/*
 * Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code 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.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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 in the LICENSE file that
 * accompanied this code).
 *
 * 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/*
 *
 *  (C) Copyright IBM Corp. 1999 All Rights Reserved.
 *  Copyright 1997 The Open Group Research Institute.  All rights reserved.
 */

package sun.security.krb5;

import sun.security.krb5.internal.*;
import sun.security.util.*;
import java.net.*;
import java.util.Vector;
import java.util.Locale;
import java.io.IOException;
import java.math.BigInteger;
import java.util.Arrays;
import sun.security.krb5.internal.ccache.CCacheOutputStream;
import sun.security.krb5.internal.util.KerberosString;


Implements the ASN.1 PrincipalName type and its realm in a single class.

   Realm           ::= KerberosString
   PrincipalName   ::= SEQUENCE {
           name-type       [0] Int32,
           name-string     [1] SEQUENCE OF KerberosString
   }

This class is immutable.
See Also:
Realm/**
 * Implements the ASN.1 PrincipalName type and its realm in a single class.
 * <xmp>
 *    Realm           ::= KerberosString
 *
 *    PrincipalName   ::= SEQUENCE {
 *            name-type       [0] Int32,
 *            name-string     [1] SEQUENCE OF KerberosString
 *    }
 * </xmp>
 * This class is immutable.
 * @see Realm
 */
public class PrincipalName implements Cloneable {

    //name types

    
Name type not known
/**
     * Name type not known
     */
    public static final int KRB_NT_UNKNOWN =   0;

    
Just the name of the principal as in DCE, or for users
/**
     * Just the name of the principal as in DCE, or for users
     */
    public static final int KRB_NT_PRINCIPAL = 1;

    
Service and other unique instance (krbtgt)
/**
     * Service and other unique instance (krbtgt)
     */
    public static final int KRB_NT_SRV_INST =  2;

    
Service with host name as instance (telnet, rcommands)
/**
     * Service with host name as instance (telnet, rcommands)
     */
    public static final int KRB_NT_SRV_HST =   3;

    
Service with host as remaining components
/**
     * Service with host as remaining components
     */
    public static final int KRB_NT_SRV_XHST =  4;

    
Unique ID
/**
     * Unique ID
     */
    public static final int KRB_NT_UID = 5;

    
TGS Name
/**
     * TGS Name
     */
    public static final String TGS_DEFAULT_SRV_NAME = "krbtgt";
    public static final int TGS_DEFAULT_NT = KRB_NT_SRV_INST;

    public static final char NAME_COMPONENT_SEPARATOR = '/';
    public static final char NAME_REALM_SEPARATOR = '@';
    public static final char REALM_COMPONENT_SEPARATOR = '.';

    public static final String NAME_COMPONENT_SEPARATOR_STR = "/";
    public static final String NAME_REALM_SEPARATOR_STR = "@";
    public static final String REALM_COMPONENT_SEPARATOR_STR = ".";

    // Instance fields.

    
The name type, from PrincipalName's name-type field.
/**
     * The name type, from PrincipalName's name-type field.
     */
    private final int nameType;

    
The name strings, from PrincipalName's name-strings field. This field
must be neither null nor empty. Each entry of it must also be neither
null nor empty. Make sure to clone the field when it's passed in or out.
/**
     * The name strings, from PrincipalName's name-strings field. This field
     * must be neither null nor empty. Each entry of it must also be neither
     * null nor empty. Make sure to clone the field when it's passed in or out.
     */
    private final String[] nameStrings;

    
The realm this principal belongs to.
/**
     * The realm this principal belongs to.
     */
    private final Realm nameRealm;      // not null


    
When constructing a PrincipalName, whether the realm is included in
the input, or deduced from default realm or domain-realm mapping.
/**
     * When constructing a PrincipalName, whether the realm is included in
     * the input, or deduced from default realm or domain-realm mapping.
     */
    private final boolean realmDeduced;

    // cached default salt, not used in clone
    private transient String salt = null;

