[
https://issues.apache.org/jira/browse/DIRSERVER-2071?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Emmanuel Lecharny closed DIRSERVER-2071.
----------------------------------------
> MinaKerberosDecoder fails with NullPointerException if the kerberos message
> is split in multiple packets
> --------------------------------------------------------------------------------------------------------
>
> Key: DIRSERVER-2071
> URL: https://issues.apache.org/jira/browse/DIRSERVER-2071
> Project: Directory ApacheDS
> Issue Type: Bug
> Components: asn1
> Affects Versions: 2.0.0-M15
> Reporter: Sangjin Lee
> Assignee: Kiran Ayyagari
> Priority: Major
> Fix For: 2.0.0.AM26
>
> Attachments: TestAsn1Decoder.java, TestAsn1Decoder.java
>
>
> On some machines (but not all), kerberos authentication to Apache DS is
> consistently failing with a NullPointerException:
> {noformat}
> 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
> {noformat}
> I traced it down to a 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:
> {noformat}
> 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[... ]]
> {noformat}
> 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. The following is
> the gist of the tcpdump capture of this TCP conversation:
> {noformat}
> 13:35:57.186758 IP localhost.54477 > localhost.40829: Flags [S], seq
> 1599306555, win 32792, options [mss 16396,sackOK,TS val 318374489 ecr
> 0,nop,wscale 8], length 0
> 13:35:57.186771 IP localhost.40829 > localhost.54477: Flags [S.], seq
> 7524064, ack 1599306556, win 1140, options [mss 16396,sackOK,TS val 318374489
> ecr 318374489,nop,wscale 0], length 0
> 13:35:57.186781 IP localhost.54477 > localhost.40829: Flags [.], ack 1, win
> 129, options [nop,nop,TS val 318374489 ecr 318374489], length 0
> 13:35:57.186903 IP localhost.54477 > localhost.40829: Flags [.], seq 1:571,
> ack 1, win 129, options [nop,nop,TS val 318374490 ecr 318374489], length 570
> 13:35:57.186909 IP localhost.40829 > localhost.54477: Flags [.], ack 571, win
> 570, options [nop,nop,TS val 318374490 ecr 318374490], length 0
> 13:35:57.186914 IP localhost.54477 > localhost.40829: Flags [P.], seq
> 571:586, ack 1, win 129, options [nop,nop,TS val 318374490 ecr 318374489],
> length 15
> 13:35:57.187519 IP localhost.40829 > localhost.54477: Flags [.], ack 571, win
> 1140, options [nop,nop,TS val 318374490 ecr 318374490], length 0
> 13:35:57.190641 IP localhost.40829 > localhost.54477: Flags [F.], seq 1, ack
> 571, win 1140, options [nop,nop,TS val 318374493 ecr 318374490], length 0
> 13:35:57.190687 IP localhost.54477 > localhost.40829: Flags [F.], seq 586,
> ack 2, win 129, options [nop,nop,TS val 318374493 ecr 318374493], length 0
> 13:35:57.190701 IP localhost.40829 > localhost.54477: Flags [R], seq 7524066,
> win 0, length 0
> {noformat}
> Having small TCP window sizes aside, this strikes me as a code issue. The
> server should be able to handle the kerberos message even if it is split into
> multiple packets.
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