Hi Daniel!
On Wed, 24 Oct 2018 at 18:07, Daniel Borkmann wrote:
>
> [ +John ]
>
> On 10/22/2018 05:41 PM, Taehee Yoo wrote:
> > The dev_map_notification() removes interface in devmap if
> > unregistering interface's ifindex is same.
> > But only checking ifindex is not enough because other netns can have
> > same ifindex. so that wrong interface selection could occurred.
> > Hence the net_eq() is needed.
> >
> > Fixes: 2ddf71e23cc2 ("net: add notifier hooks for devmap bpf map")
> > Signed-off-by: Taehee Yoo
> > ---
> > kernel/bpf/devmap.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
> > index 141710b82a6c..0d9211e49a4a 100644
> > --- a/kernel/bpf/devmap.c
> > +++ b/kernel/bpf/devmap.c
> > @@ -496,6 +496,7 @@ static int dev_map_notification(struct notifier_block
> > *notifier,
> > ulong event, void *ptr)
> > {
> > struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
> > + struct net *net = dev_net(netdev);
> > struct bpf_dtab *dtab;
> > int i;
> >
> > @@ -512,7 +513,7 @@ static int dev_map_notification(struct notifier_block
> > *notifier,
> > struct bpf_dtab_netdev *dev, *odev;
> >
> > dev = READ_ONCE(dtab->netdev_map[i]);
> > - if (!dev ||
> > + if (!dev || !net_eq(net, dev_net(dev->dev)) ||
> > dev->dev->ifindex != netdev->ifindex)
>
> Can't we just compare netdev pointers directly here?
>
Thank you for review!
I tested what you suggested, It works well and it's more simple.
So that I will send v2 patch that just compares netdev pointer instead of
using ifindex and net_eq().
> > continue;
> > odev = cmpxchg(>netdev_map[i], dev,
> > NULL);
> >
>
Thanks!
