Re: [Bug-tar] Possible bug in auto detection of extraction program

[Sasa Vilic]

----- Ursprüngliche Mail -----
> Paul Eggert <address@hidden> wrote:
> 
> > On 04/14/2014 06:41 AM, Sasa Vilic wrote:
> > > I guess that in out particular case it just might be that accidentally
> > > checksum is correct.
> >
> > Thanks for the bug report.  Perhaps tar could be modified to not only
> > look at the checksum, but also attempt to decode the first header (as a
> > sort of "larger" checksum).  That would have fixed your problemand would
> > fix the typical case of this sort of thing,though I suppose it still
> > wouldn't work in general.
> 
> Yesterday, I reconstructed the data from the last mail and it is obvious that
> the checksum is not "correct". 

I patched gtar now to print out debug information and I hope that this 
information could help in further investigation.

The tar_checksum (list.c) function did return HEADER_SUCCESS and following 
checksum inside tar_checksum have been computed:

* unsigned_sum: 55552
* signed_sum: 0
* parsed_sum/recorded_sum: 0. 

Since tar_checksum returns HEADER_SUCCESS, the function 
check_compressed_archive (buffer.c) will return ct_tar (plain tar file) as 
detected type and will not try look into magic number to detect compression 
algorithm, which is exactly the issue here.

Regards,

Sasa Vilic


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