From patchwork Mon Nov 19 05:41:31 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexey Budankov X-Patchwork-Id: 10688313 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id CEEAF6C5 for ; Mon, 19 Nov 2018 09:17:01 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BCFB1299DD for ; Mon, 19 Nov 2018 09:17:01 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B0A2A299E3; Mon, 19 Nov 2018 09:17:01 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id F1BA8299DD for ; Mon, 19 Nov 2018 09:17:00 +0000 (UTC) Received: (qmail 9895 invoked by uid 550); 19 Nov 2018 09:16:53 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Delivered-To: moderator for kernel-hardening@lists.openwall.com Received: (qmail 12254 invoked from network); 19 Nov 2018 05:41:49 -0000 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,251,1539673200"; d="scan'208";a="86982871" Subject: [PATCH v1 1/2]: Documentation/admin-guide: update admin-guide index.rst From: Alexey Budankov To: Thomas Gleixner , Kees Cook , Jann Horn , Ingo Molnar , Peter Zijlstra , Arnaldo Carvalho de Melo , Andi Kleen , Jonatan Corbet Cc: Alexander Shishkin , Jiri Olsa , Namhyung Kim , Mark Rutland , Tvrtko Ursulin , linux-kernel , kernel-hardening@lists.openwall.com, linux-doc@vger.kernel.org References: <0ac97cd0-4773-fff6-7d4e-74c4a1f076c4@linux.intel.com> Organization: Intel Corp. Message-ID: <810bb4aa-777f-77ed-19f0-882354bdf9c7@linux.intel.com> Date: Mon, 19 Nov 2018 08:41:31 +0300 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <0ac97cd0-4773-fff6-7d4e-74c4a1f076c4@linux.intel.com> Content-Language: en-US X-Virus-Scanned: ClamAV using ClamSMTP Extend index.rst index file at admin-guide root directory with the reference to perf-security.rst file being introduced. Signed-off-by: Alexey Budankov --- Documentation/admin-guide/index.rst | 1 + 1 file changed, 1 insertion(+) diff --git a/Documentation/admin-guide/index.rst b/Documentation/admin-guide/index.rst index 0873685bab0f..885cc0de9114 100644 --- a/Documentation/admin-guide/index.rst +++ b/Documentation/admin-guide/index.rst @@ -75,6 +75,7 @@ configure specific aspects of kernel behavior to your liking. thunderbolt LSM/index mm/index + perf-security .. only:: subproject and html From patchwork Mon Nov 19 05:42:52 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexey Budankov X-Patchwork-Id: 10688315 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 10F33109C for ; Mon, 19 Nov 2018 09:17:11 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F072D299DD for ; Mon, 19 Nov 2018 09:17:10 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E2B17299E3; Mon, 19 Nov 2018 09:17:10 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id D929A299DD for ; Mon, 19 Nov 2018 09:17:09 +0000 (UTC) Received: (qmail 10185 invoked by uid 550); 19 Nov 2018 09:16:56 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Delivered-To: moderator for kernel-hardening@lists.openwall.com Received: (qmail 13996 invoked from network); 19 Nov 2018 05:43:11 -0000 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,251,1539673200"; d="scan'208";a="87489973" Subject: [PATCH v1 2/2]: Documentation/admin-guide: introduce perf-security.rst file From: Alexey Budankov To: Thomas Gleixner , Kees Cook , Jann Horn , Ingo Molnar , Peter Zijlstra , Arnaldo Carvalho de Melo , Andi Kleen , Jonatan Corbet Cc: Alexander Shishkin , Jiri Olsa , Namhyung Kim , Mark Rutland , Tvrtko Ursulin , linux-kernel , kernel-hardening@lists.openwall.com, linux-doc@vger.kernel.org References: <0ac97cd0-4773-fff6-7d4e-74c4a1f076c4@linux.intel.com> Organization: Intel Corp. Message-ID: Date: Mon, 19 Nov 2018 08:42:52 +0300 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <0ac97cd0-4773-fff6-7d4e-74c4a1f076c4@linux.intel.com> Content-Language: en-US X-Virus-Scanned: ClamAV using ClamSMTP Implement initial version of perf-security.rst documentation file