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;
From:   Alexey Budankov <alexey.budankov@linux.intel.com>
Subject: Re: [RFC 0/5] perf: Per PMU access controls (paranoid setting)
To:     Thomas Gleixner <tglx@linutronix.de>
Cc:     Jann Horn <jannh@google.com>, Mark Rutland <mark.rutland@arm.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Kees Cook <keescook@chromium.org>,
        Andi Kleen <ak@linux.intel.com>, tursulin@ursulin.net,
        kernel list <linux-kernel@vger.kernel.org>,
        tvrtko.ursulin@linux.intel.com,
        the arch/x86 maintainers <x86@kernel.org>,
        "H . Peter Anvin" <hpa@zytor.com>, acme@kernel.org,
        alexander.shishkin@linux.intel.com, jolsa@redhat.com,
        namhyung@kernel.org, maddy@linux.vnet.ibm.com
References: <20180919122751.12439-1-tvrtko.ursulin@linux.intel.com>
 <alpine.DEB.2.21.1809281151190.2004@nanos.tec.linutronix.de>
 <20180928164111.i6nba2j6mnegwslw@lakrids.cambridge.arm.com>
 <20180928172340.GA32651@tassilo.jf.intel.com>
 <20180928174016.i7d24puv7y3jwzf6@lakrids.cambridge.arm.com>
 <20180928204930.GC32651@tassilo.jf.intel.com>
 <CAG48ez16ECnLMNggTZQQJOuPK5ZJ8dLSkGDzvxwK1zVh1BFExw@mail.gmail.com>
 <20180928205907.GD32651@tassilo.jf.intel.com>
 <CAG48ez1xJ+Y=snnHJ5k6J6O3qqD=bHdjRioLFuzPZpxU9v7xxA@mail.gmail.com>
 <20180928212757.GE32651@tassilo.jf.intel.com>
 <22155f49-2f57-73b8-6e89-ddd8a127967b@linux.intel.com>
 <alpine.DEB.2.21.1810011741070.32062@nanos.tec.linutronix.de>
 <905796f8-4704-66a8-ee0a-ac8aba90b179@linux.intel.com>
 <alpine.DEB.2.21.1810020832430.32062@nanos.tec.linutronix.de>
Organization: Intel Corp.
Message-ID: <47c60dc1-47ed-ca31-cc3d-d26a1b00d19a@linux.intel.com>
Date:   Tue, 2 Oct 2018 14:44:04 +0300
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101
 Thunderbird/52.9.1
MIME-Version: 1.0
In-Reply-To: <alpine.DEB.2.21.1810020832430.32062@nanos.tec.linutronix.de>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk


Hello,

On 02.10.2018 9:40, Thomas Gleixner wrote:

<SNIP>

> 
> Not only the user group, it really should do the full security checks which
> are done on open().

I expect it is already implemented by some internal kernel API so that 
it could be reused.

> 
>>    b) then traditional checks against perf_event_pranoid content are applied;
> 
> Hmm, not sure about that because that might be conflicting.

Well, possible contradictions could be converged to some reasonable point 
during technical review stage.

Current perf_event_paranoid semantics is still required for PMUs 
that are governed by global setting at /proc/sys/kernel/perf_event_paranoid.

<SNIP>

>> 4. Documentation/admin-guide/perf-security.rst file is introduced that:
> 
>      0) Better documentation of /proc/sys/kernel/perf_even_paranoid

Exactly. perf_event_open man7 [1] requires update as well, however 
this is not a part of kernel source tree so these docs changes are 
to be mailed TO: mtk.manpages@gmail.com and CC: linux-api@vger.kernel.org.

Thanks,
Alexey

[1] http://man7.org/linux/man-pages/man2/perf_event_open.2.html