/*

 * 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

 * particular file as subject to the "Classpath" exception as provided

 *

 * 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.

 *

 */

package sun.security.ssl;

import java.util.*;

import java.math.BigInteger;

import java.security.*;

import java.security.interfaces.RSAPublicKey;

import java.security.spec.RSAPublicKeySpec;

import java.security.spec.*;

import javax.crypto.*;

// explicit import to override the Provider class in this package

import java.security.Provider;

// need internal Sun classes for FIPS tricks

import sun.security.jca.Providers;

import sun.security.jca.ProviderList;

import sun.security.ec.ECParameters;

import sun.security.ec.NamedCurve;

import static sun.security.ssl.SunJSSE.cryptoProvider;

/**

 * This class contains a few static methods for interaction with the JCA/JCE

 * to obtain implementations, etc.

 *

 * @author  Andreas Sterbenz

 */

final class JsseJce {

    private final static Debug debug = Debug.getInstance("ssl");

    private final static ProviderList fipsProviderList;

    // Flag indicating whether EC crypto is available.

    // If null, then we have not checked yet.

    // If yes, then all the EC based crypto we need is available.

    private static volatile Boolean ecAvailable;

    // Flag indicating whether Kerberos crypto is available.

    // If true, then all the Kerberos-based crypto we need is available.

    private final static boolean kerberosAvailable;

    static {

        boolean temp;

        try {

            AccessController.doPrivileged(

                new PrivilegedExceptionAction<Void>() {

                    public Void run() throws Exception {

                        // Test for Kerberos using the bootstrap class loader

                        Class.forName("sun.security.krb5.PrincipalName", true,

                                null);

                        return null;

                    }

                });

            temp = true;

        } catch (Exception e) {

            temp = false;

        }

        kerberosAvailable = temp;

    }

    static {

        // force FIPS flag initialization

        // Because isFIPS() is synchronized and cryptoProvider is not modified

        // after it completes, this also eliminates the need for any further

        // synchronization when accessing cryptoProvider

        if (SunJSSE.isFIPS() == false) {

            fipsProviderList = null;

        } else {

            // Setup a ProviderList that can be used by the trust manager

            // during certificate chain validation. All the crypto must be

            // from the FIPS provider, but we also allow the required

            // certificate related services from the SUN provider.

            Provider sun = Security.getProvider("SUN");

            if (sun == null) {

                throw new RuntimeException

                    ("FIPS mode: SUN provider must be installed");

            }

            Provider sunCerts = new SunCertificates(sun);

            fipsProviderList = ProviderList.newList(cryptoProvider, sunCerts);

        }

    }

    private static final class SunCertificates extends Provider {

        SunCertificates(final Provider p) {

            super("SunCertificates", 1.0d, "SunJSSE internal");

            AccessController.doPrivileged(new PrivilegedAction<Object>() {

                public Object run() {

                    // copy certificate related services from the Sun provider

                    for (Map.Entry<Object,Object> entry : p.entrySet()) {

                        String key = (String)entry.getKey();

                        if (key.startsWith("CertPathValidator.")

                                || key.startsWith("CertPathBuilder.")

                                || key.startsWith("CertStore.")

                                || key.startsWith("CertificateFactory.")) {

                            put(key, entry.getValue());

                        }

                    }

                    return null;

                }

            });

        }

    }

    /**

     * JCE transformation string for RSA with PKCS#1 v1.5 padding.

     * Can be used for encryption, decryption, signing, verifying.

     */

    final static String CIPHER_RSA_PKCS1 = "RSA/ECB/PKCS1Padding";

    /**

     * JCE transformation string for the stream cipher RC4.

     */

    final static String CIPHER_RC4 = "RC4";

    /**

     * JCE transformation string for DES in CBC mode without padding.

     */

    final static String CIPHER_DES = "DES/CBC/NoPadding";

    /**

     * JCE transformation string for (3-key) Triple DES in CBC mode

     * without padding.

     */

    final static String CIPHER_3DES = "DESede/CBC/NoPadding";

    /**

     * JCE transformation string for AES in CBC mode

     * without padding.

     */

    final static String CIPHER_AES = "AES/CBC/NoPadding";

    /**

     * JCA identifier string for DSA, i.e. a DSA with SHA-1.

