/*

 * Copyright (c) 2005, 2015, 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.pkcs11;

import java.io.*;

import java.util.*;

import java.security.*;

import java.security.KeyStore.*;

import java.security.cert.X509Certificate;

import sun.security.pkcs11.wrapper.*;

import static sun.security.pkcs11.wrapper.PKCS11Constants.*;

/**

 * The Secmod class defines the interface to the native NSS

 * library and the configuration information it stores in its

 * secmod.db file.

 *

 * <p>Example code:

 * <pre>

 *   Secmod secmod = Secmod.getInstance();

 *   if (secmod.isInitialized() == false) {

 *       secmod.initialize("/home/myself/.mozilla");

 *   }

 *

 *   Provider p = secmod.getModule(ModuleType.KEYSTORE).getProvider();

 *   KeyStore ks = KeyStore.getInstance("PKCS11", p);

 *   ks.load(null, password);

 * </pre>

 *

 * @since   1.6

 * @author  Andreas Sterbenz

 */

public final class Secmod {

    private final static boolean DEBUG = false;

    private final static Secmod INSTANCE;

    static {

        sun.security.pkcs11.wrapper.PKCS11.loadNative();

        INSTANCE = new Secmod();

    }

    private final static String NSS_LIB_NAME = "nss3";

    private final static String SOFTTOKEN_LIB_NAME = "softokn3";

    private final static String TRUST_LIB_NAME = "nssckbi";

    // handle to be passed to the native code, 0 means not initialized

    private long nssHandle;

    // whether this is a supported version of NSS

    private boolean supported;

    // list of the modules

    private List<Module> modules;

    private String configDir;

    private String nssLibDir;

    private Secmod() {

        // empty

    }

    /**

     * Return the singleton Secmod instance.

     */

    public static Secmod getInstance() {

        return INSTANCE;

    }

    private boolean isLoaded() {

        if (nssHandle == 0) {

            nssHandle = nssGetLibraryHandle(System.mapLibraryName(NSS_LIB_NAME));

            if (nssHandle != 0) {

                fetchVersions();

            }

        }

        return (nssHandle != 0);

    }

    private void fetchVersions() {

        supported = nssVersionCheck(nssHandle, "3.7");

    }

    /**

     * Test whether this Secmod has been initialized. Returns true

     * if NSS has been initialized using either the initialize() method

     * or by directly calling the native NSS APIs. The latter may be

     * the case if the current process contains components that use

     * NSS directly.

     *

     * @throws IOException if an incompatible version of NSS

     *   has been loaded

     */

    public synchronized boolean isInitialized() throws IOException {

        // NSS does not allow us to check if it is initialized already

        // assume that if it is loaded it is also initialized

        if (isLoaded() == false) {

            return false;

        }

        if (supported == false) {

            throw new IOException

                ("An incompatible version of NSS is already loaded, "

                + "3.7 or later required");

        }

        return true;

    }

    String getConfigDir() {

        return configDir;

    }

    String getLibDir() {

        return nssLibDir;

    }

    /**

     * Initialize this Secmod.

     *

     * @param configDir the directory containing the NSS configuration

     *   files such as secmod.db

     * @param nssLibDir the directory containing the NSS libraries

     *   (libnss3.so or nss3.dll) or null if the library is on

     *   the system default shared library path

     *

     * @throws IOException if NSS has already been initialized,

     *   the specified directories are invalid, or initialization

     *   fails for any other reason

     */

    public void initialize(String configDir, String nssLibDir)

            throws IOException {

        initialize(DbMode.READ_WRITE, configDir, nssLibDir, false);

    }

    public void initialize(DbMode dbMode, String configDir, String nssLibDir)

            throws IOException {

        initialize(dbMode, configDir, nssLibDir, false);

    }

    public synchronized void initialize(DbMode dbMode, String configDir,

        String nssLibDir, boolean nssOptimizeSpace) throws IOException {

        if (isInitialized()) {

            throw new IOException("NSS is already initialized");

        }

        if (dbMode == null) {

            throw new NullPointerException();

        }

        if ((dbMode != DbMode.NO_DB) && (configDir == null)) {

            throw new NullPointerException();

        }

        String platformLibName = System.mapLibraryName("nss3");

        String platformPath;

        if (nssLibDir == null) {

            platformPath = platformLibName;

        } else {

            File base = new File(nssLibDir);

            if (base.isDirectory() == false) {

                throw new IOException("nssLibDir must be a directory:" + nssLibDir);

            }

            File platformFile = new File(base, platformLibName);

            if (platformFile.isFile() == false) {

                throw new FileNotFoundException(platformFile.getPath());

            }

            platformPath = platformFile.getPath();

        }

        if (configDir != null) {

            String configDirPath = null;

            if (!configDir.startsWith(sqlPrefix)) {

                configDirPath = configDir;

