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From Thorsten Schäfer (JIRA) <j...@apache.org>
Subject [jira] [Commented] (TIKA-1631) OutOfMemoryException in ZipContainerDetector
Date Thu, 13 Apr 2017 16:32:41 GMT

    [ https://issues.apache.org/jira/browse/TIKA-1631?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15967838#comment-15967838
] 

Thorsten Schäfer commented on TIKA-1631:
----------------------------------------

Hi Tim,

I have attached the file cache.mpgindex that just contains four bytes, the magic string for
the .Z compressed file, a code size of 30 and one byte in order to be greater then 3: 0x1f
0x9d 0x1e 0x42
Using this file I could reproduce the error in a unit test. As a side note: A code size of
31 (0x1f) which would be allowed in theory by the .Z algorithm and the {{ZCompressorInputStream}}
would lead to an integer overflow. I read in the man page of compress that in practice a code
size greater than 16 is not used.

Kinds,

Thorsten

> OutOfMemoryException in ZipContainerDetector
> --------------------------------------------
>
>                 Key: TIKA-1631
>                 URL: https://issues.apache.org/jira/browse/TIKA-1631
>             Project: Tika
>          Issue Type: Bug
>          Components: detector
>    Affects Versions: 1.8
>            Reporter: Pavel Micka
>         Attachments: cache.mpgindex
>
>
> When I try to detect ZIP container I rarely get this exception. It is caused by the fact
that the file looks like ZIP container (magics), but in fact its random noise. So Apache decompress
tries to find the size of tables (expects correct stream), loads coincidentally huge number
(as on the given place there can be anything in the stream) and tries to allocate array of
several GB in size (hence the exception).
> This bug negatively influences stability of systems running Tika, as the decompressor
can accidentally allocate as much memory as is available and other parts of the system then
might not be able to allocate their objects.
> A solution might be to add additional parameter to Tika config that would limit size
of these arrays. If the size would be bigger, it would throw exception. This change should
not be hard, as method InternalLZWInputStream.initializeTables() is protected.  
> Exception in thread "pool-2-thread-2" java.lang.OutOfMemoryError: Java heap space
> 	at org.apache.commons.compress.compressors.z._internal_.InternalLZWInputStream.initializeTables(InternalLZWInputStream.java:111)
> 	at org.apache.commons.compress.compressors.z.ZCompressorInputStream.<init>(ZCompressorInputStream.java:52)
> 	at org.apache.commons.compress.compressors.CompressorStreamFactory.createCompressorInputStream(CompressorStreamFactory.java:186)
> 	at org.apache.tika.parser.pkg.ZipContainerDetector.detectCompressorFormat(ZipContainerDetector.java:106)
> 	at org.apache.tika.parser.pkg.ZipContainerDetector.detect(ZipContainerDetector.java:92)
> 	at org.apache.tika.detect.CompositeDetector.detect(CompositeDetector.java:61)



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