Re: [PATCH 2/2] net: Implement SO_PASSCGROUP to enable passing cgroup path

[Simo Sorce <ssorce@redhat.com>]

On Wed, 2014-04-16 at 07:37 -0700, Andy Lutomirski wrote:
> On Wed, Apr 16, 2014 at 5:57 AM, David Miller <davem@davemloft.net> wrote:
> >
> > Please, just stop.
> 
> No.
> 
> This thread is proposing an ABI.  This means that, if the ABI ends up
> in Linus's kernel, then it has to be supported forever.  Now is the
> time to find and fix any issues with it before they become much harder
> to fix.

Ok, but so far I haven't seen a single objection from you that has solid
grounds.

The only one that *may* be reasonable is the "secret" cgroup name one,
however nobody seem to come up with a reason why it is legitimate to
allow to keep cgroup names secret.

And if you can come up with such a good reason the SO_NOPASSCGROUP
option seem the right solution.

> This ABI is especially tricky because programs will use it even if
> they don't explicitly try to.  So just adding the ABI may break
> existing assumptions that are relevant to security or correctness.

It's not clear to me what you mean by this, either you explicitly use
SO_PASSCGROUP or not, it's not like you can involuntarily add a flag ...

Simo.