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my-jdk/jdkSrc/jdk8/sun/security/ssl/krb5/KrbClientKeyExchangeHelperImpl.java

467 lines
18 KiB
Java

/*
* Copyright (c) 2003, 2020, 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.
*/
package sun.security.ssl.krb5;
import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.security.AccessController;
import java.security.AccessControlContext;
import java.security.PrivilegedExceptionAction;
import java.security.PrivilegedActionException;
import java.util.Arrays;
import java.security.PrivilegedAction;
import javax.security.auth.kerberos.KerberosTicket;
import javax.net.ssl.SSLKeyException;
import javax.security.auth.kerberos.KerberosKey;
import javax.security.auth.kerberos.KerberosPrincipal;
import javax.security.auth.kerberos.ServicePermission;
import sun.security.jgss.GSSCaller;
import sun.security.krb5.EncryptionKey;
import sun.security.krb5.EncryptedData;
import sun.security.krb5.PrincipalName;
import sun.security.krb5.internal.Ticket;
import sun.security.krb5.internal.EncTicketPart;
import sun.security.krb5.internal.crypto.KeyUsage;
import sun.security.jgss.krb5.Krb5Util;
import sun.security.jgss.krb5.ServiceCreds;
import sun.security.krb5.KrbException;
import sun.security.ssl.Krb5Helper;
import sun.security.ssl.SSLLogger;
public final class KrbClientKeyExchangeHelperImpl
implements sun.security.ssl.KrbClientKeyExchangeHelper {
private byte[] preMaster;
private byte[] preMasterEnc;
private byte[] encodedTicket;
private KerberosPrincipal peerPrincipal;
private KerberosPrincipal localPrincipal;
/**
* Initialises an instance of KrbClientKeyExchangeHelperImpl.
* Used by the TLS client to create a Kerberos Client Key Exchange
* message.
*
* @param preMaster plain pre-master secret
* @param serverName name of the TLS server to perform the handshake;
* used by the TLS client to get a Kerberos service
* ticket which contains the session key to encrypt
* the pre-master secret
* @param acc the TLS client security context for the handshake
*/
@Override
public void init(byte[] preMaster, String serverName,
AccessControlContext acc) throws IOException {
this.preMaster = preMaster;
// Get service ticket
KerberosTicket ticket = getServiceTicket(serverName, acc);
encodedTicket = ticket.getEncoded();
// Record the Kerberos principals
peerPrincipal = ticket.getServer();
localPrincipal = ticket.getClient();
// Encrypt the pre-master secret with the Kerberos session key
EncryptionKey sessionKey = new EncryptionKey(
ticket.getSessionKeyType(),
ticket.getSessionKey().getEncoded());
encryptPremasterSecret(sessionKey);
}
/**
* Initialises an instance of KrbClientKeyExchangeHelperImpl.
* Used by the TLS server to process the content of a Kerberos Client Key
* Exchange message (received from a TLS client).
*
* @param encodedTicket the encoded Kerberos ticket (TGS) received from the
* TLS client. This ticket seals the Kerberos session
* key.
* @param preMasterEnc the pre-master secret encrypted with the Kerberos
* session key
* @param serviceCreds the TLS server Kerberos credentials used to process
* the received Kerberos ticket.
* @param acc the TLS server security context for the handshake
*/
@Override
public void init(byte[] encodedTicket, byte[] preMasterEnc,
Object serviceCreds, AccessControlContext acc) throws IOException {
this.encodedTicket = encodedTicket;
this.preMasterEnc = preMasterEnc;
EncryptionKey sessionKey = null;
try {
Ticket t = new Ticket(encodedTicket);
EncryptedData encPart = t.encPart;
PrincipalName ticketSname = t.sname;
final ServiceCreds creds = (ServiceCreds) serviceCreds;
final KerberosPrincipal princ =
new KerberosPrincipal(ticketSname.toString());
// For bound service, permission already checked at setup
if (creds.getName() == null) {
SecurityManager sm = System.getSecurityManager();
try {
if (sm != null) {
// Eliminate dependency on ServicePermission
sm.checkPermission(Krb5Helper.getServicePermission(
ticketSname.toString(), "accept"), acc);
}
} catch (SecurityException se) {
// Do not destroy keys. Will affect Subject
if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
SSLLogger.fine("Permission to access Kerberos"
+ " secret key denied");
}
throw new IOException("Kerberos service not allowed");
}
}
KerberosKey[] serverKeys = AccessController.doPrivileged(
new PrivilegedAction<KerberosKey[]>() {
@Override
public KerberosKey[] run() {
return creds.getKKeys(princ);
}
});
if (serverKeys.length == 0) {
throw new IOException("Found no key for " + princ +
(creds.getName() == null ? "" :
(", this keytab is for " + creds.getName() + " only")));
}
// See if we have the right key to decrypt the ticket to get
// the session key.
