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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 23D70C433E2 for ; Wed, 2 Sep 2020 16:48:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 09DFA20767 for ; Wed, 2 Sep 2020 16:48:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728298AbgIBQsb (ORCPT ); Wed, 2 Sep 2020 12:48:31 -0400 Received: from foss.arm.com ([217.140.110.172]:42456 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726526AbgIBQsa (ORCPT ); Wed, 2 Sep 2020 12:48:30 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 7F34E1045; Wed, 2 Sep 2020 09:48:29 -0700 (PDT) Received: from arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2FFFE3F66F; Wed, 2 Sep 2020 09:48:28 -0700 (PDT) Date: Wed, 2 Sep 2020 17:48:26 +0100 From: Dave Martin To: Boyan Karatotev Cc: linux-arm-kernel@lists.infradead.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Will Deacon , boian4o1@gmail.com, Catalin Marinas , amit.kachhap@arm.com, vincenzo.frascino@arm.com, Shuah Khan Subject: Re: [PATCH 0/4] kselftests/arm64: add PAuth tests Message-ID: <20200902164825.GH6642@arm.com> References: <20200828131606.7946-1-boyan.karatotev@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200828131606.7946-1-boyan.karatotev@arm.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 28, 2020 at 02:16:02PM +0100, Boyan Karatotev wrote: > Pointer Authentication (PAuth) is a security feature introduced in ARMv8.3. > It introduces instructions to sign addresses and later check for potential > corruption using a second modifier value and one of a set of keys. The > signature, in the form of the Pointer Authentication Code (PAC), is stored > in some of the top unused bits of the virtual address (e.g. [54: 49] if > TBID0 is enabled and TnSZ is set to use a 48 bit VA space). A set of > controls are present to enable/disable groups of instructions (which use > certain keys) for compatibility with libraries that do not utilize the > feature. PAuth is used to verify the integrity of return addresses on the > stack with less memory than the stack canary. > > This patchset adds kselftests to verify the kernel's configuration of the > feature and its runtime behaviour. There are 7 tests which verify that: > * an authentication failure leads to a SIGSEGV > * the data/instruction instruction groups are enabled > * the generic instructions are enabled > * all 5 keys are unique for a single thread > * exec() changes all keys to new unique ones > * context switching preserves the 4 data/instruction keys > * context switching preserves the generic keys > > The tests have been verified to work on qemu without a working PAUTH > Implementation and on ARM's FVP with a full or partial PAuth > implementation. > > Note: This patchset is only verified for ARMv8.3 and there will be some > changes required for ARMv8.6. More details can be found here [1]. Once > ARMv8.6 PAuth is merged the first test in this series will required to be > updated. Nit: is it worth running checkpatch over this series? Although this is not kernel code, there are a number of formatting weirdnesses and surplus blank lines etc. that checkpatch would probably warn about. [...] Cheers ---Dave