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=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 5E5B7C433DF for ; Wed, 5 Aug 2020 07:57:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3593822B40 for ; Wed, 5 Aug 2020 07:57:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728037AbgHEH5G (ORCPT ); Wed, 5 Aug 2020 03:57:06 -0400 Received: from mga12.intel.com ([192.55.52.136]:41212 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726980AbgHEH5A (ORCPT ); Wed, 5 Aug 2020 03:57:00 -0400 IronPort-SDR: uds12QRwwSPT3JLfbFWOjajMo2QJAEOrWY94TLXF+8D6g/DBy1N81sHR9jsLiiBQ/4OkL6qt6C rs2Cm+HDi/1Q== X-IronPort-AV: E=McAfee;i="6000,8403,9703"; a="132047052" X-IronPort-AV: E=Sophos;i="5.75,436,1589266800"; d="scan'208";a="132047052" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Aug 2020 00:57:00 -0700 IronPort-SDR: j5lv7mJNN8SZ/0Y4oelgcCirF5HrweytE33Vc+SQFdp+JbwgQIbRAC7WzcU65IFRQLqitRleZ7 B96+iMPaCdPg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,436,1589266800"; d="scan'208";a="396842529" Received: from linux.intel.com ([10.54.29.200]) by fmsmga001.fm.intel.com with ESMTP; 05 Aug 2020 00:57:00 -0700 Received: from [10.249.227.101] (abudanko-mobl.ccr.corp.intel.com [10.249.227.101]) by linux.intel.com (Postfix) with ESMTP id 1C23A580713; Wed, 5 Aug 2020 00:56:57 -0700 (PDT) To: Peter Zijlstra , Arnaldo Carvalho de Melo Cc: Alexander Shishkin , Jiri Olsa , Namhyung Kim , Ingo Molnar , Andi Kleen , linux-kernel From: Alexey Budankov Subject: [PATCH v1] perf/core: take over CAP_SYS_PTRACE creds to CAP_PERFMON cap Organization: Intel Corp. Message-ID: <6e8392ff-4732-0012-2949-e1587709f0f6@linux.intel.com> Date: Wed, 5 Aug 2020 10:56:56 +0300 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Open access to per-process monitoring for CAP_PERFMON only privileged processes [1]. Extend ptrace_may_access() check in perf_events subsystem with perfmon_capable() to simplify user experience and make monitoring more secure by reducing attack surface. [1] https://lore.kernel.org/lkml/7776fa40-6c65-2aa6-1322-eb3a01201000@linux.intel.com/ Signed-off-by: Alexey Budankov --- kernel/events/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 856d98c36f56..f50d528af444 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -11587,7 +11587,7 @@ SYSCALL_DEFINE5(perf_event_open, goto err_task; /* - * Reuse ptrace permission checks for now. + * Preserve ptrace permission check for backwards compatibility. * * We must hold exec_update_mutex across this and any potential * perf_install_in_context() call for this new event to @@ -11595,7 +11595,7 @@ SYSCALL_DEFINE5(perf_event_open, * perf_event_exit_task() that could imply). */ err = -EACCES; - if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) + if (!perfmon_capable() && !ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) goto err_cred; } -- 2.24.1