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[209.132.180.67]) by mx.google.com with ESMTP id s7si2148813otd.280.2020.02.18.11.24.40; Tue, 18 Feb 2020 11:24:52 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726391AbgBRTX0 (ORCPT + 99 others); Tue, 18 Feb 2020 14:23:26 -0500 Received: from namei.org ([65.99.196.166]:46600 "EHLO namei.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726339AbgBRTXZ (ORCPT ); Tue, 18 Feb 2020 14:23:25 -0500 Received: from localhost (localhost [127.0.0.1]) by namei.org (8.14.4/8.14.4) with ESMTP id 01IJMet4013185; Tue, 18 Feb 2020 19:22:40 GMT Date: Wed, 19 Feb 2020 06:22:40 +1100 (AEDT) From: James Morris To: Alexey Budankov cc: Serge Hallyn , Stephen Smalley , Peter Zijlstra , Arnaldo Carvalho de Melo , Ingo Molnar , "joonas.lahtinen@linux.intel.com" , Alexei Starovoitov , Will Deacon , Paul Mackerras , Helge Deller , Thomas Gleixner , Andi Kleen , Stephane Eranian , Igor Lubashev , Jiri Olsa , linux-kernel , "intel-gfx@lists.freedesktop.org" , "linux-security-module@vger.kernel.org" , "selinux@vger.kernel.org" , linux-arm-kernel , "linuxppc-dev@lists.ozlabs.org" , "linux-parisc@vger.kernel.org" , oprofile-list@lists.sf.net, "linux-doc@vger.kernel.org" , linux-man@vger.kernel.org Subject: Re: [PATCH v7 03/12] perf/core: open access to probes for CAP_PERFMON privileged process In-Reply-To: <3364fa26-b5d1-1808-aaee-c057f26e0eb4@linux.intel.com> Message-ID: References: <3364fa26-b5d1-1808-aaee-c057f26e0eb4@linux.intel.com> User-Agent: Alpine 2.21 (LRH 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 17 Feb 2020, Alexey Budankov wrote: > > Open access to monitoring via kprobes and uprobes and eBPF tracing 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. > > perf kprobes and uprobes are used by ftrace and eBPF. perf probe uses > ftrace to define new kprobe events, and those events are treated as > tracepoint events. eBPF defines new probes via perf_event_open interface > and then the probes are used in eBPF tracing. > > 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 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 -- James Morris