[Boost-bugs] [Boost C++ Libraries] #5908: iostreams gzip fails to handle optional extra fields in gzip header

Subject: [Boost-bugs] [Boost C++ Libraries] #5908: iostreams gzip fails to handle optional extra fields in gzip header
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2011-09-17 21:33:55

#5908: iostreams gzip fails to handle optional extra fields in gzip header
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 Reporter:  Travis Abbott <typedef.struct@…>          |       Owner:  turkanis 
     Type:  Bugs                                      |      Status:  new      
Milestone:  To Be Determined                          |   Component:  iostreams
  Version:  Boost 1.47.0                              |    Severity:  Problem  
 Keywords:  gzip                                      |  
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 When bit 2 (FEXTRA) is set in a gzip header's flags, the iostreams code
 fails to read the XLEN field before starting to read the extra comment.
 The code is actually there to do it, but it gets skipped. This means the
 code goes directly a loop like: while (--xlen != 0) with xlen still set to
 0. This results in the rest of the file being slurped in by this comment
 reading code (or at least until xlen wraps around to 0 again, which could
 take awhile). I ran into this because many popular file formats in
 bioinformatics (BAM, tabix) are gzipped and include extra optional fields
 in their headers.

 I've attached an example gzipped file with an optional header, a test
 program that should demonstrate the problem (against 1.47 and latest svn),
 as well as a patch that fixes it.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/5908>
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