Re: How do we store/install apps?

[Alexander Larsson <alexl redhat com>]

On fre, 2014-10-10 at 05:10 -0700, Greg KH wrote:
> On Fri, Oct 10, 2014 at 01:52:05PM +0200, Alexander Larsson wrote:
> > * Don't pass untrusted data to the kernel. For instance, it is risky
> >   to download raw filesystem data and then mount that, or mount a
> >   loopback file that the user can modify. The raw filesystem data is
> >   directly parsed by the kernel and weird data there can cause kernel
> >   panics.
>
> If that happens, the kernel is doing something wrong, and needs to be
> fixed :)
>
> Seriously, if you know of any such bugs, please let the kernel
> developers know and they will be fixed, just like we've fixed this same
> type of bug many many times in the past.
>
> So don't worry too much about this one, it shouldn't be an issue.

Sure, it *should* not happen. But empirically it does. For instance
there was this recent mail:

https://lists.fedoraproject.org/pipermail/devel/2014-October/203101.html

Where light fuzzing of a btrfs filesystem caused pretty bad behaviour in
many cases. I also know people who had similar issues with btrfs on
usbdisks that where bad.

Can you imagine instead of random fuzzying someone was actively trying
to attach the kernel code by creating creative invalid file systems.
These codepaths are *not* well tested or reviewed...