Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751490AbdCHIhf (ORCPT ); Wed, 8 Mar 2017 03:37:35 -0500 Received: from mail-oi0-f52.google.com ([209.85.218.52]:33257 "EHLO mail-oi0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750715AbdCHIhd (ORCPT ); Wed, 8 Mar 2017 03:37:33 -0500 MIME-Version: 1.0 In-Reply-To: <20170308081857.GB12600@dhcp-128-65.nay.redhat.com> References: <1488959258-4731-1-git-send-email-bhe@redhat.com> <1488959258-4731-2-git-send-email-bhe@redhat.com> <20170308081857.GB12600@dhcp-128-65.nay.redhat.com> From: Bhupesh Sharma Date: Wed, 8 Mar 2017 14:05:53 +0530 Message-ID: Subject: Re: [PATCH 2/2] x86/mm/KASLR: Correct the upper boundary of KALSR mm regions if adjacent to EFI To: Dave Young Cc: Baoquan He , linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, thgarnie@google.com, Kees Cook , Thomas Gleixner , mingo@redhat.com, hpa@zytor.com, x86@kernel.org, akpm@linux-foundation.org Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1911 Lines: 52 On Wed, Mar 8, 2017 at 1:48 PM, Dave Young wrote: > On 03/08/17 at 03:47pm, Baoquan He wrote: >> EFI allocates runtime services regions top-down, starting from EFI_VA_START >> to EFI_VA_END. So EFI_VA_START is bigger than EFI_VA_END and is the end of >> EFI region. The upper boundary of memory regions randomized by KASLR should >> be EFI_VA_END if it's adjacent to EFI region, but not EFI_VA_START. >> >> Correct it in this patch. >> >> Signed-off-by: Baoquan He >> --- >> arch/x86/mm/kaslr.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c >> index 887e571..aed2064 100644 >> --- a/arch/x86/mm/kaslr.c >> +++ b/arch/x86/mm/kaslr.c >> @@ -48,7 +48,7 @@ static const unsigned long vaddr_start = __PAGE_OFFSET_BASE; >> #if defined(CONFIG_X86_ESPFIX64) >> static const unsigned long vaddr_end = ESPFIX_BASE_ADDR; >> #elif defined(CONFIG_EFI) >> -static const unsigned long vaddr_end = EFI_VA_START; >> +static const unsigned long vaddr_end = EFI_VA_END; >> #else >> static const unsigned long vaddr_end = __START_KERNEL_map; >> #endif >> @@ -105,7 +105,7 @@ void __init kernel_randomize_memory(void) >> */ >> BUILD_BUG_ON(vaddr_start >= vaddr_end); >> BUILD_BUG_ON(IS_ENABLED(CONFIG_X86_ESPFIX64) && >> - vaddr_end >= EFI_VA_START); >> + vaddr_end >= EFI_VA_END); >> BUILD_BUG_ON((IS_ENABLED(CONFIG_X86_ESPFIX64) || >> IS_ENABLED(CONFIG_EFI)) && >> vaddr_end >= __START_KERNEL_map); >> -- >> 2.5.5 >> > > Acked-by: Dave Young > Thanks Bao for this fix. This makes the KASLR code consistent with Address space markers hints in [1] [1] http://lxr.free-electrons.com/source/arch/x86/mm/dump_pagetables.c#L82 Reviewed-by: Bhupesh Sharma Regards, Bhupesh