Java tutorial
/* * Copyright (c) 2000, 2017, 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 java.security.cert; import java.security.AccessController; import java.security.InvalidAlgorithmParameterException; import java.security.NoSuchAlgorithmException; import java.security.NoSuchProviderException; import java.security.PrivilegedAction; import java.security.Provider; import java.security.Security; import java.util.Objects; import sun.security.jca.*; import sun.security.jca.GetInstance.Instance; /** * A class for building certification paths (also known as certificate chains). * <p> * This class uses a provider-based architecture. * To create a {@code CertPathBuilder}, call * one of the static {@code getInstance} methods, passing in the * algorithm name of the {@code CertPathBuilder} desired and optionally * the name of the provider desired. * * <p>Once a {@code CertPathBuilder} object has been created, certification * paths can be constructed by calling the {@link #build build} method and * passing it an algorithm-specific set of parameters. If successful, the * result (including the {@code CertPath} that was built) is returned * in an object that implements the {@code CertPathBuilderResult} * interface. * * <p>The {@link #getRevocationChecker} method allows an application to specify * additional algorithm-specific parameters and options used by the * {@code CertPathBuilder} when checking the revocation status of certificates. * Here is an example demonstrating how it is used with the PKIX algorithm: * * <pre> * CertPathBuilder cpb = CertPathBuilder.getInstance("PKIX"); * PKIXRevocationChecker rc = (PKIXRevocationChecker)cpb.getRevocationChecker(); * rc.setOptions(EnumSet.of(Option.PREFER_CRLS)); * params.addCertPathChecker(rc); * CertPathBuilderResult cpbr = cpb.build(params); * </pre> * * <p>Every implementation of the Java platform is required to support the * following standard {@code CertPathBuilder} algorithm: * <ul> * <li>{@code PKIX}</li> * </ul> * This algorithm is described in the <a href= * "{@docRoot}/../specs/security/standard-names.html#certpathbuilder-algorithms"> * CertPathBuilder section</a> of the * Java Security Standard Algorithm Names Specification. * Consult the release documentation for your implementation to see if any * other algorithms are supported. * * <p> * <b>Concurrent Access</b> * <p> * The static methods of this class are guaranteed to be thread-safe. * Multiple threads may concurrently invoke the static methods defined in * this class with no ill effects. * <p> * However, this is not true for the non-static methods defined by this class. * Unless otherwise documented by a specific provider, threads that need to * access a single {@code CertPathBuilder} instance concurrently should * synchronize amongst themselves and provide the necessary locking. Multiple * threads each manipulating a different {@code CertPathBuilder} instance * need not synchronize. * * @see CertPath * * @since 1.4 * @author Sean Mullan * @author Yassir Elley */ public class CertPathBuilder { /* * Constant to lookup in the Security properties file to determine * the default certpathbuilder type. In the Security properties file, * the default certpathbuilder type is given as: * <pre> * certpathbuilder.type=PKIX * </pre> */ private static final String CPB_TYPE = "certpathbuilder.type"; private final CertPathBuilderSpi builderSpi; private final Provider provider; private final String algorithm; /** * Creates a {@code CertPathBuilder} object of the given algorithm, * and encapsulates the given provider implementation (SPI object) in it. * * @param builderSpi the provider implementation * @param provider the provider * @param algorithm the algorithm name */ protected CertPathBuilder(CertPathBuilderSpi builderSpi, Provider provider, String algorithm) { this.builderSpi = builderSpi; this.provider = provider; this.algorithm = algorithm; } /** * Returns a {@code CertPathBuilder} object that implements the * specified algorithm. * * <p> This method traverses the list of registered security Providers, * starting with the most preferred Provider. * A new CertPathBuilder object encapsulating the * CertPathBuilderSpi implementation from the first * Provider that supports the specified algorithm is returned. * * <p> Note that the list of registered providers may be retrieved via * the {@link Security#getProviders() Security.getProviders()} method. * * @implNote * The JDK Reference Implementation additionally uses the * {@code jdk.security.provider.preferred} * {@link Security#getProperty(String) Security} property to determine * the preferred provider order for the specified algorithm. This * may be different than the order of providers returned by * {@link Security#getProviders() Security.getProviders()}. * * @param algorithm the name of the requested {@code CertPathBuilder} * algorithm. See the CertPathBuilder section in the <a href= * "{@docRoot}/../specs/security/standard-names.html#certpathbuilder-algorithms"> * Java Security Standard Algorithm Names Specification</a> * for information about standard algorithm names. * * @return a {@code CertPathBuilder} object that implements the * specified algorithm * * @throws NoSuchAlgorithmException if no {@code Provider} supports a * {@code CertPathBuilderSpi} implementation for the * specified algorithm * * @throws NullPointerException if {@code algorithm} is {@code null} * * @see java.security.Provider */ public static CertPathBuilder getInstance(String algorithm) throws NoSuchAlgorithmException { Objects.requireNonNull(algorithm, "null algorithm name"); Instance instance = GetInstance.getInstance("CertPathBuilder", CertPathBuilderSpi.class, algorithm); return new CertPathBuilder((CertPathBuilderSpi) instance.impl, instance.provider, algorithm); } /** * Returns a {@code CertPathBuilder} object that implements the * specified algorithm. * * <p> A new CertPathBuilder object encapsulating the * CertPathBuilderSpi