Re: [PATCH v2] vfio/pci: Fix a use-after-free issue

[Alex Williamson]

On Tue, 23 May 2023 11:17:47 -0600
Alex Williamson <alex.williamson@redhat.com> wrote:

> On Tue, 23 May 2023 13:00:53 -0400
> Matthew Rosato <mjrosato@linux.ibm.com> wrote:
> 
> > On 5/16/23 10:46 PM, Zhenzhong Duan wrote:  
> > > vbasedev->name is freed wrongly which leads to garbage VFIO trace log.
> > > Fix it by allocating a dup of vbasedev->name and then free the dup.
> > > 
> > > Fixes: 2dca1b37a7 ("vfio/pci: add support for VF token")
> > > Suggested-by: Alex Williamson <alex.williamson@redhat.com>
> > > Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>    
> > 
> > Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
> > 
> > Also verified that this resolves an issue seen on s390, as we were
> > seeing not just garbage logs but QEMU crashes in certain cases e.g.
> > during device unplug.  Thanks!  
> 
> Thanks for the testing and reminder, I'll get a pull request out for
> this.  Thanks,

Actually Cedric volunteered to bundle this with some pending patches,
so...

Acked-by: Alex Williamson <alex.williamson@redhat.com>

> > > ---
> > > v2: "toke" -> "token", Cedric
> > >     Update with Alex suggested change
> > > 
> > >  hw/vfio/pci.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> > > index bf27a3990564..73874a94de12 100644
> > > --- a/hw/vfio/pci.c
> > > +++ b/hw/vfio/pci.c
> > > @@ -2994,7 +2994,7 @@ static void vfio_realize(PCIDevice *pdev,
> > > Error **errp) qemu_uuid_unparse(&vdev->vf_token, uuid);
> > >          name = g_strdup_printf("%s vf_token=%s", vbasedev->name,
> > > uuid); } else {
> > > -        name = vbasedev->name;
> > > +        name = g_strdup(vbasedev->name);
> > >      }
> > >  
> > >      ret = vfio_get_device(group, name, vbasedev, errp);    
> >   
>