Re: [Patch net-next] ipip: fix a regression in ioctl

[Cong Wang <amwang@redhat.com>]

On Sat, 2013-06-29 at 20:43 -0700, Pravin Shelar wrote:
> On Fri, Jun 28, 2013 at 9:11 PM, Cong Wang <amwang@redhat.com> wrote:
> > From: Cong Wang <amwang@redhat.com>
> >
> > This is a regression introduced by
> > commit fd58156e456d9f68fe0448 (IPIP: Use ip-tunneling code.)
> >
> > Similar to GRE tunnel, previously we only check the parameters
> > for SIOCADDTUNNEL and SIOCCHGTUNNEL, after that commit, the
> > check is moved for all commands.
> >
> > So, just check for SIOCADDTUNNEL and SIOCCHGTUNNEL.
> >
> > Also, the check for i_key, o_key etc. is suspicious too,
> > which did not exist before.
> >
> This check is sanity check since ipip is not suppose to have these
> parameters set, generic layer do allow all parameters.
> Earlier ipip was not using generic layer, therefore that check was not present.

So, if old code doesn't reject this case with EINVAL, then your change
_does_ break user-space applications... no matter whether ipip is
supposed to have these parameters.