Overwritten SecHandler for PDF-Protection

2 files changed, 429 insertions, 0 deletions

diff --git a/pdf-as-lib/src/main/java/at/gv/egiz/pdfas/lib/util/DefaultSecHandlerFactory.java b/pdf-as-lib/src/main/java/at/gv/egiz/pdfas/lib/util/DefaultSecHandlerFactory.java
new file mode 100644
index 00000000..f1f4ab38
--- /dev/null
+++ b/pdf-as-lib/src/main/java/at/gv/egiz/pdfas/lib/util/DefaultSecHandlerFactory.java
@@ -0,0 +1,162 @@
+package at.gv.egiz.pdfas.lib.util;/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import org.apache.pdfbox.pdmodel.encryption.*;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+import java.util.HashMap;
+import java.util.Map;
+
+
+/**
+ * Manages security handlers for the application.
+ * It follows the singleton pattern.
+ * To be usable, security managers must be registered in it.
+ * Security managers are retrieved by the application when necessary.
+ *
+ * @author Benoit Guillon
+ * @author John Hewson
+ */
+public final class DefaultSecHandlerFactory
+{
+    /** Singleton instance */
+    public static final DefaultSecHandlerFactory INSTANCE = new DefaultSecHandlerFactory();
+
+    static
+    {
+
+        //Security.addProvider(new BouncyCastleProvider());
+    }
+
+    private final Map<String, Class<? extends SecurityHandler>> nameToHandler =
+            new HashMap<String, Class<? extends SecurityHandler>>();
+
+    private final Map<Class<? extends ProtectionPolicy>,
+            Class<? extends SecurityHandler>> policyToHandler =
+            new HashMap<Class<? extends ProtectionPolicy>,
+                    Class<? extends SecurityHandler>>();
+
+    private DefaultSecHandlerFactory()
+    {
+        registerHandler(StandardSecurityHandler.FILTER,
+                StandardSecurityHandler.class,
+                StandardProtectionPolicy.class);
+
+        registerHandler(PublicKeySecurityHandler.FILTER,
+                PublicKeySecurityHandler.class,
+                PublicKeyProtectionPolicy.class);
+    }
+
+    /**
+     * Registers a security handler.
+     *
+     * If the security handler was already registered an exception is thrown.
+     * If another handler was previously registered for the same filter name or
+     * for the same policy name, an exception is thrown
+     *
+     * @param name the name of the filter
+     * @param securityHandler security handler class to register
+     * @param protectionPolicy protection policy class to register
+     */
+    public void registerHandler(String name,
+                                Class<? extends SecurityHandler> securityHandler,
+                                Class<? extends ProtectionPolicy> protectionPolicy)
+    {
+        if (nameToHandler.containsKey(name))
+        {
+            throw new IllegalStateException("The security handler name is already registered");
+        }
+
+        nameToHandler.put(name, securityHandler);
+        policyToHandler.put(protectionPolicy, securityHandler);
+    }
+
+    /**
+     * Returns a new security handler for the given protection policy, or null none is available.
+     * @param policy the protection policy for which to create a security handler
+     * @return a new SecurityHandler instance, or null if none is available
+     */
+    public SecurityHandler newSecurityHandlerForPolicy(ProtectionPolicy policy)
+    {
+        Class<? extends SecurityHandler> handlerClass = policyToHandler.get(policy.getClass());
+        if (handlerClass == null)
+        {
+            return null;
+        }
+
+        Class<?>[] argsClasses = { policy.getClass() };
+        Object[] args = { policy };
+        return newSecurityHandler(handlerClass, argsClasses, args);
+    }
+
+    /**
+     * Returns a new security handler for the given Filter name, or null none is available.
+     * @param name the Filter name from the PDF encryption dictionary
+     * @return a new SecurityHandler instance, or null if none is available
+     */
+    public SecurityHandler newSecurityHandlerForFilter(String name)
+    {
+        Class<? extends SecurityHandler> handlerClass = nameToHandler.get(name);
+        if (handlerClass == null)
+        {
+            return null;
+        }
+
+        Class<?>[] argsClasses = { };
+        Object[] args = { };
+        return newSecurityHandler(handlerClass, argsClasses, args);
+    }
+
+    /* Returns a new security handler for the given parameters, or null none is available.
+     *
+     * @param handlerClass the handler class.
+     * @param argsClasses the parameter array.
+     * @param args array of objects to be passed as arguments to the constructor call.
+     * @return a new SecurityHandler instance, or null if none is available.
