From: Oleg Nesterov <oleg@redhat.com>
To: Amnon Shiloh <u3557@miso.sublimeip.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>,
Michael Kerrisk <mtk.manpages@gmail.com>,
Serge Hallyn <serge.hallyn@canonical.com>,
Chris Evans <scarybeasts@gmail.com>,
David Howells <dhowells@redhat.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Andrew Morton <akpm@linux-foundation.org>,
u3557@dialix.com.au, security@kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: PT_EXITKILL (Was: pdeath_signal)
Date: Thu, 8 Nov 2012 13:37:16 +0100 [thread overview]
Message-ID: <20121108123716.GA20917@redhat.com> (raw)
In-Reply-To: <20121108062935.BFF3A592024@miso.sublimeip.com>
Hi Amnon,
On 11/08, Amnon Shiloh wrote:
>
> Thanks for the patch, I tried it and it works nicely!
OK, thanks. I'll wait for other comments a bit and then send
the patch to Andrew.
> Also, I just noticed that this new option (PTRACE_O_EXITKILL) is not
> safe with ptrace(PTRACE_TRACEME)+execve, because the parent may die
> before even having a chance to set PTRACE_O_EXITKILL!
Not safe? I guess you meant that PTRACE_O_EXITKILL can't prevent
this race? Yes sure. Or the parent can die before it does
PTRACE_O_EXITKILL.
> However, that's easy to fix by using PTRACE_ATTACH instead.
Or the child can check getppid() == saved_parent_pid after PTRACE_TRACEME.
But if you switch to PTRACE_ATTACH, I'd suggest to use PTRACE_SEIZE.
Note that, in particular, this allows you to specify the options at
attach.
As for PF_NO_SIGSTOP, I'll write another email.
Oleg.
next prev parent reply other threads:[~2012-11-08 12:36 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20121106152050.GA18218@sergelap>
[not found] ` <20121106201428.9D72959201A@miso.sublimeip.com>
2012-11-07 15:09 ` PT_EXITKILL (Was: pdeath_signal) Oleg Nesterov
2012-11-08 6:29 ` Amnon Shiloh
2012-11-08 12:37 ` Oleg Nesterov [this message]
2012-11-08 13:03 ` Amnon Shiloh
2012-11-18 20:21 ` [PATCH 0/1] ptrace: introduce PTRACE_O_EXITKILL Oleg Nesterov
2012-11-18 20:21 ` [PATCH 1/1] " Oleg Nesterov
2012-11-08 12:48 ` PF_NO_SIGSTOP (Was: PT_EXITKILL) Oleg Nesterov
2012-11-08 14:05 ` Amnon Shiloh
2012-11-08 12:16 ` PT_EXITKILL (Was: pdeath_signal) Pedro Alves
2012-11-08 12:44 ` Oleg Nesterov
2012-11-08 13:00 ` Pedro Alves
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20121108123716.GA20917@redhat.com \
--to=oleg@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=dhowells@redhat.com \
--cc=dvlasenk@redhat.com \
--cc=ebiederm@xmission.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mtk.manpages@gmail.com \
--cc=scarybeasts@gmail.com \
--cc=security@kernel.org \
--cc=serge.hallyn@canonical.com \
--cc=u3557@dialix.com.au \
--cc=u3557@miso.sublimeip.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.