[HADOOP-14327] KerberosAuthenticationHandler#authenticate throws meaningless exception when server principals set is empty

• Type: Bug
• Status: Patch Available
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 3.0.0-alpha2
• Component/s: security
• Assignee: Yuanbo Liu
• Reporter: Wei-Chiu Chuang
• Created: 19/Apr/17 18:51
• Updated: 24/Apr/17 10:16

Description

If somehow KerberosAuthenticationHandler#authenticate gets an empty service principal set, it throws a useless exception like the following:

2017-04-19 10:11:39,812 DEBUG org.apache.hadoop.security.authentication.server.AuthenticationFilter: Authentication exception: org.apache.hadoop.security.authentication.client.AuthenticationExceptio
n
org.apache.hadoop.security.authentication.client.AuthenticationException: org.apache.hadoop.security.authentication.client.AuthenticationException
        at org.apache.hadoop.security.authentication.server.KerberosAuthenticationHandler.authenticate(KerberosAuthenticationHandler.java:452)
        at org.apache.hadoop.security.authentication.server.MultiSchemeAuthenticationHandler.authenticate(MultiSchemeAuthenticationHandler.java:193)
        at org.apache.hadoop.security.token.delegation.web.DelegationTokenAuthenticationHandler.authenticate(DelegationTokenAuthenticationHandler.java:400)
        at org.apache.hadoop.security.token.delegation.web.MultiSchemeDelegationTokenAuthenticationHandler.authenticate(MultiSchemeDelegationTokenAuthenticationHandler.java:180)
        at org.apache.solr.security.RequestContinuesRecorderAuthenticationHandler.authenticate(RequestContinuesRecorderAuthenticationHandler.java:69)
        at org.apache.hadoop.security.authentication.server.AuthenticationFilter.doFilter(AuthenticationFilter.java:532)

The following code has a logic error. If serverPrincipals is empty, token remains null in the end, but lastException is also null too, so throwing it is meaningless. It should throw with a more meaningful message.

KerberosAuthenticationHandler#authenticate

                AuthenticationToken token = null;
                Exception lastException = null;
                for (String serverPrincipal : serverPrincipals) {
                  try {
                    token = runWithPrincipal(serverPrincipal, clientToken,
                        base64, response);
                  } catch (Exception ex) {
                    lastException = ex;
                    LOG.trace("Auth {} failed with {}", serverPrincipal, ex);
                  } finally {
                      if (token != null) {
                        LOG.trace("Auth {} successfully", serverPrincipal);
                        break;
                    }
                  }
                }
                if (token != null) {
                  return token;
                } else {
                  throw new AuthenticationException(lastException);
                }

Issue Links

• is depended upon by: HADOOP-12649 Improve Kerberos diagnostics and failure handling