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From: Ben Hutchings <ben@decadent.org.uk>
To: Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	kernel-hardening@lists.openwall.com
Subject: Re: [PATCH 2/2] security,perf: Allow further restriction of perf_event_open
Date: Fri, 17 Jun 2016 13:18:01 +0100
Message-ID: <1466165881.27155.84.camel@decadent.org.uk> (raw)
In-Reply-To: <871t3wuzmp.fsf@ashishki-desk.ger.corp.intel.com>


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On Fri, 2016-06-17 at 08:56 +0300, Alexander Shishkin wrote:
> Ben Hutchings <ben@decadent.org.uk> writes:
> 
> > When kernel.perf_event_open is set to 3 (or greater), disallow all
> > access to performance events by users without CAP_SYS_ADMIN.
> > Add a Kconfig symbol CONFIG_SECURITY_PERF_EVENTS_RESTRICT that
> > makes this value the default.
> 
> So this patch does two things, can it then be made into two patches?

It could.

> > 
> > This is based on a similar feature in grsecurity
> > (CONFIG_GRKERNSEC_PERF_HARDEN).  This version doesn't include making
> > the variable read-only.  It also allows enabling further restriction
> > at run-time regardless of whether the default is changed.
> 
> This paragraph doesn't seem to belong in the commit message.

I'm giving credit where credit is due.

> What this commit message is missing entirely is the rationale behind
> this change other than "grsecurity does the same". Can you please
> elaborate?

It allows disabling a facility which in many systems is not needed and
is only a security risk.

> > Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
> > ---
> > I made a similar change to Debian's kernel packages in August,
> > including the more restrictive default, and no-one has complained yet.
> 
> As a debian user, is this a good place to complain? Because it does get
> it the way.

OK, then you're the first one.  And you know how to change this, don't
you?

Ben.

-- 
Ben Hutchings
We get into the habit of living before acquiring the habit of thinking.
                                                              - Albert
Camus

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  reply index

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-11 15:19 [PATCH 0/2] Document and extend kernel.perf_event_paranoid Ben Hutchings
2016-01-11 15:21 ` [PATCH 1/2] Documentation,perf: Document the perf sysctls Ben Hutchings
2016-01-11 15:23 ` [PATCH 2/2] security,perf: Allow further restriction of perf_event_open Ben Hutchings
2016-04-13 16:12   ` [kernel-hardening] " Kees Cook
2016-06-04 20:56     ` Jeffrey Vander Stoep
     [not found]     ` <CABXk95BE3wpgq-Y08G+Z3ZJbxJwgiuVvtQGaV4n-tD6GKNiFKg@mail.gmail.com>
2016-06-16 22:27       ` Kees Cook
2016-06-17  6:54         ` Peter Zijlstra
2016-06-17 16:16           ` Daniel Micay
2016-06-17 20:00             ` Arnaldo Carvalho de Melo
2016-06-18  0:51               ` Daniel Micay
2016-06-17  5:56   ` Alexander Shishkin
2016-06-17 12:18     ` Ben Hutchings [this message]
2016-06-17 15:24     ` [kernel-hardening] " Daniel Micay
2016-01-19 21:35 ` [PATCH RESEND] perf: Document the perf sysctls Ben Hutchings
2016-01-21 14:25   ` Arnaldo Carvalho de Melo
2016-02-03 10:08   ` [tip:perf/core] perf tools: " tip-bot for Ben Hutchings

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