    // There are 3 basic constructors. All other constructors must call them.
    // All basic constructors must call validateNameStrings.
    // 1. From name components
    // 2. From name
    // 3. From DER encoding

    
Creates a PrincipalName.
/**
     * Creates a PrincipalName.
     */
    public PrincipalName(int nameType, String[] nameStrings, Realm nameRealm) {
        if (nameRealm == null) {
            throw new IllegalArgumentException("Null realm not allowed");
        }
        validateNameStrings(nameStrings);
        this.nameType = nameType;
        this.nameStrings = nameStrings.clone();
        this.nameRealm = nameRealm;
        this.realmDeduced = false;
    }

    // This method is called by Windows NativeCred.c
    public PrincipalName(String[] nameParts, String realm) throws RealmException {
        this(KRB_NT_UNKNOWN, nameParts, new Realm(realm));
    }

    // Validate a nameStrings argument
    private static void validateNameStrings(String[] ns) {
        if (ns == null) {
            throw new IllegalArgumentException("Null nameStrings not allowed");
        }
        if (ns.length == 0) {
            throw new IllegalArgumentException("Empty nameStrings not allowed");
        }
        for (String s: ns) {
            if (s == null) {
                throw new IllegalArgumentException("Null nameString not allowed");
            }
            if (s.isEmpty()) {
                throw new IllegalArgumentException("Empty nameString not allowed");
            }
        }
    }

    public Object clone() {
        try {
            PrincipalName pName = (PrincipalName) super.clone();
            UNSAFE.putObject(this, NAME_STRINGS_OFFSET, nameStrings.clone());
            return pName;
        } catch (CloneNotSupportedException ex) {
            throw new AssertionError("Should never happen");
        }
    }

    private static final long NAME_STRINGS_OFFSET;
    private static final sun.misc.Unsafe UNSAFE;
    static {
        try {
            sun.misc.Unsafe unsafe = sun.misc.Unsafe.getUnsafe();
            NAME_STRINGS_OFFSET = unsafe.objectFieldOffset(
                    PrincipalName.class.getDeclaredField("nameStrings"));
            UNSAFE = unsafe;
        } catch (ReflectiveOperationException e) {
            throw new Error(e);
        }
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o instanceof PrincipalName) {
            PrincipalName other = (PrincipalName)o;
            return nameRealm.equals(other.nameRealm) &&
                    Arrays.equals(nameStrings, other.nameStrings);
        }
        return false;
    }

    
Returns the ASN.1 encoding of the

PrincipalName    ::= SEQUENCE {
         name-type       [0] Int32,
         name-string     [1] SEQUENCE OF KerberosString
}
KerberosString   ::= GeneralString (IA5String)


This definition reflects the Network Working Group RFC 4120
specification available at

