J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2000-2003 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package java.security.cert; |
| 27 | |
| 28 | import java.util.Collection; |
| 29 | import java.util.Set; |
| 30 | |
| 31 | /** |
| 32 | * An abstract class that performs one or more checks on an |
| 33 | * <code>X509Certificate</code>. |
| 34 | * |
| 35 | * <p>A concrete implementation of the <code>PKIXCertPathChecker</code> class |
| 36 | * can be created to extend the PKIX certification path validation algorithm. |
| 37 | * For example, an implementation may check for and process a critical private |
| 38 | * extension of each certificate in a certification path. |
| 39 | * |
| 40 | * <p>Instances of <code>PKIXCertPathChecker</code> are passed as parameters |
| 41 | * using the {@link PKIXParameters#setCertPathCheckers setCertPathCheckers} |
| 42 | * or {@link PKIXParameters#addCertPathChecker addCertPathChecker} methods |
| 43 | * of the <code>PKIXParameters</code> and <code>PKIXBuilderParameters</code> |
| 44 | * class. Each of the <code>PKIXCertPathChecker</code>s {@link #check check} |
| 45 | * methods will be called, in turn, for each certificate processed by a PKIX |
| 46 | * <code>CertPathValidator</code> or <code>CertPathBuilder</code> |
| 47 | * implementation. |
| 48 | * |
| 49 | * <p>A <code>PKIXCertPathChecker</code> may be called multiple times on |
| 50 | * successive certificates in a certification path. Concrete subclasses |
| 51 | * are expected to maintain any internal state that may be necessary to |
| 52 | * check successive certificates. The {@link #init init} method is used |
| 53 | * to initialize the internal state of the checker so that the certificates |
| 54 | * of a new certification path may be checked. A stateful implementation |
| 55 | * <b>must</b> override the {@link #clone clone} method if necessary in |
| 56 | * order to allow a PKIX <code>CertPathBuilder</code> to efficiently |
| 57 | * backtrack and try other paths. In these situations, the |
| 58 | * <code>CertPathBuilder</code> is able to restore prior path validation |
| 59 | * states by restoring the cloned <code>PKIXCertPathChecker</code>s. |
| 60 | * |
| 61 | * <p>The order in which the certificates are presented to the |
| 62 | * <code>PKIXCertPathChecker</code> may be either in the forward direction |
| 63 | * (from target to most-trusted CA) or in the reverse direction (from |
| 64 | * most-trusted CA to target). A <code>PKIXCertPathChecker</code> implementation |
| 65 | * <b>must</b> support reverse checking (the ability to perform its checks when |
| 66 | * it is presented with certificates in the reverse direction) and <b>may</b> |
| 67 | * support forward checking (the ability to perform its checks when it is |
| 68 | * presented with certificates in the forward direction). The |
| 69 | * {@link #isForwardCheckingSupported isForwardCheckingSupported} method |
| 70 | * indicates whether forward checking is supported. |
| 71 | * <p> |
| 72 | * Additional input parameters required for executing the check may be |
| 73 | * specified through constructors of concrete implementations of this class. |
| 74 | * <p> |
| 75 | * <b>Concurrent Access</b> |
| 76 | * <p> |
| 77 | * Unless otherwise specified, the methods defined in this class are not |
| 78 | * thread-safe. Multiple threads that need to access a single |
| 79 | * object concurrently should synchronize amongst themselves and |
| 80 | * provide the necessary locking. Multiple threads each manipulating |
| 81 | * separate objects need not synchronize. |
| 82 | * |
| 83 | * @see PKIXParameters |
| 84 | * @see PKIXBuilderParameters |
| 85 | * |
| 86 | * @since 1.4 |
| 87 | * @author Yassir Elley |
| 88 | * @author Sean Mullan |
| 89 | */ |
| 90 | public abstract class PKIXCertPathChecker implements Cloneable { |
| 91 | |
| 92 | /** |
| 93 | * Default constructor. |
| 94 | */ |
| 95 | protected PKIXCertPathChecker() {} |
| 96 | |
| 97 | /** |
| 98 | * Initializes the internal state of this <code>PKIXCertPathChecker</code>. |
| 99 | * <p> |
