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Date: Tue, 9 Feb 2016 08:07:10 -0800 From: tip-bot for Andrey Ryabinin <tipbot@...or.com> To: linux-tip-commits@...r.kernel.org Cc: bp@...e.de, torvalds@...ux-foundation.org, toshi.kani@...com, dave.hansen@...ux.intel.com, bp@...en8.de, mcgrof@...e.com, dvlasenk@...hat.com, akpm@...ux-foundation.org, linux-kernel@...r.kernel.org, luto@...nel.org, aryabinin@...tuozzo.com, oleg@...hat.com, peterz@...radead.org, hpa@...or.com, brgerst@...il.com, luto@...capital.net, mingo@...nel.org, tglx@...utronix.de Subject: [tip:x86/mm] x86/kasan: Write protect kasan zero shadow Commit-ID: 063fb3e56f6dd29b2633b678b837e1d904200e6f Gitweb: http://git.kernel.org/tip/063fb3e56f6dd29b2633b678b837e1d904200e6f Author: Andrey Ryabinin <aryabinin@...tuozzo.com> AuthorDate: Mon, 11 Jan 2016 15:51:19 +0300 Committer: Ingo Molnar <mingo@...nel.org> 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 <aryabinin@...tuozzo.com> Reviewed-by: Borislav Petkov <bp@...e.de> Cc: Andrew Morton <akpm@...ux-foundation.org> Cc: Andy Lutomirski <luto@...capital.net> Cc: Andy Lutomirski <luto@...nel.org> Cc: Borislav Petkov <bp@...en8.de> Cc: Brian Gerst <brgerst@...il.com> Cc: Dave Hansen <dave.hansen@...ux.intel.com> Cc: Denys Vlasenko <dvlasenk@...hat.com> Cc: H. Peter Anvin <hpa@...or.com> Cc: Linus Torvalds <torvalds@...ux-foundation.org> Cc: Luis R. Rodriguez <mcgrof@...e.com> Cc: Oleg Nesterov <oleg@...hat.com> Cc: Peter Zijlstra <peterz@...radead.org> Cc: Thomas Gleixner <tglx@...utronix.de> Cc: Toshi Kani <toshi.kani@...com> Cc: linux-mm@...ck.org Link: http://lkml.kernel.org/r/1452516679-32040-3-git-send-email-aryabinin@virtuozzo.com Signed-off-by: Ingo Molnar <mingo@...nel.org> --- 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");
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