linux-kernel - Re: [PATCH] x86/setup: fix low identity map for >= 2GB kernel range

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20151106141139.GA2233@shrek.podlesie.net>
Date:	Fri, 6 Nov 2015 15:11:39 +0100
From:	Krzysztof Mazur <krzysiek@...lesie.net>
To:	Borislav Petkov <bp@...en8.de>
Cc:	x86@...nel.org, linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	Andy Lutomirski <luto@...capital.net>,
	"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...hat.com>,
	Laszlo Ersek <lersek@...hat.com>,
	Matt Fleming <matt.fleming@...el.com>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH] x86/setup: fix low identity map for >= 2GB kernel range

On Fri, Nov 06, 2015 at 02:27:33PM +0100, Borislav Petkov wrote:
> On Fri, Nov 06, 2015 at 02:18:36PM +0100, Krzysztof Mazur wrote:
> > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> > index a3cccbf..37c8ea8 100644
> > --- a/arch/x86/kernel/setup.c
> > +++ b/arch/x86/kernel/setup.c
> > @@ -1180,7 +1180,7 @@ void __init setup_arch(char **cmdline_p)
> >  	 */
> >  	clone_pgd_range(initial_page_table,
> >  			swapper_pg_dir     + KERNEL_PGD_BOUNDARY,
> > -			KERNEL_PGD_PTRS);
> > +			min(KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY));
> >  #endif
> >  
> >  	tboot_probe();
> 
> http://git.kernel.org/tip/1c5dac914794f0170e1582d8ffdee52d30e0e4dd
> 

Thanks and sorry. Yes, it has been already fixed. I've rechecked only
mainline.

However, I think that there should be
min(KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY), not just KERNEL_PGD_BOUNDARY
(usually 768 for normal 1G/3G split), because swapper_pg_dir has only
1024 entries and 768+768 is 1536.

Krzysiek
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/