| 100 | * The <code>forward</code> flag specifies the order that |
| 101 | * certificates will be passed to the {@link #check check} method |
| 102 | * (forward or reverse). A <code>PKIXCertPathChecker</code> <b>must</b> |
| 103 | * support reverse checking and <b>may</b> support forward checking. |
| 104 | * |
| 105 | * @param forward the order that certificates are presented to |
| 106 | * the <code>check</code> method. If <code>true</code>, certificates |
| 107 | * are presented from target to most-trusted CA (forward); if |
| 108 | * <code>false</code>, from most-trusted CA to target (reverse). |
| 109 | * @throws CertPathValidatorException if this |
| 110 | * <code>PKIXCertPathChecker</code> is unable to check certificates in |
| 111 | * the specified order; it should never be thrown if the forward flag |
| 112 | * is false since reverse checking must be supported |
| 113 | */ |
| 114 | public abstract void init(boolean forward) |
| 115 | throws CertPathValidatorException; |
| 116 | |
| 117 | /** |
| 118 | * Indicates if forward checking is supported. Forward checking refers |
| 119 | * to the ability of the <code>PKIXCertPathChecker</code> to perform |
| 120 | * its checks when certificates are presented to the <code>check</code> |
| 121 | * method in the forward direction (from target to most-trusted CA). |
| 122 | * |
| 123 | * @return <code>true</code> if forward checking is supported, |
| 124 | * <code>false</code> otherwise |
| 125 | */ |
| 126 | public abstract boolean isForwardCheckingSupported(); |
| 127 | |
| 128 | /** |
| 129 | * Returns an immutable <code>Set</code> of X.509 certificate extensions |
| 130 | * that this <code>PKIXCertPathChecker</code> supports (i.e. recognizes, is |
| 131 | * able to process), or <code>null</code> if no extensions are supported. |
| 132 | * <p> |
| 133 | * Each element of the set is a <code>String</code> representing the |
| 134 | * Object Identifier (OID) of the X.509 extension that is supported. |
| 135 | * The OID is represented by a set of nonnegative integers separated by |
| 136 | * periods. |
| 137 | * <p> |
| 138 | * All X.509 certificate extensions that a <code>PKIXCertPathChecker</code> |
| 139 | * might possibly be able to process should be included in the set. |
| 140 | * |
| 141 | * @return an immutable <code>Set</code> of X.509 extension OIDs (in |
| 142 | * <code>String</code> format) supported by this |
| 143 | * <code>PKIXCertPathChecker</code>, or <code>null</code> if no |
| 144 | * extensions are supported |
| 145 | */ |
| 146 | public abstract Set<String> getSupportedExtensions(); |
| 147 | |
| 148 | /** |
| 149 | * Performs the check(s) on the specified certificate using its internal |
| 150 | * state and removes any critical extensions that it processes from the |
| 151 | * specified collection of OID strings that represent the unresolved |
| 152 | * critical extensions. The certificates are presented in the order |
| 153 | * specified by the <code>init</code> method. |
| 154 | * |
| 155 | * @param cert the <code>Certificate</code> to be checked |
| 156 | * @param unresolvedCritExts a <code>Collection</code> of OID strings |
| 157 | * representing the current set of unresolved critical extensions |
| 158 | * @exception CertPathValidatorException if the specified certificate does |
| 159 | * not pass the check |
| 160 | */ |
| 161 | public abstract void check(Certificate cert, |
| 162 | Collection<String> unresolvedCritExts) |
| 163 | throws CertPathValidatorException; |
| 164 | |
| 165 | /** |
| 166 | * Returns a clone of this object. Calls the <code>Object.clone()</code> |
| 167 | * method. |
| 168 | * All subclasses which maintain state must support and |
| 169 | * override this method, if necessary. |
| 170 | * |
| 171 | * @return a copy of this <code>PKIXCertPathChecker</code> |
| 172 | */ |
| 173 | public Object clone() { |
| 174 | try { |
| 175 | return super.clone(); |
| 176 | } catch (CloneNotSupportedException e) { |
| 177 | /* Cannot happen */ |
| 178 | throw new InternalError(e.toString()); |
| 179 | } |
| 180 | } |
| 181 | } |