de.intarsys.pdf.crypt.SystemSecurityHandler Maven / Gradle / Ivy
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This is a fork of http://sourceforge.net/projects/jpodlib/ as development seems to be frozen.
We're providing some bug fixes along with deployments to maven.
/*
* Copyright (c) 2007, intarsys consulting GmbH
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* - Neither the name of intarsys nor the names of its contributors may be used
* to endorse or promote products derived from this software without specific
* prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
package de.intarsys.pdf.crypt;
import de.intarsys.pdf.cos.COSArray;
import de.intarsys.pdf.cos.COSCompositeObject;
import de.intarsys.pdf.cos.COSDictionary;
import de.intarsys.pdf.cos.COSInteger;
import de.intarsys.pdf.cos.COSNumber;
import de.intarsys.pdf.cos.COSStream;
import de.intarsys.pdf.cos.COSTrailer;
import de.intarsys.pdf.st.EnumWriteMode;
import de.intarsys.pdf.st.STDocument;
import de.intarsys.pdf.st.STStreamXRefSection;
/**
* An abstract superclass for implementing the PDF security process.
*/
public abstract class SystemSecurityHandler implements ISystemSecurityHandler {
public static final int DEFAULT_LENGTH = 40;
public static SystemSecurityHandler createFromSt(STDocument doc) throws COSSecurityException {
SystemSecurityHandler systemSecurityHandler = null;
COSDictionary dict = doc.cosGetTrailer().get(COSTrailer.DK_Encrypt).asDictionary();
if (dict != null) {
int version = 0;
COSNumber cosVersion = dict.get(COSEncryption.DK_V).asNumber();
if (cosVersion != null) {
version = cosVersion.intValue();
}
if (version == 0) {
systemSecurityHandler = new SystemSecurityHandlerV0(dict);
} else if (version == 1) {
systemSecurityHandler = new SystemSecurityHandlerV1(dict);
} else if (version == 2) {
systemSecurityHandler = new SystemSecurityHandlerV2(dict);
} else if (version == 3) {
systemSecurityHandler = new SystemSecurityHandlerV3(dict);
} else if (version == 4) {
systemSecurityHandler = new SystemSecurityHandlerV4(dict);
} else {
throw new COSSecurityException("unsupported security version " + version);
}
systemSecurityHandler.initialize(doc);
}
return systemSecurityHandler;
}
public static SystemSecurityHandler createNewV1() {
COSDictionary dict = COSDictionary.create();
dict.beIndirect();
SystemSecurityHandler result = new SystemSecurityHandlerV1(dict);
result.initializeFromScratch();
return result;
}
public static SystemSecurityHandler createNewV2() {
COSDictionary dict = COSDictionary.create();
dict.beIndirect();
SystemSecurityHandler result = new SystemSecurityHandlerV2(dict);
result.initializeFromScratch();
return result;
}
public static SystemSecurityHandler createNewV4() {
COSDictionary dict = COSDictionary.create();
dict.beIndirect();
SystemSecurityHandler result = new SystemSecurityHandlerV4(dict);
result.initializeFromScratch();
return result;
}
private final COSDictionary cosEncryption;
private COSArray currentCosIDs;
private final COSEncryption encryption;
private COSDictionary currentCosTrailer;
private COSDictionary currentCosEncryption;
private ISecurityHandler securityHandler;
private STDocument stDoc;
private COSCompositeObject[] contextStack = new COSCompositeObject[5];
private short stackPtr = -1;
private boolean enabled = true;
protected SystemSecurityHandler(COSDictionary dict) {
this.cosEncryption = dict;
this.currentCosEncryption = cosEncryption;
this.encryption = (COSEncryption) COSEncryption.META.createFromCos(dict);
}
@Override
public void attach(STDocument stDoc) throws COSSecurityException {
this.stDoc = stDoc;
currentCosTrailer = stDoc.cosGetTrailer();
currentCosIDs = currentCosTrailer.get(COSTrailer.DK_ID).asArray();
currentCosTrailer.put(COSTrailer.DK_Encrypt, cosGetEncryption());