http://www.ietf.org/rfc/rfc4120.txt.
Params:
encoding – DER-encoded PrincipalName (without Realm)
realm – the realm for this name
Throws:
Asn1Exception – if an error occurs while decoding
an ASN1 encoded data.
Asn1Exception – if there is an ASN1 encoding error
IOException – if an I/O error occurs
IllegalArgumentException – if encoding is null
reading encoded data./**
     * Returns the ASN.1 encoding of the
     * <xmp>
     * PrincipalName    ::= SEQUENCE {
     *          name-type       [0] Int32,
     *          name-string     [1] SEQUENCE OF KerberosString
     * }
     *
     * KerberosString   ::= GeneralString (IA5String)
     * </xmp>
     *
     * <p>
     * This definition reflects the Network Working Group RFC 4120
     * specification available at
     * <a href="http://www.ietf.org/rfc/rfc4120.txt">
     * http://www.ietf.org/rfc/rfc4120.txt</a>.
     *
     * @param encoding DER-encoded PrincipalName (without Realm)
     * @param realm the realm for this name
     * @exception Asn1Exception if an error occurs while decoding
     * an ASN1 encoded data.
     * @exception Asn1Exception if there is an ASN1 encoding error
     * @exception IOException if an I/O error occurs
     * @exception IllegalArgumentException if encoding is null
     * reading encoded data.
     */
    public PrincipalName(DerValue encoding, Realm realm)
            throws Asn1Exception, IOException {
        if (realm == null) {
            throw new IllegalArgumentException("Null realm not allowed");
        }
        realmDeduced = false;
        nameRealm = realm;
        DerValue der;
        if (encoding == null) {
            throw new IllegalArgumentException("Null encoding not allowed");
        }
        if (encoding.getTag() != DerValue.tag_Sequence) {
            throw new Asn1Exception(Krb5.ASN1_BAD_ID);
        }
        der = encoding.getData().getDerValue();
        if ((der.getTag() & 0x1F) == 0x00) {
            BigInteger bint = der.getData().getBigInteger();
            nameType = bint.intValue();
        } else {
            throw new Asn1Exception(Krb5.ASN1_BAD_ID);
        }
        der = encoding.getData().getDerValue();
        if ((der.getTag() & 0x01F) == 0x01) {
            DerValue subDer = der.getData().getDerValue();
            if (subDer.getTag() != DerValue.tag_SequenceOf) {
                throw new Asn1Exception(Krb5.ASN1_BAD_ID);
            }
            Vector<String> v = new Vector<>();
            DerValue subSubDer;
            while(subDer.getData().available() > 0) {
                subSubDer = subDer.getData().getDerValue();
                String namePart = new KerberosString(subSubDer).toString();
                v.addElement(namePart);
            }
            nameStrings = new String[v.size()];
            v.copyInto(nameStrings);
            validateNameStrings(nameStrings);
        } else  {
            throw new Asn1Exception(Krb5.ASN1_BAD_ID);
        }
    }

    
Parse (unmarshal) a PrincipalName from a DER
input stream.  This form
parsing might be used when expanding a value which is part of
a constructed sequence and uses explicitly tagged type.
Params:
data – the Der input stream value, which contains one or
more marshaled value.
explicitTag – tag number.
optional – indicate if this data field is optional
realm – the realm for the name
Throws:
Asn1Exception – on error.
Returns:
an instance of PrincipalName, or null if the
field is optional and missing./**
     * Parse (unmarshal) a <code>PrincipalName</code> from a DER
     * input stream.  This form
     * parsing might be used when expanding a value which is part of
     * a constructed sequence and uses explicitly tagged type.
     *
     * @exception Asn1Exception on error.
     * @param data the Der input stream value, which contains one or
     * more marshaled value.
     * @param explicitTag tag number.
     * @param optional indicate if this data field is optional
     * @param realm the realm for the name
     * @return an instance of <code>PrincipalName</code>, or null if the
     * field is optional and missing.
     */
    public static PrincipalName parse(DerInputStream data,
                                      byte explicitTag, boolean
                                      optional,
                                      Realm realm)
        throws Asn1Exception, IOException, RealmException {

        if ((optional) && (((byte)data.peekByte() & (byte)0x1F) !=
                           explicitTag))
            return null;
        DerValue der = data.getDerValue();
        if (explicitTag != (der.getTag() & (byte)0x1F)) {
            throw new Asn1Exception(Krb5.ASN1_BAD_ID);
        } else {
            DerValue subDer = der.getData().getDerValue();
            if (realm == null) {
                realm = Realm.getDefault();
            }
            return new PrincipalName(subDer, realm);
        }
    }


    // XXX Error checkin consistent with MIT krb5_parse_name
    // Code repetition, realm parsed again by class Realm
    private static String[] parseName(String name) {

