From: "H. Peter Anvin" <hpa@zytor.com>
To: Kees Cook <kees.cook@canonical.com>
Cc: Arjan van de Ven <arjan@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
x86@kernel.org, Pekka Enberg <penberg@cs.helsinki.fi>,
Jan Beulich <jbeulich@novell.com>,
Vegard Nossum <vegardno@ifi.uio.no>,
Yinghai Lu <yinghai@kernel.org>,
Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4] [x86] detect and report lack of NX protections
Date: Tue, 10 Nov 2009 10:53:33 -0800 [thread overview]
Message-ID: <4AF9B6AD.8020505@zytor.com> (raw)
In-Reply-To: <20091110174622.GK5129@outflux.net>
On 11/10/2009 09:46 AM, Kees Cook wrote:
>
> The kernel as-is does not set nx_enabled for 64-bit, so this message is
> skipped completely:
>
> if (nx_enabled)
> printk(KERN_INFO "NX (Execute Disable) protection: active\n");
>
> The only time this printk is shown is on 32-bit with PAE (with NX).
> There is no "else" currently.
>
The structure you have is:
if (nx_enabled)
else if (cpu_has_pae)
The test for cpu_has_pae is unconditional (you only #ifdef the message)
-- in fact, this should cause a compile-time error on 64 bits:
#undef cpu_has_pae
#define cpu_has_pae ___BUG___
-hpa
next prev parent reply other threads:[~2009-11-10 18:57 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-19 18:42 [PATCH] [x86] detect and report lack of NX protections Kees Cook
2009-10-19 23:43 ` Arjan van de Ven
2009-10-20 2:04 ` [PATCH v2] " Kees Cook
2009-10-20 2:18 ` H. Peter Anvin
2009-10-20 4:44 ` Kees Cook
2009-10-20 4:55 ` [PATCH v3] " Kees Cook
2009-11-09 22:10 ` [PATCH v4] " Kees Cook
2009-11-09 23:16 ` H. Peter Anvin
2009-11-10 15:49 ` Kees Cook
2009-11-10 16:47 ` H. Peter Anvin
2009-11-10 16:57 ` Kees Cook
2009-11-10 17:12 ` H. Peter Anvin
2009-11-10 17:46 ` Kees Cook
2009-11-10 18:53 ` H. Peter Anvin [this message]
2009-11-10 19:43 ` Kees Cook
2009-11-10 19:59 ` H. Peter Anvin
2009-11-10 20:55 ` Kees Cook
2009-11-10 21:22 ` H. Peter Anvin
2009-11-10 22:15 ` Kees Cook
2009-11-10 22:25 ` H. Peter Anvin
2009-11-12 18:01 ` Yuhong Bao
2009-11-10 20:25 ` H. Peter Anvin
2009-11-10 16:55 ` [PATCH v5] " Kees Cook
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