if (getSecurityHandler() != null) {
getSecurityHandler().attach(stDoc);
}
forceFullWrite();
}
@Override
public void authenticate() throws COSSecurityException {
securityHandler.authenticate();
}
public COSDictionary cosGetEncryption() {
return cosEncryption;
}
@Override
public void detach(STDocument stDoc) throws COSSecurityException {
if (getSecurityHandler() != null) {
getSecurityHandler().detach(stDoc);
}
stDoc.cosGetTrailer().remove(COSTrailer.DK_Encrypt);
forceFullWrite();
// don't eliminate back reference
}
protected void forceFullWrite() {
if (stGetDoc() == null) {
return;
}
stGetDoc().setWriteModeHint(EnumWriteMode.FULL);
}
@Override
public COSCompositeObject getContextObject() {
if (stackPtr < 0) {
return null;
}
return contextStack[stackPtr];
}
public COSEncryption getEncryption() {
return encryption;
}
@Override
public int getLength() {
COSEncryption encryption = getEncryption();
return encryption.getFieldInt(COSEncryption.DK_Length, DEFAULT_LENGTH);
}
@Override
public ISecurityHandler getSecurityHandler() {
return securityHandler;
}
public abstract int getVersion();
@Override
public void initialize(STDocument doc) throws COSSecurityException {
this.stDoc = doc;
initializeFromSt();
}
protected void initializeFromScratch() {
COSEncryption encryption = getEncryption();
encryption.cosSetField(COSEncryption.DK_V, COSInteger.create(getVersion()));
}
protected void initializeFromSt() throws COSSecurityException {
COSEncryption encryption = getEncryption();
securityHandler = SecurityHandlerFactory.get().getSecurityHandler(encryption);
securityHandler.initialize(stGetDoc());
}
protected boolean isEnabled() {
return enabled;
}
@Override
public COSCompositeObject popContextObject() {
COSCompositeObject contextObject = contextStack[stackPtr--];
// enable encryption when no longer in encryption dict of file id's
if (contextObject == currentCosEncryption || contextObject == currentCosIDs) {
enabled = true;
}
if (contextObject instanceof COSStream) {
COSDictionary dict = contextObject.asStream().getDict();
if (dict != null && dict.get(STStreamXRefSection.DK_Type).equals(STStreamXRefSection.CN_Type_XRef)) {
// /XRef streams are not encrypted
enabled = true;
}
}
return contextObject;
}
@Override
public void pushContextObject(COSCompositeObject contextObject) {
stackPtr++;
if (stackPtr >= contextStack.length) {
COSCompositeObject[] tempStack = new COSCompositeObject[contextStack.length + 5];
System.arraycopy(contextStack, 0, tempStack, 0, contextStack.length);
contextStack = tempStack;
}
contextStack[stackPtr] = contextObject;
// do not encrypt within encryption dict and file id's
if (contextObject == currentCosEncryption || contextObject == currentCosIDs) {
enabled = false;
}
if (contextObject instanceof COSStream) {
COSDictionary dict = contextObject.asStream().getDict();
if (dict != null && dict.get(STStreamXRefSection.DK_Type).equals(STStreamXRefSection.CN_Type_XRef)) {
// /XRef streams are not encrypted
enabled = false;
}
}
}
public void setLength(int length) {
COSEncryption encryption = getEncryption();
encryption.setFieldInt(COSEncryption.DK_Length, length);
}
@Override
public void setSecurityHandler(ISecurityHandler pSecurityHandler) throws COSSecurityException {
if (securityHandler != null) {
securityHandler.detach(stGetDoc());
}
securityHandler = pSecurityHandler;
if (securityHandler != null) {
securityHandler.attach(stGetDoc());
}
}
@Override
public STDocument stGetDoc() {
return stDoc;
}
@Override
public void updateTrailer(COSDictionary trailer) {
this.currentCosTrailer = trailer;
this.currentCosIDs = currentCosTrailer.get(COSTrailer.DK_ID).asArray();
this.currentCosEncryption = trailer.get(COSTrailer.DK_Encrypt).asDictionary();
}
}