RE: [libreoffice-users] Document 'corrupt' for LibreOffice, opens fine with other OOo-based software

Corruption could indeed be triggered by there being an inconsistency between META-INF/manifest.xml 
and what is present in the package.

It is interesting if that is a complaint about Configurations/.../current.xml (usually a 
zero-length useless component), which is private information from the producer that is not defined 
by ODF and can't be meaningfully used by any software other than the producer.  For the most part, 
that material appears to be gratuitous and unnecessary.

The missing Thumbnails/thumbnail.png is also benign.

Working from memory in order to reply quickly, I believe that there *IS* an ODF requirement for 
every stream in the package (a Zip) to be accounted for in META-INF/manifest.xml except the 
manifest itself, mimetype, and anything else in META-INF/ (except if it is meant to be 
encryptable).  I suspect the specifications are silent concerning META-INF/manifest.xml entries 
that have no corresponding stream in the Zip.  I need to confirm the facts. 

 - Dennis

THINKING OUT LOUD:

I would not be surprised if this tightening of consistency with the manifest is for purposes of 
improved detection of tampering and the possible incidence of a security exploit of one kind or 
another.  There is a practice in security cases to avoid providing details since it provides too 
much information for someone attempting to craft an exploit.  That's a stretch in this case.  

It would be useful to soften the message to one of "There are inconsistencies and it is possible 
the document is corrupted."  The request for permission to attempt correction by eliminating the 
inconsistencies should be quite clear.  It would also be valuable to report whether there was any 
apparent data loss or that repair did not involve loss of anything critical to the document.  
Encouraging a save-as of the repaired document to a different location would also be handy in 
restoring the confidence of the user in the successful effort.


MORE THINKING OUT LOUD:

PS: If the original document was digitally signed, repair will lose the signature of course, but 
there should have been difficulties with verification of the presumed original too. If the original 
document was encrypted ("Saved with Password"), how that fails is very dicey. 

PPS: It is cumbersome to put too much into the analysis and repair as part of the mainstream 
operation of a product such as LibreOffice where performance is an important feature.  A separate 
analysis and repair utility might be more valuable (and LO could launch it, of course) for 
providing smoother handling and forensic analysis when the product software detects an 
inconsistency.


-----Original Message-----
From: Barry Say [mailto:barry12@nspipes.co.uk] 
Sent: Monday, June 04, 2012 13:36
To: users@global.libreoffice.org
Subject: Re: [libreoffice-users] Document 'corrupt' for LibreOffice, opens fine with other 
OOo-based software

Eric Brunel wrote:
> So if anyone could have a look and tell us what we are doing wrong. Or 
> even better, if there's a way to make LibreOffice tell us what's 
> actually wrong in the document, that would be great.
Hi Eric,

I've followed most of the discussion to date and I have had similar 
experiences in the past. When I repaired the document you posted, two 
new directories appeared, Configurations2 and Thumbnails.

In your original document, the directory META-INF contains a file 
manifest.xml whose contents contain references to the two missing 
directories and two files:

Configurations2/accelerator/current.xml
Thumbnails/thumbnail.png

The first is empty and the second is a 181x 256 image of the page.  I do 
not not know whether this is the core of your problem or not, but it is 
a place I for one would investigate.

Barry






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