kernel-hardening - Re: [PATCH 1/2] procfs: restore 0400 permissions on /proc/*/{syscall,stack,personality}

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Date: Thu, 29 Aug 2013 10:11:27 +0100
From: Djalal Harouni <tixxdz@...ndz.org>
To: "Eric W. Biederman" <ebiederm@...ssion.com>
Cc: Kees Cook <keescook@...omium.org>, Al Viro <viro@...iv.linux.org.uk>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Solar Designer <solar@...nwall.com>,
	Vasiliy Kulikov <segoon@...nwall.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Ingo Molnar <mingo@...nel.org>, LKML <linux-kernel@...r.kernel.org>,
	"kernel-hardening@...ts.openwall.com" <kernel-hardening@...ts.openwall.com>
Subject: Re: [PATCH 1/2] procfs: restore 0400 permissions on
 /proc/*/{syscall,stack,personality}

Hi Eric,

On Wed, Aug 28, 2013 at 05:26:56PM -0700, Eric W. Biederman wrote:
> 
> I have take a moment and read this thread, and have been completely
> unenlightend.  People are upset but it is totally unclear why.
> 
> There is no explanation why it is ok to ignore the suid-exec case, as
> the posted patches do.  Which ultimately means the patches provide
Please, did you take a look at the patches ?
-       INF("syscall",    S_IRUGO, proc_pid_syscall),
+       INF("syscall",    S_IRUSR, proc_pid_syscall),

Can you please tell me how did you come to the conclusion that the
patches "ignore the suid-exec case as the posted patches do" ?

I just did s/0444/0400/ which is pretty obvious and did not remove
that ptrace check at read() added by Al.

> little to no security benefit, and that the posted patches as written
> are broken.
They are correct. Perhaps you didn't take a closer look

Thanks Eric

-- 
Djalal Harouni
http://opendz.org

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