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 * Copyright (c) 2002, 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,

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 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package sun.security.ssl;

import java.util.*;

import java.security.NoSuchAlgorithmException;

import java.security.InvalidKeyException;

import java.security.SecureRandom;

import javax.crypto.SecretKey;

import javax.crypto.spec.IvParameterSpec;

import javax.crypto.spec.SecretKeySpec;

import sun.security.ssl.CipherSuite.*;

import static sun.security.ssl.CipherSuite.KeyExchange.*;

import static sun.security.ssl.CipherSuite.PRF.*;

import static sun.security.ssl.JsseJce.*;

/**

 * An SSL/TLS CipherSuite. Constants for the standard key exchange, cipher,

 * and mac algorithms are also defined in this class.

 *

 * The CipherSuite class and the inner classes defined in this file roughly

 * follow the type safe enum pattern described in Effective Java. This means:

 *

 *  . instances are immutable, classes are final

 *

 *  . there is a unique instance of every value, i.e. there are never two

 *    instances representing the same CipherSuite, etc. This means equality

 *    tests can be performed using == instead of equals() (although that works

 *    as well). [A minor exception are *unsupported* CipherSuites read from a

 *    handshake message, but this is usually irrelevant]

 *

 *  . instances are obtained using the static valueOf() factory methods.

 *

 *  . properties are defined as final variables and made available as

 *    package private variables without method accessors

 *

 *  . if the member variable allowed is false, the given algorithm is either

 *    unavailable or disabled at compile time

 *

 */

final class CipherSuite implements Comparable {

    // minimum priority for supported CipherSuites

    final static int SUPPORTED_SUITES_PRIORITY = 1;

    // minimum priority for default enabled CipherSuites

    final static int DEFAULT_SUITES_PRIORITY = 300;

    // Flag indicating if CipherSuite availability can change dynamically.

    // This is the case when we rely on a JCE cipher implementation that

    // may not be available in the installed JCE providers.

    // It is true because we might not have an ECC implementation.

    final static boolean DYNAMIC_AVAILABILITY = true;

    private final static boolean ALLOW_ECC = Debug.getBooleanProperty

        ("com.sun.net.ssl.enableECC", true);

    // Map Integer(id) -> CipherSuite

    // contains all known CipherSuites

    private final static Map<Integer,CipherSuite> idMap;

    // Map String(name) -> CipherSuite

    // contains only supported CipherSuites (i.e. allowed == true)

    private final static Map<String,CipherSuite> nameMap;

    // Protocol defined CipherSuite name, e.g. SSL_RSA_WITH_RC4_128_MD5

    // we use TLS_* only for new CipherSuites, still SSL_* for old ones

    final String name;

    // id in 16 bit MSB format, i.e. 0x0004 for SSL_RSA_WITH_RC4_128_MD5

    final int id;

    // priority for the internal default preference order. the higher the

    // better. Each supported CipherSuite *must* have a unique priority.

    // Ciphersuites with priority >= DEFAULT_SUITES_PRIORITY are enabled

    // by default

    final int priority;

    // key exchange, bulk cipher, mac and prf algorithms. See those

    // classes below.

    final KeyExchange keyExchange;

    final BulkCipher cipher;

    final MacAlg macAlg;

    final PRF prfAlg;

    // whether a CipherSuite qualifies as exportable under 512/40 bit rules.

    // TLS 1.1+ (RFC 4346) must not negotiate to these suites.

    final boolean exportable;

    // true iff implemented and enabled at compile time

    final boolean allowed;

    // obsoleted since protocol version

    final int obsoleted;

    // supported since protocol version

    final int supported;

    /**

     * Constructor for implemented CipherSuites.

