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=-11.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 3D483C433E2 for ; Wed, 2 Sep 2020 17:01:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1416120829 for ; Wed, 2 Sep 2020 17:01:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728771AbgIBRBT (ORCPT ); Wed, 2 Sep 2020 13:01:19 -0400 Received: from foss.arm.com ([217.140.110.172]:42792 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728428AbgIBRA5 (ORCPT ); Wed, 2 Sep 2020 13:00:57 -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 003021045; Wed, 2 Sep 2020 10:00:57 -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 A4BFD3F66F; Wed, 2 Sep 2020 10:00:55 -0700 (PDT) Date: Wed, 2 Sep 2020 18:00:53 +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 3/4] kselftests/arm64: add PAuth test for whether exec() changes keys Message-ID: <20200902170052.GJ6642@arm.com> References: <20200828131606.7946-1-boyan.karatotev@arm.com> <20200828131606.7946-4-boyan.karatotev@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200828131606.7946-4-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 02:16:05PM +0100, Boyan Karatotev wrote: > Kernel documentation states that it will change PAuth keys on exec() calls. > > Verify that all keys are correctly switched to new ones. > > Cc: Shuah Khan > Cc: Catalin Marinas > Cc: Will Deacon > Signed-off-by: Boyan Karatotev > --- > tools/testing/selftests/arm64/pauth/Makefile | 4 + > .../selftests/arm64/pauth/exec_target.c | 35 +++++ > tools/testing/selftests/arm64/pauth/helper.h | 10 ++ > tools/testing/selftests/arm64/pauth/pac.c | 148 ++++++++++++++++++ > 4 files changed, 197 insertions(+) > create mode 100644 tools/testing/selftests/arm64/pauth/exec_target.c > > diff --git a/tools/testing/selftests/arm64/pauth/Makefile b/tools/testing/selftests/arm64/pauth/Makefile > index a017d1c8dd58..2e237b21ccf6 100644 > --- a/tools/testing/selftests/arm64/pauth/Makefile > +++ b/tools/testing/selftests/arm64/pauth/Makefile > @@ -5,6 +5,7 @@ CFLAGS += -mbranch-protection=pac-ret > > TEST_GEN_PROGS := pac > TEST_GEN_FILES := pac_corruptor.o helper.o > +TEST_GEN_PROGS_EXTENDED := exec_target > > include ../../lib.mk > > @@ -20,6 +21,9 @@ $(OUTPUT)/helper.o: helper.c > # greater, gcc emits pac* instructions which are not in HINT NOP space, > # preventing the tests from occurring at all. Compile for ARMv8.2 so tests can > # run on earlier targets and print a meaningful error messages > +$(OUTPUT)/exec_target: exec_target.c $(OUTPUT)/helper.o > + $(CC) $^ -o $@ $(CFLAGS) -march=armv8.2-a > + > $(OUTPUT)/pac: pac.c $(OUTPUT)/pac_corruptor.o $(OUTPUT)/helper.o > $(CC) $^ -o $@ $(CFLAGS) -march=armv8.2-a > > diff --git a/tools/testing/selftests/arm64/pauth/exec_target.c b/tools/testing/selftests/arm64/pauth/exec_target.c > new file mode 100644 > index 000000000000..07addef5a1d7 > --- /dev/null > +++ b/tools/testing/selftests/arm64/pauth/exec_target.c > @@ -0,0 +1,35 @@ > +// SPDX-License-Identifier: GPL-2.0 > +// Copyright (C) 2020 ARM Limited > + > +#include > +#include > +#include > + > +#include "helper.h" > + > + > +int main(void) > +{ > + struct signatures signed_vals; > + unsigned long hwcaps; > + size_t val; > + > + fread(&val, sizeof(size_t), 1, stdin); > + > + /* don't try to execute illegal (unimplemented) instructions) caller > + * should have checked this and keep worker simple > + */ > + hwcaps = getauxval(AT_HWCAP); > + > + if (hwcaps & HWCAP_PACA) { > + signed_vals.keyia = keyia_sign(val); > + signed_vals.keyib = keyib_sign(val); > + signed_vals.keyda = keyda_sign(val); > + signed_vals.keydb = keydb_sign(val); > + } > + signed_vals.keyg = (hwcaps & HWCAP_PACG) ? keyg_sign(val) : 0; > + > + fwrite(&signed_vals, sizeof(struct signatures), 1, stdout); > + > + return 0; > +} > diff --git a/tools/testing/selftests/arm64/pauth/helper.h b/tools/testing/selftests/arm64/pauth/helper.h > index b3cf709e249d..fceaa1e4824a 100644 > --- a/tools/testing/selftests/arm64/pauth/helper.h > +++ b/tools/testing/selftests/arm64/pauth/helper.h > @@ -6,6 +6,16 @@ > > #include > > +#define NKEYS 5 > + > + > +struct signatures { > + size_t keyia; > + size_t keyib; > + size_t keyda; > + size_t keydb; > + size_t keyg; > +}; > > void pac_corruptor(void); > > diff --git a/tools/testing/selftests/arm64/pauth/pac.c b/tools/testing/selftests/arm64/pauth/pac.c > index cdbffa8bf61e..16dea47b11c7 100644 > --- a/tools/testing/selftests/arm64/pauth/pac.c > +++ b/tools/testing/selftests/arm64/pauth/pac.c > @@ -2,6 +2,8 @@ > // Copyright (C) 2020 ARM Limited > > #include > +#include > +#include > #include > > #include "../../kselftest_harness.h" > @@ -33,6 +35,117 @@ do { \ > } while (0) > > > +void sign_specific(struct signatures *sign, size_t val) > +{ > + sign->keyia = keyia_sign(val); > + sign->keyib = keyib_sign(val); > + sign->keyda = keyda_sign(val); > + sign->keydb = keydb_sign(val); > +} > + > +void sign_all(struct signatures *sign, size_t val) > +{ > + sign->keyia = keyia_sign(val); > + sign->keyib = keyib_sign(val); > + sign->keyda = keyda_sign(val); > + sign->keydb = keydb_sign(val); > + sign->keyg = keyg_sign(val); > +} > + > +int are_same(struct signatures *old, struct signatures *new, int nkeys) > +{ > + int res = 0; > + > + res |= old->keyia == new->keyia; > + res |= old->keyib == new->keyib; > + res |= old->keyda == new->keyda; > + res |= old->keydb == new->keydb; > + if (nkeys == NKEYS) > + res |= old->keyg == new->keyg; > + > + return res; > +} > + > +int exec_sign_all(struct signatures *signed_vals, size_t val) > +{ Could popen(3) be used here? Fork-and-exec is notoriously fiddly, so it's preferable to use a library function to do it where applicable. [...] Cheers ---Dave