryIndex]);
status.SetOperation(TestOperation.EntryHeader);
resultHandler(status, null);
}
try {
TestLocalHeader(this[entryIndex], test);
}
catch(ZipException ex) {
status.AddError();
if ( resultHandler != null ) {
resultHandler(status,
string.Format("Exception during test - '{0}'", ex.Message));
}
if ( strategy == TestStrategy.FindFirstError ) {
testing = false;
}
}
if ( testing && testData && this[entryIndex].IsFile ) {
if ( resultHandler != null ) {
status.SetOperation(TestOperation.EntryData);
resultHandler(status, null);
}
Crc32 crc = new Crc32();
using (Stream entryStream = this.GetInputStream(this[entryIndex]))
{
byte[] buffer = new byte[4096];
long totalBytes = 0;
int bytesRead;
while ((bytesRead = entryStream.Read(buffer, 0, buffer.Length)) > 0)
{
crc.Update(buffer, 0, bytesRead);
if (resultHandler != null)
{
totalBytes += bytesRead;
status.SetBytesTested(totalBytes);
resultHandler(status, null);
}
}
}
if (this[entryIndex].Crc != crc.Value) {
status.AddError();
if ( resultHandler != null ) {
resultHandler(status, "CRC mismatch");
}
if ( strategy == TestStrategy.FindFirstError ) {
testing = false;
}
}
if (( this[entryIndex].Flags & (int)GeneralBitFlags.Descriptor) != 0 ) {
ZipHelperStream helper = new ZipHelperStream(baseStream_);
DescriptorData data = new DescriptorData();
helper.ReadDataDescriptor(this[entryIndex].LocalHeaderRequiresZip64, data);
if (this[entryIndex].Crc != data.Crc) {
status.AddError();
}
if (this[entryIndex].CompressedSize != data.CompressedSize) {
status.AddError();
}
if (this[entryIndex].Size != data.Size) {
status.AddError();
}
}
}
if ( resultHandler != null ) {
status.SetOperation(TestOperation.EntryComplete);
resultHandler(status, null);
}
entryIndex += 1;
}
if ( resultHandler != null ) {
status.SetOperation(TestOperation.MiscellaneousTests);
resultHandler(status, null);
}
// TODO: the 'Corrina Johns' test where local headers are missing from
// the central directory. They are therefore invisible to many archivers.
}
catch (Exception ex) {
status.AddError();
if ( resultHandler != null ) {
resultHandler(status, string.Format("Exception during test - '{0}'", ex.Message));
}
}
if ( resultHandler != null ) {
status.SetOperation(TestOperation.Complete);
status.SetEntry(null);
resultHandler(status, null);
}
return (status.ErrorCount == 0);
}
private byte[] IV(Salt secret, Salt salt)
{
// Long story, this has been a little difficult to finally settle upon an algorithm.
// We know we don't want to the same value each time, and we prefer not to use only
// the public salt. My biggest concern is not generating a IV value that interacts
// with AES in a way that might divulge information unintentionally. Since we are
// using the same values (salt+secret) to derive the IV this is a very real risk.
// To mitigate this risk the primary interaction of secret in the derivation of this
// value is compressed into a CRC of both the salt and secret. This value is then
// masked with computations of salt to produce the 16 IV bytes needed.
byte[] sbytes = salt.ToArray();
byte[] result = new byte[16];
// compute a mask from CRC32(salt + secret)
int mask = new Crc32(_salt.GetData(secret.ToArray()).ToArray()).Value;
// xor part of the mask with the sum of two salt bytes
for (int i = 0; i < 16; i++)
result[i] = (byte)((mask >> i) ^ (sbytes[i] + sbytes[i + 16]));
return result;
}
void CopyEntryDataDirect(ZipUpdate update, Stream stream, bool updateCrc, ref long destinationPosition, ref long sourcePosition)
{
long bytesToCopy = update.Entry.CompressedSize;
// NOTE: Compressed size is updated elsewhere.
Crc32 crc = new Crc32();
byte[] buffer = GetBuffer();
long targetBytes = bytesToCopy;
long totalBytesRead = 0;
int bytesRead;
do
{
int readSize = buffer.Length;
if ( bytesToCopy < readSize ) {
readSize = (int)bytesToCopy;
}
stream.Position = sourcePosition;
bytesRead = stream.Read(buffer, 0, readSize);
if ( bytesRead > 0 ) {
if ( updateCrc ) {
crc.Update(buffer, 0, bytesRead);
}
stream.Position = destinationPosition;
stream.Write(buffer, 0, bytesRead);
destinationPosition += bytesRead;
sourcePosition += bytesRead;
bytesToCopy -= bytesRead;
totalBytesRead += bytesRead;
}
}
while ( (bytesRead > 0) && (bytesToCopy > 0) );
if ( totalBytesRead != targetBytes ) {
throw new ZipException(string.Format("Failed to copy bytes expected {0} read {1}", targetBytes, totalBytesRead));
}
if ( updateCrc ) {
update.OutEntry.Crc = crc.Value;
}
}
void CopyBytes(ZipUpdate update, Stream destination, Stream source,
long bytesToCopy, bool updateCrc)
{
if ( destination == source ) {
throw new InvalidOperationException("Destination and source are the same");
}
// NOTE: Compressed size is updated elsewhere.
Crc32 crc = new Crc32();
byte[] buffer = GetBuffer();
long targetBytes = bytesToCopy;
long totalBytesRead = 0;
int bytesRead;
do {
int readSize = buffer.Length;
if ( bytesToCopy < readSize ) {
readSize = (int)bytesToCopy;
}
bytesRead = source.Read(buffer, 0, readSize);
if ( bytesRead > 0 ) {
if ( updateCrc ) {
crc.Update(buffer, 0, bytesRead);
}
destination.Write(buffer, 0, bytesRead);
bytesToCopy -= bytesRead;
totalBytesRead += bytesRead;
}
}
while ( (bytesRead > 0) && (bytesToCopy > 0) );
if ( totalBytesRead != targetBytes ) {
throw new ZipException(string.Format("Failed to copy bytes expected {0} read {1}", targetBytes, totalBytesRead));
}
if ( updateCrc ) {
update.OutEntry.Crc = crc.Value;
}
}
public static int getCRC(string inputString)
{
Crc32 crc = new Crc32();
crc.ComputeHash(System.Text.ASCIIEncoding.ASCII.GetBytes(inputString));
return (int)crc.CrcValue;
}
protected static UInt32 ComputeFingerprint(byte[] bytes, int length)
{
// Length correction is requred like in ComputeMessageIntegrity, but
// I assume that Fingerprint is last item always. It's true in most cases.
using (Crc32 crc32 = new Crc32())
{
crc32.ComputeHash(bytes, 0, length);
return crc32.CrcValue ^ 0x5354554e;
}
}
public static int CRC(byte[] bytes)
{
Crc32 crc32 = new Crc32();
return BitConverter.ToInt32(crc32.ComputeHash(bytes), 0);
}