     */

    private CipherSuite(String name, int id, int priority,

            KeyExchange keyExchange, BulkCipher cipher,

            boolean allowed, int obsoleted, int supported, PRF prfAlg) {

        this.name = name;

        this.id = id;

        this.priority = priority;

        this.keyExchange = keyExchange;

        this.cipher = cipher;

        this.exportable = cipher.exportable;

        if (name.endsWith("_MD5")) {

            macAlg = M_MD5;

        } else if (name.endsWith("_SHA")) {

            macAlg = M_SHA;

        } else if (name.endsWith("_SHA256")) {

            macAlg = M_SHA256;

        } else if (name.endsWith("_SHA384")) {

            macAlg = M_SHA384;

        } else if (name.endsWith("_NULL")) {

            macAlg = M_NULL;

        } else if (name.endsWith("_SCSV")) {

            macAlg = M_NULL;

        } else {

            throw new IllegalArgumentException

                    ("Unknown MAC algorithm for ciphersuite " + name);

        }

        allowed &= keyExchange.allowed;

        allowed &= cipher.allowed;

        this.allowed = allowed;

        this.obsoleted = obsoleted;

        this.supported = supported;

        this.prfAlg = prfAlg;

    }

    /**

     * Constructor for unimplemented CipherSuites.

     */

    private CipherSuite(String name, int id) {

        this.name = name;

        this.id = id;

        this.allowed = false;

        this.priority = 0;

        this.keyExchange = null;

        this.cipher = null;

        this.macAlg = null;

        this.exportable = false;

        this.obsoleted = ProtocolVersion.LIMIT_MAX_VALUE;

        this.supported = ProtocolVersion.LIMIT_MIN_VALUE;

        this.prfAlg = P_NONE;

    }

    /**

     * Return whether this CipherSuite is available for use. A

     * CipherSuite may be unavailable even if it is supported

     * (i.e. allowed == true) if the required JCE cipher is not installed.

     * In some configuration, this situation may change over time, call

     * CipherSuiteList.clearAvailableCache() before this method to obtain

     * the most current status.

     */

    boolean isAvailable() {

        return allowed && keyExchange.isAvailable() && cipher.isAvailable();

    }

    boolean isNegotiable() {

        return this != C_SCSV && isAvailable();

    }

    /**

     * Compares CipherSuites based on their priority. Has the effect of

     * sorting CipherSuites when put in a sorted collection, which is

     * used by CipherSuiteList. Follows standard Comparable contract.

     *

     * Note that for unsupported CipherSuites parsed from a handshake

     * message we violate the equals() contract.

     */

    public int compareTo(Object o) {

        return ((CipherSuite)o).priority - priority;

    }

    /**

     * Returns this.name.

     */

    public String toString() {

        return name;

    }

    /**

     * Return a CipherSuite for the given name. The returned CipherSuite

     * is supported by this implementation but may not actually be

     * currently useable. See isAvailable().

     *

     * @exception IllegalArgumentException if the CipherSuite is unknown or

     * unsupported.

     */

    static CipherSuite valueOf(String s) {

        if (s == null) {

            throw new IllegalArgumentException("Name must not be null");

        }

        CipherSuite c = nameMap.get(s);

        if ((c == null) || (c.allowed == false)) {

            throw new IllegalArgumentException("Unsupported ciphersuite " + s);

        }

        return c;

    }

    /**

     * Return a CipherSuite with the given ID. A temporary object is

     * constructed if the ID is unknown. Use isAvailable() to verify that

     * the CipherSuite can actually be used.

     */

    static CipherSuite valueOf(int id1, int id2) {

        id1 &= 0xff;

        id2 &= 0xff;

        int id = (id1 << 8) | id2;

        CipherSuite c = idMap.get(id);

        if (c == null) {

            String h1 = Integer.toString(id1, 16);

            String h2 = Integer.toString(id2, 16);

            c = new CipherSuite("Unknown 0x" + h1 + ":0x" + h2, id);

        }

        return c;

    }

    // for use by CipherSuiteList only

    static Collection<CipherSuite> allowedCipherSuites() {

        return nameMap.values();

    }

    /*

     * Use this method when all of the values need to be specified.

     * This is primarily used when defining a new ciphersuite for

     * TLS 1.2+ that doesn't use the "default" PRF.

