From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 43FFBC433DB for ; Tue, 9 Mar 2021 12:36:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 14B3965274 for ; Tue, 9 Mar 2021 12:36:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230523AbhCIMgQ (ORCPT ); Tue, 9 Mar 2021 07:36:16 -0500 Received: from mx2.suse.de ([195.135.220.15]:59944 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230122AbhCIMf4 (ORCPT ); Tue, 9 Mar 2021 07:35:56 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id AEF72AB8C; Tue, 9 Mar 2021 12:35:55 +0000 (UTC) From: Michal Suchanek To: linux-arm-kernel@lists.infradead.org Cc: Michal Suchanek , Catalin Marinas , Will Deacon , linux-kernel@vger.kernel.org, Masahiro Yamada Subject: [PATCH] arm64: make STACKPROTECTOR_PER_TASK configurable. Date: Tue, 9 Mar 2021 13:35:44 +0100 Message-Id: <20210309123544.14040-1-msuchanek@suse.de> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When using dummy-tools STACKPROTECTOR_PER_TASK is unconditionally selected. This defeats the purpose of the all-enabled tool. Description copied from arm Cc: Masahiro Yamada Signed-off-by: Michal Suchanek --- arch/arm64/Kconfig | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index a8ff7cd5f096..f59d391e31a4 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1549,9 +1549,20 @@ config RANDOMIZE_MODULE_REGION_FULL config CC_HAVE_STACKPROTECTOR_SYSREG def_bool $(cc-option,-mstack-protector-guard=sysreg -mstack-protector-guard-reg=sp_el0 -mstack-protector-guard-offset=0) + config STACKPROTECTOR_PER_TASK - def_bool y + bool "Use a unique stack canary value for each task" depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_SYSREG + default y + help + Due to the fact that GCC uses an ordinary symbol reference from + which to load the value of the stack canary, this value can only + change at reboot time on SMP systems, and all tasks running in the + kernel's address space are forced to use the same canary value for + the entire duration that the system is up. + + Enable this option to switch to a different method that uses a + different canary value for each task. endmenu -- 2.26.2