jdk/src/java.security.jgss/share/classes/sun/security/ssl/krb5/KerberosPreMasterSecret.java
changeset 25859 3317bb8137f4
parent 7039 6464c8e62a18
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/java.security.jgss/share/classes/sun/security/ssl/krb5/KerberosPreMasterSecret.java	Sun Aug 17 15:54:13 2014 +0100
@@ -0,0 +1,272 @@
+/*
+ * Copyright (c) 2003, 2010, 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.*;
+import java.security.*;
+import java.util.Arrays;
+
+import javax.net.ssl.*;
+
+import sun.security.krb5.EncryptionKey;
+import sun.security.krb5.EncryptedData;
+import sun.security.krb5.KrbException;
+import sun.security.krb5.internal.crypto.KeyUsage;
+
+import sun.security.ssl.Debug;
+import sun.security.ssl.HandshakeInStream;
+import sun.security.ssl.HandshakeMessage;
+import sun.security.ssl.ProtocolVersion;
+
+/**
+ * This is the Kerberos premaster secret in the Kerberos client key
+ * exchange message (CLIENT --> SERVER); it holds the
+ * Kerberos-encrypted pre-master secret. The secret is encrypted using the
+ * Kerberos session key.  The padding and size of the resulting message
+ * depends on the session key type, but the pre-master secret is
+ * always exactly 48 bytes.
+ *
+ */
+final class KerberosPreMasterSecret {
+
+    private ProtocolVersion protocolVersion; // preMaster [0,1]
+    private byte preMaster[];           // 48 bytes
+    private byte encrypted[];
+
+    /**
+     * Constructor used by client to generate premaster secret.
+     *
+     * Client randomly creates a pre-master secret and encrypts it
+     * using the Kerberos session key; only the server can decrypt
+     * it, using the session key available in the service ticket.
+     *
+     * @param protocolVersion used to set preMaster[0,1]
+     * @param generator random number generator for generating premaster secret
+     * @param sessionKey Kerberos session key for encrypting premaster secret
+     */
+    KerberosPreMasterSecret(ProtocolVersion protocolVersion,
+        SecureRandom generator, 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");
+        }
+
+        this.protocolVersion = protocolVersion;
+        preMaster = generatePreMaster(generator, protocolVersion);
+
+        // Encrypt premaster secret
+        try {
+            EncryptedData eData = new EncryptedData(sessionKey, preMaster,
+                KeyUsage.KU_UNKNOWN);
+            encrypted = eData.getBytes();  // not ASN.1 encoded.
+
+        } catch (KrbException e) {
+            throw (SSLKeyException)new SSLKeyException
+                ("Kerberos premaster secret error").initCause(e);
+        }
+    }
+
+    /*
+     * Constructor used by server to decrypt encrypted premaster secret.
+     * The protocol version in preMaster[0,1] must match either currentVersion
+     * or clientVersion, otherwise, the premaster secret is set to
+     * a random one to foil possible attack.
