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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, 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 CCFA4C2D0CD for ; Mon, 16 Dec 2019 17:08:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AC84720717 for ; Mon, 16 Dec 2019 17:08:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726928AbfLPRIq (ORCPT ); Mon, 16 Dec 2019 12:08:46 -0500 Received: from mga14.intel.com ([192.55.52.115]:59257 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727788AbfLPRIm (ORCPT ); Mon, 16 Dec 2019 12:08:42 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 16 Dec 2019 08:33:58 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,322,1571727600"; d="scan'208";a="240090657" Received: from linux.intel.com ([10.54.29.200]) by fmsmga004.fm.intel.com with ESMTP; 16 Dec 2019 08:33:57 -0800 Received: from [10.251.95.214] (abudanko-mobl.ccr.corp.intel.com [10.251.95.214]) by linux.intel.com (Postfix) with ESMTP id 52C38580458; Mon, 16 Dec 2019 08:33:49 -0800 (PST) Subject: Re: [PATCH v2 2/7] perf/core: open access for CAP_SYS_PERFMON privileged process To: "Lubashev, Igor" , Peter Zijlstra , Arnaldo Carvalho de Melo , Ingo Molnar , "jani.nikula@linux.intel.com" , "joonas.lahtinen@linux.intel.com" , "rodrigo.vivi@intel.com" , Alexei Starovoitov , "james.bottomley@hansenpartnership.com" , "benh@kernel.crashing.org" , Casey Schaufler , "serge@hallyn.com" , James Morris Cc: Jiri Olsa , Andi Kleen , Stephane Eranian , Alexander Shishkin , Namhyung Kim , Jann Horn , Kees Cook , Thomas Gleixner , Tvrtko Ursulin , "linux-security-module@vger.kernel.org" , "selinux@vger.kernel.org" , linux-kernel , "linux-perf-users@vger.kernel.org" , "intel-gfx@lists.freedesktop.org" , "bgregg@netflix.com" , Song Liu , "bpf@vger.kernel.org" , "linux-parisc@vger.kernel.org" , "linuxppc-dev@lists.ozlabs.org" References: <26101427-c0a3-db9f-39e9-9e5f4ddd009c@linux.intel.com> <9316a1ab21f6441eb2b421acb818a2a1@ustx2ex-dag1mb6.msg.corp.akamai.com> From: Alexey Budankov Organization: Intel Corp. Message-ID: <3f2ac76c-6108-7769-4b99-a7a2da31af3d@linux.intel.com> Date: Mon, 16 Dec 2019 19:33:48 +0300 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.9.1 MIME-Version: 1.0 In-Reply-To: <9316a1ab21f6441eb2b421acb818a2a1@ustx2ex-dag1mb6.msg.corp.akamai.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-parisc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org On 16.12.2019 19:12, Lubashev, Igor wrote: > On Mon, Dec 16, 2019 at 2:15 AM, Alexey Budankov wrote: >> >> Open access to perf_events monitoring for CAP_SYS_PERFMON privileged >> processes. >> For backward compatibility reasons access to perf_events subsystem remains >> open for CAP_SYS_ADMIN privileged processes but CAP_SYS_ADMIN usage >> for secure perf_events monitoring is discouraged with respect to >> CAP_SYS_PERFMON capability. >> >> Signed-off-by: Alexey Budankov >> --- >> include/linux/perf_event.h | 9 ++++++--- >> 1 file changed, 6 insertions(+), 3 deletions(-) >> >> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index >> 34c7c6910026..52313d2cc343 100644 >> --- a/include/linux/perf_event.h >> +++ b/include/linux/perf_event.h >> @@ -1285,7 +1285,8 @@ static inline int perf_is_paranoid(void) >> >> static inline int perf_allow_kernel(struct perf_event_attr *attr) { >> - if (sysctl_perf_event_paranoid > 1 && !capable(CAP_SYS_ADMIN)) >> + if (sysctl_perf_event_paranoid > 1 && >> + !(capable(CAP_SYS_PERFMON) || capable(CAP_SYS_ADMIN))) >> return -EACCES; >> >> return security_perf_event_open(attr, PERF_SECURITY_KERNEL); @@ >> -1293,7 +1294,8 @@ static inline int perf_allow_kernel(struct >> perf_event_attr *attr) >> >> static inline int perf_allow_cpu(struct perf_event_attr *attr) { >> - if (sysctl_perf_event_paranoid > 0 && !capable(CAP_SYS_ADMIN)) >> + if (sysctl_perf_event_paranoid > 0 && >> + !(capable(CAP_SYS_PERFMON) || capable(CAP_SYS_ADMIN))) >> return -EACCES; >> >> return security_perf_event_open(attr, PERF_SECURITY_CPU); @@ - >> 1301,7 +1303,8 @@ static inline int perf_allow_cpu(struct perf_event_attr >> *attr) >> >> static inline int perf_allow_tracepoint(struct perf_event_attr *attr) { >> - if (sysctl_perf_event_paranoid > -1 && !capable(CAP_SYS_ADMIN)) >> + if (sysctl_perf_event_paranoid > -1 && >> + !(capable(CAP_SYS_PERFMON) || capable(CAP_SYS_ADMIN))) >> return -EPERM; >> >> return security_perf_event_open(attr, PERF_SECURITY_TRACEPOINT); >> -- >> 2.20.1 > > Thanks. I like the idea of CAP_SYS_PERFMON that does not require CAP_SYS_ADMIN. It makes granting users ability to run perf a bit safer. > > I see a lot of "(capable(CAP_SYS_PERFMON) || capable(CAP_SYS_ADMIN)" constructs now. Maybe wrapping it in an " inline bool perfmon_capable()" defined somewhere (like in /include/linux/capability.h)? Yes, it makes sense. Thanks, Alexey > > - Igor >