        Vector<String> tempStrings = new Vector<>();
        String temp = name;
        int i = 0;
        int componentStart = 0;
        String component;

        while (i < temp.length()) {
            if (temp.charAt(i) == NAME_COMPONENT_SEPARATOR) {
                /*
                 * If this separator is escaped then don't treat it
                 * as a separator
                 */
                if (i > 0 && temp.charAt(i - 1) == '\\') {
                    temp = temp.substring(0, i - 1) +
                        temp.substring(i, temp.length());
                    continue;
                }
                else {
                    if (componentStart <= i) {
                        component = temp.substring(componentStart, i);
                        tempStrings.addElement(component);
                    }
                    componentStart = i + 1;
                }
            } else {
                if (temp.charAt(i) == NAME_REALM_SEPARATOR) {
                    /*
                     * If this separator is escaped then don't treat it
                     * as a separator
                     */
                    if (i > 0 && temp.charAt(i - 1) == '\\') {
                        temp = temp.substring(0, i - 1) +
                            temp.substring(i, temp.length());
                        continue;
                    } else {
                        if (componentStart < i) {
                            component = temp.substring(componentStart, i);
                            tempStrings.addElement(component);
                        }
                        componentStart = i + 1;
                        break;
                    }
                }
            }
            i++;
        }

        if (i == temp.length()) {
            component = temp.substring(componentStart, i);
            tempStrings.addElement(component);
        }

        String[] result = new String[tempStrings.size()];
        tempStrings.copyInto(result);
        return result;
    }

    
Constructs a PrincipalName from a string.
Params:
name – the name
type – the type
realm – the realm, null if not known. Note that when realm is not
null, it will be always used even if there is a realm part in name. When
realm is null, will read realm part from name, or try to map a realm
(for KRB_NT_SRV_HST), or use the default realm, or fail
Throws:
RealmException – /**
     * Constructs a PrincipalName from a string.
     * @param name the name
     * @param type the type
     * @param realm the realm, null if not known. Note that when realm is not
     * null, it will be always used even if there is a realm part in name. When
     * realm is null, will read realm part from name, or try to map a realm
     * (for KRB_NT_SRV_HST), or use the default realm, or fail
     * @throws RealmException
     */
    public PrincipalName(String name, int type, String realm)
            throws RealmException {
        if (name == null) {
            throw new IllegalArgumentException("Null name not allowed");
        }
        String[] nameParts = parseName(name);
        validateNameStrings(nameParts);
        if (realm == null) {
            realm = Realm.parseRealmAtSeparator(name);
        }

        // No realm info from parameter and string, must deduce later
        realmDeduced = realm == null;

        switch (type) {
        case KRB_NT_SRV_HST:
            if (nameParts.length >= 2) {
                String hostName = nameParts[1];
                try {
                    // RFC4120 does not recommend canonicalizing a hostname.
                    // However, for compatibility reason, we will try
                    // canonicalize it and see if the output looks better.

                    String canonicalized = (InetAddress.getByName(hostName)).
                            getCanonicalHostName();

                    // Looks if canonicalized is a longer format of hostName,
                    // we accept cases like
                    //     bunny -> bunny.rabbit.hole
                    if (canonicalized.toLowerCase(Locale.ENGLISH).startsWith(
                                hostName.toLowerCase(Locale.ENGLISH)+".")) {
                        hostName = canonicalized;
                    }
                } catch (UnknownHostException | SecurityException e) {
                    // not canonicalized or no permission to do so, use old
                }
                nameParts[1] = hostName.toLowerCase(Locale.ENGLISH);
            }
            nameStrings = nameParts;
            nameType = type;

            if (realm != null) {
                nameRealm = new Realm(realm);
            } else {
                // We will try to get realm name from the mapping in
                // the configuration. If it is not specified
                // we will use the default realm. This nametype does
                // not allow a realm to be specified. The name string must of
                // the form service@host and this is internally changed into
                // service/host by Kerberos
                String mapRealm =  mapHostToRealm(nameParts[1]);
                if (mapRealm != null) {
                    nameRealm = new Realm(mapRealm);
                } else {
                    nameRealm = Realm.getDefault();
                }
            }
            break;
        case KRB_NT_UNKNOWN:
        case KRB_NT_PRINCIPAL:
        case KRB_NT_SRV_INST:
        case KRB_NT_SRV_XHST:
        case KRB_NT_UID:
            nameStrings = nameParts;
            nameType = type;
            if (realm != null) {
                nameRealm = new Realm(realm);
            } else {
                nameRealm = Realm.getDefault();
            }
            break;
        default:
            throw new IllegalArgumentException("Illegal name type");
        }
    }

