Re: AF_UNIX status report

[Corinna Vinschen <corinna-cygwin@cygwin.com>]

On Nov 17 14:57, Ken Brown via Cygwin-developers wrote:
> On 11/9/2020 4:08 AM, Corinna Vinschen wrote:
> > The duplicated handle has to be closed at one point but otherwise
> > the approach makes sense.
> 
> After wasting a ridiculous amount of time because of careless mistakes with
> handle duplication, I've finally gotten something working (currently for
> disk files only and with some limitations that have to removed).  I've
> pushed it to the topic/af_unix branch in case you want to review it and/or
> test it.

This is soooo fantastic!  Apart from files, the nexst most interesting
case is sharing a socket, probably.  We could activcate the 2nd half of
privilege separation in sshd then.

> If you do test it, the main limitation currently is that the sending process
> can't exit until the receiving process has received and processed the
> SCM_RIGHTS data.

While this is strictly a flaw, that may not be much of a limitation.
It would be interesting to know how many applications send descriptors
just to exit immediately.  Not so many, probably.

> I'll keep working on improving this and removing limitations, but at least
> I'm confident now that the basic idea of sending serialized fhandlers works.
> Thanks for suggesting that.  I wouldn't have known where to start otherwise.

Thanks for working on this stuff!


Corinna