From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: matthieu castet <castet.matthieu@free.fr>
Cc: Ian Campbell <Ian.Campbell@eu.citrix.com>,
Kees Cook <kees.cook@canonical.com>,
Jeremy Fitzhardinge <jeremy@goop.org>,
"keir.fraser@eu.citrix.com" <keir.fraser@eu.citrix.com>,
"mingo@redhat.com" <mingo@redhat.com>,
"hpa@zytor.com" <hpa@zytor.com>,
"sliakh.lkml@gmail.com" <sliakh.lkml@gmail.com>,
"jmorris@namei.org" <jmorris@namei.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"rusty@rustcorp.com.au" <rusty@rustcorp.com.au>,
"torvalds@linux-foundation.org" <torvalds@linux-foundation.org>,
"ak@muc.de" <ak@muc.de>, "davej@redhat.com" <davej@redhat.com>,
"jiang@cs.ncsu.edu" <jiang@cs.ncsu.edu>,
"arjan@infradead.org" <arjan@infradead.org>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"sfr@canb.auug.org.au" <sfr@canb.auug.org.au>,
"mingo@elte.hu" <mingo@elte.hu>,
Stefan Bader <stefan.bader@canonical.com>
Subject: Re: [tip:x86/security] x86: Add NX protection for kernel data
Date: Thu, 20 Jan 2011 16:55:56 -0500 [thread overview]
Message-ID: <20110120215556.GA29700@dumpdata.com> (raw)
In-Reply-To: <20110120211939.GA32262@dumpdata.com>
> - * .data and .bss should always be writable.
> + * .data and .bss should always be writable, but xen won't like
> + * if we make page table rw (that live in .data or .bss)
> */
> +#ifdef CONFIG_X86_32
> if (within(address, (unsigned long)_sdata, (unsigned long)_edata) ||
> - within(address, (unsigned long)__bss_start, (unsigned long)__bss_stop))
> - pgprot_val(required) |= _PAGE_RW;
> + within(address, (unsigned long)__bss_start, (unsigned long)__bss_stop)) {
> + unsigned int level;
> + if (lookup_address(address, &level) && (level != PG_LEVEL_4K))
> + pgprot_val(forbidden) |= _PAGE_RW;
> + }
> +#endif
>
> #if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA)
>
> fyi, it does make it boot.
Hold it.. ccache is a wonderful tool but I think I've just "rebuilt" the
binaries with the .bss HPAGE_ALIGN aligment by mistake, so this path got never
taken.
next prev parent reply other threads:[~2011-01-20 21:58 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-16 21:31 [PATCH 2/3 V8] " matthieu castet
2010-11-18 14:08 ` [tip:x86/security] x86: Add " tip-bot for Matthieu Castet
2011-01-11 23:31 ` Kees Cook
2011-01-14 20:15 ` Konrad Rzeszutek Wilk
2011-01-19 21:14 ` Konrad Rzeszutek Wilk
2011-01-19 22:59 ` matthieu castet
2011-01-19 23:38 ` Konrad Rzeszutek Wilk
2011-01-20 11:18 ` castet.matthieu
2011-01-20 15:06 ` Konrad Rzeszutek Wilk
2011-01-20 15:37 ` Ian Campbell
2011-01-20 19:05 ` Konrad Rzeszutek Wilk
2011-01-20 20:23 ` matthieu castet
2011-01-20 21:04 ` Konrad Rzeszutek Wilk
2011-01-20 21:19 ` Konrad Rzeszutek Wilk
2011-01-20 21:55 ` Konrad Rzeszutek Wilk [this message]
2011-01-21 21:41 ` matthieu castet
2011-01-22 5:11 ` Konrad Rzeszutek Wilk
2011-01-23 14:27 ` matthieu castet
2011-01-24 15:31 ` Konrad Rzeszutek Wilk
2011-01-27 16:30 ` Was: [tip:x86/security] x86: Add NX protection for kernel data. Is: don't set RW on RO regions in .bss Konrad Rzeszutek Wilk
2011-01-21 23:20 ` [tip:x86/security] x86: Add NX protection for kernel data Konrad Rzeszutek Wilk
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