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 * Copyright (c) 1999, 2018, 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
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package sun.security.ssl;

import java.net.Socket;
import java.security.Key;
import java.security.KeyStore;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.Principal;
import java.security.PrivateKey;
import java.security.UnrecoverableKeyException;
import java.security.cert.Certificate;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import javax.net.ssl.SSLEngine;
import javax.net.ssl.X509ExtendedKeyManager;
import javax.security.auth.x500.X500Principal;


An implementation of X509KeyManager backed by a KeyStore.
The backing KeyStore is inspected when this object is constructed.
All key entries containing a PrivateKey and a non-empty chain of
X509Certificate are then copied into an internal store. This means
that subsequent modifications of the KeyStore have no effect on the
X509KeyManagerImpl object.
Note that this class assumes that all keys are protected by the same
password.
The JSSE handshake code currently calls into this class via
chooseClientAlias() and chooseServerAlias() to find the certificates to
use. As implemented here, both always return the first alias returned by
getClientAliases() and getServerAliases(). In turn, these methods are
implemented by calling getAliases(), which performs the actual lookup.
Note that this class currently implements no checking of the local
certificates. In particular, it is *not* guaranteed that:
 . the certificates are within their validity period and not revoked
 . the signatures verify
 . they form a PKIX compliant chain.
 . the certificate extensions allow the certificate to be used for
   the desired purpose.
Chains that fail any of these criteria will probably be rejected by
the remote peer.
/**
 * An implementation of X509KeyManager backed by a KeyStore.
 *
 * The backing KeyStore is inspected when this object is constructed.
 * All key entries containing a PrivateKey and a non-empty chain of
 * X509Certificate are then copied into an internal store. This means
 * that subsequent modifications of the KeyStore have no effect on the
 * X509KeyManagerImpl object.
 *
 * Note that this class assumes that all keys are protected by the same
 * password.
 *
 * The JSSE handshake code currently calls into this class via
 * chooseClientAlias() and chooseServerAlias() to find the certificates to
 * use. As implemented here, both always return the first alias returned by
 * getClientAliases() and getServerAliases(). In turn, these methods are
 * implemented by calling getAliases(), which performs the actual lookup.
 *
 * Note that this class currently implements no checking of the local
 * certificates. In particular, it is *not* guaranteed that:
 *  . the certificates are within their validity period and not revoked
 *  . the signatures verify
 *  . they form a PKIX compliant chain.
 *  . the certificate extensions allow the certificate to be used for
 *    the desired purpose.
 *
 * Chains that fail any of these criteria will probably be rejected by
 * the remote peer.
 *
 */
final class SunX509KeyManagerImpl extends X509ExtendedKeyManager {

    private static final String[] STRING0 = new String[0];

    /*
     * The credentials from the KeyStore as
     * Map: String(alias) -> X509Credentials(credentials)
     */
    private Map<String,X509Credentials> credentialsMap;

    /*
     * Cached server aliases for the case issuers == null.
     * (in the current JSSE implementation, issuers are always null for
     * server certs). See chooseServerAlias() for details.
     *
     * Map: String(keyType) -> String[](alias)
     */
    private final Map<String,String[]> serverAliasCache;

    /*
     * Basic container for credentials implemented as an inner class.
     */
    private static class X509Credentials {
        PrivateKey privateKey;
        X509Certificate[] certificates;
        private Set<X500Principal> issuerX500Principals;

        X509Credentials(PrivateKey privateKey, X509Certificate[] certificates) {
            // assert privateKey and certificates != null
            this.privateKey = privateKey;
            this.certificates = certificates;
        }

        synchronized Set<X500Principal> getIssuerX500Principals() {
            // lazy initialization
            if (issuerX500Principals == null) {
                issuerX500Principals = new HashSet<X500Principal>();
                for (int i = 0; i < certificates.length; i++) {
                    issuerX500Principals.add(
                                certificates[i].getIssuerX500Principal());
                }
            }
            return issuerX500Principals;
        }
    }

