[libvirt] [PATCH RFC] qemu: caps: Don't try to ask for CAP_DAC_OVERRIDE if non-root

[Daniel P. Berrangé]

On Mon, Feb 04, 2019 at 04:32:52PM +0100, Peter Krempa wrote:
> On Mon, Feb 04, 2019 at 16:26:02 +0100, Peter Krempa wrote:
> > It will not work. This breaks qemu capabilities probing as a user.
> > ---
> >  src/qemu/qemu_capabilities.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> > 
> > diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
> > index 7ed5f94803..81ef0357e7 100644
> > --- a/src/qemu/qemu_capabilities.c
> > +++ b/src/qemu/qemu_capabilities.c
> > @@ -4524,7 +4524,8 @@ virQEMUCapsInitQMPCommandRun(virQEMUCapsInitQMPCommandPtr cmd,
> >  #if WITH_CAPNG
> >      /* QEMU might run into permission issues, e.g. /dev/sev (0600), override
> >       * them just for the purpose of probing */
> > -    virCommandAllowCap(cmd->cmd, CAP_DAC_OVERRIDE);
> > +    if (geteuid() == 0)
> 
> Possibly replacing this with driver->privileged for the qemu driver but
> that is not easily accessible.

It doesn't really matter as  privileged == (geteuid() == 0)  since we purged
the hack for Solaris that tried to run privileged libvirtd as non-root for
Xen.  We've got many other cases using geteuid() == 0 where they cannot
access the 'privileged' flag alrady.

Regards,
Daniel
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