     */

    private static void add(String name, int id, int priority,

            KeyExchange keyExchange, BulkCipher cipher,

            boolean allowed, int obsoleted, int supported, PRF prf) {

        CipherSuite c = new CipherSuite(name, id, priority, keyExchange,

            cipher, allowed, obsoleted, supported, prf);

        if (idMap.put(id, c) != null) {

            throw new RuntimeException("Duplicate ciphersuite definition: "

                                        + id + ", " + name);

        }

        if (c.allowed) {

            if (nameMap.put(name, c) != null) {

                throw new RuntimeException("Duplicate ciphersuite definition: "

                                            + id + ", " + name);

            }

        }

    }

    /*

     * Use this method when there is no lower protocol limit where this

     * suite can be used, and the PRF is P_SHA256.  That is, the

     * existing ciphersuites.  From RFC 5246:

     *

     *     All cipher suites in this document use P_SHA256.

     */

    private static void add(String name, int id, int priority,

            KeyExchange keyExchange, BulkCipher cipher,

            boolean allowed, int obsoleted) {

        // If this is an obsoleted suite, then don't let the TLS 1.2

        // protocol have a valid PRF value.

        PRF prf = P_SHA256;

        if (obsoleted < ProtocolVersion.TLS12.v) {

            prf = P_NONE;

        }

        add(name, id, priority, keyExchange, cipher, allowed, obsoleted,

            ProtocolVersion.LIMIT_MIN_VALUE, prf);

    }

    /*

     * Use this method when there is no upper protocol limit.  That is,

     * suites which have not been obsoleted.

     */

    private static void add(String name, int id, int priority,

            KeyExchange keyExchange, BulkCipher cipher, boolean allowed) {

        add(name, id, priority, keyExchange,

            cipher, allowed, ProtocolVersion.LIMIT_MAX_VALUE);

    }

    /*

     * Use this method to define an unimplemented suite.  This provides

     * a number<->name mapping that can be used for debugging.

     */

    private static void add(String name, int id) {

        CipherSuite c = new CipherSuite(name, id);

        if (idMap.put(id, c) != null) {

            throw new RuntimeException("Duplicate ciphersuite definition: "

                                        + id + ", " + name);

        }

    }

    /**

     * An SSL/TLS key exchange algorithm.

     */

    static enum KeyExchange {

        // key exchange algorithms

        K_NULL       ("NULL",       false),

        K_RSA        ("RSA",        true),

        K_RSA_EXPORT ("RSA_EXPORT", true),

        K_DH_RSA     ("DH_RSA",     false),

        K_DH_DSS     ("DH_DSS",     false),

        K_DHE_DSS    ("DHE_DSS",    true),

        K_DHE_RSA    ("DHE_RSA",    true),

        K_DH_ANON    ("DH_anon",    true),

        K_ECDH_ECDSA ("ECDH_ECDSA",  ALLOW_ECC),

        K_ECDH_RSA   ("ECDH_RSA",    ALLOW_ECC),

        K_ECDHE_ECDSA("ECDHE_ECDSA", ALLOW_ECC),

        K_ECDHE_RSA  ("ECDHE_RSA",   ALLOW_ECC),

        K_ECDH_ANON  ("ECDH_anon",   ALLOW_ECC),

        // Kerberos cipher suites

        K_KRB5       ("KRB5", true),

        K_KRB5_EXPORT("KRB5_EXPORT", true),

        // renegotiation protection request signaling cipher suite

        K_SCSV       ("SCSV",        true);

        // name of the key exchange algorithm, e.g. DHE_DSS

        final String name;

        final boolean allowed;

        private final boolean alwaysAvailable;

        KeyExchange(String name, boolean allowed) {

            this.name = name;

            this.allowed = allowed;

            this.alwaysAvailable = allowed &&

                (!name.startsWith("EC")) && (!name.startsWith("KRB"));

        }

        boolean isAvailable() {

            if (alwaysAvailable) {

                return true;

            }

            if (name.startsWith("EC")) {

                return (allowed && JsseJce.isEcAvailable());

            } else if (name.startsWith("KRB")) {

                return (allowed && JsseJce.isKerberosAvailable());

            } else {

                return allowed;

            }

        }

        public String toString() {

            return name;

        }

    }

    /**

     * An SSL/TLS bulk cipher algorithm. One instance per combination of

     * cipher and key length.