+     */
+    private SecurityHandler newSecurityHandler(Class<? extends SecurityHandler> handlerClass,
+                                               Class<?>[] argsClasses, Object[] args)
+    {
+        try
+        {
+            Constructor<? extends SecurityHandler> ctor =
+                    handlerClass.getDeclaredConstructor(argsClasses);
+            return ctor.newInstance(args);
+        }
+        catch(NoSuchMethodException e)
+        {
+            // should not happen in normal operation
+            throw new RuntimeException(e);
+        }
+        catch(IllegalAccessException e)
+        {
+            // should not happen in normal operation
+            throw new RuntimeException(e);
+        }
+        catch(InstantiationException e)
+        {
+            // should not happen in normal operation
+            throw new RuntimeException(e);
+        }
+        catch(InvocationTargetException e)
+        {
+            // should not happen in normal operation
+            throw new RuntimeException(e);
+        }
+    }
+}
diff --git a/pdf-as-lib/src/main/java/at/gv/egiz/pdfas/lib/util/PDDocumentUtil.java b/pdf-as-lib/src/main/java/at/gv/egiz/pdfas/lib/util/PDDocumentUtil.java
new file mode 100644
index 00000000..11ecf2bc
--- /dev/null
+++ b/pdf-as-lib/src/main/java/at/gv/egiz/pdfas/lib/util/PDDocumentUtil.java
@@ -0,0 +1,267 @@
+package at.gv.egiz.pdfas.lib.util;/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import org.apache.commons.logging.LogFactory;
+import org.apache.pdfbox.cos.COSDocument;
+import org.apache.pdfbox.io.*;
+import org.apache.pdfbox.pdfparser.PDFParser;
+import org.apache.pdfbox.pdmodel.PDDocument;
+import org.apache.pdfbox.pdmodel.encryption.AccessPermission;
+import org.apache.pdfbox.pdmodel.encryption.PDEncryption;
+import org.apache.pdfbox.pdmodel.encryption.ProtectionPolicy;
+import org.apache.pdfbox.pdmodel.encryption.SecurityHandler;
+import org.slf4j.Logger;
+import sun.rmi.runtime.Log;
+
+import java.io.Closeable;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * This is the in-memory representation of the PDF document.
+ * The #close() method must be called once the document is no longer needed.
+ *
+ * @author Ben Litchfield
+ */
+public class PDDocumentUtil extends PDDocument
+{
+    private static final org.apache.commons.logging.Log logger = LogFactory.getLog(PDDocumentUtil.class);
+
+    // the encryption will be cached here. When the document is decrypted then
+    // the COSDocument will not have an "Encrypt" dictionary anymore and this object must be used
+    private PDEncryption encryption;
+
+    // holds a flag which tells us if we should remove all security from this documents.
+    private boolean allSecurityToBeRemoved;
+
+
+    // the access permissions of the document
+    private AccessPermission accessPermission;
+
+    private  COSDocument document=null;
+    // the pdf to be read
+    private  RandomAccessRead pdfSource=null;
+
+
+
+    public PDDocumentUtil()
+    {
+    }
+
+    /**
+     * Constructor that uses an existing document. The COSDocument that is passed in must be valid.
+     *
+     * @param doc The COSDocument that this document wraps.
+     * @param source the parser which is used to read the pdf
+     * @param permission he access permissions of the pdf
+     *
+     */
+    public PDDocumentUtil(COSDocument doc, RandomAccessRead source, AccessPermission permission)
+    {
+        document = doc;
+        pdfSource = source;
+        accessPermission = permission;
+    }
+
+    public static PDDocument load(File file) throws IOException
+    {
+        return load(file, "", MemoryUsageSetting.setupMainMemoryOnly());
+    }
+
+    /**
+     * Parses a PDF.
+     *
+     * @param file file to be loaded
+     * @param memUsageSetting defines how memory is used for buffering PDF streams
+     *
+     * @return loaded document
+     *
+     * @throws IOException in case of a file reading or parsing error
+     */
+    public static PDDocument load(File file, MemoryUsageSetting memUsageSetting) throws IOException
+    {
+        return load(file, "", null, null, memUsageSetting);
+    }
+
+    /**
+     * Parses a PDF. Unrestricted main memory will be used for buffering PDF streams.
+     *
+     * @param file file to be loaded
+     * @param password password to be used for decryption
+     *
+     * @return loaded document
+     *
+     * @throws IOException in case of a file reading or parsing error
+     */
+    public static PDDocument load(File file, String password) throws IOException
+    {
+        return load(file, password, null, null, MemoryUsageSetting.setupMainMemoryOnly());
+    }
+
+    /**
+     * Parses a PDF.
+     *
+     * @param file file to be loaded
+     * @param password password to be used for decryption
+     * @param memUsageSetting defines how memory is used for buffering PDF streams
+     *
+     * @return loaded document
+     *
+     * @throws IOException in case of a file reading or parsing error
+     */
+    public static PDDocument load(File file, String password, MemoryUsageSetting memUsageSetting) throws IOException
+    {
+        return load(file, password, null, null, memUsageSetting);
+    }
+
+    /**
+     * Parses a PDF. Unrestricted main memory will be used for buffering PDF streams.
