/*
* @(#)BasicConstraintsExtension.java 1.20 06/10/10
*
* Copyright 1990-2008 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 only, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License version 2 for more details (a copy is
* included at /legal/license.txt).
*
* You should have received a copy of the GNU General Public License
* version 2 along with this work; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
* Clara, CA 95054 or visit www.sun.com if you need additional
* information or have any questions.
*
*/
package sun.security.x509;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.reflect.Array;
import java.util.Enumeration;
import sun.security.util.*;
/**
* This class represents the Basic Constraints Extension.
*
* <p>The basic constraints extension identifies whether the subject of the
* certificate is a CA and how deep a certification path may exist
* through that CA.
*
* <pre>
* The ASN.1 syntax for this extension is:
* BasicConstraints ::= SEQUENCE {
* cA BOOLEAN DEFAULT FALSE,
* pathLenConstraint INTEGER (0..MAX) OPTIONAL
* }
* </pre>
* @author Amit Kapoor
* @author Hemma Prafullchandra
* @version 1.13
* @see CertAttrSet
* @see Extension
*/
public class BasicConstraintsExtension extends Extension
implements CertAttrSet {
/**
* Identifier for this attribute, to be used with the
* get, set, delete methods of Certificate, x509 type.
*/
public static final String IDENT = "x509.info.extensions.BasicConstraints";
/**
* Attribute names.
*/
public static final String NAME = "BasicConstraints";
public static final String IS_CA = "is_ca";
public static final String PATH_LEN = "path_len";
// Private data members
private boolean ca = false;
private int pathLen = -1;
// Encode this extension value
private void encodeThis() throws IOException {
if (ca == false && pathLen < 0) {
this.extensionValue = null;
return;
}
DerOutputStream out = new DerOutputStream();
DerOutputStream tmp = new DerOutputStream();
if (ca) {
tmp.putBoolean(ca);
}
if (pathLen >= 0) {
tmp.putInteger(pathLen);
}
out.write(DerValue.tag_Sequence, tmp);
this.extensionValue = out.toByteArray();
}
/**
* Default constructor for this object. The extension is marked
* critical if the ca flag is true, false otherwise.
*
* @param ca true, if the subject of the Certificate is a CA.
* @param len specifies the depth of the certification path.
*/
public BasicConstraintsExtension(boolean ca, int len) throws IOException {
this(new Boolean(ca), ca, len);
}
/**
* Constructor for this object with specified criticality.
*
* @param critical true, if the extension should be marked critical
* @param ca true, if the subject of the Certificate is a CA.
* @param len specifies the depth of the certification path.
*/
public BasicConstraintsExtension(Boolean critical, boolean ca, int len)
throws IOException {
this.ca = ca;
this.pathLen = len;
this.extensionId = PKIXExtensions.BasicConstraints_Id;
this.critical = critical.booleanValue();
encodeThis();
}
/**
* Create the extension from the passed DER encoded value of the same.
*
* @param extension the DER encoded value of the extension.
* @exception IOException on error.
*/
public BasicConstraintsExtension(Boolean critical, Object value)
throws IOException
{
this.extensionId = PKIXExtensions.BasicConstraints_Id;
this.critical = critical.booleanValue();
if (value instanceof byte[]) {
int len = Array.getLength(value);
byte[] extValue = new byte[len];
System.arraycopy(value, 0, extValue, 0, len);
this.extensionValue = extValue;
DerValue val = new DerValue(extValue);
if (val.tag != DerValue.tag_Sequence) {
throw new IOException("Invalid encoding of BasicConstraints");
}
if (val.data == null) {
// non-CA cert ("cA" field is FALSE by default), return -1
return;
}
DerValue opt = val.data.getDerValue();
if (opt.tag != DerValue.tag_Boolean) {
// non-CA cert ("cA" field is FALSE by default), return -1
return;
}
this.ca = opt.getBoolean();
if (val.data.available() == 0) {
// From PKIX profile:
// Where pathLenConstraint does not appear, there is no
// limit to the allowed length of the certification path.
this.pathLen = Integer.MAX_VALUE;
return;
}
opt = val.data.getDerValue();
if (opt.tag != DerValue.tag_Integer) {
throw new IOException("Invalid encoding of BasicConstraints");
}
this.pathLen = opt.getInteger();
/*
* Activate this check once again after PKIX profiling
* is a standard and this check no longer imposes an
* interoperability barrier.
* if (ca) {
* if (!this.critical) {
* throw new IOException("Criticality cannot be false for CA.");
* }
* }
*/
} else
throw new IOException("Invalid argument type");
}
/**
* Return user readable form of extension.
*/
public String toString() {
String s = super.toString() + "BasicConstraints:[\n";
s += ((ca) ? ("CA:true") : ("CA:false")) + "\n";
if (pathLen >= 0) {
s += "PathLen:" + pathLen + "\n";
} else {
s += "PathLen: undefined\n";
}
return (s + "]\n");
}
/**
* Decode the extension from the InputStream.
*
* @param in the InputStream to unmarshal the contents from.
* @exception IOException on decoding or validity errors.
*/
public void decode(InputStream in) throws IOException {
throw new IOException("Method not to be called directly.");
}
/**
* Encode this extension value to the output stream.
*
* @param out the DerOutputStream to encode the extension to.
*/
public void encode(OutputStream out) throws IOException {
DerOutputStream tmp = new DerOutputStream();
if (extensionValue == null) {
this.extensionId = PKIXExtensions.BasicConstraints_Id;
if (ca) {
critical = true;
} else {
critical = false;
}
encodeThis();
}
super.encode(tmp);
out.write(tmp.toByteArray());
}
/**
* Set the attribute value.
*/
public void set(String name, Object obj) throws IOException {
if (name.equalsIgnoreCase(IS_CA)) {
if (!(obj instanceof Boolean)) {
throw new IOException("Attribute value should be of type Boolean.");
}
ca = ((Boolean)obj).booleanValue();
} else if (name.equalsIgnoreCase(PATH_LEN)) {
if (!(obj instanceof Integer)) {
throw new IOException("Attribute value should be of type Integer.");
}
pathLen = ((Integer)obj).intValue();
} else {
throw new IOException("Attribute name not recognized by " +
"CertAttrSet:BasicConstraints.");
}
encodeThis();
}
/**
* Get the attribute value.
*/
public Object get(String name) throws IOException {
if (name.equalsIgnoreCase(IS_CA)) {
return (new Boolean(ca));
} else if (name.equalsIgnoreCase(PATH_LEN)) {
return (new Integer(pathLen));
} else {
throw new IOException("Attribute name not recognized by " +
"CertAttrSet:BasicConstraints.");
}
}
/**
* Delete the attribute value.
*/
public void delete(String name) throws IOException {
if (name.equalsIgnoreCase(IS_CA)) {
ca = false;
} else if (name.equalsIgnoreCase(PATH_LEN)) {
pathLen = -1;
} else {
throw new IOException("Attribute name not recognized by " +
"CertAttrSet:BasicConstraints.");
}
encodeThis();
}
/**
* Return an enumeration of names of attributes existing within this
* attribute.
*/
public Enumeration getElements() {
AttributeNameEnumeration elements = new AttributeNameEnumeration();
elements.addElement(IS_CA);
elements.addElement(PATH_LEN);
return (elements.elements());
}
/**
* Return the name of this attribute.
*/
public String getName() {
return (NAME);
}
}