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;
Date:   Wed, 17 Jul 2019 09:10:27 +0200
From:   Jiri Olsa <jolsa@redhat.com>
To:     "Lubashev, Igor" <ilubashe@akamai.com>
Cc:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Namhyung Kim <namhyung@kernel.org>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>,
        James Morris <jmorris@namei.org>
Subject: Re: [PATCH 2/3] perf: Use CAP_SYS_ADMIN with perf_event_paranoid
 checks
Message-ID: <20190717071027.GG28722@krava>
References: <1562112605-6235-1-git-send-email-ilubashe@akamai.com>
 <1562112605-6235-3-git-send-email-ilubashe@akamai.com>
 <20190716084744.GB22317@krava>
 <cd2b162a59804cdaa7f4de18c3337aa8@ustx2ex-dag1mb5.msg.corp.akamai.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <cd2b162a59804cdaa7f4de18c3337aa8@ustx2ex-dag1mb5.msg.corp.akamai.com>
User-Agent: Mutt/1.12.0 (2019-05-25)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Tue, Jul 16, 2019 at 05:01:26PM +0000, Lubashev, Igor wrote:
> I could add another patch to the series for that.  Any suggestion for what capability to check for here?

it's:

	if (geteuid() != 0) {
		pr_err("ftrace only works for root!\n");
		return -1
	}

so I think check for CAP_SYS_ADMIN should be fine in here

jirka

> 
> (There is always an alternative to not check for anything and let the kernel refuse to perform actions that the user does not have permissions to perform.)
> 
> - Igor
> 
> -----Original Message-----
> From: Jiri Olsa <jolsa@redhat.com> 
> Sent: Tuesday, July 16, 2019 4:48 AM
> Subject: Re: [PATCH 2/3] perf: Use CAP_SYS_ADMIN with perf_event_paranoid checks
> 
> On Tue, Jul 02, 2019 at 08:10:04PM -0400, Igor Lubashev wrote:
> > The kernel is using CAP_SYS_ADMIN instead of euid==0 to override
> > perf_event_paranoid check. Make perf do the same.
> 
> I see another geteuid check in __cmd_ftrace,
> perhaps we should cover this one as well
> 
> jirka