From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757661AbcBIQIg (ORCPT ); Tue, 9 Feb 2016 11:08:36 -0500 Received: from terminus.zytor.com ([198.137.202.10]:38361 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757619AbcBIQI3 (ORCPT ); Tue, 9 Feb 2016 11:08:29 -0500 Date: Tue, 9 Feb 2016 08:07:10 -0800 From: tip-bot for Andrey Ryabinin Message-ID: Cc: bp@suse.de, torvalds@linux-foundation.org, toshi.kani@hp.com, dave.hansen@linux.intel.com, bp@alien8.de, mcgrof@suse.com, dvlasenk@redhat.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, luto@kernel.org, aryabinin@virtuozzo.com, oleg@redhat.com, peterz@infradead.org, hpa@zytor.com, brgerst@gmail.com, luto@amacapital.net, mingo@kernel.org, tglx@linutronix.de Reply-To: dave.hansen@linux.intel.com, bp@alien8.de, bp@suse.de, torvalds@linux-foundation.org, toshi.kani@hp.com, aryabinin@virtuozzo.com, luto@kernel.org, oleg@redhat.com, dvlasenk@redhat.com, mcgrof@suse.com, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, peterz@infradead.org, luto@amacapital.net, mingo@kernel.org, tglx@linutronix.de, hpa@zytor.com, brgerst@gmail.com In-Reply-To: <1452516679-32040-3-git-send-email-aryabinin@virtuozzo.com> References: <1452516679-32040-3-git-send-email-aryabinin@virtuozzo.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/mm] x86/kasan: Write protect kasan zero shadow Git-Commit-ID: 063fb3e56f6dd29b2633b678b837e1d904200e6f X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 063fb3e56f6dd29b2633b678b837e1d904200e6f Gitweb: http://git.kernel.org/tip/063fb3e56f6dd29b2633b678b837e1d904200e6f Author: Andrey Ryabinin AuthorDate: Mon, 11 Jan 2016 15:51:19 +0300 Committer: Ingo Molnar CommitDate: Tue, 9 Feb 2016 13:33:14 +0100 x86/kasan: Write protect kasan zero shadow After kasan_init() executed, no one is allowed to write to kasan_zero_page, so write protect it. Signed-off-by: Andrey Ryabinin Reviewed-by: Borislav Petkov Cc: Andrew Morton Cc: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Luis R. Rodriguez Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Toshi Kani Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/1452516679-32040-3-git-send-email-aryabinin@virtuozzo.com Signed-off-by: Ingo Molnar --- arch/x86/mm/kasan_init_64.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c index 303e470..1b1110f 100644 --- a/arch/x86/mm/kasan_init_64.c +++ b/arch/x86/mm/kasan_init_64.c @@ -125,10 +125,16 @@ void __init kasan_init(void) /* * kasan_zero_page has been used as early shadow memory, thus it may - * contain some garbage. Now we can clear it, since after the TLB flush - * no one should write to it. + * contain some garbage. Now we can clear and write protect it, since + * after the TLB flush no one should write to it. */ memset(kasan_zero_page, 0, PAGE_SIZE); + for (i = 0; i < PTRS_PER_PTE; i++) { + pte_t pte = __pte(__pa(kasan_zero_page) | __PAGE_KERNEL_RO); + set_pte(&kasan_zero_pte[i], pte); + } + /* Flush TLBs again to be sure that write protection applied. */ + __flush_tlb_all(); init_task.kasan_depth = 0; pr_info("KernelAddressSanitizer initialized\n");