From: Oleg Nesterov <oleg@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Djalal Harouni <tixxdz@opendz.org>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
linux-kernel@vger.kernel.org,
kernel-hardening@lists.openwall.com,
Al Viro <viro@zeniv.linux.org.uk>,
Alexey Dobriyan <adobriyan@gmail.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Vasiliy Kulikov <segoon@openwall.com>,
Kees Cook <keescook@chromium.org>,
Solar Designer <solar@openwall.com>,
WANG Cong <xiyou.wangcong@gmail.com>,
James Morris <james.l.morris@oracle.com>,
linux-security-module@vger.kernel.org,
linux-fsdevel@vger.kernel.org,
Greg KH <gregkh@linuxfoundation.org>, Ingo Molnar <mingo@elte.hu>,
Stephen Wilson <wilsons@start.ca>,
"Jason A. Donenfeld" <Jason@zx2c4.com>,
Roland McGrath <roland@hack.frob.com>
Subject: [kernel-hardening] Re: [PATCH 1/1] CLONE_PARENT shouldn't allow to set ->exit_signal
Date: Sun, 18 Mar 2012 21:53:42 +0100 [thread overview]
Message-ID: <20120318205342.GA14383@redhat.com> (raw)
In-Reply-To: <CA+55aFzKc578eWYaq4+OaOM6hFjW+ePYCeC++_1p8f09YWV_hA@mail.gmail.com>
On 03/18, Linus Torvalds wrote:
>
> On Wed, Mar 14, 2012 at 11:55 AM, Oleg Nesterov <oleg@redhat.com> wrote:
> > + if (clone_flags & CLONE_THREAD)
> > + p->exit_signal = -1;
> > + else if (clone_flags & CLONE_PARENT)
> > + p->exit_signal = current->group_leader->exit_signal;
> > + else
> > + p->exit_signal = (clone_flags & CSIGNAL);
>
> So why is it "current->group_leader->exit_signal" rather than the much
> more logical (imho) and simpler "current->exit_signal"?
This would be wrong if current is not the main thread. In this
case current->exit_signal = -1. Only group_leader has the "real"
exit_signal used for notification.
Historically "exit_signal = -1" meant different things, currently
it only means "I am not the leader", see thread_group_leader().
I'll write another email tomorrow. Yes, I do remember I promised
the security fixes in this area, sorry for delay.
Oleg.
WARNING: multiple messages have this Message-ID (diff)
From: Oleg Nesterov <oleg@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Djalal Harouni <tixxdz@opendz.org>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
linux-kernel@vger.kernel.org,
kernel-hardening@lists.openwall.com,
Al Viro <viro@zeniv.linux.org.uk>,
Alexey Dobriyan <adobriyan@gmail.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Vasiliy Kulikov <segoon@openwall.com>,
Kees Cook <keescook@chromium.org>,
Solar Designer <solar@openwall.com>,
WANG Cong <xiyou.wangcong@gmail.com>,
James Morris <james.l.morris@oracle.com>,
linux-security-module@vger.kernel.org,
linux-fsdevel@vger.kernel.org,
Greg KH <gregkh@linuxfoundation.org>, Ingo Molnar <mingo@elte.hu>,
Stephen Wilson <wilsons@start.ca>,
"Jason A. Donenfeld" <Jason@zx2c4.com>,
Roland McGrath <roland@hack.frob.com>
Subject: Re: [PATCH 1/1] CLONE_PARENT shouldn't allow to set ->exit_signal
Date: Sun, 18 Mar 2012 21:53:42 +0100 [thread overview]
Message-ID: <20120318205342.GA14383@redhat.com> (raw)
In-Reply-To: <CA+55aFzKc578eWYaq4+OaOM6hFjW+ePYCeC++_1p8f09YWV_hA@mail.gmail.com>
On 03/18, Linus Torvalds wrote:
>
> On Wed, Mar 14, 2012 at 11:55 AM, Oleg Nesterov <oleg@redhat.com> wrote:
> > + if (clone_flags & CLONE_THREAD)
> > + p->exit_signal = -1;
> > + else if (clone_flags & CLONE_PARENT)
> > + p->exit_signal = current->group_leader->exit_signal;
> > + else
> > + p->exit_signal = (clone_flags & CSIGNAL);
>
> So why is it "current->group_leader->exit_signal" rather than the much
> more logical (imho) and simpler "current->exit_signal"?
This would be wrong if current is not the main thread. In this
case current->exit_signal = -1. Only group_leader has the "real"
exit_signal used for notification.
