Re: rights(4) split? CAP_WRITE -> CAP_WRITE_DATA + CAP_WRITE_CTRL

Reply: Kyle Evans : "Re: rights(4) split? CAP_WRITE -> CAP_WRITE_DATA + CAP_WRITE_CTRL"
In reply to: Kyle Evans : "rights(4) split? CAP_WRITE -> CAP_WRITE_DATA + CAP_WRITE_CTRL"
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From: Vinícius_dos_Santos_Oliveira <vini.ipsmaker_at_gmail.com>
Date: Wed, 03 Jun 2026 17:21:35 UTC

Em ter., 2 de jun. de 2026 às 15:20, Kyle Evans <kevans@freebsd.org> escreveu:
> I'm looking at an application where it would be useful to be able to construct a socketpair(2) that can't be used to send fds over, out of an abundance of caution.

FWIW Linux added SO_PASSRIGHTS to disable the reception of fds:
https://lwn.net/Articles/1023085/

>The application in prison0 is effectively a broker between two jails that it hands each an end of the socketpair, then steps out of the way -- I don't see a reason to leave it capable of carrying SCM_RIGHTS.

This case can't be dealt with using Linux's SO_PASSRIGHTS so a new
design that deviates from previous solutions (such as Linux's) is
required.

I don't have much to say on this matter, so my comments end here.