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* accompanied this code).
*
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package sun.security.x509;
import java.io.IOException;
import java.io.OutputStream;
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
* @see CertAttrSet
* @see Extension
*/
public class BasicConstraintsExtension extends Extension
implements CertAttrSet<String> {
/**
* 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 {
DerOutputStream out = new DerOutputStream();
DerOutputStream tmp = new DerOutputStream();
if (ca) {
tmp.putBoolean(ca);
// Only encode pathLen when ca == true
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(Boolean.valueOf(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 critical flag indicating if extension is critical or not
* @param value an array containing the DER encoded bytes of the extension.
* @exception ClassCastException if value is not an array of bytes
* @exception IOException on error.
*/
public BasicConstraintsExtension(Boolean critical, Object value)
throws IOException
{
this.extensionId = PKIXExtensions.BasicConstraints_Id;
this.critical = critical.booleanValue();
this.extensionValue = (byte[]) value;
DerValue val = new DerValue(this.extensionValue);
if (val.tag != DerValue.tag_Sequence) {
throw new IOException("Invalid encoding of BasicConstraints");
}
if (val.data == null || val.data.available() == 0) {
// 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.");
* }
* }
*/
}
/**
* Return user readable form of extension.
*/
public String toString() {
return super.toString() +
"BasicConstraints:[\n CA:" + ca +
"\n PathLen:" +
((pathLen >= 0) ? String.valueOf(pathLen) : " undefined") +
"\n]\n";
}
/**
* 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 (Boolean.valueOf(ca));
} else if (name.equalsIgnoreCase(PATH_LEN)) {
return (Integer.valueOf(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<String> 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);
}
}