Re: [PATCHSET] FUSE: extend FUSE to support more operations

From: Tejun Heo
Date: Thu Nov 13 2008 - 06:30:01 EST


Hello,

Miklos Szeredi wrote:
> Not with '-oallow_other'. Consider the case that the caller invoked a
> non well formed ioctl, but since there's no way to know this we
> allowed the fuse server to tinker with the caller's address space
> _as if_ the ioctl was well formed.

Right, allow_other.

> So we should always make sure that the server has enough privilege to
> read/write the caller's memory, i.e. it can ptrace the caller.
>
> At this point we could allow any ioctls, not just well formed ones.
> But I don't want that for a different reason: if the possibility is
> there people will find new "innovative" uses for it and just get
> themselves into a big mess.

I don't really mind people doing strange things in userland as long as
it's safe but you're the maintainer. It's a bit strange to export the
feature only for CUSE, so I'm a little bit hesitant. I wanna make it
useful for both. So, at the kernel level, only well formed for FUSE and
everything goes for CUSE. Does that sound good enough?

--
tejun
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