1 /* 2 * Copyright (c) 2018, Red Hat, Inc. 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. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package sun.security.krb5.internal; 27 28 import java.util.Date; 29 import java.util.HashMap; 30 import java.util.LinkedList; 31 import java.util.List; 32 import java.util.Map; 33 import java.util.Map.Entry; 34 35 import sun.security.krb5.PrincipalName; 36 37 final class ReferralsCache { 38 39 private static Map<PrincipalName, Map<String, ReferralCacheEntry>> referralsMap = 40 new HashMap<>(); 41 42 private static final class ReferralCacheEntry { 43 private final String toRealm; 44 private final Date validUntil; 45 ReferralCacheEntry(String toRealm, Date validUntil) { 46 this.toRealm = toRealm; 47 this.validUntil = validUntil; 48 } 49 String getToRealm() { 50 return toRealm; 51 } 52 Date getValidUntil() { 53 return validUntil; 54 } 55 } 56 57 static synchronized void put(PrincipalName service, 58 String fromRealm, String toRealm, Date validUntil) { 59 pruneExpired(service); 60 if (validUntil.before(new Date())) { 61 return; 62 } 63 Map<String, ReferralCacheEntry> entries = referralsMap.get(service); 64 if (entries == null) { 65 entries = new HashMap<String, ReferralCacheEntry>(); 66 referralsMap.put(service, entries); 67 } 68 entries.remove(fromRealm); 69 ReferralCacheEntry newEntry = new ReferralCacheEntry(toRealm, validUntil); 70 entries.put(fromRealm, newEntry); 71 72 // Remove loops within the cache 73 ReferralCacheEntry current = newEntry; 74 List<ReferralCacheEntry> seen = new LinkedList<>(); 75 while (current != null) { 76 if (seen.contains(current)) { 77 // Loop found. Remove the first referral to cut the loop. 78 entries.remove(newEntry.getToRealm()); 79 break; 80 } 81 seen.add(current); 82 current = entries.get(current.getToRealm()); 83 } 84 } 85 86 static synchronized String get(PrincipalName service, String fromRealm) { 87 pruneExpired(service); 88 Map<String, ReferralCacheEntry> entries = referralsMap.get(service); 89 if (entries != null) { 90 ReferralCacheEntry toRef = entries.get(fromRealm); 91 if (toRef != null) { 92 return toRef.getToRealm(); 93 } 94 } 95 return null; 96 } 97 98 private static void pruneExpired(PrincipalName service) { 99 Date now = new Date(); 100 Map<String, ReferralCacheEntry> entries = referralsMap.get(service); 101 if (entries != null) { 102 for (Entry<String, ReferralCacheEntry> mapEntry : entries.entrySet()) { 103 if (mapEntry.getValue().getValidUntil().before(now)) { 104 entries.remove(mapEntry.getKey()); 105 } 106 } 107 } 108 } 109 }