initially covering security concerns related to PCL/Perf performance monitoring in multiuser environments. Suggested-by: Thomas Gleixner Signed-off-by: Alexey Budankov --- Documentation/admin-guide/perf-security.rst | 83 +++++++++++++++++++++++++++++ 1 file changed, 83 insertions(+) diff --git a/Documentation/admin-guide/perf-security.rst b/Documentation/admin-guide/perf-security.rst new file mode 100644 index 000000000000..b9564066e686 --- /dev/null +++ b/Documentation/admin-guide/perf-security.rst @@ -0,0 +1,83 @@ +.. _perf_security: + +PCL/Perf security +================= + +Overview +-------- + +Usage of Performance Counters for Linux (PCL) [1]_ , [2]_ , [3]_ can impose a +considerable risk of leaking sensitive data accessed by monitored processes. +The data leakage is possible both in scenarios of direct usage of PCL system +call API [2]_ and over data files generated by Perf tool user mode utility +(Perf) [3]_ , [4]_ . The risk depends on the nature of data that PCL performance +monitoring units (PMU) [2]_ collect and expose for performance analysis. +Having that said PCL/Perf performance monitoring is the subject for security +access control management [5]_ . + +PCL/Perf access control +----------------------- + +For the purpose of performing security checks Linux implementation splits +processes into two categories [6]_ : a) privileged processes (whose effective +user ID is 0, referred to as superuser or root), and b) unprivileged processes +(whose effective UID is nonzero). Privileged processes bypass all kernel +security permission checks so PCL performance monitoring is fully available to +privileged processes without *access*, *scope* and *resource* restrictions. +Unprivileged processes are subject to full security permission check based +on the process's credentials [5]_ (usually: effective UID, effective GID, +and supplementary group list). + +PCL/Perf unprivileged users +--------------------------- + +PCL/Perf *scope* and *access* control for unprivileged processes is governed by +perf_event_paranoid [2]_ setting: + +**-1**: + Impose no *scope* and *access* restrictions on using PCL performance + monitoring. Per-user per-cpu perf_event_mlock_kb [2]_ locking limit is + ignored when allocating memory buffers for storing performance data. + This is the least secure mode since allowed monitored *scope* is + maximized and no PCL specific limits are imposed on *resources* + allocated for performance monitoring. + +**>=0**: + *scope* includes per-process and system wide performance monitoring + but excludes raw tracepoints and ftrace function tracepoints monitoring. + CPU and system events happened when executing either in user or + in kernel space can be monitored and captured for later analysis. + Per-user per-cpu perf_event_mlock_kb locking limit is imposed but + ignored for unprivileged processes with CAP_IPC_LOCK [6]_ capability. + +**>=1**: + *scope* includes per-process performance monitoring only and excludes + system wide performance monitoring. CPU and system events happened when + executing either in user or in kernel space can be monitored and + captured for later analysis. Per-user per-cpu perf_event_mlock_kb + locking limit is imposed but ignored for unprivileged processes with + CAP_IPC_LOCK capability. + +**>=2**: + *scope* includes per-process performance monitoring only. CPU and system + events happened when executing in user space only can be monitored and + captured for later analysis. Per-user per-cpu perf_event_mlock_kb + locking limit is imposed but ignored for unprivileged processes with + CAP_IPC_LOCK capability. + +**>=3**: + Restrict *access* to PCL performance monitoring for unprivileged processes. + This is the default on Debian and Android [7]_ , [8]_ . + +Bibliography +------------ + +.. [1] ``_ +.. [2] ``_ +.. [3] ``_ +.. [4] ``_ +.. [5] ``_ +.. [6] ``_ +.. [7] ``_ +.. [8] ``_ +