    public PrincipalName(String name, int type) throws RealmException {
        this(name, type, (String)null);
    }

    public PrincipalName(String name) throws RealmException {
        this(name, KRB_NT_UNKNOWN);
    }

    public PrincipalName(String name, String realm) throws RealmException {
        this(name, KRB_NT_UNKNOWN, realm);
    }

    public static PrincipalName tgsService(String r1, String r2)
            throws KrbException {
        return new PrincipalName(PrincipalName.KRB_NT_SRV_INST,
                new String[] {PrincipalName.TGS_DEFAULT_SRV_NAME, r1},
                new Realm(r2));
    }

    public String getRealmAsString() {
        return getRealmString();
    }

    public String getPrincipalNameAsString() {
        StringBuffer temp = new StringBuffer(nameStrings[0]);
        for (int i = 1; i < nameStrings.length; i++)
            temp.append(nameStrings[i]);
        return temp.toString();
    }

    public int hashCode() {
        return toString().hashCode();
    }

    public String getName() {
        return toString();
    }

    public int getNameType() {
        return nameType;
    }

    public String[] getNameStrings() {
        return nameStrings.clone();
    }

    public byte[][] toByteArray() {
        byte[][] result = new byte[nameStrings.length][];
        for (int i = 0; i < nameStrings.length; i++) {
            result[i] = new byte[nameStrings[i].length()];
            result[i] = nameStrings[i].getBytes();
        }
        return result;
    }

    public String getRealmString() {
        return nameRealm.toString();
    }

    public Realm getRealm() {
        return nameRealm;
    }

    public String getSalt() {
        if (salt == null) {
            StringBuffer salt = new StringBuffer();
            salt.append(nameRealm.toString());
            for (int i = 0; i < nameStrings.length; i++) {
                salt.append(nameStrings[i]);
            }
            return salt.toString();
        }
        return salt;
    }

    public String toString() {
        StringBuffer str = new StringBuffer();
        for (int i = 0; i < nameStrings.length; i++) {
            if (i > 0)
                str.append("/");
            str.append(nameStrings[i]);
        }
        str.append("@");
        str.append(nameRealm.toString());
        return str.toString();
    }

    public String getNameString() {
        StringBuffer str = new StringBuffer();
        for (int i = 0; i < nameStrings.length; i++) {
            if (i > 0)
                str.append("/");
            str.append(nameStrings[i]);
        }
        return str.toString();
    }

    
Encodes a PrincipalName object. Note that only the type and
names are encoded. To encode the realm, call getRealm().asn1Encode().
Throws:
Asn1Exception – if an error occurs while decoding an ASN1 encoded data.
IOException – if an I/O error occurs while reading encoded data.
Returns:
the byte array of the encoded PrncipalName object./**
     * Encodes a <code>PrincipalName</code> object. Note that only the type and
     * names are encoded. To encode the realm, call getRealm().asn1Encode().
     * @return the byte array of the encoded PrncipalName object.
     * @exception Asn1Exception if an error occurs while decoding an ASN1 encoded data.
     * @exception IOException if an I/O error occurs while reading encoded data.
     *
     */
    public byte[] asn1Encode() throws Asn1Exception, IOException {
        DerOutputStream bytes = new DerOutputStream();
        DerOutputStream temp = new DerOutputStream();
        BigInteger bint = BigInteger.valueOf(this.nameType);
        temp.putInteger(bint);
        bytes.write(DerValue.createTag(DerValue.TAG_CONTEXT, true, (byte)0x00), temp);
        temp = new DerOutputStream();
        DerValue der[] = new DerValue[nameStrings.length];
        for (int i = 0; i < nameStrings.length; i++) {
            der[i] = new KerberosString(nameStrings[i]).toDerValue();
        }
        temp.putSequence(der);
        bytes.write(DerValue.createTag(DerValue.TAG_CONTEXT, true, (byte)0x01), temp);
        temp = new DerOutputStream();
        temp.write(DerValue.tag_Sequence, bytes);
        return temp.toByteArray();
    }


