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=-2.3 required=3.0 tests=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 888F7C31E40 for ; Mon, 12 Aug 2019 09:13:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 609A72087B for ; Mon, 12 Aug 2019 09:13:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727300AbfHLJNw (ORCPT ); Mon, 12 Aug 2019 05:13:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33902 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727154AbfHLJNv (ORCPT ); Mon, 12 Aug 2019 05:13:51 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4FB5030BCB86; Mon, 12 Aug 2019 09:13:51 +0000 (UTC) Received: from krava (unknown [10.43.17.33]) by smtp.corp.redhat.com (Postfix) with SMTP id D192F19C65; Mon, 12 Aug 2019 09:13:48 +0000 (UTC) Date: Mon, 12 Aug 2019 11:13:48 +0200 From: Jiri Olsa To: Igor Lubashev Cc: linux-kernel@vger.kernel.org, Arnaldo Carvalho de Melo , Alexey Budankov , Peter Zijlstra , Ingo Molnar , Mathieu Poirier , Alexander Shishkin , Namhyung Kim , Suzuki K Poulose , linux-arm-kernel@lists.infradead.org, James Morris Subject: Re: [PATCH v3 0/4] perf: Use capabilities instead of uid and euid Message-ID: <20190812091348.GA11946@krava> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.49]); Mon, 12 Aug 2019 09:13:51 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 07, 2019 at 10:44:13AM -0400, Igor Lubashev wrote: > Series v1: https://lkml.kernel.org/lkml/1562112605-6235-1-git-send-email-ilubashe@akamai.com > > > Kernel is using capabilities instead of uid and euid to restrict access to > kernel pointers and tracing facilities. This patch series updates the perf to > better match the security model used by the kernel. > > This series enables instructions in Documentation/admin-guide/perf-security.rst > to actually work, even when kernel.perf_event_paranoid=2 and > kernel.kptr_restrict=1. > > The series consists of four patches: > > 01: perf: Add capability-related utilities > Add utility functions to check capabilities and perf_event_paranoid checks, > if libcap-dev[el] is available. (Otherwise, assume no capabilities.) > > 02: perf: Use CAP_SYS_ADMIN with perf_event_paranoid checks > Replace the use of euid==0 with a check for CAP_SYS_ADMIN whenever > perf_event_paranoid level is verified. > > 03: perf: Use CAP_SYSLOG with kptr_restrict checks > Replace the use of uid and euid with a check for CAP_SYSLOG when > kptr_restrict is verified (similar to kernel/kallsyms.c and lib/vsprintf.c). > Consult perf_event_paranoid when kptr_restrict==0 (see kernel/kallsyms.c). > > 04: perf: Use CAP_SYS_ADMIN instead of euid==0 with ftrace > Replace the use of euid==0 with a check for CAP_SYS_ADMIN before mounting > debugfs for ftrace. > > I tested this by following Documentation/admin-guide/perf-security.rst > guidelines and setting sysctls: > > kernel.perf_event_paranoid=2 > kernel.kptr_restrict=1 > > As an unprivileged user who is in perf_users group (setup via instructions > above), I executed: > perf record -a -- sleep 1 > > Without the patch, perf record did not capture any kernel functions. > With the patch, perf included all kernel functions. > > > Changelog: > v3: * Fix arm64 compilation (thanks, Alexey and Jiri) Acked-by: Jiri Olsa thanks, jirka > v2: * Added a build feature check for libcap-dev[el] as suggested by Arnaldo > > > Igor Lubashev (4): > perf: Add capability-related utilities > perf: Use CAP_SYS_ADMIN with perf_event_paranoid checks > perf: Use CAP_SYSLOG with kptr_restrict checks > perf: Use CAP_SYS_ADMIN instead of euid==0 with ftrace > > tools/build/Makefile.feature | 2 ++ > tools/build/feature/Makefile | 4 ++++ > tools/build/feature/test-libcap.c | 20 ++++++++++++++++++++ > tools/perf/Makefile.config | 11 +++++++++++ > tools/perf/Makefile.perf | 2 ++ > tools/perf/arch/arm/util/cs-etm.c | 3 ++- > tools/perf/arch/arm64/util/arm-spe.c | 3 ++- > tools/perf/arch/x86/util/intel-bts.c | 3 ++- > tools/perf/arch/x86/util/intel-pt.c | 2 +- > tools/perf/builtin-ftrace.c | 4 +++- > tools/perf/util/Build | 2 ++ > tools/perf/util/cap.c | 29 +++++++++++++++++++++++++++++ > tools/perf/util/cap.h | 24 ++++++++++++++++++++++++ > tools/perf/util/event.h | 1 + > tools/perf/util/evsel.c | 2 +- > tools/perf/util/python-ext-sources | 1 + > tools/perf/util/symbol.c | 15 +++++++++++---- > tools/perf/util/util.c | 9 +++++++++ > 18 files changed, 127 insertions(+), 10 deletions(-) > create mode 100644 tools/build/feature/test-libcap.c > create mode 100644 tools/perf/util/cap.c > create mode 100644 tools/perf/util/cap.h > > -- > 2.7.4 >