int encPartKeyType = encPart.getEType();
Integer encPartKeyVersion = encPart.getKeyVersionNumber();
KerberosKey dkey = null;
try {
dkey = findKey(encPartKeyType, encPartKeyVersion, serverKeys);
} catch (KrbException ke) { // a kvno mismatch
throw new IOException(
"Cannot find key matching version number", ke);
}
if (dkey == null) {
// %%% Should print string repr of etype
throw new IOException("Cannot find key of appropriate type" +
" to decrypt ticket - need etype " + encPartKeyType);
}
EncryptionKey secretKey = new EncryptionKey(
encPartKeyType,
dkey.getEncoded());
// Decrypt encPart using server's secret key
byte[] bytes = encPart.decrypt(secretKey, KeyUsage.KU_TICKET);
// Reset data stream after decryption, remove redundant bytes
byte[] temp = encPart.reset(bytes);
EncTicketPart encTicketPart = new EncTicketPart(temp);
// Record the Kerberos Principals
peerPrincipal =
new KerberosPrincipal(encTicketPart.cname.getName());
localPrincipal = new KerberosPrincipal(ticketSname.getName());
sessionKey = encTicketPart.key;
if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
SSLLogger.fine("server principal: " + ticketSname);
SSLLogger.fine("cname: " + encTicketPart.cname.toString());
}
} catch (Exception e) {
sessionKey = null;
if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
SSLLogger.fine("Error getting the Kerberos session key" +
" to decrypt the pre-master secret");
}
}
if (sessionKey != null)
decryptPremasterSecret(sessionKey);
}
@Override
public byte[] getEncodedTicket() {
return encodedTicket;
}
@Override
public byte[] getEncryptedPreMasterSecret() {
return preMasterEnc;
}
@Override
public byte[] getPlainPreMasterSecret() {
return preMaster;
}
@Override
public KerberosPrincipal getPeerPrincipal() {
return peerPrincipal;
}
@Override
public KerberosPrincipal getLocalPrincipal() {
return localPrincipal;
}
private void encryptPremasterSecret(EncryptionKey sessionKey)
throws IOException {
if (sessionKey.getEType() ==
EncryptedData.ETYPE_DES3_CBC_HMAC_SHA1_KD) {
throw new IOException(
"session keys with des3-cbc-hmac-sha1-kd encryption type " +
"are not supported for TLS Kerberos cipher suites");
}
try {
EncryptedData eData = new EncryptedData(sessionKey, preMaster,
KeyUsage.KU_UNKNOWN);
preMasterEnc = eData.getBytes(); // not ASN.1 encoded.
} catch (KrbException e) {
throw (IOException) new SSLKeyException("Kerberos pre-master" +
" secret error").initCause(e);
}
}
private void decryptPremasterSecret(EncryptionKey sessionKey)
throws IOException {
if (sessionKey.getEType() ==
EncryptedData.ETYPE_DES3_CBC_HMAC_SHA1_KD) {
throw new IOException(
"session keys with des3-cbc-hmac-sha1-kd encryption type " +
"are not supported for TLS Kerberos cipher suites");
}
try {
EncryptedData data = new EncryptedData(sessionKey.getEType(),
null /* optional kvno */, preMasterEnc);
byte[] temp = data.decrypt(sessionKey, KeyUsage.KU_UNKNOWN);
if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
if (preMasterEnc != null) {
SSLLogger.fine("decrypted premaster secret", temp);
}
}
// Remove padding bytes after decryption. Only DES and DES3 have
// paddings and we don't support DES3 in TLS (see above)
if (temp.length == 52 &&
data.getEType() == EncryptedData.ETYPE_DES_CBC_CRC) {
// For des-cbc-crc, 4 paddings. Value can be 0x04 or 0x00.
if (paddingByteIs(temp, 52, (byte)4) ||
paddingByteIs(temp, 52, (byte)0)) {
temp = Arrays.copyOf(temp, 48);
}
} else if (temp.length == 56 &&
data.getEType() == EncryptedData.ETYPE_DES_CBC_MD5) {
// For des-cbc-md5, 8 paddings with 0x08, or no padding
if (paddingByteIs(temp, 56, (byte)8)) {
temp = Arrays.copyOf(temp, 48);
}
}
preMaster = temp;
} catch (Exception e) {
// Decrypting the pre-master secret was not possible.
