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From: Kees Cook <keescook@chromium.org>
To: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-kernel@vger.kernel.org, Guenter Roeck <linux@roeck-us.net>,
	Ard Biesheuvel <ardb@kernel.org>,
	Darren Hart <dvhart@infradead.org>,
	Andy Shevchenko <andy@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	x86@kernel.org, linux-efi@vger.kernel.org,
	"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH] x86/mm: Disable W^X detection and enforcement on 32-bit
Date: Fri, 23 Sep 2022 21:26:36 -0700	[thread overview]
Message-ID: <202209232126.64AA2AC570@keescook> (raw)
In-Reply-To: <20220923221730.1860518-1-dave.hansen@linux.intel.com>

On Fri, Sep 23, 2022 at 03:17:30PM -0700, Dave Hansen wrote:
> The 32-bit code is in a weird spot.  Some 32-bit builds (non-PAE) do not
> even have NX support.  Even PAE builds that support NX have to contend
> with things like EFI data and code mixed in the same pages where W+X
> is unavoidable.
> 
> The folks still running X86_32=y kernels are unlikely to care much about
> NX.  That combined with the fundamental inability fix _all_ of the W+X
> things means this code had little value on X86_32=y.  Disable the checks.
> 
> Reported-by: Guenter Roeck <linux@roeck-us.net>
> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook

  parent reply	other threads:[~2022-09-24  4:26 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-23 22:17 [PATCH] x86/mm: Disable W^X detection and enforcement on 32-bit Dave Hansen
2022-09-24  0:09 ` Kirill A. Shutemov
2022-09-24  0:12   ` Dave Hansen
2022-09-24  4:38     ` Guenter Roeck
2022-09-24  4:26 ` Kees Cook [this message]
2022-09-24  6:52 ` Guenter Roeck
2022-09-24  7:26 ` Ard Biesheuvel
2022-10-02 10:33 ` Pavel Machek

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