     */

    final static String SIGNATURE_DSA = "DSA";

    /**

     * JCA identifier string for ECDSA, i.e. a ECDSA with SHA-1.

     */

    final static String SIGNATURE_ECDSA = "SHA1withECDSA";

    /**

     * JCA identifier string for Raw DSA, i.e. a DSA signature without

     * hashing where the application provides the SHA-1 hash of the data.

     * Note that the standard name is "NONEwithDSA" but we use "RawDSA"

     * for compatibility.

     */

    final static String SIGNATURE_RAWDSA = "RawDSA";

    /**

     * JCA identifier string for Raw ECDSA, i.e. a DSA signature without

     * hashing where the application provides the SHA-1 hash of the data.

     */

    final static String SIGNATURE_RAWECDSA = "NONEwithECDSA";

    /**

     * JCA identifier string for Raw RSA, i.e. a RSA PKCS#1 v1.5 signature

     * without hashing where the application provides the hash of the data.

     * Used for RSA client authentication with a 36 byte hash.

     */

    final static String SIGNATURE_RAWRSA = "NONEwithRSA";

    /**

     * JCA identifier string for the SSL/TLS style RSA Signature. I.e.

     * an signature using RSA with PKCS#1 v1.5 padding signing a

     * concatenation of an MD5 and SHA-1 digest.

     */

    final static String SIGNATURE_SSLRSA = "MD5andSHA1withRSA";

    private JsseJce() {

        // no instantiation of this class

    }

    static boolean isEcAvailable() {

        if (ecAvailable == null) {

            try {

                JsseJce.getSignature(SIGNATURE_ECDSA);

                JsseJce.getSignature(SIGNATURE_RAWECDSA);

                JsseJce.getKeyAgreement("ECDH");

                JsseJce.getKeyFactory("EC");

                JsseJce.getKeyPairGenerator("EC");

                ecAvailable = true;

            } catch (Exception e) {

                ecAvailable = false;

            }

        }

        return ecAvailable;

    }

    static void clearEcAvailable() {

        ecAvailable = null;

    }

    static boolean isKerberosAvailable() {

        return kerberosAvailable;

    }

    /**

     * Return an JCE cipher implementation for the specified algorithm.

     */

    static Cipher getCipher(String transformation)

            throws NoSuchAlgorithmException {

        try {

            if (cryptoProvider == null) {

                return Cipher.getInstance(transformation);

            } else {

                return Cipher.getInstance(transformation, cryptoProvider);

            }

        } catch (NoSuchPaddingException e) {

            throw new NoSuchAlgorithmException(e);

        }

    }

    /**

     * Return an JCA signature implementation for the specified algorithm.

     * The algorithm string should be one of the constants defined

     * in this class.

     */

    static Signature getSignature(String algorithm)

            throws NoSuchAlgorithmException {

        if (cryptoProvider == null) {

            return Signature.getInstance(algorithm);

        } else {

            // reference equality

            if (algorithm == SIGNATURE_SSLRSA) {

                // The SunPKCS11 provider currently does not support this

                // special algorithm. We allow a fallback in this case because

                // the SunJSSE implementation does the actual crypto using

                // a NONEwithRSA signature obtained from the cryptoProvider.

                if (cryptoProvider.getService("Signature", algorithm) == null) {

                    // Calling Signature.getInstance() and catching the exception

                    // would be cleaner, but exceptions are a little expensive.

                    // So we check directly via getService().

                    try {

                        return Signature.getInstance(algorithm, "SunJSSE");

                    } catch (NoSuchProviderException e) {

                        throw new NoSuchAlgorithmException(e);

                    }

                }

            }

            return Signature.getInstance(algorithm, cryptoProvider);

        }

    }

    static KeyGenerator getKeyGenerator(String algorithm)

            throws NoSuchAlgorithmException {

        if (cryptoProvider == null) {

            return KeyGenerator.getInstance(algorithm);

        } else {

            return KeyGenerator.getInstance(algorithm, cryptoProvider);

        }

    }

    static KeyPairGenerator getKeyPairGenerator(String algorithm)

            throws NoSuchAlgorithmException {

        if (cryptoProvider == null) {

            return KeyPairGenerator.getInstance(algorithm);

        } else {

            return KeyPairGenerator.getInstance(algorithm, cryptoProvider);

