问题似乎出在密钥表中。有一些动作序列会导致一些特定的 keytab 文件状态：
(A) keytab 适用于 Java，但不适用于 k5start/kinit；
(B) keytab 不适用于 Java，但适用于 k5start/kinit；
(C) keytab 对它们都有效。
允许检查 Java 是否可以使用 keytab 文件进行身份验证的简短 Java 代码：
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;
import javax.security.auth.Subject;
import com.sun.security.auth.module.Krb5LoginModule;
/**
* This is simple Java program that tests ability to authenticate
* with Kerberos using the JDK implementation.
*
* The program uses no libraries but JDK itself.
*/
public class Krb {
private void loginImpl(final String propertiesFileName) throws Exception {
System.out.println("NB: system property to specify the krb5 config: [java.security.krb5.conf]");
//System.setProperty("java.security.krb5.conf", "/etc/krb5.conf");
System.out.println(System.getProperty("java.version"));
System.setProperty("sun.security.krb5.debug", "true");
final Subject subject = new Subject();
final Krb5LoginModule krb5LoginModule = new Krb5LoginModule();
final Map<String,String> optionMap = new HashMap<String,String>();
if (propertiesFileName == null) {
//optionMap.put("ticketCache", "/tmp/krb5cc_1000");
optionMap.put("keyTab", "/etc/krb5.keytab");
optionMap.put("principal", "foo"); // default realm
optionMap.put("doNotPrompt", "true");
optionMap.put("refreshKrb5Config", "true");
optionMap.put("useTicketCache", "true");
optionMap.put("renewTGT", "true");
optionMap.put("useKeyTab", "true");
optionMap.put("storeKey", "true");
optionMap.put("isInitiator", "true");
} else {
File f = new File(propertiesFileName);
System.out.println("======= loading property file ["+f.getAbsolutePath()+"]");
Properties p = new Properties();
InputStream is = new FileInputStream(f);
try {
p.load(is);
} finally {
is.close();
}
optionMap.putAll((Map)p);
}
optionMap.put("debug", "true"); // switch on debug of the Java implementation
krb5LoginModule.initialize(subject, null, new HashMap<String,String>(), optionMap);
boolean loginOk = krb5LoginModule.login();
System.out.println("======= login: " + loginOk);
boolean commitOk = krb5LoginModule.commit();
System.out.println("======= commit: " + commitOk);
System.out.println("======= Subject: " + subject);
}
public static void main(String[] args) throws Exception {
System.out.println("A property file with the login context can be specified as the 1st and the only paramater.");
final Krb krb = new Krb();
krb.loginImpl(args.length == 0 ? null : args[0]);
}
}
，以及要使用的属性文件：
#ticketCache=/tmp/krb5cc_1000
keyTab=/etc/krb5.keytab
principal=foo
doNotPrompt=true
refreshKrb5Config=true
useTicketCache=true
renewTGT=true
useKeyTab=true
storeKey=true
isInitiator=true
(下面我们假设krb/kdc已经正确安装和配置，数据库是用kdb5_util创建的。每个命令序列的起始状态是：keytab文件被删除，token缓存被删除，用户“foo”被删除数据库。）
以下动作序列导致keytab状态（A）：
$ echo -e "foo\nfoo" | kadmin.local -q "addprinc foo"
$ echo -e "foo\nfoo" | kadmin.local -q "ktadd foo"
$ java -cp . Krb ./krb5.properties
# Now java auth okay, but the following command fails:
$ k5start foo
Kerberos initialization for foo@EXAMPLE.COM
Password for foo@EXAMPLE.COM:
k5start: error getting credentials: Decrypt integrity check failed
$
以下动作序列导致keytab状态（B）：
$ echo -e "foo\nfoo" | kadmin.local -q "addprinc foo"
$ echo -e "foo\nfoo" | kadmin.local -q "ktadd foo"
$ echo -e "foo\nfoo" | kadmin.local -q "cpw foo"
$ java -cp . Krb ./krb5.properties
A property file with the login context can be specified as the 1st and the only paramater.
NB: system property to specify the krb5 config: [java.security.krb5.conf]
1.6.0_33
======= loading property file [/tmp/krb-test/yhadoop-common/./krb5.properties]
Debug is true storeKey true useTicketCache true useKeyTab true doNotPrompt true ticketCache is null isInitiator true KeyTab is /etc/krb5.keytab refreshKrb5Config is true principal is foo tryFirstPass is false useFirstPass is false storePass is false clearPass is false
Refreshing Kerberos configuration
Config name: /etc/krb5.conf
>>> KdcAccessibility: reset
>>> KdcAccessibility: reset
Acquire TGT from Cache
>>>KinitOptions cache name is /tmp/krb5cc_0
Principal is foo@EXAMPLE.COM
null credentials from Ticket Cache
>>> KeyTabInputStream, readName(): EXAMPLE.COM
>>> KeyTabInputStream, readName(): foo
>>> KeyTab: load() entry length: 49; type: 23
Added key: 23version: 3
Ordering keys wrt default_tkt_enctypes list
default etypes for default_tkt_enctypes: 23.
