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Posted to dev@directory.apache.org by "Emmanuel Lecharny (JIRA)" <ji...@apache.org> on 2017/02/24 11:25:44 UTC
[jira] [Resolved] (DIRKRB-620) KerberosChannel does not read whole
response
[ https://issues.apache.org/jira/browse/DIRKRB-620?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Emmanuel Lecharny resolved DIRKRB-620.
--------------------------------------
Resolution: Fixed
Fix Version/s: 2.0.0-RC1
Fixed with http://svn.apache.org/viewvc?rev=1784265&view=rev
> KerberosChannel does not read whole response
> --------------------------------------------
>
> Key: DIRKRB-620
> URL: https://issues.apache.org/jira/browse/DIRKRB-620
> Project: Directory Kerberos
> Issue Type: Bug
> Components: changepw
> Reporter: Maciej Miklas
> Fix For: 2.0.0-RC1
>
>
> We have in production some customers who cannot change their password. In log we observe following exception:
> {noformat}
> 20.02.2017 10:59:11,987 DEBUG [http-bio-127.22.1.62-80-exec-383] org.apache.directory.api.asn1.ber.Asn1Decoder - <<<==========================================
> 20.02.2017 10:59:11,987 ERROR [http-bio-127.22.1.62-80-exec-383] org.apache.directory.kerberos.client.KdcConnection - Authentication failed : timeout occured
> 20.02.2017 10:59:11,987 WARN [http-bio-127.22.1.62-80-exec-383] org.apache.directory.kerberos.client.KdcConnection - failed to change the password
> org.apache.directory.shared.kerberos.exceptions.KerberosException: TimeOut occured
> at org.apache.directory.kerberos.client.KdcConnection._getTgt(KdcConnection.java:294)
> at org.apache.directory.kerberos.client.KdcConnection.getTgt(KdcConnection.java:181)
> at org.apache.directory.kerberos.client.KdcConnection.changePassword(KdcConnection.java:535)
> {noformat}
> Real reason for this error is incorrect socket implementation:
> {code:title=org.apache.directory.kerberos.client.KerberosChannel|borderStyle=solid}
> byte[] tmp = new byte[ 1024 * 8 ];
> while ( in.available() > 0 )
> {
> int read = in.read( tmp );
> repData.put( tmp, 0, read );
> }
> {code}
> You should not relay on _available()_ - it returns only assumption. In our case for some users it returns 0 before whole message has been consumed.
> In order to fix it, you should first read header of the message in order to figure out its size. Now use _in.read(...)_ until you consume expected amount of bytes. Eventually you will run into timeout, which is fine and happens if server does not keep its promise from header and cuts the message.
> I've changed code into this:
> {code:title=org.apache.directory.kerberos.client.KerberosChannel|borderStyle=solid}
> byte[] tmp = new byte[1024 * 8];
> int read;
> try {
> while ((read = in.read(tmp)) > 0) {
> repData.put(tmp, 0, read);
> }
> }
> catch (SocketTimeoutException e) {
> // OK
> }
> {code}
> and customers now can change their password. Obviously this implementation is *incorrect*, because it runs into timeout with every call. Bu it proves that using _available()_ does not work.
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