        }

    }

    static KeyAgreement getKeyAgreement(String algorithm)

            throws NoSuchAlgorithmException {

        if (cryptoProvider == null) {

            return KeyAgreement.getInstance(algorithm);

        } else {

            return KeyAgreement.getInstance(algorithm, cryptoProvider);

        }

    }

    static Mac getMac(String algorithm)

            throws NoSuchAlgorithmException {

        if (cryptoProvider == null) {

            return Mac.getInstance(algorithm);

        } else {

            return Mac.getInstance(algorithm, cryptoProvider);

        }

    }

    static KeyFactory getKeyFactory(String algorithm)

            throws NoSuchAlgorithmException {

        if (cryptoProvider == null) {

            return KeyFactory.getInstance(algorithm);

        } else {

            return KeyFactory.getInstance(algorithm, cryptoProvider);

        }

    }

    static SecureRandom getSecureRandom() throws KeyManagementException {

        if (cryptoProvider == null) {

            return new SecureRandom();

        }

        // Try "PKCS11" first. If that is not supported, iterate through

        // the provider and return the first working implementation.

        try {

            return SecureRandom.getInstance("PKCS11", cryptoProvider);

        } catch (NoSuchAlgorithmException e) {

            // ignore

        }

        for (Provider.Service s : cryptoProvider.getServices()) {

            if (s.getType().equals("SecureRandom")) {

                try {

                    return SecureRandom.getInstance(s.getAlgorithm(), cryptoProvider);

                } catch (NoSuchAlgorithmException ee) {

                    // ignore

                }

            }

        }

        throw new KeyManagementException("FIPS mode: no SecureRandom "

            + " implementation found in provider " + cryptoProvider.getName());

    }

    static MessageDigest getMD5() {

        return getMessageDigest("MD5");

    }

    static MessageDigest getSHA() {

        return getMessageDigest("SHA");

    }

    static MessageDigest getMessageDigest(String algorithm) {

        try {

            if (cryptoProvider == null) {

                return MessageDigest.getInstance(algorithm);

            } else {

                return MessageDigest.getInstance(algorithm, cryptoProvider);

            }

        } catch (NoSuchAlgorithmException e) {

            throw new RuntimeException

                        ("Algorithm " + algorithm + " not available", e);

        }

    }

    static int getRSAKeyLength(PublicKey key) {

        BigInteger modulus;

        if (key instanceof RSAPublicKey) {

            modulus = ((RSAPublicKey)key).getModulus();

        } else {

            RSAPublicKeySpec spec = getRSAPublicKeySpec(key);

            modulus = spec.getModulus();

        }

        return modulus.bitLength();

    }

    static RSAPublicKeySpec getRSAPublicKeySpec(PublicKey key) {

        if (key instanceof RSAPublicKey) {

            RSAPublicKey rsaKey = (RSAPublicKey)key;

            return new RSAPublicKeySpec(rsaKey.getModulus(),

                                        rsaKey.getPublicExponent());

        }

        try {

            KeyFactory factory = JsseJce.getKeyFactory("RSA");

            return factory.getKeySpec(key, RSAPublicKeySpec.class);

        } catch (Exception e) {

            throw (RuntimeException)new RuntimeException().initCause(e);

        }

    }

    static ECParameterSpec getECParameterSpec(String namedCurveOid) {

        return NamedCurve.getECParameterSpec(namedCurveOid);

    }

    static String getNamedCurveOid(ECParameterSpec params) {

        return ECParameters.getCurveName(params);

    }

    static ECPoint decodePoint(byte[] encoded, EllipticCurve curve)

            throws java.io.IOException {

        return ECParameters.decodePoint(encoded, curve);

    }

    static byte[] encodePoint(ECPoint point, EllipticCurve curve) {

        return ECParameters.encodePoint(point, curve);

    }

    // In FIPS mode, set thread local providers; otherwise a no-op.

    // Must be paired with endFipsProvider.

    static Object beginFipsProvider() {

        if (fipsProviderList == null) {

            return null;

        } else {

            return Providers.beginThreadProviderList(fipsProviderList);

        }

    }

    static void endFipsProvider(Object o) {

        if (fipsProviderList != null) {

            Providers.endThreadProviderList((ProviderList)o);

        }

    }

}