linux-kernel - Re: [PATCH 1/3] ptrace: ptrace_attach: check PF_KTHREAD + exit

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: <20090505235736.GA7526@redhat.com>
Date:	Wed, 6 May 2009 01:57:36 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	chrisw@...s-sol.org, roland@...hat.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] ptrace: ptrace_attach: check PF_KTHREAD +
	exit_state instead of ->mm

On 05/05, Andrew Morton wrote:
>
> On Wed, 6 May 2009 00:47:22 +0200
> Oleg Nesterov <oleg@...hat.com> wrote:
>
> > - Add PF_KTHREAD check to prevent attaching to the kernel thread
> >   with a borrowed ->mm.
> >
> >   With or without this change we can race with daemonize() which
> >   can set PF_KTHREAD or clear ->mm after ptrace_attach() does the
> >   check, but this doesn't matter because reparent_to_kthreadd()
> >   does ptrace_unlink().
> >
> > - Kill "!task->mm" check. We don't really care about ->mm != NULL,
> >   and the task can call exit_mm() right after we drop task_lock().
> >   What we need is to make sure we can't attach after exit_notify(),
> >   check task->exit_state != 0 instead.
> >
>
> These patches make a mess of utrace-core.patch.  Do we really want to do that?

Aaaah. Sorry! forgot to clearify...

These patches depend on

	utrace-core-kill-exclude_xtrace-logic.patch

which hopefully can be folded into utrace-core.patch. In that case these
changes do not depend on utrace, and they can go ahead of utrace.

Is this acceptable for you ?

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/