Re: [PATCH 1/6 net-next] net: uapi: Add __kernel_sockaddr_unspec for sockaddr of unknown length

[Kees Cook <kees@kernel.org>]

On Thu, Jul 24, 2025 at 02:40:46PM -0700, Jakub Kicinski wrote:
> On Wed, 23 Jul 2025 16:19:08 -0700 Kees Cook wrote:
> > I added this to UAPI in the hopes that it could also be used for any
> > future "arbitrarily sized" sockaddr needs. But it may be better to
> > use a different UAPI with an explicit size member:
> > 
> > struct sockaddr_unspec {
> > 	u16 sa_data_len;
> > 	u16 sa_family;
> > 	u8  sa_data[] __counted_by(sa_data_len);
> > };
> 
> Right, not sure how likely we are to add completely new future APIs 
> that take sockaddr directly. Most new interfaces will be wrapped in
> Netlink. I may be missing the point but the need to add this struct
> in uAPI right now is not obvious to me.

Yeah, it was pure speculation on my part. I am perfectly happy keeping
it strictly internal to the kernel, but I thought I'd try to show some
possibilities.

-- 
Kees Cook