Hi. Pavel Machek wrote: > On Fri 2008-01-04 21:54:06, Oliver Neukum wrote: >> Am Donnerstag, 3. Januar 2008 23:06:07 schrieb Nigel Cunningham: >>> Oliver Neukum wrote: >>>> Am Donnerstag, 3. Januar 2008 10:52:53 schrieb Nigel Cunningham: >>>>> Oliver Neukum wrote: >>>>>> Am Donnerstag 03 Januar 2008 schrieb Nigel Cunningham: >>>>>>> On top of this, I made a (too simple at the moment) freeze_filesystems >>>>>>> function which iterates through &super_blocks in reverse order, freezing >>>>>>> fuse filesystems or ordinary ones. I say 'too simple' because it doesn't >>>>>>> currently allow for the possibility of someone mounting (say) ext3 on >>>>>>> fuse, but that would just be an extension of what's already done. >>>>>> How do you deal with fuse server tasks using other fuse filesystems? >>>>> Since they're frozen in reverse order, the dependant one would be frozen >>>>> first. >>>> Say I do: >>>> >>>> a) mount fuse on /tmp/first >>>> b) mount fuse on /tmp/second >>>> >>>> Then the server task for (a) does "ls /tmp/second". So it will be frozen, >>>> right? How do you then freeze (a)? And keep in mind that the server task >>>> may have forked. >>> I guess I should first ask, is this a real life problem or a >>> hypothetical twisted web? I don't see why you would want to make two >>> filesystems interdependent - it sounds like the way to create livelock >>> and deadlocks in normal use, before we even begin to think about >>> hibernating. >> Good questions. I personally don't use fuse, but I do care about power >> management. The problem I see is that an unprivileged user could make >> that dependency, even inadvertedly. > > Other problem is that unprivileged user can do it with evil intent. So > called "denial-of-service" attack.
Only in this case it would be a denial-of-denial-of-service attack, since it would stop you hibernating or suspending :). This is still all hypothetical. If I could have a real life case where this could actually happen, it would help a lot. Nigel -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/