+     *
+     * @param currentVersion version of protocol being used
+     * @param clientVersion version requested by client
+     * @param generator random number generator used to generate
+     *        bogus premaster secret if premaster secret verification fails
+     * @param input input stream from which to read the encrypted
+     *        premaster secret
+     * @param sessionKey Kerberos session key to be used for decryption
+     */
+    KerberosPreMasterSecret(ProtocolVersion currentVersion,
+        ProtocolVersion clientVersion,
+        SecureRandom generator, HandshakeInStream input,
+        EncryptionKey sessionKey) throws IOException {
+
+         // Extract encrypted premaster secret from message
+         encrypted = input.getBytes16();
+
+         if (HandshakeMessage.debug != null && Debug.isOn("handshake")) {
+            if (encrypted != null) {
+                Debug.println(System.out,
+                     "encrypted premaster secret", encrypted);
+            }
+         }
+
+        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");
+        }
+
+        // Decrypt premaster secret
+        try {
+            EncryptedData data = new EncryptedData(sessionKey.getEType(),
+                        null /* optional kvno */, encrypted);
+
+            byte[] temp = data.decrypt(sessionKey, KeyUsage.KU_UNKNOWN);
+            if (HandshakeMessage.debug != null && Debug.isOn("handshake")) {
+                 if (encrypted != null) {
+                     Debug.println(System.out,
+                         "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;
+
+            protocolVersion = ProtocolVersion.valueOf(preMaster[0],
+                 preMaster[1]);
+            if (HandshakeMessage.debug != null && Debug.isOn("handshake")) {
+                 System.out.println("Kerberos PreMasterSecret version: "
+                        + protocolVersion);
+            }
+        } catch (Exception e) {
+            // catch exception & process below
+            preMaster = null;
+            protocolVersion = currentVersion;
+        }
+
+        // check if the premaster secret version is ok
+        // the specification says that it must be the maximum version supported
+        // by the client from its ClientHello message. However, many
+        // old implementations send the negotiated version, so accept both
+        // for SSL v3.0 and TLS v1.0.
+        // NOTE that we may be comparing two unsupported version numbers in
+        // the second case, which is why we cannot use object references
+        // equality in this special case
+        boolean versionMismatch = (protocolVersion.v != clientVersion.v);
+
+        /*
+         * we never checked the client_version in server side
+         * for TLS v1.0 and SSL v3.0. For compatibility, we
+         * maintain this behavior.
+         */
+        if (versionMismatch && (clientVersion.v <= 0x0301)) {
+            versionMismatch = (protocolVersion.v != currentVersion.v);
+        }
+
+        /*
+         * Bogus decrypted ClientKeyExchange? If so, conjure a
+         * a random preMaster secret that will fail later during
+         * Finished message processing. This is a countermeasure against
+         * the "interactive RSA PKCS#1 encryption envelop attack" reported
+         * in June 1998. Preserving the executation path will
+         * mitigate timing attacks and force consistent error handling
+         * that will prevent an attacking client from differentiating
+         * different kinds of decrypted ClientKeyExchange bogosities.
+         */
+         if ((preMaster == null) || (preMaster.length != 48)
+                || versionMismatch) {
+            if (HandshakeMessage.debug != null && Debug.isOn("handshake")) {
+                System.out.println("Kerberos PreMasterSecret error, "
+                                   + "generating random secret");
+                if (preMaster != null) {
+                    Debug.println(System.out, "Invalid secret", preMaster);
+                }
+            }
+
+            /*
+             * Randomize the preMaster secret with the
+             * ClientHello.client_version, as will produce invalid master
+             * secret to prevent the attacks.
+             */
+            preMaster = generatePreMaster(generator, clientVersion);
+            protocolVersion = clientVersion;
+        }
+    }
+
+    /**
+     * 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;
+    }
+
+    /*
+     * Used by server to generate premaster secret in case of
+     * problem decoding ticket.
+     *
+     * @param protocolVersion used for preMaster[0,1]
+     * @param generator random number generator to use for generating secret.
+     */
+    KerberosPreMasterSecret(ProtocolVersion protocolVersion,
+        SecureRandom generator) {
+
+        this.protocolVersion = protocolVersion;
+        preMaster = generatePreMaster(generator, protocolVersion);
+    }
+
+    private static byte[] generatePreMaster(SecureRandom rand,
+        ProtocolVersion ver) {
+
+        byte[] pm = new byte[48];
+        rand.nextBytes(pm);
+        pm[0] = ver.major;
+        pm[1] = ver.minor;
+
+        return pm;
+    }
+
+    // Clone not needed; internal use only
+    byte[] getUnencrypted() {
+        return preMaster;
+    }
+
+    // Clone not needed; internal use only
+    byte[] getEncrypted() {
+        return encrypted;
+    }
+}