0: EncryptionKey: keyType=23 kvno=3 keyValue (hex dump)=
0000: 5F 7F 9B 42 BB 02 51 81 32 05 1D 7B C0 9F 19 C0 _..B..Q.2.......
principal's key obtained from the keytab
Acquire TGT using AS Exchange
default etypes for default_tkt_enctypes: 23.
>>> KrbAsReq calling createMessage
>>> KrbAsReq in createMessage
>>> KrbKdcReq send: kdc=localhost UDP:88, timeout=30000, number of retries =3, #bytes=128
>>> KDCCommunication: kdc=localhost UDP:88, timeout=30000,Attempt =1, #bytes=128
>>> KrbKdcReq send: #bytes read=611
>>> KrbKdcReq send: #bytes read=611
>>> KdcAccessibility: remove localhost:88
>>> EType: sun.security.krb5.internal.crypto.ArcFourHmacEType
Checksum failed !
[Krb5LoginModule] authentication failed
Checksum failed
Exception in thread "main" javax.security.auth.login.LoginException: Checksum failed
at com.sun.security.auth.module.Krb5LoginModule.attemptAuthentication(Krb5LoginModule.java:696)
at com.sun.security.auth.module.Krb5LoginModule.login(Krb5LoginModule.java:542)
at Krb.loginImpl(Krb.java:65)
at Krb.main(Krb.java:77)
Caused by: KrbException: Checksum failed
at sun.security.krb5.internal.crypto.ArcFourHmacEType.decrypt(ArcFourHmacEType.java:85)
at sun.security.krb5.internal.crypto.ArcFourHmacEType.decrypt(ArcFourHmacEType.java:77)
at sun.security.krb5.EncryptedData.decrypt(EncryptedData.java:168)
at sun.security.krb5.KrbAsRep.<init>(KrbAsRep.java:87)
at sun.security.krb5.KrbAsReq.getReply(KrbAsReq.java:446)
at sun.security.krb5.Credentials.sendASRequest(Credentials.java:401)
at sun.security.krb5.Credentials.acquireTGT(Credentials.java:350)
at com.sun.security.auth.module.Krb5LoginModule.attemptAuthentication(Krb5LoginModule.java:672)
... 3 more
Caused by: java.security.GeneralSecurityException: Checksum failed
at sun.security.krb5.internal.crypto.dk.ArcFourCrypto.decrypt(ArcFourCrypto.java:388)
at sun.security.krb5.internal.crypto.ArcFourHmac.decrypt(ArcFourHmac.java:74)
at sun.security.krb5.internal.crypto.ArcFourHmacEType.decrypt(ArcFourHmacEType.java:83)
... 10 more
$
但是“k5start foo”在这种状态下是可以的，“kinit foo”也是如此。
以下动作序列导致状态（C）：
$ echo -e "foo\nfoo" | kadmin.local -q "addprinc foo"
$ ktutil
ktutil: addent -password -p foo -k 1 -e rc4-hmac
Password for foo@EXAMPLE.COM:
ktutil: wkt /etc/krb5.keytab
ktutil: q
之后 k5start/kinit 和 java 验证都给出了肯定的结果。
环境：
yum list krb5-appl-servers krb5-libs krb5-server krb5-workstation kstart pam_krb5
...
Installed Packages
krb5-libs.x86_64 1.9-33.el6_3.3 @updates
krb5-server.x86_64 1.9-33.el6_3.3 @updates
krb5-workstation.x86_64 1.9-33.el6_3.3 @updates
kstart.x86_64 4.1-2.el6 @epel
...
$ cat /etc/redhat-release
CentOS release 6.3 (Final)
$ java -version
java version "1.6.0_33"
Java(TM) SE Runtime Environment (build 1.6.0_33-b03)
Java HotSpot(TM) 64-Bit Server VM (build 20.8-b03, mixed mode)
在 Java 7 中观察到的行为也相同。
在使用 MIT 的 kerberos 5-1.10.3 从源代码分发版编译的 Ubuntu 精确版（12.04.1 LTS）上也观察到了相同的行为。