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SubjectRe: System reboot triggered by just reading a device file....!?
>There is.. it's called "root privileges".
yes, true.

but - regardless of being a windows app or not - what if you want to take a look on your system as a whole, especially when using some tool which graphically shows how and where your diskspace is being used? if i let this run from ordinary useraccount it would get lot`s of "permission denied" and then it`s only telling half of the truth.....
>I'd say running pretty much anything through Wine as root is
> not a good idea, a Windows app could hose the system without even
> meaning to through exactly such things.
yes, true indeed. but maybe wine has an option to sandbox the windows app to do only r/o access. if that feature doesn`t exist, (set r/o flag to dosdevices) maybe it would be an useful addon.
but that`s OT here....

> -----Ursprüngliche Nachricht-----
> Von: "Robert Hancock" <hancockr@shaw.ca>
> Gesendet: 21.11.07 00:35:23
> An: devzero@web.de
> CC: linux-kernel@vger.kernel.org
> Betreff: Re: System reboot triggered by just reading a device file....!?


>
> devzero@web.de wrote:
> > good evening,
> >
> > i stumbled over some funny issue when trying windirstat (like KDirStat) with wine.
> >
> > after running that tool for a while my system rebooted. i could reproduce this with every run.
> >
> > after some deep investigation (i thought i had stability issues with my system and spent more than an hour on this) i found out, that the reboot is being triggered by iTCO_wdt ( /dev/watchdog )
> >
> > this is how to reproduce:
> >
> > - be root
> > - cat /dev/watchdog or dd if=/dev/watchdog of=/dev/zero bs=1 count=1 or .....
> > - wait one minute........
> >
> > *reboot*!
> >
> > i have heard 2 opinions for now (contacted the author and also discussed on wine-devel ) that this should be expected behaviour.
>
> Yes, it is. It's a watchdog device, it's meant to reboot the machine if
> whatever task is poking the watchdog dies.
>
> > being sysadmin quite a while, i cannot believe that (accidentally) reading a device file (being root or not - what does that matter) triggers a system reboot.
> >
> > ok - when i`m root , i shouldn`t do stupid things and be careful, but i thought reading/crawling trough a filesystem (r/o, btw.) with some tool which is built to do exactly this wasn`t so stupid - even from within wine.
>
> I would say that running a Windows tool that opens up and reads random
> files, on the /dev directory tree, as root, probably does qualify as
> "stupid". I'd say running pretty much anything through Wine as root is
> not a good idea, a Windows app could hose the system without even
> meaning to through exactly such things.
>
> >
> > think of an admin writing a quick&dirty script for intrusion detection (find / -exec md5sum {} \; >/tmp/need-no-tripwire) and forgetting to exclude /dev, /sys or /proc appropriately......
> > think of someone exporting "/" via samba (readonly) and then navigating trough the /dev directory....
> >
> > stupid?
> > i don`t think so.....i have seen worse things...... :)
> >
> > should someone get punished by an accidental system reboot and should he need to spend his time on this to investigate why this happens?
> >
> > i`d wish there would be some fence around this or iTCO_wdt /dev/watchdog not being active after a default desktop installation.
>
> There is.. it's called "root privileges".
>
> >
> > i`d be interested if i`m the only one who thinks this is strange/dangerous behaviour.
> >
> > regards
> > roland
>
>
> --
> Robert Hancock Saskatoon, SK, Canada
> To email, remove "nospam" from hancockr@nospamshaw.ca
> Home Page: http://www.roberthancock.com/
>
>


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