Re: [PATCH] ipv6: fix NULL pointer dereference in ip6_output()

[Stephen Suryaputra]

On Wed, Dec 08, 2021 at 08:46:37AM -0700, David Ahern wrote:
> On 12/8/21 3:51 AM, Florian Westphal wrote:
> > David Ahern <dsahern@xxxxxxxxx> wrote:
> >> On 12/7/21 5:21 PM, Andrea Mayer wrote:
> >>> +        IP6CB(skb)->iif = skb->skb_iif;
> >>>          [...]
> >>>
> >>> What do you think?
> >>>
> >>
> >> I like that approach over the need for a fall back in core ipv6 code.
> > 
> > What if the device is removed after ->iif assignment and before dev lookup?
> > 
> 
> good point. SR6 should make sure the iif is not cleared, and the
> fallback to the skb->dev is still needed in case of delete.

Thanks for the explanation. I was thinking that ->iif can safely be
assumed to be valid. Florian's point that device can be removed is a
good one. My bad for not putting the check and thanks for fixing.