            } else {

                StringBuilder configDirPathSB = new StringBuilder(configDir);

                configDirPath = configDirPathSB.substring(sqlPrefix.length());

            }

            File configBase = new File(configDirPath);

            if (configBase.isDirectory() == false ) {

                throw new IOException("configDir must be a directory: " + configDirPath);

            }

            if (!configDir.startsWith(sqlPrefix)) {

                File secmodFile = new File(configBase, "secmod.db");

                if (secmodFile.isFile() == false) {

                    throw new FileNotFoundException(secmodFile.getPath());

                }

            }

        }

        if (DEBUG) System.out.println("lib: " + platformPath);

        nssHandle = nssLoadLibrary(platformPath);

        if (DEBUG) System.out.println("handle: " + nssHandle);

        fetchVersions();

        if (supported == false) {

            throw new IOException

                ("The specified version of NSS is incompatible, "

                + "3.7 or later required");

        }

        if (DEBUG) System.out.println("dir: " + configDir);

        boolean initok = nssInitialize(dbMode.functionName, nssHandle,

            configDir, nssOptimizeSpace);

        if (DEBUG) System.out.println("init: " + initok);

        if (initok == false) {

            throw new IOException("NSS initialization failed");

        }

        this.configDir = configDir;

        this.nssLibDir = nssLibDir;

    }

    /**

     * Return an immutable list of all available modules.

     *

     * @throws IllegalStateException if this Secmod is misconfigured

     *   or not initialized

     */

    public synchronized List<Module> getModules() {

        try {

            if (isInitialized() == false) {

                throw new IllegalStateException("NSS not initialized");

            }

        } catch (IOException e) {

            // IOException if misconfigured

            throw new IllegalStateException(e);

        }

        if (modules == null) {

            @SuppressWarnings("unchecked")

            List<Module> modules = (List<Module>)nssGetModuleList(nssHandle,

                nssLibDir);

            this.modules = Collections.unmodifiableList(modules);

        }

        return modules;

    }

    private static byte[] getDigest(X509Certificate cert, String algorithm) {

        try {

            MessageDigest md = MessageDigest.getInstance(algorithm);

            return md.digest(cert.getEncoded());

        } catch (GeneralSecurityException e) {

            throw new ProviderException(e);

        }

    }

    boolean isTrusted(X509Certificate cert, TrustType trustType) {

        Bytes bytes = new Bytes(getDigest(cert, "SHA-1"));

        TrustAttributes attr = getModuleTrust(ModuleType.KEYSTORE, bytes);

        if (attr == null) {

            attr = getModuleTrust(ModuleType.FIPS, bytes);

            if (attr == null) {

                attr = getModuleTrust(ModuleType.TRUSTANCHOR, bytes);

            }

        }

        return (attr == null) ? false : attr.isTrusted(trustType);

    }

    private TrustAttributes getModuleTrust(ModuleType type, Bytes bytes) {

        Module module = getModule(type);

        TrustAttributes t = (module == null) ? null : module.getTrust(bytes);

        return t;

    }

    /**

     * Constants describing the different types of NSS modules.

     * For this API, NSS modules are classified as either one

     * of the internal modules delivered as part of NSS or

     * as an external module provided by a 3rd party.

     */

    public static enum ModuleType {

        /**

         * The NSS Softtoken crypto module. This is the first

         * slot of the softtoken object.

         * This module provides

         * implementations for cryptographic algorithms but no KeyStore.

         */

        CRYPTO,

        /**

         * The NSS Softtoken KeyStore module. This is the second

         * slot of the softtoken object.

         * This module provides

         * implementations for cryptographic algorithms (after login)

         * and the KeyStore.

         */

        KEYSTORE,

        /**

         * The NSS Softtoken module in FIPS mode. Note that in FIPS mode the

         * softtoken presents only one slot, not separate CRYPTO and KEYSTORE

         * slots as in non-FIPS mode.

         */

        FIPS,

        /**

         * The NSS builtin trust anchor module. This is the

         * NSSCKBI object. It provides no crypto functions.

         */

        TRUSTANCHOR,

        /**

         * An external module.

         */

        EXTERNAL,

    }

    /**

     * Returns the first module of the specified type. If no such

     * module exists, this method returns null.

