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/*
* Copyright (C) 2005-2015 Schlichtherle IT Services.
* All rights reserved. Use is subject to license terms.
*/
package net.java.truevfs.driver.zip.raes;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.channels.SeekableByteChannel;
import javax.annotation.CheckForNull;
import javax.annotation.WillNotClose;
import javax.annotation.concurrent.Immutable;
import net.java.truecommons.cio.Entry;
import net.java.truecommons.cio.Entry.Type;
import net.java.truecommons.cio.InputService;
import net.java.truecommons.cio.OutputService;
import net.java.truecommons.shed.BitField;
import net.java.truevfs.comp.zipdriver.JarDriver;
import net.java.truevfs.comp.zipdriver.JarDriverEntry;
import net.java.truevfs.comp.zipdriver.ZipInputService;
import net.java.truevfs.comp.zipdriver.ZipOutputService;
import net.java.truevfs.driver.zip.raes.crypto.RaesOutputStream;
import net.java.truevfs.driver.zip.raes.crypto.RaesParameters;
import net.java.truevfs.driver.zip.raes.crypto.RaesReadOnlyChannel;
import net.java.truevfs.kernel.spec.FsAccessOption;
import static net.java.truevfs.kernel.spec.FsAccessOption.*;
import net.java.truevfs.kernel.spec.FsController;
import net.java.truevfs.kernel.spec.FsInputSocketSource;
import net.java.truevfs.kernel.spec.FsModel;
import net.java.truevfs.kernel.spec.FsNodeName;
import net.java.truevfs.kernel.spec.FsOutputSocketSink;
import net.java.truevfs.kernel.spec.cio.MultiplexingOutputService;
/**
* An abstract archive driver for RAES encrypted ZIP files which optionally
* authenticates the cipher data of the input archive files presented to it.
*
* Sub-classes must be thread-safe and should be immutable!
*
* @author Christian Schlichtherle
*/
@Immutable
public abstract class ZipRaesDriver extends JarDriver {
/**
* {@inheritDoc}
*
* The implementation in the class {@link ZipRaesDriver} returns
* {@code true} for future use.
*
* @return {@code true}
*/
@Override
public final boolean getPreambled() { return true; }
/**
* Returns the RAES parameters for the given file system model.
*
* The implementation in the class {@link ZipRaesDriver} returns
* {@code new KeyManagerRaesParameters(getKeyManagerMap().getKeyManager(AesPbeParameters.class), mountPointUri(model))}.
*
* @param model the file system model.
* @return The RAES parameters for the given file system model.
*/
protected RaesParameters raesParameters(FsModel model) {
return new KeyManagerRaesParameters(getKeyManagerMap(),
mountPointUri(model));
}
/**
* Returns the value of the property {@code authenticationTrigger}.
*
* If the cipher text length of an input RAES file is smaller than or equal
* to this value, then the Hash-based Message Authentication Code (HMAC)
* for the entire cipher text is computed and verified in order to
* authenticate the input RAES file.
*
* Otherwise, if the cipher text length of an input RAES file is greater
* than this value, then initially only the cipher key and the cipher text
* length getKeyManager authenticated.
* In addition, whenever an entry is subsequently accessed, then it's
* CRC-32 value is checked.
*
* Consequently, if the value of this property is set to a negative value,
* then the entire cipher text gets never authenticated (CRC-32
* checking only), and if set to {@link Long#MAX_VALUE}, then the entire
* cipher text gets always authenticated (no CRC-32 checking).
*
* @return The value of the property {@code authenticationTrigger}.
*/
protected abstract long getAuthenticationTrigger();
@Override
public final boolean check(JarDriverEntry local, ZipInputService input) {
// Optimization: If the cipher text alias the encrypted ZIP file is
// smaller than the authentication trigger, then its entire cipher text
// has already been authenticated by {@link ZipRaesDriver#zipInput}.
