linux-kernel - Re: [PATCH v2 5/7] clone4: Add a CLONE_AUTOREAP flag to automatically reap the child process

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]

Date:	Fri, 20 Mar 2015 20:09:14 +0100
From:	Oleg Nesterov <oleg@...hat.com>
To:	Thiago Macieira <thiago.macieira@...el.com>
Cc:	Josh Triplett <josh@...htriplett.org>,
	Al Viro <viro@...iv.linux.org.uk>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Andy Lutomirski <luto@...nel.org>,
	Ingo Molnar <mingo@...hat.com>,
	Kees Cook <keescook@...omium.org>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	"H. Peter Anvin" <hpa@...or.com>, Rik van Riel <riel@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Michael Kerrisk <mtk.manpages@...il.com>,
	linux-kernel@...r.kernel.org, linux-api@...r.kernel.org,
	linux-fsdevel@...r.kernel.org, x86@...nel.org
Subject: Re: [PATCH v2 5/7] clone4: Add a CLONE_AUTOREAP flag to
	automatically reap the child process

On 03/20, Thiago Macieira wrote:
>
> On Friday 20 March 2015 19:14:04 Oleg Nesterov wrote:
> > Also. I forgot that the kernel always resets ->exit_signal to SIGCHLD on
> > exec or reparenting. Reparenting is probably fine. But what about exec?
> > Should it keep ->exit_signal == 0 if "autoreap" ? I think it should not, to
> > avoid the strange special case.
>
> Not delivering any signal was the objective of this patch series, so yes
> exit_signal == 0 should survive an exec and even re-exec.

OK, but then perhaps we should never send SIGCHLD (on exit) if "autoreap",
to make the logic simple.

And copy_process() should probably do

	if ((clone_flags & CSIGNAL) && (clone_flags && CLONE_AUTOREAP))
		return -EINVAL;

so that we still can change this behaviour later.

Oleg.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/