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

On 4 juin 12, at 23:39, Dennis E. Hamilton wrote:
> 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.

Thanks for the hints. Worked on that, but no luck so far: I removed  
the references to the non-existing files and directories in the META- 
INF/manifest.xml file, but the document is still reported as corrupt.  
Then I did the reverse: keeping the existing META-INF/manifest.xml  
file and copying all the missing files and directories from the  
repaired document: LO still says the document is corrupt… I've checked  
the manifest.xml file thoroughly, and it does reference exactly all  
the files in the document, except everything in the META-INF directory  
itself and the mimetype file.

> 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.

This was what came to my mind too…

> 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.

Well again, telling the reason why the document is reported as corrupt  
would be a great help too. As it is now, we have to rely on wild  
guesses to figure out what to correct in the generated document, and  
that's a long and painful thing to do…

Anyway, thanks a lot again for your answers.
 - Eric -


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