Generate SPNEGO Token Failured - kerberos

Question

I tried to generate the token which can be used as the HTTP header to authenticate to the HDFS WebHDFS URL and Oozie REST API URL.
I referenced the url below to have the below code to generate the Negotiate token.
https://www.ibm.com/support/knowledgecenter/en/SS7JFU_8.5.5/com.ibm.websphere.express.doc/ae/tsec_SPNEGO_token.html
public class TokenCreation {
private static final String SPNEGO_OID = "1.3.6.1.5.5.2";
private static final String KERBEROS_OID = "1.2.840.113554.1.2.2";
public static byte[] genToken(String principal) {
System.setProperty("javax.security.auth.useSubjectCredsOnly", "false");
byte[] spnegoToken = new byte[0];
try {
Oid spnegoMechOid = new Oid(SPNEGO_OID);
Oid krb5MechOid = new Oid(KERBEROS_OID);
GSSCredential clientGssCreds = null;
GSSManager manager = GSSManager.getInstance();
GSSName gssUserName = manager.createName(principal, GSSName.NT_USER_NAME, krb5MechOid);
clientGssCreds = manager.createCredential(gssUserName.canonicalize(krb5MechOid),
GSSCredential.INDEFINITE_LIFETIME,
krb5MechOid,
GSSCredential.INITIATE_ONLY);
clientGssCreds.add(gssUserName,
GSSCredential.INDEFINITE_LIFETIME,
GSSCredential.INDEFINITE_LIFETIME,
spnegoMechOid, GSSCredential.INITIATE_ONLY);
GSSName gssServerName = manager.createName(principal, GSSName.NT_USER_NAME);
GSSContext clientContext = manager.createContext(gssServerName.canonicalize(spnegoMechOid),
spnegoMechOid,
clientGssCreds,
GSSContext.DEFAULT_LIFETIME);
// optional enable GSS credential delegation
clientContext.requestCredDeleg(true);
// create a SPNEGO token for the target server
spnegoToken = clientContext.initSecContext(spnegoToken, 0, spnegoToken.length);
} catch (GSSException e) {
e.printStackTrace();
}
return spnegoToken;
}
But after running the above code, I always got the below prompt:
2019-09-25 14:12:51 760 [INFO] [pool-2-thread-1] c.s.n.c.u.security.KrbUtils - after loginUserFromKeytab............AtoimcUser:HTTP/host1.exmaple.com#EXAMPLE.COM
2019-09-25 14:12:51 760 [INFO] [pool-2-thread-1] c.s.n.app.oozie.OozieAppCaller - ->>>>>>User Name is HTTP/host1.exmaple.com#EXAMPLE.COM
2019-09-25 14:12:51 760 [INFO] [pool-2-thread-1] c.s.n.app.oozie.OozieAppCaller - ->>>>>>Mode is KERBEROS
>>>KinitOptions cache name is /tmp/krb5cc_0
Kerberos username [root]: ^C^C^C
Kerberos password for root:
You can see at the end of the above output log.
The "Kerberos username" is always prompt to ask for username.
Also I have tried to manually run kinit the keytab.
and the above class can generate the token successfully.
But manually run kinit is NOT the way I wanted.
Would you please help it?
Thanks.

Answer 1

Kerberos and SPNEGO support in Java is cumbersome unfortunately.
I've created a small library to simplify some Kerberos use cases: https://github.com/bedrin/kerb4j
You can use it like this to generate SPNEGO token:
SpnegoClient spnegoClient = SpnegoClient.loginWithKeyTab("svc_consumer", "/opt/myapp/consumer.keytab");
URL url = new URL("http://api.provider.acme.com/api/operation1");
SpnegoContext context = spnegoClient.createContext("http://provider.acme.com"); // Will result in HTTP/provider.acme.com SPN
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestProperty("Authorization", context.createTokenAsAuthroizationHeader());