From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932788AbeE2JQe (ORCPT ); Tue, 29 May 2018 05:16:34 -0400 Received: from mail-pl0-f66.google.com ([209.85.160.66]:39318 "EHLO mail-pl0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932284AbeE2JQ0 (ORCPT ); Tue, 29 May 2018 05:16:26 -0400 X-Google-Smtp-Source: AB8JxZohPEkaeKyIwH5nXCrewcWL9BUWFJHXagLc/d4gSoaQOwVdtrvnF2Mp53uP+AJ/BRrbM10Uyg== From: YaoJun To: kernel-hardening@lists.openwall.com Cc: linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, jmorris@namei.org Subject: [PATCH] mark tramp_pg_dir read-only Date: Tue, 29 May 2018 17:16:09 +0800 Message-Id: <20180529091609.9830-1-yaojun8558363@gmail.com> X-Mailer: git-send-email 2.17.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org To prevent KSMA(Kernel Space Mirroring Attack), it's necessary to set tramp_pg_dir read-only after initialization. --- arch/arm64/mm/mmu.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 2dbb2c9f1ec1..964520e4e675 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -551,6 +551,9 @@ static int __init map_entry_trampoline(void) __create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, PAGE_SIZE, prot, pgd_pgtable_alloc, 0); + update_mapping_prot(__pa_symbol(tramp_pg_dir), (unsigned long)tramp_pg_dir, + PGD_SIZE, PAGE_KERNEL_RO); + /* Map both the text and data into the kernel page table */ __set_fixmap(FIX_ENTRY_TRAMP_TEXT, pa_start, prot); if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { -- 2.17.0