Re: [libreoffice-users] opening powerpoint files restart the computer

Hi Gabriel

I agree, you make some valid points, but the MS hive (collection of the 
boot code plus apps running in memory in one big monolith file, unlike 
the Linux kernel with separate "clients" commucating with the kernel, 
all separate), is not as robust as we would like to believe, even in 
Windows 7 and 8. So as you covered in your reply, any bad data files 
forcing it's host app, as in this case LO with a presentation data file, 
to exceed it's memory boundaries, will cause the processor and microcode 
to force a reboot intentionally or accidentally, due to creating 
instability with the rest of the memory content, the hive. This is the 
weakness of the MS way of doing things.

As to my coverage of malware in the data files, it could cause a system 
crash and reboot, if the malware code is written badly or incomplete.

I also noticed that Demétrio Soares is running Windows 7 32 bit on only 
1.5MB of RAM, this in itself could be the problem. Although Windows 7  
can run on  1.5GB of RAM, it is recommended to run it on at least 2GB, 
and even better with 3 or 4GB. The 4GB will be a bit of a waste as a 
32bit system can only see a physical max of 3.2GB, so installing 4GB 
would not see or use the last 800MB (as layman terms as I can explain 
it). With only 1.5GB of RAM, the O/S is using at least 1GB of this RAM 
leaving 500MB for apps and data file, so I would also expect a system 
crash if the data file was a large one. As an example I am using Windows 
7 64bit with 6GB of RAM, and I am consuming 35% (2GB) of this RAM right 
now as I type this email, Thunderbird open, Firefox open, and not much 
else except some system resources running.

Regards

Andrew Brown

On 21/07/2013 06:25 PM, Gabriel Risterucci wrote:
> While it's totally true that malicious code might be embedded in 
> anything (especially ms formats... but we won't talk about this :)), I 
> doubt it would trigger a reaction as bad as a reboot, especially under 
> recent OS.
> Crashing a user program is very unlikely to cause a system reboot, 
> except if it call some regular reboot code, that would trigger a 
> "clean" reboot, windows closing and stuff. Most likely output is 
> simply the program crashing/getting in an unstable state.
>
> As I said, it's not completely ruling out the possibility of a 
> catastrophic crash caused by some code issue, but it's fearly 
> reasonnable to suppose that loading this file make LO expand to use 
> more memory than usual, touching a faulty area. If the computer 
> usually work without issue, maybe the ppt file is very large, or very 
> complex, or the LO loading routine doesn't handle it nicely and cause 
> the memory cost to increase.
>
> It would be interesting to know wether the reboot is "hard" (instant 
> black screen) or soft (windows closing down normally).
> Also, if the ppt file isn't sensitive, it would be useful to put it on 
> some kind of file sharing site for people to try loading it.
>
> --
> Cley Faye
> http://cleyfaye.net
>
>
> 2013/7/21 Andrew Brown <andrewbr@icon.co.za <mailto:andrewbr@icon.co.za>>
>
>     Hello
>
>     My two cents worth would rather be to focus on the actual
>     Powerpoint data file that is the source of the problem, when
>     attempted to being opened. If it has any corruption in it, or
>     possibly a piece of malware made to disguise and represent itself
>     as a Powerpoint presentation, then I would accept it crashing and
>     forcing a reboot of the PC, especially if there is no malware
>     protection in place, on a Windows system especially. Virus writers
>     can easily embed bad and malicious code into documents,
>     presentations and spreadsheets.
>
>     Try another known working presentation data file, and see if this
>     also causes the crash with LO and the PC, if not, then you know
>     where your source of your problem is.
>
>     Cheers
>
>     Andrew Brown
>
>
>     On 21/07/2013 05:20 PM, Gabriel Risterucci wrote:
>
>         There is not much stuff (if any) in LO that could cause a
>         reboot of a
>         computer. Although it's not possible to completely rule out a
>         LO issue, I'd
>         suggest you run some memory testing program (like memtest86+),
>         as it's much
>         more likely that your issue is related to faulty memory/hardware.


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