implementation from the specified provider * is returned. The specified provider must be registered * in the security provider list. * * <p> Note that the list of registered providers may be retrieved via * the {@link Security#getProviders() Security.getProviders()} method. * * @param algorithm the name of the requested {@code CertPathBuilder} * algorithm. See the CertPathBuilder section in the <a href= * "{@docRoot}/../specs/security/standard-names.html#certpathbuilder-algorithms"> * Java Security Standard Algorithm Names Specification</a> * for information about standard algorithm names. * * @param provider the name of the provider. * * @return a {@code CertPathBuilder} object that implements the * specified algorithm * * @throws IllegalArgumentException if the {@code provider} is * {@code null} or empty * * @throws NoSuchAlgorithmException if a {@code CertPathBuilderSpi} * implementation for the specified algorithm is not * available from the specified provider * * @throws NoSuchProviderException if the specified provider is not * registered in the security provider list * * @throws NullPointerException if {@code algorithm} is {@code null} * * @see java.security.Provider */ public static CertPathBuilder getInstance(String algorithm, String provider) throws NoSuchAlgorithmException, NoSuchProviderException { Objects.requireNonNull(algorithm, "null algorithm name"); Instance instance = GetInstance.getInstance("CertPathBuilder", CertPathBuilderSpi.class, algorithm, provider); return new CertPathBuilder((CertPathBuilderSpi) instance.impl, instance.provider, algorithm); } /** * Returns a {@code CertPathBuilder} object that implements the * specified algorithm. * * <p> A new CertPathBuilder object encapsulating the * CertPathBuilderSpi implementation from the specified Provider * object is returned. Note that the specified Provider object * does not have to be registered in the provider list. * * @param algorithm the name of the requested {@code CertPathBuilder} * algorithm. See the CertPathBuilder section in the <a href= * "{@docRoot}/../specs/security/standard-names.html#certpathbuilder-algorithms"> * Java Security Standard Algorithm Names Specification</a> * for information about standard algorithm names. * * @param provider the provider. * * @return a {@code CertPathBuilder} object that implements the * specified algorithm * * @throws IllegalArgumentException if the {@code provider} is * {@code null} * * @throws NoSuchAlgorithmException if a {@code CertPathBuilderSpi} * implementation for the specified algorithm is not available * from the specified {@code Provider} object * * @throws NullPointerException if {@code algorithm} is {@code null} * * @see java.security.Provider */ public static CertPathBuilder getInstance(String algorithm, Provider provider) throws NoSuchAlgorithmException { Objects.requireNonNull(algorithm, "null algorithm name"); Instance instance = GetInstance.getInstance("CertPathBuilder", CertPathBuilderSpi.class, algorithm, provider); return new CertPathBuilder((CertPathBuilderSpi) instance.impl, instance.provider, algorithm); } /** * Returns the provider of this {@code CertPathBuilder}. * * @return the provider of this {@code CertPathBuilder} */ public final Provider getProvider() { return this.provider; } /** * Returns the name of the algorithm of this {@code CertPathBuilder}. * * @return the name of the algorithm of this {@code CertPathBuilder} */ public final String getAlgorithm() { return this.algorithm; } /** * Attempts to build a certification path using the specified algorithm * parameter set. * * @param params the algorithm parameters * @return the result of the build algorithm * @throws CertPathBuilderException if the builder is unable to construct * a certification path that satisfies the specified parameters * @throws InvalidAlgorithmParameterException if the specified parameters * are inappropriate for this {@code CertPathBuilder} */ public final CertPathBuilderResult build(CertPathParameters params) throws CertPathBuilderException, InvalidAlgorithmParameterException { return builderSpi.engineBuild(params); } /** * Returns the default {@code CertPathBuilder} type as specified by * the {@code certpathbuilder.type} security property, or the string * {@literal "PKIX"} if no such property exists. * * <p>The default {@code CertPathBuilder} type can be used by * applications that do not want to use a hard-coded type when calling one * of the {@code getInstance} methods, and want to provide a default * type in case a user does not specify its own. * * <p>The default {@code CertPathBuilder} type can be changed by * setting the value of the {@code certpathbuilder.type} security property * to the desired type. * * @see java.security.Security security properties * @return the default {@code CertPathBuilder} type as specified * by the {@code certpathbuilder.type} security property, or the string * {@literal "PKIX"} if no such property exists. */ public static final String getDefaultType() { String cpbtype = AccessController.doPrivileged(new PrivilegedAction<>() { public String run() { return Security.getProperty(CPB_TYPE); } }); return (cpbtype == null) ? "PKIX" : cpbtype; } /** * Returns a {@code CertPathChecker} that the encapsulated * {@code CertPathBuilderSpi} implementation uses to check the revocation * status of certificates. A PKIX implementation returns objects of * type {@code PKIXRevocationChecker}. Each invocation of this method * returns a new instance of {@code CertPathChecker}. * * <p>The primary purpose of this method is to allow callers to specify * additional input parameters and options specific to revocation checking. * See the class description for an example. * * @return a {@code CertPathChecker} * @throws UnsupportedOperationException if the service provider does not * support this method * @since 1.8 */ public final CertPathChecker getRevocationChecker() { return builderSpi.engineGetRevocationChecker(); } }