linux-kernel - Re: RFC: on adding new CLONE_* flags [WAS Re: [PATCH 0/4] clone: add CLONE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20190417125422.bhyrmzom4kwuenwm@brauner.io>
Date:   Wed, 17 Apr 2019 14:54:23 +0200
From:   Christian Brauner <christian@...uner.io>
To:     "Enrico Weigelt, metux IT consult" <lkml@...ux.net>
Cc:     Andy Lutomirski <luto@...nel.org>,
        Aleksa Sarai <cyphar@...har.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Al Viro <viro@...iv.linux.org.uk>,
        Jann Horn <jannh@...gle.com>,
        David Howells <dhowells@...hat.com>,
        Linux API <linux-api@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        "Serge E. Hallyn" <serge@...lyn.com>,
        Arnd Bergmann <arnd@...db.de>,
        "Eric W. Biederman" <ebiederm@...ssion.com>,
        Kees Cook <keescook@...omium.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Michael Kerrisk <mtk.manpages@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Oleg Nesterov <oleg@...hat.com>,
        Joel Fernandes <joel@...lfernandes.org>,
        Daniel Colascione <dancol@...gle.com>
Subject: Re: RFC: on adding new CLONE_* flags [WAS Re: [PATCH 0/4] clone: add
 CLONE_PIDFD]

On Wed, Apr 17, 2019 at 02:03:16PM +0200, Enrico Weigelt, metux IT consult wrote:
> On 16.04.19 23:31, Andy Lutomirski wrote:
> 
> >> How exactly would the pidfd improve this scenario ?
> >> IMHO, would just need to pass the inherited fd's to that daemon (eg.
> >> via unix socket) which then sets them up in the new child process.
> > 
> > It makes it easier to wait until the privileged program exits.
> > Without pidfd, you can't just wait(2) because the program that gets
> > spawned isn't a child.  
> 
> Ah, that is a cool thing !
> I suppose that also works across namespaces ?

Yes, it should. If you hand off the pidfd to another pidns (e.g. via SCM
credentials) for example.

> 
> What other things can be done via pidfd ?

Very basic things right now and until CLONE_PIDFD is accepted (possibly
for 5.2) we won't enable any more features.
I'm not a fan of wild speculations and grand schemes that then don't
come to fruition. :) Right now it's about focussing on somewhat cleanly
covering the basics. Coming to a consensus there was hard enough. We
have no intention in making this more complex right now as it needs to
be.

Christian