Historically "exit_signal = -1" meant different things, currently
it only means "I am not the leader", see thread_group_leader().
I'll write another email tomorrow. Yes, I do remember I promised
the security fixes in this area, sorry for delay.
Oleg.
next prev parent reply other threads:[~2012-03-18 20:53 UTC|newest]
Thread overview: 102+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-10 23:25 [kernel-hardening] [PATCH 0/9] proc: protect /proc/<pid>/* files across execve Djalal Harouni
2012-03-10 23:25 ` Djalal Harouni
2012-03-10 23:25 ` [kernel-hardening] [PATCH 1/9] exec: add a global execve counter Djalal Harouni
2012-03-10 23:25 ` Djalal Harouni
2012-03-11 0:12 ` [kernel-hardening] " Linus Torvalds
2012-03-11 0:12 ` Linus Torvalds
2012-03-11 0:36 ` [kernel-hardening] " Linus Torvalds
2012-03-11 0:36 ` Linus Torvalds
2012-03-11 0:58 ` [kernel-hardening] " Linus Torvalds
2012-03-11 0:58 ` Linus Torvalds
2012-03-11 8:24 ` [kernel-hardening] " Solar Designer
2012-03-11 8:24 ` Solar Designer
2012-03-11 9:56 ` [kernel-hardening] " Ingo Molnar
2012-03-11 9:56 ` Ingo Molnar
2012-03-11 14:03 ` [kernel-hardening] " Alan Cox
2012-03-11 14:03 ` Alan Cox
2012-03-11 17:15 ` [kernel-hardening] " Djalal Harouni
2012-03-11 17:15 ` Djalal Harouni
2012-03-11 8:39 ` [kernel-hardening] " Djalal Harouni
2012-03-11 8:39 ` Djalal Harouni
2012-03-11 9:40 ` [kernel-hardening] " Solar Designer
2012-03-11 9:40 ` Solar Designer
2012-03-11 17:25 ` [kernel-hardening] " Oleg Nesterov
2012-03-11 17:25 ` Oleg Nesterov
2012-03-11 17:49 ` [kernel-hardening] self_exec_id/parent_exec_id && CLONE_PARENT Oleg Nesterov
2012-03-11 17:49 ` Oleg Nesterov
2012-03-11 18:02 ` [kernel-hardening] " Linus Torvalds
2012-03-11 18:02 ` Linus Torvalds
2012-03-11 18:37 ` [kernel-hardening] " richard -rw- weinberger
2012-03-11 18:37 ` richard -rw- weinberger
2012-03-11 18:39 ` [kernel-hardening] " Oleg Nesterov
2012-03-11 18:39 ` Oleg Nesterov
2012-03-14 18:55 ` [kernel-hardening] [PATCH 0/1] (Was: self_exec_id/parent_exec_id && CLONE_PARENT) Oleg Nesterov
2012-03-14 18:55 ` Oleg Nesterov
2012-03-14 18:55 ` [kernel-hardening] [PATCH 1/1] CLONE_PARENT shouldn't allow to set ->exit_signal Oleg Nesterov
2012-03-14 18:55 ` Oleg Nesterov
2012-03-18 18:25 ` [kernel-hardening] " Linus Torvalds
2012-03-18 18:25 ` Linus Torvalds
2012-03-18 20:53 ` Oleg Nesterov [this message]
2012-03-18 20:53 ` Oleg Nesterov
[not found] ` <20120314190939.GC14172@redhat.com>
2012-03-19 16:02 ` [PATCH 0/3] exec_id/exit_signal fixes Oleg Nesterov
2012-03-19 16:03 ` [PATCH 1/3] exit_signal: simplify the "we have changed execution domain" logic Oleg Nesterov
2012-03-19 16:03 ` [PATCH 2/3] exit_signal: fix the "parent has changed security " Oleg Nesterov
2012-03-19 16:04 ` [PATCH 3/3] exec: move de_thread()->setmax_mm_hiwater_rss() into exec_mmap() Oleg Nesterov
2012-03-11 22:48 ` [kernel-hardening] Re: [PATCH 1/9] exec: add a global execve counter Linus Torvalds
2012-03-11 22:48 ` Linus Torvalds
2012-03-11 23:32 ` [kernel-hardening] " Djalal Harouni
2012-03-11 23:32 ` Djalal Harouni
2012-03-11 23:42 ` [kernel-hardening] " Linus Torvalds
2012-03-11 23:42 ` Linus Torvalds
