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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 665A7C282DD for ; Fri, 10 Jan 2020 16:41:57 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 40FEE20721 for ; Fri, 10 Jan 2020 16:41:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 40FEE20721 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id D276E6EA5D; Fri, 10 Jan 2020 16:41:56 +0000 (UTC) Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by gabe.freedesktop.org (Postfix) with ESMTPS id 71CCD6EA5D for ; Fri, 10 Jan 2020 16:41:55 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 10 Jan 2020 08:41:54 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,417,1571727600"; d="scan'208";a="423650444" Received: from linux.intel.com ([10.54.29.200]) by fmsmga006.fm.intel.com with ESMTP; 10 Jan 2020 08:41:53 -0800 Received: from [10.252.24.8] (abudanko-mobl.ccr.corp.intel.com [10.252.24.8]) by linux.intel.com (Postfix) with ESMTP id C1A285802C9; Fri, 10 Jan 2020 08:41:42 -0800 (PST) To: Peter Zijlstra References: <20200108160713.GI2844@hirez.programming.kicks-ass.net> <20200110140234.GO2844@hirez.programming.kicks-ass.net> From: Alexey Budankov Organization: Intel Corp. Message-ID: Date: Fri, 10 Jan 2020 19:41:41 +0300 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.3.1 MIME-Version: 1.0 In-Reply-To: <20200110140234.GO2844@hirez.programming.kicks-ass.net> Content-Language: en-US Subject: Re: [Intel-gfx] [PATCH v4 2/9] perf/core: open access for CAP_SYS_PERFMON privileged process X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Song Liu , Alexander Shishkin , Benjamin Herrenschmidt , Will Deacon , Alexei Starovoitov , Stephane Eranian , "james.bottomley@hansenpartnership.com" , Paul Mackerras , Jiri Olsa , Andi Kleen , Michael Ellerman , Igor Lubashev , James Morris , Ingo Molnar , oprofile-list@lists.sf.net, Serge Hallyn , Robert Richter , Kees Cook , Jann Horn , "selinux@vger.kernel.org" , "intel-gfx@lists.freedesktop.org" , Arnaldo Carvalho de Melo , Namhyung Kim , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, "linux-parisc@vger.kernel.org" , linux-kernel , "linux-perf-users@vger.kernel.org" , "linux-security-module@vger.kernel.org" , mhiramat@kernel.org, Casey Schaufler , "bpf@vger.kernel.org" , "linuxppc-dev@lists.ozlabs.org" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On 10.01.2020 17:02, Peter Zijlstra wrote: > On Thu, Jan 09, 2020 at 02:36:50PM +0300, Alexey Budankov wrote: >> On 08.01.2020 19:07, Peter Zijlstra wrote: >>> On Wed, Dec 18, 2019 at 12:25:35PM +0300, Alexey Budankov wrote: > >>>> 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. >> >> This unblocks creation of local trace kprobes and uprobes by CAP_SYS_PERFMON >> privileged process, exactly the same as for CAP_SYS_ADMIN privileged process. > > I've no idea what you just said; it's just words. > > Again, this only allows attaching to previously created kprobes, it does > not allow creating kprobes, right? Not really, this allows creating a kprobe using perf_event_open syscall that associates file descriptor with the kprobe [1]. Lifetime of that kprobe is equal to the lifetime of the file descriptor and the kprobe is not visible in tracefs: /sys/kernel/debug/tracing/kprobe_events > > That is; I don't think CAP_SYS_PERFMON should be allowed to create > kprobes. > > As might be clear; I don't actually know what the user-ABI is for > creating kprobes. ~Alexey --- [1] https://lore.kernel.org/lkml/20171206224518.3598254-1-songliubraving@fb.com/ _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx