From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:40540 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753074AbeAEVpJ (ORCPT ); Fri, 5 Jan 2018 16:45:09 -0500 Subject: Patch "x86/kasan: Write protect kasan zero shadow" has been added to the 4.4-stable tree To: aryabinin@virtuozzo.com, akpm@linux-foundation.org, bp@alien8.de, bp@suse.de, brgerst@gmail.com, dave.hansen@linux.intel.com, dvlasenk@redhat.com, gregkh@linuxfoundation.org, hpa@zytor.com, linux@roeck-us.net, luto@amacapital.net, luto@kernel.org, mcgrof@suse.com, mingo@kernel.org, oleg@redhat.com, peterz@infradead.org, tglx@linutronix.de, torvalds@linux-foundation.org, toshi.kani@hp.com Cc: , From: Date: Fri, 05 Jan 2018 22:45:12 +0100 Message-ID: <151518871231213@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled x86/kasan: Write protect kasan zero shadow to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: x86-kasan-write-protect-kasan-zero-shadow.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 063fb3e56f6dd29b2633b678b837e1d904200e6f Mon Sep 17 00:00:00 2001 From: Andrey Ryabinin Date: Mon, 11 Jan 2016 15:51:19 +0300 Subject: x86/kasan: Write protect kasan zero shadow From: Andrey Ryabinin commit 063fb3e56f6dd29b2633b678b837e1d904200e6f upstream. 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 Cc: Guenter Roeck Signed-off-by: Greg Kroah-Hartman --- arch/x86/mm/kasan_init_64.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) --- a/arch/x86/mm/kasan_init_64.c +++ b/arch/x86/mm/kasan_init_64.c @@ -126,10 +126,16 @@ 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"); Patches currently in stable-queue which might be from aryabinin@virtuozzo.com are queue-4.4/x86-kasan-write-protect-kasan-zero-shadow.patch