2012-03-12 0:25 ` [kernel-hardening] " Djalal Harouni
2012-03-12 0:25 ` Djalal Harouni
2012-03-12 10:11 ` [kernel-hardening] " Linus Torvalds
2012-03-12 10:11 ` Linus Torvalds
2012-03-12 10:11 ` Linus Torvalds
2012-03-12 14:01 ` [kernel-hardening] " Djalal Harouni
2012-03-12 14:01 ` Djalal Harouni
2012-03-12 14:01 ` Djalal Harouni
2012-03-11 23:36 ` [kernel-hardening] " Djalal Harouni
2012-03-11 23:36 ` Djalal Harouni
2012-03-12 14:34 ` [kernel-hardening] " Oleg Nesterov
2012-03-12 14:34 ` Oleg Nesterov
2012-03-10 23:25 ` [kernel-hardening] [PATCH 2/9] proc: add proc_file_private struct to store private information Djalal Harouni
2012-03-10 23:25 ` Djalal Harouni
2012-03-10 23:25 ` [kernel-hardening] [PATCH 3/9] proc: new proc_exec_id_ok() helper function Djalal Harouni
2012-03-10 23:25 ` Djalal Harouni
2012-03-10 23:25 ` [kernel-hardening] [PATCH 4/9] proc: protect /proc/<pid>/* INF files from reader across execve Djalal Harouni
2012-03-10 23:25 ` Djalal Harouni
2012-03-10 23:25 ` [kernel-hardening] [PATCH 5/9] proc: add protection support for /proc/<pid>/* ONE files Djalal Harouni
2012-03-10 23:25 ` Djalal Harouni
2012-03-10 23:25 ` [kernel-hardening] [PATCH 6/9] proc: protect /proc/<pid>/* ONE files from reader across execve Djalal Harouni
2012-03-10 23:25 ` Djalal Harouni
2012-03-10 23:25 ` [kernel-hardening] [PATCH 7/9] proc: protect /proc/<pid>/{maps,smaps,numa_maps} Djalal Harouni
2012-03-10 23:25 ` Djalal Harouni
2012-03-10 23:25 ` [kernel-hardening] [PATCH 8/9] proc: protect /proc/<pid>/{environ,pagemap} across execve Djalal Harouni
2012-03-10 23:25 ` Djalal Harouni
2012-03-11 8:05 ` [kernel-hardening] " Alexey Dobriyan
2012-03-11 8:05 ` Alexey Dobriyan
2012-03-11 17:01 ` [kernel-hardening] " Djalal Harouni
2012-03-11 17:01 ` Djalal Harouni
2012-03-10 23:25 ` [kernel-hardening] [PATCH 9/9] proc: improve and clean up /proc/<pid>/mem protection Djalal Harouni
2012-03-10 23:25 ` Djalal Harouni
2012-03-11 0:01 ` [kernel-hardening] Re: [PATCH 0/9] proc: protect /proc/<pid>/* files across execve Linus Torvalds
2012-03-11 0:01 ` Linus Torvalds
2012-03-11 0:27 ` [kernel-hardening] " Djalal Harouni
2012-03-11 0:27 ` Djalal Harouni
2012-03-11 8:46 ` [kernel-hardening] " Djalal Harouni
2012-03-11 8:46 ` Djalal Harouni
2012-03-11 10:35 ` [kernel-hardening] exec_id protection from bad child exit signals (was: Re: [PATCH 0/9] proc: protect /proc/<pid>/* files across execve) Solar Designer
2012-03-11 10:35 ` Solar Designer
2012-03-11 18:20 ` [kernel-hardening] " Oleg Nesterov
2012-03-11 18:20 ` Oleg Nesterov
2012-03-12 19:13 ` [kernel-hardening] Re: [PATCH 0/9] proc: protect /proc/<pid>/* files across execve Eric W. Biederman
2012-03-12 19:13 ` Eric W. Biederman
2012-03-12 20:44 ` [kernel-hardening] " Djalal Harouni
2012-03-12 20:44 ` Djalal Harouni
2012-03-12 21:47 ` [kernel-hardening] " Eric W. Biederman
2012-03-12 21:47 ` Eric W. Biederman
2012-03-12 22:41 ` [kernel-hardening] " Djalal Harouni
2012-03-12 22:41 ` Djalal Harouni
2012-03-12 23:10 ` [kernel-hardening] " Eric W. Biederman
2012-03-12 23:10 ` Eric W. Biederman
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