Re: [Qemu-devel] [PATCH] util: secure memfd_create fallback mechanism

["Marc-André Lureau" <mlureau@redhat.com>]

Hi

----- Original Message -----
> 
> > On Sep 27, 2016, at 05:36, Daniel P. Berrange <berrange@redhat.com> wrote:
> > 
> > On Tue, Sep 27, 2016 at 03:06:21AM +0000, Rafael David Tinoco wrote:
> > We should not have QEMU creating unpredictabile filenames in the
> > first place - any filenames should be determined by libvirt
> > explicitly.
> 
> Note that the filename, per se, is not as important as other files,
> since qemu won't provide it for being accessed by external programs, and,
> deletes the file, while keeping the descriptor, right after its creation
> (due to its nature, that is probably why it was created in /tmp).
> 
> Having libvirt to define a filename that would not be used for recent
> kernels (> 3.17) and would exist for a fraction of second doesn't seem
> right to me.
> 

There are other parts of qemu that rely on creating temporary files, and this seems to lack a bit of uniformity. Would it make sense to define a place where qemu could create those? Or setting TMPDIR should help too. Could libvirt set a per-vm TMPDIR with appropriate security rules?