     *

     * Also contains a factory method to obtain in initialized CipherBox

     * for this algorithm.

     */

    final static class BulkCipher {

        // Map BulkCipher -> Boolean(available)

        private final static Map<BulkCipher,Boolean> availableCache =

                                            new HashMap<BulkCipher,Boolean>(8);

        // descriptive name including key size, e.g. AES/128

        final String description;

        // JCE cipher transformation string, e.g. AES/CBC/NoPadding

        final String transformation;

        // algorithm name, e.g. AES

        final String algorithm;

        // supported and compile time enabled. Also see isAvailable()

        final boolean allowed;

        // number of bytes of entropy in the key

        final int keySize;

        // length of the actual cipher key in bytes.

        // for non-exportable ciphers, this is the same as keySize

        final int expandedKeySize;

        // size of the IV (also block size)

        final int ivSize;

        // exportable under 512/40 bit rules

        final boolean exportable;

        BulkCipher(String transformation, int keySize,

                int expandedKeySize, int ivSize, boolean allowed) {

            this.transformation = transformation;

            this.algorithm = transformation.split("/")[0];

            this.description = this.algorithm + "/" + (keySize << 3);

            this.keySize = keySize;

            this.ivSize = ivSize;

            this.allowed = allowed;

            this.expandedKeySize = expandedKeySize;

            this.exportable = true;

        }

        BulkCipher(String transformation, int keySize,

                int ivSize, boolean allowed) {

            this.transformation = transformation;

            this.algorithm = transformation.split("/")[0];

            this.description = this.algorithm + "/" + (keySize << 3);

            this.keySize = keySize;

            this.ivSize = ivSize;

            this.allowed = allowed;

            this.expandedKeySize = keySize;

            this.exportable = false;

        }

        /**

         * Return an initialized CipherBox for this BulkCipher.

         * IV must be null for stream ciphers.

         *

         * @exception NoSuchAlgorithmException if anything goes wrong

         */

        CipherBox newCipher(ProtocolVersion version, SecretKey key,

                IvParameterSpec iv, SecureRandom random,

                boolean encrypt) throws NoSuchAlgorithmException {

            return CipherBox.newCipherBox(version, this,

                                            key, iv, random, encrypt);

        }

        /**

         * Test if this bulk cipher is available. For use by CipherSuite.

         *

         * Currently all supported ciphers except AES are always available

         * via the JSSE internal implementations. We also assume AES/128

         * is always available since it is shipped with the SunJCE provider.

         * However, AES/256 is unavailable when the default JCE policy

         * jurisdiction files are installed because of key length restrictions.

         */

        boolean isAvailable() {

            if (allowed == false) {

                return false;

            }

            if (this == B_AES_256) {

                return isAvailable(this);

            }

            // always available

            return true;

        }

        // for use by CipherSuiteList.clearAvailableCache();

        static synchronized void clearAvailableCache() {

            if (DYNAMIC_AVAILABILITY) {

                availableCache.clear();

            }

        }

        private static synchronized boolean isAvailable(BulkCipher cipher) {

            Boolean b = availableCache.get(cipher);

            if (b == null) {

                try {

                    SecretKey key = new SecretKeySpec

                        (new byte[cipher.expandedKeySize], cipher.algorithm);

                    IvParameterSpec iv =

                        new IvParameterSpec(new byte[cipher.ivSize]);

                    cipher.newCipher(ProtocolVersion.DEFAULT,

                                                key, iv, null, true);

                    b = Boolean.TRUE;

                } catch (NoSuchAlgorithmException e) {

                    b = Boolean.FALSE;

                }

                availableCache.put(cipher, b);

            }

            return b.booleanValue();

        }

        public String toString() {

            return description;

        }

    }

    /**

     * An SSL/TLS key MAC algorithm.

     *