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From:   "Lubashev, Igor" <ilubashe@akamai.com>
To:     Jiri Olsa <jolsa@redhat.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
Thread-Topic: [PATCH 2/3] perf: Use CAP_SYS_ADMIN with perf_event_paranoid
 checks
Thread-Index: AQHVMTPFo1SW8Ha07Ua7MbRsBb5FgabNV64AgAAy/wCAAUQogIAAamrQ
Date:   Wed, 17 Jul 2019 18:33:58 +0000
Message-ID: <4693ccba52114913afaafd498ae284de@ustx2ex-dag1mb5.msg.corp.akamai.com>
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>
 <20190717071027.GG28722@krava>
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> On Wednesday, July 17, 2019 3:10 AM Jiri Olsa wrote:
> 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 w=
hat
> capability to check for here?
>=20
> it's:
>=20
> 	if (geteuid() !=3D 0) {
> 		pr_err("ftrace only works for root!\n");
> 		return -1
> 	}
>=20
> so I think check for CAP_SYS_ADMIN should be fine in here

Thanks.  Added the [PATCH 4/3] to this series (https://lore.kernel.org/lkml=
/1563387359-27694-1-git-send-email-ilubashe@akamai.com/).
Let me know if you'd rather I reroll a V2 of this series.

- Igor


>=20
> jirka
>=20
> >
> > (There is always an alternative to not check for anything and let the k=
ernel
> refuse to perform actions that the user does not have permissions to perf=
orm.)
> >
> > - 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_parano=
id
> checks
> >
> > On Tue, Jul 02, 2019 at 08:10:04PM -0400, Igor Lubashev wrote:
> > > The kernel is using CAP_SYS_ADMIN instead of euid=3D=3D0 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