8210821: Support dns_canonicalize_hostname in krb5.conf

Reviewed-by: valeriep

src/java.security.jgss/share/classes/sun/security/krb5/PrincipalName.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 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
@@ -406,26 +406,37 @@ public class PrincipalName implements Cloneable {
         case KRB_NT_SRV_HST:
             if (nameParts.length >= 2) {
                 String hostName = nameParts[1];
+                Boolean option;
                 try {
-                    // RFC4120 does not recommend canonicalizing a hostname.
+                    // If true, try canonicalizing and accept it if it starts
-                    // However, for compatibility reason, we will try
+                    // with the short name. Otherwise, never. Default true.
-                    // canonicalize it and see if the output looks better.
+                    option = Config.getInstance().getBooleanObject(
-
+                            "libdefaults", "dns_canonicalize_hostname");
-                    String canonicalized = (InetAddress.getByName(hostName)).
+                } catch (KrbException e) {
-                            getCanonicalHostName();
+                    option = null;
-
-                    // Looks if canonicalized is a longer format of hostName,
-                    // we accept cases like
-                    //     bunny -> bunny.rabbit.hole
-                    if (canonicalized.toLowerCase(Locale.ENGLISH).startsWith(
-                                hostName.toLowerCase(Locale.ENGLISH)+".")) {
-                        hostName = canonicalized;
-                    }
-                } catch (UnknownHostException | SecurityException e) {
-                    // not canonicalized or no permission to do so, use old
                 }
-                if (hostName.endsWith(".")) {
+                if (option != Boolean.FALSE) {
-                    hostName = hostName.substring(0, hostName.length() - 1);
+                    try {
+                        // RFC4120 does not recommend canonicalizing a hostname.
+                        // However, for compatibility reason, we will try
+                        // canonicalizing it and see if the output looks better.
+
+                        String canonicalized = (InetAddress.getByName(hostName)).
+                                getCanonicalHostName();
+
+                        // Looks if canonicalized is a longer format of hostName,
+                        // we accept cases like
+                        //     bunny -> bunny.rabbit.hole
+                        if (canonicalized.toLowerCase(Locale.ENGLISH).startsWith(
+                                hostName.toLowerCase(Locale.ENGLISH) + ".")) {
+                            hostName = canonicalized;
+                        }
+                    } catch (UnknownHostException | SecurityException e) {
+                        // not canonicalized or no permission to do so, use old
+                    }
+                    if (hostName.endsWith(".")) {
+                        hostName = hostName.substring(0, hostName.length() - 1);
+                    }
                 }
                 nameParts[1] = hostName.toLowerCase(Locale.ENGLISH);
             }

test/jdk/sun/security/krb5/auto/DnsCanonicalizeHostname.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 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.
+ *
+ * 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.
+ */
+
+import jdk.test.lib.Asserts;
+import sun.security.krb5.PrincipalName;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.List;
+
+/*
+ * @test
+ * @bug 8210821
+ * @summary Support dns_canonicalize_hostname in krb5.conf
+ * @library /test/lib
+ * @compile -XDignore.symbol.file DnsCanonicalizeHostname.java
+ * @run main jdk.test.lib.FileInstaller dns_canonicalize_hostname.hosts hosts
+ * @run main/othervm -Djdk.net.hosts.file=hosts DnsCanonicalizeHostname none
+ * @run main/othervm -Djdk.net.hosts.file=hosts DnsCanonicalizeHostname true
+ * @run main/othervm -Djdk.net.hosts.file=hosts DnsCanonicalizeHostname false
+ */
+public class DnsCanonicalizeHostname {
+
+    // In dns_canonicalize_hostname.hosts, all "dummy.example.com", "dummy",
+    // and "bogus" are resolved to 127.0.0.1. Since "dummy.example.com" is on
+    // the first line, it is returned at the reverse lookup.
+
+    public static void main(String[] args) throws Exception {
+
+        Files.write(Path.of("krb5.conf"), List.of(
+                "[libdefaults]",
+                "default_realm = R",
+                args[0].equals("none")
+                        ? "# empty line"
+                        : "dns_canonicalize_hostname = " + args[0],
+                "",
+                "[realms]",
+                "R = {",
+                "    kdc = 127.0.0.1",
+                "}"
+        ));
+        System.setProperty("java.security.krb5.conf", "krb5.conf");
+
+        String n1 = new PrincipalName("host/dummy", PrincipalName.KRB_NT_SRV_HST)
+                .getNameStrings()[1];
+        String n2 = new PrincipalName("host/bogus", PrincipalName.KRB_NT_SRV_HST)
+                .getNameStrings()[1];
+
+        switch (args[0]) {
+            case "none":
+            case "true":
+                Asserts.assertEQ(n1, "dummy.example.com");
+                Asserts.assertEQ(n2, "bogus");
+                break;
+            case "false":
+                Asserts.assertEQ(n1, "dummy");
+                Asserts.assertEQ(n2, "bogus");
+                break;
+        }
+    }
+}

test/jdk/sun/security/krb5/auto/dns_canonicalize_hostname.hosts

@@ -0,0 +1,8 @@
+# The preferred name at reverse lookup
+127.0.0.1 dummy.example.com
+
+# The short name
+127.0.0.1 dummy
+
+# The strange name
+127.0.0.1 bogus