    SunX509KeyManagerImpl(KeyStore ks, char[] password)
            throws KeyStoreException,
            NoSuchAlgorithmException, UnrecoverableKeyException {

        credentialsMap = new HashMap<String,X509Credentials>();
        serverAliasCache = Collections.synchronizedMap(
                            new HashMap<String,String[]>());
        if (ks == null) {
            return;
        }

        for (Enumeration<String> aliases = ks.aliases();
                                        aliases.hasMoreElements(); ) {
            String alias = aliases.nextElement();
            if (!ks.isKeyEntry(alias)) {
                continue;
            }
            Key key = ks.getKey(alias, password);
            if (key instanceof PrivateKey == false) {
                continue;
            }
            Certificate[] certs = ks.getCertificateChain(alias);
            if ((certs == null) || (certs.length == 0) ||
                    !(certs[0] instanceof X509Certificate)) {
                continue;
            }
            if (!(certs instanceof X509Certificate[])) {
                Certificate[] tmp = new X509Certificate[certs.length];
                System.arraycopy(certs, 0, tmp, 0, certs.length);
                certs = tmp;
            }

            X509Credentials cred = new X509Credentials((PrivateKey)key,
                (X509Certificate[])certs);
            credentialsMap.put(alias, cred);
            if (SSLLogger.isOn && SSLLogger.isOn("keymanager")) {
                SSLLogger.fine("found key for : " + alias, (Object[])certs);
            }
        }
    }

    /*
     * Returns the certificate chain associated with the given alias.
     *
     * @return the certificate chain (ordered with the user's certificate first
     * and the root certificate authority last)
     */
    @Override
    public X509Certificate[] getCertificateChain(String alias) {
        if (alias == null) {
            return null;
        }
        X509Credentials cred = credentialsMap.get(alias);
        if (cred == null) {
            return null;
        } else {
            return cred.certificates.clone();
        }
    }

    /*
     * Returns the key associated with the given alias
     */
    @Override
    public PrivateKey getPrivateKey(String alias) {
        if (alias == null) {
            return null;
        }
        X509Credentials cred = credentialsMap.get(alias);
        if (cred == null) {
            return null;
        } else {
            return cred.privateKey;
        }
    }

    /*
     * Choose an alias to authenticate the client side of a secure
     * socket given the public key type and the list of
     * certificate issuer authorities recognized by the peer (if any).
     */
    @Override
    public String chooseClientAlias(String[] keyTypes, Principal[] issuers,
            Socket socket) {
        /*
         * We currently don't do anything with socket, but
         * someday we might.  It might be a useful hint for
         * selecting one of the aliases we get back from
         * getClientAliases().
         */

        if (keyTypes == null) {
            return null;
        }

        for (int i = 0; i < keyTypes.length; i++) {
            String[] aliases = getClientAliases(keyTypes[i], issuers);
            if ((aliases != null) && (aliases.length > 0)) {
                return aliases[0];
            }
        }
        return null;
    }

    /*
     * Choose an alias to authenticate the client side of an
     * <code>SSLEngine</code> connection given the public key type
     * and the list of certificate issuer authorities recognized by
     * the peer (if any).
     *
     * @since 1.5
     */
    @Override
    public String chooseEngineClientAlias(String[] keyType,
            Principal[] issuers, SSLEngine engine) {
        /*
         * If we ever start using socket as a selection criteria,
         * we'll need to adjust this.
         */
        return chooseClientAlias(keyType, issuers, null);
    }

    /*
     * Choose an alias to authenticate the server side of a secure
     * socket given the public key type and the list of
     * certificate issuer authorities recognized by the peer (if any).
     */
    @Override
    public String chooseServerAlias(String keyType,
            Principal[] issuers, Socket socket) {
        /*
         * We currently don't do anything with socket, but
         * someday we might.  It might be a useful hint for
         * selecting one of the aliases we get back from
         * getServerAliases().
         */
        if (keyType == null) {
            return null;
        }

        String[] aliases;

        if (issuers == null || issuers.length == 0) {
            aliases = serverAliasCache.get(keyType);
            if (aliases == null) {
                aliases = getServerAliases(keyType, issuers);
                // Cache the result (positive and negative lookups)
                if (aliases == null) {
                    aliases = STRING0;
                }
                serverAliasCache.put(keyType, aliases);
            }
        } else {
            aliases = getServerAliases(keyType, issuers);
        }
        if ((aliases != null) && (aliases.length > 0)) {
            return aliases[0];
        }
        return null;
    }