+     *
+     * @param file file to be loaded
+     * @param password password to be used for decryption
+     * @param keyStore key store to be used for decryption when using public key security
+     * @param alias alias to be used for decryption when using public key security
+     *
+     * @return loaded document
+     *
+     * @throws IOException in case of a file reading or parsing error
+     */
+    public static PDDocument load(File file, String password, InputStream keyStore, String alias)
+            throws IOException
+    {
+        return load(file, password, keyStore, alias, MemoryUsageSetting.setupMainMemoryOnly());
+    }
+
+    /**
+     * Parses a PDF.
+     *
+     * @param file file to be loaded
+     * @param password password to be used for decryption
+     * @param keyStore key store to be used for decryption when using public key security
+     * @param alias alias to be used for decryption when using public key security
+     * @param memUsageSetting defines how memory is used for buffering PDF streams
+     *
+     * @return loaded document
+     *
+     * @throws IOException in case of a file reading or parsing error
+     */
+    public static PDDocument load(File file, String password, InputStream keyStore, String alias,
+                                  MemoryUsageSetting memUsageSetting) throws IOException
+    {
+        RandomAccessBufferedFileInputStream raFile = new RandomAccessBufferedFileInputStream(file);
+        try
+        {
+            ScratchFile scratchFile = new ScratchFile(memUsageSetting);
+            try
+            {
+                PDFParser parser = new PDFParser(raFile, password, keyStore, alias, scratchFile);
+                parser.parse();
+                return parser.getPDDocument();
+            }
+            catch (IOException ioe)
+            {
+                IOUtils.closeQuietly(scratchFile);
+                throw ioe;
+            }
+        }
+        catch (IOException ioe)
+        {
+            IOUtils.closeQuietly(raFile);
+            throw ioe;
+        }
+    }
+
+
+
+
+    /**
+     * Protects the document with a protection policy. The document content will be really
+     * encrypted when it will be saved. This method only marks the document for encryption. It also
+     * calls {@link #setAllSecurityToBeRemoved(boolean)} with a false argument if it was set to true
+     * previously and logs a warning.
+     *
+     * @see org.apache.pdfbox.pdmodel.encryption.StandardProtectionPolicy
+     * @see org.apache.pdfbox.pdmodel.encryption.PublicKeyProtectionPolicy
+     *
+     * @param policy The protection policy.
+     * @throws IOException if there isn't any suitable security handler.
+     */
+    public void protect(ProtectionPolicy policy) throws IOException
+    {
+        if (isAllSecurityToBeRemoved())
+        {
+            logger.warn("do not call setAllSecurityToBeRemoved(true) before calling protect(), "
+                    + "as protect() implies setAllSecurityToBeRemoved(false)");
+            setAllSecurityToBeRemoved(false);
+        }
+
+        if (!isEncrypted())
+        {
+            encryption = new PDEncryption();
+        }
+
+        SecurityHandler securityHandler = DefaultSecHandlerFactory.INSTANCE.newSecurityHandlerForPolicy(policy);
+       if (securityHandler == null)
+        {
+          throw new IOException("No security handler for policy " + policy);
+        }
+
+        try {
+            getEncryption().setSecurityHandler(securityHandler);
+        } catch (NullPointerException nle){logger.warn("Could not set Encryption type");}
+    }
+
+    /**
+     * Returns the access permissions granted when the document was decrypted. If the document was not decrypted this
+     * method returns the access permission for a document owner (ie can do everything). The returned object is in read
+     * only mode so that permissions cannot be changed. Methods providing access to content should rely on this object
+     * to verify if the current user is allowed to proceed.
+     *
+     * @return the access permissions for the current user on the document.
+     */
+    public AccessPermission getCurrentAccessPermission()
+    {
+        if (accessPermission == null)
+        {
+            accessPermission = AccessPermission.getOwnerAccessPermission();
+        }
+        return accessPermission;
+    }
+
+    /**
+     * Indicates if all security is removed or not when writing the pdf.
+     *
+     * @return returns true if all security shall be removed otherwise false
+     */
+    public boolean isAllSecurityToBeRemoved()
+    {
+        return allSecurityToBeRemoved;
+    }
+
+    /**
+     * Activates/Deactivates the removal of all security when writing the pdf.
+     *
+     * @param removeAllSecurity remove all security if set to true
+     */
+    public void setAllSecurityToBeRemoved(boolean removeAllSecurity)
+    {
+        allSecurityToBeRemoved = removeAllSecurity;
+    }
+
+    }
+