Re: [PATCH 0/3] SG_IO command filtering via sysfs

[Christoph Hellwig]

On Mon, Nov 12, 2018 at 11:17:29AM +0100, Paolo Bonzini wrote:
> > Well, that's what we have the security_file_ioctl() LSM hook for so that
> > your security model can arbitrate access to ioctls.
> 
> Doesn't that have TOC-TOU races by design?

If you want to look at the command - yes.  If you just want to filter
read vs write vs ioctl, no.

> Also, what about SG_IO giving write access to files that are only opened
> read-only (and only have read permissions)?

Allowing SG_IO on read-only permissions sounds like a reall bad idea,
filtering or not.