    
Checks if two PrincipalName objects have identical values in their corresponding data fields.
Params:
pname – the other PrincipalName object.
Returns:
true if two have identical values, otherwise, return false./**
     * Checks if two <code>PrincipalName</code> objects have identical values in their corresponding data fields.
     *
     * @param pname the other <code>PrincipalName</code> object.
     * @return true if two have identical values, otherwise, return false.
     */
    // It is used in <code>sun.security.krb5.internal.ccache</code> package.
    public boolean match(PrincipalName pname) {
        boolean matched = true;
        //name type is just a hint, no two names can be the same ignoring name type.
        // if (this.nameType != pname.nameType) {
        //      matched = false;
        // }
        if ((this.nameRealm != null) && (pname.nameRealm != null)) {
            if (!(this.nameRealm.toString().equalsIgnoreCase(pname.nameRealm.toString()))) {
                matched = false;
            }
        }
        if (this.nameStrings.length != pname.nameStrings.length) {
            matched = false;
        } else {
            for (int i = 0; i < this.nameStrings.length; i++) {
                if (!(this.nameStrings[i].equalsIgnoreCase(pname.nameStrings[i]))) {
                    matched = false;
                }
            }
        }
        return matched;
    }

    
Writes data field values of PrincipalName in FCC format to an output stream.
Params:
cos – a CCacheOutputStream for writing data.
Throws:
IOException – if an I/O exception occurs.
See Also:
CCacheOutputStream/**
     * Writes data field values of <code>PrincipalName</code> in FCC format to an output stream.
     *
     * @param cos a <code>CCacheOutputStream</code> for writing data.
     * @exception IOException if an I/O exception occurs.
     * @see sun.security.krb5.internal.ccache.CCacheOutputStream
     */
    public void writePrincipal(CCacheOutputStream cos) throws IOException {
        cos.write32(nameType);
        cos.write32(nameStrings.length);
        byte[] realmBytes = null;
        realmBytes = nameRealm.toString().getBytes();
        cos.write32(realmBytes.length);
        cos.write(realmBytes, 0, realmBytes.length);
        byte[] bytes = null;
        for (int i = 0; i < nameStrings.length; i++) {
            bytes = nameStrings[i].getBytes();
            cos.write32(bytes.length);
            cos.write(bytes, 0, bytes.length);
        }
    }

    
Returns the instance component of a name.
In a multi-component name such as a KRB_NT_SRV_INST
name, the second component is returned.
Null is returned if there are not two or more
components in the name.
@returns
instance component of a multi-component name./**
     * Returns the instance component of a name.
     * In a multi-component name such as a KRB_NT_SRV_INST
     * name, the second component is returned.
     * Null is returned if there are not two or more
     * components in the name.
     * @returns instance component of a multi-component name.
     */
    public String getInstanceComponent()
    {
        if (nameStrings != null && nameStrings.length >= 2)
            {
                return new String(nameStrings[1]);
            }

        return null;
    }

    static String mapHostToRealm(String name) {
        String result = null;
        try {
            String subname = null;
            Config c = Config.getInstance();
            if ((result = c.get("domain_realm", name)) != null)
                return result;
            else {
                for (int i = 1; i < name.length(); i++) {
                    if ((name.charAt(i) == '.') && (i != name.length() - 1)) { //mapping could be .ibm.com = AUSTIN.IBM.COM
                        subname = name.substring(i);
                        result = c.get("domain_realm", subname);
                        if (result != null) {
                            break;
                        }
                        else {
                            subname = name.substring(i + 1);      //or mapping could be ibm.com = AUSTIN.IBM.COM
                            result = c.get("domain_realm", subname);
                            if (result != null) {
                                break;
                            }
                        }
                    }
                }
            }
        } catch (KrbException e) {
        }
        return result;
    }

    public boolean isRealmDeduced() {
        return realmDeduced;
    }
}