// Hence, checking the CRC-32 value of the entry is redundant.
return input.length() > getAuthenticationTrigger();
}
/**
* {@inheritDoc}
*
* The implementation in the class {@link ZipRaesDriver} decorates the given controller with a package private
* controller which keeps track of the AES PBE parameters, e.g. the encryption passwords.
* This method should be overridden in order to return just {@code controller} if and only if you are overriding
* {@link #raesParameters(FsModel)}, too, and do not want to use a locatable key manager to resolve
* passwords for RAES encryption.
*/
@Override
public FsController decorate(FsController controller) { return new ZipRaesKeyController(controller, this); }
@Override
protected ZipInputService newZipInput(
final FsModel model,
final FsInputSocketSource source)
throws IOException {
final class Source extends FsInputSocketSource {
Source() { super(source); }
@Override
public SeekableByteChannel channel() throws IOException {
final RaesReadOnlyChannel channel = RaesReadOnlyChannel
.create(raesParameters(model), source);
try {
if (channel.size() <= getAuthenticationTrigger())
channel.authenticate();
return channel;
} catch (final Throwable ex) {
try {
channel.close();
} catch (final IOException ex2) {
ex.addSuppressed(ex2);
}
throw ex;
}
}
}
return new ZipInputService<>(model, new Source(), this);
}
@Override
protected OutputService newOutput(
final FsModel model,
final FsOutputSocketSink sink,
final @CheckForNull @WillNotClose InputService input)
throws IOException {
final ZipInputService zis = (ZipInputService) input;
return new MultiplexingOutputService<>(getPool(),
new ZipOutputService<>(model, new RaesSocketSink(model, sink), zis, this));
}
@SuppressWarnings("PackageVisibleInnerClass")
final class RaesSocketSink extends FsOutputSocketSink {
private final FsModel model;
private final FsOutputSocketSink sink;
RaesSocketSink(final FsModel model, final FsOutputSocketSink sink) {
super(sink);
this.model = model;
this.sink = sink;
}
@Override
public OutputStream stream() throws IOException {
return RaesOutputStream.create(raesParameters(model), sink);
}
@Override
public SeekableByteChannel channel() throws IOException {
throw new UnsupportedOperationException();
}
}
/**
* Sets {@link FsAccessOption#STORE} in {@code options} before
* forwarding the call to {@code controller}.
*/
@Override
protected final FsOutputSocketSink sink(
BitField options,
final FsController controller,
final FsNodeName name) {
// Leave FsAccessOption.COMPRESS untouched - the driver shall be given
// opportunity to apply its own preferences to sort out such a conflict.
options = options.set(STORE);
// The RAES file format cannot support GROWing.
options = options.clear(GROW);
return new FsOutputSocketSink(options,
controller.output(options, name, null));
}
/**
* Returns a new {@link JarDriverEntry}, requesting that the data gets
* {@code DEFLATED} if no template is provided.
* This feature strengthens the security level of the authentication
* process and inhibits the use of an unencrypted temporary I/O entry
* (usually a temporary file) in case the sink is not copied from a file
* system entry as its input.
*
* Furthermore, the method {@link JarDriverEntry#clearEncryption()} is
* called in order to prevent adding a redundant encryption layer for the
* individual ZIP entry because this would confuse users, increase the size
* of the resulting archive file and unecessarily heat the CPU.
*/
@Override
public JarDriverEntry newEntry(
final BitField options,
final String name,
final Type type,
final @CheckForNull Entry template) {
final JarDriverEntry entry
= super.newEntry(options.set(COMPRESS), name, type, template);
// Fix for http://java.net/jira/browse/TRUEZIP-176 :
// Entry level encryption is enabled if make.getKeyManager(ENCRYPTED) is true
// OR template is an instance of ZipEntry
// AND ((ZipEntry) template).isEncrypted() is true.
// Now switch off entry level encryption because encryption is already
// provided by the RAES wrapper file format.
entry.clearEncryption();
return entry;
}
}