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=-15.3 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_SANE_1 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 02345C433E0 for ; Tue, 9 Mar 2021 13:36:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B2D2F650F5 for ; Tue, 9 Mar 2021 13:36:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231127AbhCINf5 (ORCPT ); Tue, 9 Mar 2021 08:35:57 -0500 Received: from mx2.suse.de ([195.135.220.15]:43834 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230084AbhCINf0 (ORCPT ); Tue, 9 Mar 2021 08:35:26 -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 0FA16AB8C; Tue, 9 Mar 2021 13:35:25 +0000 (UTC) Date: Tue, 9 Mar 2021 14:35:23 +0100 From: Michal =?iso-8859-1?Q?Such=E1nek?= To: Masahiro Yamada Cc: linux-arm-kernel , Catalin Marinas , Will Deacon , Linux Kernel Mailing List Subject: Re: [PATCH] arm64: make STACKPROTECTOR_PER_TASK configurable. Message-ID: <20210309133523.GX6564@kitsune.suse.cz> References: <20210309123544.14040-1-msuchanek@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.3 (2019-02-01) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 09, 2021 at 10:22:36PM +0900, Masahiro Yamada wrote: > On Tue, Mar 9, 2021 at 9:35 PM Michal Suchanek wrote: > > > > 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 > > > Could you explain what problem > this patch is trying to solve? The option cannot be disabled when compiler has the required capability. Thanks Michal > > > > --- > > 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 > > > > > -- > Best Regards > Masahiro Yamada 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=-15.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 EAB21C433E0 for ; Tue, 9 Mar 2021 13:50:16 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D1A62650EC for ; Tue, 9 Mar 2021 13:50:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D1A62650EC Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=CyIu/Q5qxck/ZUeJg/UQ/Iop8otY6cPfZoC5pMsEgMo=; b=PuCVyGirkoqPrhrDfmcAX8SCn yAcs3BiZCqNseneAJ76odQaCQUZ1X4UZcYavHSGCQgj+wqkz41SoB1RVfFhs/n4GG6BZofNkwnU5R H3Klyio56YczixZWmsTcmBBkcfNEi7l17KKArYEEQeXZ/s4/a2yhu9+iOQvA98FYpE6uei7AUlrfc wKPL++yUrX/7jucKAsgdCZJnZA4oc16SvdEsC4kfLQO59QPxKD8VrQwmEwujJGh57xY590MScpF7w RGQBQx69CgyvPWxPtrm4Edxqz3b7zZfa9jLdoGUwGRNz4epU47vhDmv+Jou3N4eIYP/Vs4D6+zgJC js1BMIT6Q==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lJciR-004kNf-FA; Tue, 09 Mar 2021 13:48:03 +0000 Received: from mx2.suse.de ([195.135.220.15]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lJcWD-004frS-SL for linux-arm-kernel@lists.infradead.org; Tue, 09 Mar 2021 13:35:31 +0000 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 0FA16AB8C; Tue, 9 Mar 2021 13:35:25 +0000 (UTC) Date: Tue, 9 Mar 2021 14:35:23 +0100 From: Michal =?iso-8859-1?Q?Such=E1nek?= To: Masahiro Yamada Cc: linux-arm-kernel , Catalin Marinas , Will Deacon , Linux Kernel Mailing List Subject: Re: [PATCH] arm64: make STACKPROTECTOR_PER_TASK configurable. Message-ID: <20210309133523.GX6564@kitsune.suse.cz> References: <20210309123544.14040-1-msuchanek@suse.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.3 (2019-02-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210309_133526_652253_D9404F3F X-CRM114-Status: GOOD ( 25.47 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Mar 09, 2021 at 10:22:36PM +0900, Masahiro Yamada wrote: > On Tue, Mar 9, 2021 at 9:35 PM Michal Suchanek wrote: > > > > 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 > > > Could you explain what problem > this patch is trying to solve? The option cannot be disabled when compiler has the required capability. Thanks Michal > > > > --- > > 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 > > > > > -- > Best Regards > Masahiro Yamada _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel