From patchwork Tue Jan 28 06:13:38 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexey Budankov X-Patchwork-Id: 11353645 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1902D139A for ; Tue, 28 Jan 2020 06:13:52 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0190024685 for ; Tue, 28 Jan 2020 06:13:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0190024685 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 930946EC9F; Tue, 28 Jan 2020 06:13:51 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by gabe.freedesktop.org (Postfix) with ESMTPS id 84B7E6EC9F for ; Tue, 28 Jan 2020 06:13:49 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 27 Jan 2020 22:13:48 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,372,1574150400"; d="scan'208";a="217528129" Received: from linux.intel.com ([10.54.29.200]) by orsmga007.jf.intel.com with ESMTP; 27 Jan 2020 22:13:48 -0800 Received: from [10.252.25.124] (abudanko-mobl.ccr.corp.intel.com [10.252.25.124]) by linux.intel.com (Postfix) with ESMTP id B84CA5803C1; Mon, 27 Jan 2020 22:13:40 -0800 (PST) From: Alexey Budankov To: Peter Zijlstra , Arnaldo Carvalho de Melo , Ingo Molnar , "benh@kernel.crashing.org" , Paul Mackerras , Michael Ellerman , "james.bottomley@hansenpartnership.com" , Serge Hallyn , Will Deacon , Robert Richter , Alexei Starovoitov References: <74d524ab-ac11-a7b8-1052-eba10f117e09@linux.intel.com> Organization: Intel Corp. Message-ID: Date: Tue, 28 Jan 2020 09:13:38 +0300 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <74d524ab-ac11-a7b8-1052-eba10f117e09@linux.intel.com> Content-Language: en-US Subject: [Intel-gfx] [PATCH v6 09/10] drivers/perf: open access for CAP_PERFMON privileged process X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Song Liu , Andi Kleen , "linux-parisc@vger.kernel.org" , Alexander Shishkin , "linuxppc-dev@lists.ozlabs.org" , "intel-gfx@lists.freedesktop.org" , Igor Lubashev , linux-kernel , Stephane Eranian , "linux-perf-users@vger.kernel.org" , "selinux@vger.kernel.org" , "linux-security-module@vger.kernel.org" , oprofile-list@lists.sf.net, Namhyung Kim , Jiri Olsa , linux-arm-kernel Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Open access to monitoring for CAP_PERFMON privileged process. Providing the access under CAP_PERFMON capability singly, without the rest of CAP_SYS_ADMIN credentials, excludes chances to misuse the credentials and makes operation more secure. CAP_PERFMON implements the principal of least privilege for performance monitoring and observability operations (POSIX IEEE 1003.1e 2.2.2.39 principle of least privilege: A security design principle that states that a process or program be granted only those privileges (e.g., capabilities) necessary to accomplish its legitimate function, and only for the time that such privileges are actually required) For backward compatibility reasons access to the monitoring remains open for CAP_SYS_ADMIN privileged processes but CAP_SYS_ADMIN usage for secure monitoring is discouraged with respect to CAP_PERFMON capability. Signed-off-by: Alexey Budankov Acked-by: James Morris --- drivers/perf/arm_spe_pmu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/perf/arm_spe_pmu.c b/drivers/perf/arm_spe_pmu.c index 4e4984a55cd1..5dff81bc3324 100644 --- a/drivers/perf/arm_spe_pmu.c +++ b/drivers/perf/arm_spe_pmu.c @@ -274,7 +274,7 @@ static u64 arm_spe_event_to_pmscr(struct perf_event *event) if (!attr->exclude_kernel) reg |= BIT(SYS_PMSCR_EL1_E1SPE_SHIFT); - if (IS_ENABLED(CONFIG_PID_IN_CONTEXTIDR) && capable(CAP_SYS_ADMIN)) + if (IS_ENABLED(CONFIG_PID_IN_CONTEXTIDR) && perfmon_capable()) reg |= BIT(SYS_PMSCR_EL1_CX_SHIFT); return reg; @@ -700,7 +700,7 @@ static int arm_spe_pmu_event_init(struct perf_event *event) return -EOPNOTSUPP; reg = arm_spe_event_to_pmscr(event); - if (!capable(CAP_SYS_ADMIN) && + if (!perfmon_capable() && (reg & (BIT(SYS_PMSCR_EL1_PA_SHIFT) | BIT(SYS_PMSCR_EL1_CX_SHIFT) | BIT(SYS_PMSCR_EL1_PCT_SHIFT))))