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From Sangjin Lee <sj...@apache.org>
Subject Re: strange kerberos issue with apacheds
Date Tue, 09 Jun 2015 04:28:31 GMT
Thanks folks. I filed DIRSERVER-2071:
https://issues.apache.org/jira/browse/DIRSERVER-2071

Sangjin

On Mon, Jun 8, 2015 at 8:16 PM, Kiran Ayyagari <kayyagari@apache.org> wrote:

> Hi Sangjin,
>
> On Tue, Jun 9, 2015 at 6:45 AM, Sangjin Lee <sjlee@apache.org> wrote:
>
>> Hi,
>>
>> This might be a known issue, but I was not able to find discussions on
>> this anywhere...
>>
>> I stumbled on an interesting issue with kerberos authentication failure
>> with an Apache DS server while debugging a hadoop unit test failure. FYI,
>> hadoop is using Apache DS 1.0.0-M20 with Mina 2.0.0-M15. This problem is
>> happening on some machines but not on others.
>>
>> Basically, a kerberos message to the Apache DS server is failing with the
>> following exception:
>> 2015-06-08 20:35:57,189 ERROR KerberosProtocolHandler - /127.0.0.1:54477
>> EXCEPTION
>> org.apache.mina.filter.codec.ProtocolDecoderException:
>> java.lang.NullPointerException: message (Hexdump: ...)
>>         at
>> org.apache.mina.filter.codec.ProtocolCodecFilter.messageReceived(ProtocolCodecFilter.java:234)
>>         at
>> org.apache.mina.core.filterchain.DefaultIoFilterChain.callNextMessageReceived(DefaultIoFilterChain.java:434)
>>         at
>> org.apache.mina.core.filterchain.DefaultIoFilterChain.access$1200(DefaultIoFilterChain.java:48)
>>         at
>> org.apache.mina.core.filterchain.DefaultIoFilterChain$EntryImpl$1.messageReceived(DefaultIoFilterChain.java:802)
>>         at
>> org.apache.mina.core.filterchain.IoFilterAdapter.messageReceived(IoFilterAdapter.java:120)
>>         at
>> org.apache.mina.core.filterchain.DefaultIoFilterChain.callNextMessageReceived(DefaultIoFilterChain.java:434)
>>         at
>> org.apache.mina.core.filterchain.DefaultIoFilterChain.fireMessageReceived(DefaultIoFilterChain.java:426)
>>         at
>> org.apache.mina.core.polling.AbstractPollingIoProcessor.read(AbstractPollingIoProcessor.java:604)
>>         at
>> org.apache.mina.core.polling.AbstractPollingIoProcessor.process(AbstractPollingIoProcessor.java:564)
>>         at
>> org.apache.mina.core.polling.AbstractPollingIoProcessor.process(AbstractPollingIoProcessor.java:553)
>>         at
>> org.apache.mina.core.polling.AbstractPollingIoProcessor.access$400(AbstractPollingIoProcessor.java:57)
>>         at
>> org.apache.mina.core.polling.AbstractPollingIoProcessor$Processor.run(AbstractPollingIoProcessor.java:892)
>>         at
>> org.apache.mina.util.NamePreservingRunnable.run(NamePreservingRunnable.java:65)
>>         at
>> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
>>         at
>> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
>>         at java.lang.Thread.run(Thread.java:745)
>> Caused by: java.lang.NullPointerException: message
>>         at
>> org.apache.mina.filter.codec.AbstractProtocolDecoderOutput.write(AbstractProtocolDecoderOutput.java:44)
>>         at
>> org.apache.directory.server.kerberos.protocol.codec.MinaKerberosDecoder.decode(MinaKerberosDecoder.java:65)
>>         at
>> org.apache.mina.filter.codec.ProtocolCodecFilter.messageReceived(ProtocolCodecFilter.java:224)
>>         ... 15 more
>>
>>
>> I traced it down to a rather silent failure of Asn1Decoder. Basically the
>> ASN.1 decoder thinks the byte buffer it is passed does not have the
>> promised size payload and aborts parsing:
>> 2015-06-08 20:35:57,187 DEBUG Asn1Decoder -
>> >>>==========================================
>> 2015-06-08 20:35:57,187 DEBUG Asn1Decoder - --> Decoding a PDU
>> 2015-06-08 20:35:57,187 DEBUG Asn1Decoder -
>> >>>------------------------------------------
>> 2015-06-08 20:35:57,187 DEBUG Asn1Decoder - --- State = TAG_STATE_START
>> ---
>> 2015-06-08 20:35:57,187 DEBUG Asn1Decoder -   current byte : 0x6C
>> 2015-06-08 20:35:57,187 DEBUG Asn1Decoder - Tag 0x6C has been decoded
>> 2015-06-08 20:35:57,187 DEBUG Asn1Decoder - --- State =
>> LENGTH_STATE_START ---
>> 2015-06-08 20:35:57,187 DEBUG Asn1Decoder -   current byte : 0x82
>> 2015-06-08 20:35:57,187 DEBUG Asn1Decoder - --- State =
>> LENGTH_STATE_PENDING ---
>> 2015-06-08 20:35:57,187 DEBUG Asn1Decoder -   current byte : 0x02
>> 2015-06-08 20:35:57,187 DEBUG Asn1Decoder -   current byte : 0x02
>> 2015-06-08 20:35:57,187 DEBUG Asn1Decoder -   current byte : 0x41
>> 2015-06-08 20:35:57,187 DEBUG Asn1Decoder - --- State = LENGTH_STATE_END
>> ---
>> 2015-06-08 20:35:57,187 DEBUG Asn1Decoder -   current byte : 0x30
>> 2015-06-08 20:35:57,187 DEBUG Asn1Decoder - Parent length : TLV expected
>> length stack :  - null
>> 2015-06-08 20:35:57,187 DEBUG Asn1Decoder - Root TLV[577]
>> 2015-06-08 20:35:57,187 DEBUG Asn1Decoder - Length 577 has been decoded
>> 2015-06-08 20:35:57,187 DEBUG Asn1Decoder - --- State = VALUE_STATE_START
>> ---
>> 2015-06-08 20:35:57,187 DEBUG Asn1Decoder -   current byte : 0x30
>> 2015-06-08 20:35:57,187 DEBUG Asn1Decoder -
>> <<<------------------------------------------
>> 2015-06-08 20:35:57,187 DEBUG Asn1Decoder - <-- End decoding : TLV[ 0x6C,
>> 577, DATA[... ]]
>>
>>
>> Here's an interesting thing however. The reason the buffer has fewer
>> bytes than the length value indicates is that the TCP message is split into
>> 2 packets due to a small TCP window size on this problematic machine. For
>> the kerberos message of size 585 bytes, the first 570 bytes are sent in the
>> first packet, and the remaining 15 bytes in another packet. The Asn1Decoder
>> thinks that it is missing the last 15 bytes and aborts decoding it.
>>
>> Having small TCP window sizes aside, this strikes me as a code issue.
>> Shouldn't the server be able to handle the kerberos message even if it is
>> split into multiple packets? Is this a known issue with a
>> workaround/solution?
>>
>> I looked at MinaKerberosDecoder, and see it extend
>> ProtocolDecoderAdapter. But shouldn't it extend CumulativeProtocolDecoder
>> to be able to handle situations like this?
>>
> the current ASN.1 decoder is supposed to handle this case, can you file a
> bug, I will take a look
>
>>
>> Thanks in advance,
>> Sangjin
>>
>
>
>
> --
> Kiran Ayyagari
> http://keydap.com
>

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