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 D1536C54FCB for ; Wed, 22 Apr 2020 14:45:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B50D52076E for ; Wed, 22 Apr 2020 14:45:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726141AbgDVOpk (ORCPT ); Wed, 22 Apr 2020 10:45:40 -0400 Received: from mga04.intel.com ([192.55.52.120]:24664 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726284AbgDVOpk (ORCPT ); Wed, 22 Apr 2020 10:45:40 -0400 IronPort-SDR: H9VnpS0Im1QLX5Q5cEPMlI2QXdro6jOLBvuB6G1LzjI6bWQgB0/UXbkMq7I25a3BcMti80ogi7 bwNHsknNxHaQ== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Apr 2020 07:45:39 -0700 IronPort-SDR: 54KAWM9nApxWV+ESPLNywRaBdlkLBq0ZeFgs2REXa5BqJfDWp+rM06xnSpvFcTvavTxTWFgK1d OopyfMoas56g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,414,1583222400"; d="scan'208";a="280041924" Received: from linux.intel.com ([10.54.29.200]) by fmsmga004.fm.intel.com with ESMTP; 22 Apr 2020 07:45:38 -0700 Received: from [10.249.227.181] (abudanko-mobl.ccr.corp.intel.com [10.249.227.181]) by linux.intel.com (Postfix) with ESMTP id 84F995802C9; Wed, 22 Apr 2020 07:45:35 -0700 (PDT) Subject: [PATCH v2 3/4] perf tool: make Perf tool aware of SELinux access control From: Alexey Budankov To: Arnaldo Carvalho de Melo , Jiri Olsa Cc: Namhyung Kim , Alexander Shishkin , Peter Zijlstra , Ingo Molnar , Andi Kleen , linux-kernel , "selinux@vger.kernel.org" , "linux-security-module@vger.kernel.org" References: <66f2975b-4a69-b428-7dc5-d9aa40b3c673@linux.intel.com> Organization: Intel Corp. Message-ID: <7459371d-2ec8-4700-13b6-09b73998cc7c@linux.intel.com> Date: Wed, 22 Apr 2020 17:45:34 +0300 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <66f2975b-4a69-b428-7dc5-d9aa40b3c673@linux.intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: selinux-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org Implement SELinux sysfs check to see if the system is in enforcing mode and print warning message with pointers to check audit logs. Signed-off-by: Alexey Budankov --- tools/perf/util/cloexec.c | 4 ++-- tools/perf/util/evsel.c | 40 +++++++++++++++++++++++---------------- 2 files changed, 26 insertions(+), 18 deletions(-) diff --git a/tools/perf/util/cloexec.c b/tools/perf/util/cloexec.c index a12872f2856a..9c8ec816261b 100644 --- a/tools/perf/util/cloexec.c +++ b/tools/perf/util/cloexec.c @@ -65,7 +65,7 @@ static int perf_flag_probe(void) return 1; } - WARN_ONCE(err != EINVAL && err != EBUSY, + WARN_ONCE(err != EINVAL && err != EBUSY && err != EACCES, "perf_event_open(..., PERF_FLAG_FD_CLOEXEC) failed with unexpected error %d (%s)\n", err, str_error_r(err, sbuf, sizeof(sbuf))); @@ -83,7 +83,7 @@ static int perf_flag_probe(void) if (fd >= 0) close(fd); - if (WARN_ONCE(fd < 0 && err != EBUSY, + if (WARN_ONCE(fd < 0 && err != EBUSY && err != EACCES, "perf_event_open(..., 0) failed unexpectedly with error %d (%s)\n", err, str_error_r(err, sbuf, sizeof(sbuf)))) return -1; diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index 9fa92649adb4..82492ca12405 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -2514,32 +2514,40 @@ int perf_evsel__open_strerror(struct evsel *evsel, struct target *target, int err, char *msg, size_t size) { char sbuf[STRERR_BUFSIZE]; - int printed = 0; + int printed = 0, enforced = 0; switch (err) { case EPERM: case EACCES: + printed += scnprintf(msg + printed, size - printed, + "Access to performance monitoring and observability operations is limited.\n"); + + if (!sysfs__read_int("fs/selinux/enforce", &enforced)) { + if (enforced) { + printed += scnprintf(msg + printed, size - printed, + "Enforced MAC policy settings (SELinux) can limit access to performance\n" + "monitoring and observability operations. Inspect system audit records for\n" + "more perf_event access control information and adjusting the policy.\n"); + } + } + if (err == EPERM) - printed = scnprintf(msg, size, - "No permission to enable %s event.\n\n", + printed += scnprintf(msg, size, + "No permission to enable %s event.\n", perf_evsel__name(evsel)); return scnprintf(msg + printed, size - printed, - "You may not have permission to collect %sstats.\n\n" - "Consider tweaking /proc/sys/kernel/perf_event_paranoid,\n" - "which controls use of the performance events system by\n" - "unprivileged users (without CAP_PERFMON or CAP_SYS_ADMIN).\n\n" - "The current value is %d:\n\n" + "Consider adjusting /proc/sys/kernel/perf_event_paranoid setting to open\n" + "access to performance monitoring and observability operations for users\n" + "without CAP_PERFMON capability. perf_event_paranoid setting is %d:\n" " -1: Allow use of (almost) all events by all users\n" " Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK\n" - ">= 0: Disallow ftrace function tracepoint by users without CAP_PERFMON or CAP_SYS_ADMIN\n" - " Disallow raw tracepoint access by users without CAP_SYS_PERFMON or CAP_SYS_ADMIN\n" - ">= 1: Disallow CPU event access by users without CAP_PERFMON or CAP_SYS_ADMIN\n" - ">= 2: Disallow kernel profiling by users without CAP_PERFMON or CAP_SYS_ADMIN\n\n" - "To make this setting permanent, edit /etc/sysctl.conf too, e.g.:\n\n" - " kernel.perf_event_paranoid = -1\n" , - target->system_wide ? "system-wide " : "", - perf_event_paranoid()); + ">= 0: Disallow raw and ftrace function tracepoint access\n" + ">= 1: Disallow CPU event access\n" + ">= 2: Disallow kernel profiling\n" + "To make the adjusted perf_event_paranoid setting permanent preserve it\n" + "in /etc/sysctl.conf (e.g. kernel.perf_event_paranoid = )", + perf_event_paranoid()); case ENOENT: return scnprintf(msg, size, "The %s event is not supported.", perf_evsel__name(evsel)); -- 2.24.1