From patchwork Mon Apr 20 11:52:22 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arnaldo Carvalho de Melo X-Patchwork-Id: 11498707 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 329FB913 for ; Mon, 20 Apr 2020 11:53:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1B9AB218AC for ; Mon, 20 Apr 2020 11:53:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587383636; bh=PWjy/B+21HQPLawk/uU7/6+PxUTYrdc8ItS1u38jg7E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=0tznH8R4l/Zx1oN7TLQvvdwvUHA9h+ta0W11CDTKrFbWJh/rtcX8UwnmV8N+eEuxo jYlwSXjDgKA4FXQ0KrEjzR/Mvq7ObX8vQJKod/ea9OmppuXLrondSV+kBiDi6nnENk WU2u9zFXpj5y5/7O8WIdgm8xycD7WiIQrAyBBWJY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726615AbgDTLxz (ORCPT ); Mon, 20 Apr 2020 07:53:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:37208 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725886AbgDTLxy (ORCPT ); Mon, 20 Apr 2020 07:53:54 -0400 Received: from quaco.ghostprotocols.net (unknown [179.97.37.151]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id EE2F3206D4; Mon, 20 Apr 2020 11:53:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587383634; bh=PWjy/B+21HQPLawk/uU7/6+PxUTYrdc8ItS1u38jg7E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CrCekbuQzUEiHVCs3rvwQlRQOhBIgD9Yfij35aayQghq4Xtruet5C9dhhuUzK2CZ+ d3YqNFRVpyou2eNrp2a0PY1TfH0jRdom/Gyv95KZ7+O+sTqBVmuMoifnhQAwhz/O6I +thbwzrPtr5UJVdSyP4QNQlXSsrKp0pn1W1d7T0o= From: Arnaldo Carvalho de Melo To: Ingo Molnar , Thomas Gleixner Cc: Jiri Olsa , Namhyung Kim , Clark Williams , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Alexey Budankov , James Morris , Arnaldo Carvalho de Melo , Alexei Starovoitov , Andi Kleen , Igor Lubashev , Jiri Olsa , linux-man@vger.kernel.org, Peter Zijlstra , Serge Hallyn , Song Liu , Stephane Eranian , intel-gfx@lists.freedesktop.org, linux-doc@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org Subject: [PATCH 06/60] perf/core: Open access to the core for CAP_PERFMON privileged process Date: Mon, 20 Apr 2020 08:52:22 -0300 Message-Id: <20200420115316.18781-7-acme@kernel.org> X-Mailer: git-send-email 2.21.1 In-Reply-To: <20200420115316.18781-1-acme@kernel.org> References: <20200420115316.18781-1-acme@kernel.org> MIME-Version: 1.0 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: From: Alexey Budankov Open access to monitoring of kernel code, CPUs, tracepoints and namespaces data for a 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 principle 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 the 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_PERFMON capability. Signed-off-by: Alexey Budankov Reviewed-by: James Morris Tested-by: Arnaldo Carvalho de Melo Cc: Alexei Starovoitov Cc: Andi Kleen Cc: Igor Lubashev Cc: Jiri Olsa Cc: linux-man@vger.kernel.org Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Serge Hallyn Cc: Song Liu Cc: Stephane Eranian Cc: Thomas Gleixner Cc: intel-gfx@lists.freedesktop.org Cc: linux-doc@vger.kernel.org Cc: linux-security-module@vger.kernel.org Cc: selinux@vger.kernel.org Link: http://lore.kernel.org/lkml/471acaef-bb8a-5ce2-923f-90606b78eef9@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo --- include/linux/perf_event.h | 6 +++--- kernel/events/core.c | 2 +- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 9c3e7619c929..87e21681759c 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1305,7 +1305,7 @@ 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); @@ -1313,7 +1313,7 @@ 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); @@ -1321,7 +1321,7 @@ 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); diff --git a/kernel/events/core.c b/kernel/events/core.c index bc9b98a9af9a..74025b7b83a0 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -11504,7 +11504,7 @@ SYSCALL_DEFINE5(perf_event_open, } if (attr.namespaces) { - if (!capable(CAP_SYS_ADMIN)) + if (!perfmon_capable()) return -EACCES; }