     *

     * @throws IllegalStateException if this Secmod is misconfigured

     *   or not initialized

     */

    public Module getModule(ModuleType type) {

        for (Module module : getModules()) {

            if (module.getType() == type) {

                return module;

            }

        }

        return null;

    }

    static final String TEMPLATE_EXTERNAL =

        "library = %s\n"

        + "name = \"%s\"\n"

        + "slotListIndex = %d\n";

    static final String TEMPLATE_TRUSTANCHOR =

        "library = %s\n"

        + "name = \"NSS Trust Anchors\"\n"

        + "slotListIndex = 0\n"

        + "enabledMechanisms = { KeyStore }\n"

        + "nssUseSecmodTrust = true\n";

    static final String TEMPLATE_CRYPTO =

        "library = %s\n"

        + "name = \"NSS SoftToken Crypto\"\n"

        + "slotListIndex = 0\n"

        + "disabledMechanisms = { KeyStore }\n";

    static final String TEMPLATE_KEYSTORE =

        "library = %s\n"

        + "name = \"NSS SoftToken KeyStore\"\n"

        + "slotListIndex = 1\n"

        + "nssUseSecmodTrust = true\n";

    static final String TEMPLATE_FIPS =

        "library = %s\n"

        + "name = \"NSS FIPS SoftToken\"\n"

        + "slotListIndex = 0\n"

        + "nssUseSecmodTrust = true\n";

    /**

     * A representation of one PKCS#11 slot in a PKCS#11 module.

     */

    public static final class Module {

        // path of the native library

        final String libraryName;

        // descriptive name used by NSS

        final String commonName;

        final int slot;

        final ModuleType type;

        private String config;

        private SunPKCS11 provider;

        // trust attributes. Used for the KEYSTORE and TRUSTANCHOR modules only

        private Map<Bytes,TrustAttributes> trust;

        Module(String libraryDir, String libraryName, String commonName,

                boolean fips, int slot) {

            ModuleType type;

            if ((libraryName == null) || (libraryName.length() == 0)) {

                // must be softtoken

                libraryName = System.mapLibraryName(SOFTTOKEN_LIB_NAME);

                if (fips == false) {

                    type = (slot == 0) ? ModuleType.CRYPTO : ModuleType.KEYSTORE;

                } else {

                    type = ModuleType.FIPS;

                    if (slot != 0) {

                        throw new RuntimeException

                            ("Slot index should be 0 for FIPS slot");

                    }

                }

            } else {

                if (libraryName.endsWith(System.mapLibraryName(TRUST_LIB_NAME))

                        || commonName.equals("Builtin Roots Module")) {

                    type = ModuleType.TRUSTANCHOR;

                } else {

                    type = ModuleType.EXTERNAL;

                }

                if (fips) {

                    throw new RuntimeException("FIPS flag set for non-internal "

                        + "module: " + libraryName + ", " + commonName);

                }

            }

            // On Ubuntu the libsoftokn3 library is located in a subdirectory

            // of the system libraries directory. (Since Ubuntu 11.04.)

            File libraryFile = new File(libraryDir, libraryName);

            if (!libraryFile.isFile()) {

               File failover = new File(libraryDir, "nss/" + libraryName);

               if (failover.isFile()) {

                   libraryFile = failover;

               }

            }

            this.libraryName = libraryFile.getPath();

            this.commonName = commonName;

            this.slot = slot;

            this.type = type;

            initConfiguration();

        }

        private void initConfiguration() {

            switch (type) {

            case EXTERNAL:

                config = String.format(TEMPLATE_EXTERNAL, libraryName,

                                            commonName + " " + slot, slot);

                break;

            case CRYPTO:

                config = String.format(TEMPLATE_CRYPTO, libraryName);

                break;

            case KEYSTORE:

                config = String.format(TEMPLATE_KEYSTORE, libraryName);

                break;

            case FIPS:

                config = String.format(TEMPLATE_FIPS, libraryName);

                break;

            case TRUSTANCHOR:

                config = String.format(TEMPLATE_TRUSTANCHOR, libraryName);

                break;

            default:

                throw new RuntimeException("Unknown module type: " + type);

            }

        }

        /**

         * Get the configuration for this module. This is a string

         * in the SunPKCS11 configuration format. It can be

         * customized with additional options and then made

         * current using the setConfiguration() method.

         */

        @Deprecated

        public synchronized String getConfiguration() {

            return config;

        }

        /**

         * Set the configuration for this module.

         *

         * @throws IllegalStateException if the associated provider

         *   instance has already been created.

         */

        @Deprecated

        public synchronized void setConfiguration(String config) {

            if (provider != null) {

                throw new IllegalStateException("Provider instance already created");

            }

            this.config = config;

        }

        /**

         * Return the pathname of the native library that implements

         * this module. For example, /usr/lib/libpkcs11.so.

         */

        public String getLibraryName() {

            return libraryName;

        }

        /**

         * Returns the type of this module.

         */

        public ModuleType getType() {

            return type;

        }

        /**

         * Returns the provider instance that is associated with this

         * module. The first call to this method creates the provider

         * instance.

         */

        @Deprecated

        public synchronized Provider getProvider() {

            if (provider == null) {

                provider = newProvider();

            }

            return provider;

        }

        synchronized boolean hasInitializedProvider() {

            return provider != null;

        }

        void setProvider(SunPKCS11 p) {

            if (provider != null) {

                throw new ProviderException("Secmod provider already initialized");

            }

            provider = p;

        }