//
// ========================================================================
// Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
//
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
//
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
//
// You may elect to redistribute this code under either of these licenses.
// ========================================================================
//
package org.eclipse.jetty.server.handler;
import java.io.File;
import java.net.URI;
import java.nio.file.Files;
import java.nio.file.Path;
import org.eclipse.jetty.server.handler.ContextHandler.AliasCheck;
import org.eclipse.jetty.util.log.Log;
import org.eclipse.jetty.util.log.Logger;
import org.eclipse.jetty.util.resource.PathResource;
import org.eclipse.jetty.util.resource.Resource;
/* ------------------------------------------------------------ */
/** Symbolic Link AliasChecker.
* <p>An instance of this class can be registered with {@link ContextHandler#addAliasCheck(AliasCheck)}
* to check resources that are aliased to other locations. The checker uses the
* Java {@link Files#readSymbolicLink(Path)} and {@link Path#toRealPath(java.nio.file.LinkOption...)}
* APIs to check if a file is aliased with symbolic links.</p>
*/
public class AllowSymLinkAliasChecker implements AliasCheck
{
private static final Logger LOG = Log.getLogger(AllowSymLinkAliasChecker.class);
@Override
public boolean check(String uri, Resource resource)
{
// Only support PathResource alias checking
if (!(resource instanceof PathResource))
return false;
PathResource pathResource = (PathResource)resource;
try
{
Path path = pathResource.getPath();
// is the file itself a symlink?
if (Files.isSymbolicLink(path) && Files.isSameFile(path,pathResource.getAliasPath()))
{
if (LOG.isDebugEnabled())
LOG.debug("Allow symlink {} --> {}",resource,pathResource.getAliasPath());
return true;
}
// No, so let's check each element ourselves
Path d = path.getRoot();
for (Path e:path)
{
d=d.resolve(e);
while (Files.exists(d) && Files.isSymbolicLink(d))
{
Path link=Files.readSymbolicLink(d);
if (!link.isAbsolute())
link=d.resolve(link);
d=link;
}
}
if (pathResource.getAliasPath().equals(d))
{
if (LOG.isDebugEnabled())
LOG.debug("Allow path symlink {} --> {}",resource,d);
return true;
}
}
catch(Exception e)
{
LOG.ignore(e);
}
return false;
}
}