if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
SSLLogger.fine("Error decrypting the pre-master secret");
}
}
}
/**
* Checks if all paddings of data are b
* @param data the block with padding
* @param len length of data, >= 48
* @param b expected padding byte
*/
private static boolean paddingByteIs(byte[] data, int len, byte b) {
for (int i=48; i<len; i++) {
if (data[i] != b) return false;
}
return true;
}
// Similar to sun.security.jgss.krb5.Krb5InitCredenetial/Krb5Context
private static KerberosTicket getServiceTicket(String serverName,
final AccessControlContext acc) throws IOException {
if ("localhost".equals(serverName) ||
"localhost.localdomain".equals(serverName)) {
if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
SSLLogger.fine("Get the local hostname");
}
String localHost = java.security.AccessController.doPrivileged(
new java.security.PrivilegedAction<String>() {
public String run() {
try {
return InetAddress.getLocalHost().getHostName();
} catch (UnknownHostException e) {
if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
SSLLogger.fine("Warning,"
+ " cannot get the local hostname: "
+ e.getMessage());
}
return null;
}
}
});
if (localHost != null) {
serverName = localHost;
}
}
// Resolve serverName (possibly in IP addr form) to Kerberos principal
// name for service with hostname
String serviceName = "host/" + serverName;
PrincipalName principal;
try {
principal = new PrincipalName(serviceName,
PrincipalName.KRB_NT_SRV_HST);
} catch (SecurityException se) {
throw se;
} catch (Exception e) {
IOException ioe = new IOException("Invalid service principal" +
" name: " + serviceName);
ioe.initCause(e);
throw ioe;
}
String realm = principal.getRealmAsString();
final String serverPrincipal = principal.toString();
final String tgsPrincipal = "krbtgt/" + realm + "@" + realm;
final String clientPrincipal = null; // use default
// check permission to obtain a service ticket to initiate a
// context with the "host" service
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkPermission(new ServicePermission(serverPrincipal,
"initiate"), acc);
}
try {
KerberosTicket ticket = AccessController.doPrivileged(
new PrivilegedExceptionAction<KerberosTicket>() {
public KerberosTicket run() throws Exception {
return Krb5Util.getTicketFromSubjectAndTgs(
GSSCaller.CALLER_SSL_CLIENT,
clientPrincipal, serverPrincipal,
tgsPrincipal, acc);
}});
if (ticket == null) {
throw new IOException("Failed to find any kerberos service" +
" ticket for " + serverPrincipal);
}
return ticket;
} catch (PrivilegedActionException e) {
IOException ioe = new IOException(
"Attempt to obtain kerberos service ticket for " +
serverPrincipal + " failed!");
ioe.initCause(e);
throw ioe;
}
}
/**
* Determines if a kvno matches another kvno. Used in the method
* findKey(etype, version, keys). Always returns true if either input
* is null or zero, in case any side does not have kvno info available.
*
* Note: zero is included because N/A is not a legal value for kvno
* in javax.security.auth.kerberos.KerberosKey. Therefore, the info
* that the kvno is N/A might be lost when converting between
* EncryptionKey and KerberosKey.
*/
private static boolean versionMatches(Integer v1, int v2) {
if (v1 == null || v1 == 0 || v2 == 0) {
return true;
}
return v1.equals(v2);
}
private static KerberosKey findKey(int etype, Integer version,
KerberosKey[] keys) throws KrbException {
int ktype;
boolean etypeFound = false;
// When no matched kvno is found, returns tke key of the same
// etype with the highest kvno
int kvno_found = 0;
KerberosKey key_found = null;
for (int i = 0; i < keys.length; i++) {
ktype = keys[i].getKeyType();
if (etype == ktype) {
int kv = keys[i].getVersionNumber();
etypeFound = true;
if (versionMatches(version, kv)) {
return keys[i];
} else if (kv > kvno_found) {
key_found = keys[i];
kvno_found = kv;
}
}
}
// Key not found.
// %%% kludge to allow DES keys to be used for diff etypes
if ((etype == EncryptedData.ETYPE_DES_CBC_CRC ||
etype == EncryptedData.ETYPE_DES_CBC_MD5)) {
for (int i = 0; i < keys.length; i++) {
ktype = keys[i].getKeyType();
if (ktype == EncryptedData.ETYPE_DES_CBC_CRC ||
ktype == EncryptedData.ETYPE_DES_CBC_MD5) {
int kv = keys[i].getVersionNumber();
etypeFound = true;
if (versionMatches(version, kv)) {
return new KerberosKey(keys[i].getPrincipal(),
keys[i].getEncoded(),
etype,
kv);
} else if (kv > kvno_found) {
key_found = new KerberosKey(keys[i].getPrincipal(),
keys[i].getEncoded(),
etype,
kv);
kvno_found = kv;
}
}
}
}
if (etypeFound) {
return key_found;
}
return null;
}
}