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=-3.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 3B565C31E40 for ; Wed, 7 Aug 2019 03:36:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 10091217D7 for ; Wed, 7 Aug 2019 03:36:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=akamai.com header.i=@akamai.com header.b="J1/70TXd" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728113AbfHGDgy (ORCPT ); Tue, 6 Aug 2019 23:36:54 -0400 Received: from mx0a-00190b01.pphosted.com ([67.231.149.131]:1172 "EHLO mx0a-00190b01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726612AbfHGDgy (ORCPT ); Tue, 6 Aug 2019 23:36:54 -0400 Received: from pps.filterd (m0122332.ppops.net [127.0.0.1]) by mx0a-00190b01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id x773W2Ls004122; Wed, 7 Aug 2019 04:36:27 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=akamai.com; h=from : to : cc : subject : date : message-id : mime-version : content-type; s=jan2016.eng; bh=6wANkUgjH1gmRMqrqMRFk/IzeSS3fSaT0hAF44IhUcs=; b=J1/70TXdvnN0c/IVBDjmpuR2D5yDVDkoeMF+42brrYrhQPbgKYcehOCM/fBERfUUuPRd x8v54UnwZZ1HE6WlVc+6mQxWwuaduT29oiymT4IWveQw7XDB2couBzQcBkqIh8C21LEE rGIiVpH1DP+YLBIqtlX28pfbDsSk43nmVtIyDqbbtqRwyNTqhNoQGkMTagCKT+imcO6e oVZyRS0vMuy8qbpHEroajslXC1jDEKBdyM/nOKG61VZ05Gv+kUOSmbwce8R91Rko0kkJ rTmmTNJJDVbF7/kbXmpT9+O8k6D+Ks21fVisQcYH6POcI/emwHzfw4Q17t42r8WuEvm4 qw== Received: from prod-mail-ppoint7 (prod-mail-ppoint7.akamai.com [96.6.114.121] (may be forged)) by mx0a-00190b01.pphosted.com with ESMTP id 2u52ah0k7y-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 07 Aug 2019 04:36:27 +0100 Received: from pps.filterd (prod-mail-ppoint7.akamai.com [127.0.0.1]) by prod-mail-ppoint7.akamai.com (8.16.0.27/8.16.0.27) with SMTP id x773WWM6018948; Tue, 6 Aug 2019 23:36:26 -0400 Received: from email.msg.corp.akamai.com ([172.27.123.31]) by prod-mail-ppoint7.akamai.com with ESMTP id 2u55kvh21n-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT); Tue, 06 Aug 2019 23:36:26 -0400 Received: from USMA1EX-CAS2.msg.corp.akamai.com (172.27.123.31) by usma1ex-dag1mb3.msg.corp.akamai.com (172.27.123.103) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Tue, 6 Aug 2019 23:36:25 -0400 Received: from igorcastle.kendall.corp.akamai.com (172.29.170.135) by USMA1EX-CAS2.msg.corp.akamai.com (172.27.123.31) with Microsoft SMTP Server id 15.0.1473.3 via Frontend Transport; Tue, 6 Aug 2019 23:36:25 -0400 Received: by igorcastle.kendall.corp.akamai.com (Postfix, from userid 29659) id 0AC6761D57; Tue, 6 Aug 2019 23:36:23 -0400 (EDT) From: Igor Lubashev To: , Arnaldo Carvalho de Melo , Jiri Olsa , Alexey Budankov CC: Peter Zijlstra , Ingo Molnar , Mathieu Poirier , Alexander Shishkin , Namhyung Kim , Suzuki K Poulose , , James Morris , Igor Lubashev Subject: [PATCH v2 0/4] perf: Use capabilities instead of uid and euid Date: Tue, 6 Aug 2019 23:35:53 -0400 Message-ID: X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-08-07_01:,, signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1908070034 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:5.22.84,1.0.8 definitions=2019-08-07_01:2019-08-05,2019-08-07 signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 spamscore=0 mlxscore=0 impostorscore=0 phishscore=0 adultscore=0 bulkscore=0 priorityscore=1501 lowpriorityscore=0 malwarescore=0 mlxlogscore=999 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1906280000 definitions=main-1908070034 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 unpriviledged 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 funcitons. Changelog: 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 | 4 ++-- 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(+), 11 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