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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 4B53AC433DB for ; Wed, 31 Mar 2021 07:50:27 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id AE75B619BD for ; Wed, 31 Mar 2021 07:50:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AE75B619BD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linutronix.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id E11E86B0082; Wed, 31 Mar 2021 03:50:25 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id DBFF46B0083; Wed, 31 Mar 2021 03:50:25 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C12BE6B0088; Wed, 31 Mar 2021 03:50:25 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0183.hostedemail.com [216.40.44.183]) by kanga.kvack.org (Postfix) with ESMTP id A1B086B0082 for ; Wed, 31 Mar 2021 03:50:25 -0400 (EDT) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 4A101180AD82F for ; Wed, 31 Mar 2021 07:50:25 +0000 (UTC) X-FDA: 77979396810.20.AEA193D Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by imf06.hostedemail.com (Postfix) with ESMTP id EA428C0007C5 for ; Wed, 31 Mar 2021 07:50:22 +0000 (UTC) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1617177020; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=RZw6jkxG2tvSevv3X2+abnTHnXCHkwF4cE7lD/cYS0c=; b=jUZ1Puxo9W22AXzcFYFJ62E72Axd/SK2ZV8cEve6PHL2b0LfRU4wESftLlahc7fWxip4AM BBRqghhiGBRl7jKDiWl61U/Kd8GE0BO2yzFsmrzPH5KFvgHJ3Bxb6nEqyxkwbVsMNDyC4p 71QTjwCX7E4m3wMy0qF1RkjLiPTthV91YEW3gFxDvP8NNM6uZ42CyhB6MesNOu0wQuu1qy XPq1pF/txTA47YN+pLN3i8C8eweRc2FE3U7tq1qThEBzCMhpE9NNDxzGE0AubaVIh4W3sH UgvB+tZgA6eTvr+vAKcvVXMVUOfPorneRFlwQ+GN0M68PY7bXY2FOr1ztCMdWA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1617177020; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=RZw6jkxG2tvSevv3X2+abnTHnXCHkwF4cE7lD/cYS0c=; b=MN+pzWVv1yf6pCY2oCNeGdwPONSSKq5G0kTaSCVNpA6ZRX43kxrMo6DqtDgPG5dGcxWZs+ +KgsgvXLPSPQFzCg== To: Kees Cook Cc: Kees Cook , Elena Reshetova , x86@kernel.org, Andy Lutomirski , Peter Zijlstra , Catalin Marinas , Will Deacon , Mark Rutland , Alexander Potapenko , Alexander Popov , Ard Biesheuvel , Jann Horn , Vlastimil Babka , David Hildenbrand , Mike Rapoport , Andrew Morton , Jonathan Corbet , Randy Dunlap , kernel-hardening@lists.openwall.com, linux-hardening@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v8 4/6] x86/entry: Enable random_kstack_offset support In-Reply-To: <20210330205750.428816-5-keescook@chromium.org> References: <20210330205750.428816-1-keescook@chromium.org> <20210330205750.428816-5-keescook@chromium.org> Date: Wed, 31 Mar 2021 09:50:20 +0200 Message-ID: <87lfa369tv.ffs@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: EA428C0007C5 X-Stat-Signature: tc6spkqfs7itw6nky8j5mag8uh6nzx7k Received-SPF: none (linutronix.de>: No applicable sender policy available) receiver=imf06; identity=mailfrom; envelope-from=""; helo=galois.linutronix.de; client-ip=193.142.43.55 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1617177022-33044 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Mar 30 2021 at 13:57, Kees Cook wrote: > Allow for a randomized stack offset on a per-syscall basis, with roughly > 5-6 bits of entropy, depending on compiler and word size. Since the > method of offsetting uses macros, this cannot live in the common entry > code (the stack offset needs to be retained for the life of the syscall, > which means it needs to happen at the actual entry point). > > Signed-off-by: Kees Cook Reviewed-by: Thomas Gleixner