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, 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 48D51C43331 for ; Fri, 3 Apr 2020 14:29:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1DF4A2073B for ; Fri, 3 Apr 2020 14:29:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403878AbgDCO3I (ORCPT ); Fri, 3 Apr 2020 10:29:08 -0400 Received: from mga03.intel.com ([134.134.136.65]:15121 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727431AbgDCO3H (ORCPT ); Fri, 3 Apr 2020 10:29:07 -0400 IronPort-SDR: lxkOUMurYjhN0Y7l5fVYl8hVuGT7Tv2y6Nn6e4HkS3v4sbjKM6Ci8b80w1fz1QH1XtBSKc0NP4 oGfjxiJUY8qw== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Apr 2020 07:29:03 -0700 IronPort-SDR: QYYCSMTHxnMmHUYdTN6qK8Da/qeXWJtpW9hr4z2CR28Woc6Zx24PddrIMX5hFpFjSByE1cBk6A Lpx/dB5rmG0g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,340,1580803200"; d="scan'208";a="329180493" Received: from linux.intel.com ([10.54.29.200]) by orsmga001.jf.intel.com with ESMTP; 03 Apr 2020 07:29:03 -0700 Received: from [10.249.254.224] (abudanko-mobl.ccr.corp.intel.com [10.249.254.224]) by linux.intel.com (Postfix) with ESMTP id C813E58077B; Fri, 3 Apr 2020 07:29:00 -0700 (PDT) Subject: Re: [PATCH v4 2/9] perf/core: open access for CAP_SYS_PERFMON privileged process From: Alexey Budankov To: Peter Zijlstra Cc: Arnaldo Carvalho de Melo , Ingo Molnar , James Morris , Jiri Olsa , Andi Kleen , Alexander Shishkin , Namhyung Kim , linux-kernel References: <20200108160713.GI2844@hirez.programming.kicks-ass.net> <4e528ce4-a937-358b-47b6-7d7085ab4eaa@linux.intel.com> Organization: Intel Corp. Message-ID: <930384c0-e852-a7bf-cd61-829cb9993234@linux.intel.com> Date: Fri, 3 Apr 2020 17:28:59 +0300 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <4e528ce4-a937-358b-47b6-7d7085ab4eaa@linux.intel.com> 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 On 01.04.2020 23:49, Alexey Budankov wrote: > Hi Peter, > > On 08.01.2020 19:07, Peter Zijlstra wrote: >> On Wed, Dec 18, 2019 at 12:25:35PM +0300, 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 | 6 +++--- >>> kernel/events/core.c | 6 +++--- >>> 2 files changed, 6 insertions(+), 6 deletions(-) >>> >>> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h >>> index 34c7c6910026..f46acd69425f 100644 >>> --- a/include/linux/perf_event.h >>> +++ b/include/linux/perf_event.h >>> @@ -1285,7 +1285,7 @@ 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 && !perfmon_capable()) >>> return -EACCES; >>> >>> return security_perf_event_open(attr, PERF_SECURITY_KERNEL); >>> @@ -1293,7 +1293,7 @@ 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 && !perfmon_capable()) >>> return -EACCES; >>> >>> return security_perf_event_open(attr, PERF_SECURITY_CPU); >>> @@ -1301,7 +1301,7 @@ 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 && !perfmon_capable()) >>> return -EPERM; >>> >>> return security_perf_event_open(attr, PERF_SECURITY_TRACEPOINT); >> >> These are OK I suppose. >> >>> diff --git a/kernel/events/core.c b/kernel/events/core.c >>> index 059ee7116008..d9db414f2197 100644 >>> --- a/kernel/events/core.c >>> +++ b/kernel/events/core.c >>> @@ -9056,7 +9056,7 @@ static int perf_kprobe_event_init(struct perf_event *event) >>> if (event->attr.type != perf_kprobe.type) >>> return -ENOENT; >>> >>> - if (!capable(CAP_SYS_ADMIN)) >>> + if (!perfmon_capable()) >>> return -EACCES; >>> >>> /* >> >> This one only allows attaching to already extant kprobes, right? It does >> not allow creation of kprobes. >> >>> @@ -9116,7 +9116,7 @@ static int perf_uprobe_event_init(struct perf_event *event) >>> if (event->attr.type != perf_uprobe.type) >>> return -ENOENT; >>> >>> - if (!capable(CAP_SYS_ADMIN)) >>> + if (!perfmon_capable()) >>> return -EACCES; >>> >>> /* >> >> Idem, I presume. >> >>> @@ -11157,7 +11157,7 @@ SYSCALL_DEFINE5(perf_event_open, >>> } >>> >>> if (attr.namespaces) { >>> - if (!capable(CAP_SYS_ADMIN)) >>> + if (!perfmon_capable()) >>> return -EACCES; >>> } >> >> And given we basically make the entire kernel observable with this CAP, >> busting namespaces shoulnd't be a problem either. >> >> So yeah, I suppose that works. > > Could this have you explicit Reviewed-by or Acked-by tag > so the changes could be driven into the kernel? > Latest v7 is here: > https://lore.kernel.org/lkml/c8de937a-0b3a-7147-f5ef-69f467e87a13@linux.intel.com/ Posted v8 with all acquired tags so far: https://lore.kernel.org/lkml/f96f8f8a-e65c-3f36-dc85-fc3f5191e8c5@linux.intel.com/ Thanks, Alexey