    /*
     * Choose an alias to authenticate the server side of an
     * <code>SSLEngine</code> connection given the public key type
     * and the list of certificate issuer authorities recognized by
     * the peer (if any).
     *
     * @since 1.5
     */
    @Override
    public String chooseEngineServerAlias(String keyType,
            Principal[] issuers, SSLEngine engine) {
        /*
         * If we ever start using socket as a selection criteria,
         * we'll need to adjust this.
         */
        return chooseServerAlias(keyType, issuers, null);
    }

    /*
     * Get the matching aliases for authenticating the client side of a secure
     * socket given the public key type and the list of
     * certificate issuer authorities recognized by the peer (if any).
     */
    @Override
    public String[] getClientAliases(String keyType, Principal[] issuers) {
        return getAliases(keyType, issuers);
    }

    /*
     * Get the matching aliases for authenticating the server side of a secure
     * socket given the public key type and the list of
     * certificate issuer authorities recognized by the peer (if any).
     */
    @Override
    public String[] getServerAliases(String keyType, Principal[] issuers) {
        return getAliases(keyType, issuers);
    }

    /*
     * Get the matching aliases for authenticating the either side of a secure
     * socket given the public key type and the list of
     * certificate issuer authorities recognized by the peer (if any).
     *
     * Issuers comes to us in the form of X500Principal[].
     */
    private String[] getAliases(String keyType, Principal[] issuers) {
        if (keyType == null) {
            return null;
        }
        if (issuers == null) {
            issuers = new X500Principal[0];
        }
        if (issuers instanceof X500Principal[] == false) {
            // normally, this will never happen but try to recover if it does
            issuers = convertPrincipals(issuers);
        }
        String sigType;
        if (keyType.contains("_")) {
            int k = keyType.indexOf('_');
            sigType = keyType.substring(k + 1);
            keyType = keyType.substring(0, k);
        } else {
            sigType = null;
        }

        X500Principal[] x500Issuers = (X500Principal[])issuers;
        // the algorithm below does not produce duplicates, so avoid Set
        List<String> aliases = new ArrayList<>();

        for (Map.Entry<String,X509Credentials> entry :
                                                credentialsMap.entrySet()) {

            String alias = entry.getKey();
            X509Credentials credentials = entry.getValue();
            X509Certificate[] certs = credentials.certificates;

            if (!keyType.equals(certs[0].getPublicKey().getAlgorithm())) {
                continue;
            }
            if (sigType != null) {
                if (certs.length > 1) {
                    // if possible, check the public key in the issuer cert
                    if (!sigType.equals(
                            certs[1].getPublicKey().getAlgorithm())) {
                        continue;
                    }
                } else {
                    // Check the signature algorithm of the certificate itself.
                    // Look for the "withRSA" in "SHA1withRSA", etc.
                    String sigAlgName =
                        certs[0].getSigAlgName().toUpperCase(Locale.ENGLISH);
                    String pattern = "WITH" +
                        sigType.toUpperCase(Locale.ENGLISH);
                    if (sigAlgName.contains(pattern) == false) {
                        continue;
                    }
                }
            }

            if (issuers.length == 0) {
                // no issuer specified, match all
                aliases.add(alias);
                if (SSLLogger.isOn && SSLLogger.isOn("keymanager")) {
                    SSLLogger.fine("matching alias: " + alias);
                }
            } else {
                Set<X500Principal> certIssuers =
                                        credentials.getIssuerX500Principals();
                for (int i = 0; i < x500Issuers.length; i++) {
                    if (certIssuers.contains(issuers[i])) {
                        aliases.add(alias);
                        if (SSLLogger.isOn && SSLLogger.isOn("keymanager")) {
                            SSLLogger.fine("matching alias: " + alias);
                        }
                        break;
                    }
                }
            }
        }

        String[] aliasStrings = aliases.toArray(STRING0);
        return ((aliasStrings.length == 0) ? null : aliasStrings);
    }

    /*
     * Convert an array of Principals to an array of X500Principals, if
     * possible. Principals that cannot be converted are ignored.
     */
    private static X500Principal[] convertPrincipals(Principal[] principals) {
        List<X500Principal> list = new ArrayList<>(principals.length);
        for (int i = 0; i < principals.length; i++) {
            Principal p = principals[i];
            if (p instanceof X500Principal) {
                list.add((X500Principal)p);
            } else {
                try {
                    list.add(new X500Principal(p.getName()));
                } catch (IllegalArgumentException e) {
                    // ignore
                }
            }
        }
        return list.toArray(new X500Principal[list.size()]);
    }
}