From: Alexey Budankov <alexey.budankov@linux.intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Kees Cook <keescook@chromium.org>, Jann Horn <jannh@google.com>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Andi Kleen <ak@linux.intel.com>, Jonatan Corbet <corbet@lwn.net>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Tvrtko Ursulin <tursulin@ursulin.net>,
linux-kernel <linux-kernel@vger.kernel.org>,
kernel-hardening@lists.openwall.com, linux-doc@vger.kernel.org
Subject: Re: [PATCH v1 2/2]: Documentation/admin-guide: introduce perf-security.rst file
Date: Mon, 19 Nov 2018 18:13:16 +0300 [thread overview]
Message-ID: <2a4e0b60-ba52-2d79-ec7d-d9b75f0ae5a1@linux.intel.com> (raw)
In-Reply-To: <20181119103337.GZ9761@hirez.programming.kicks-ass.net>
Hi,
On 19.11.2018 13:33, Peter Zijlstra wrote:
> On Mon, Nov 19, 2018 at 08:42:52AM +0300, Alexey Budankov wrote:
>>
>> Implement initial version of perf-security.rst documentation file
>> initially covering security concerns related to PCL/Perf performance
>> monitoring in multiuser environments.
>
> Ditch the PCL thing. That's not a term used anywhere in the kernel.
Ok. Which is the proper wording to reference to Perf kernel subsystem?
>
> Also:
>
>> +PCL/Perf unprivileged users
>> +---------------------------
>> +
>> +PCL/Perf *scope* and *access* control for unprivileged processes is governed by
>> +perf_event_paranoid [2]_ setting:
>> +
>> +**-1**:
>> + Impose no *scope* and *access* restrictions on using PCL performance
>> + monitoring. Per-user per-cpu perf_event_mlock_kb [2]_ locking limit is
>> + ignored when allocating memory buffers for storing performance data.
>> + This is the least secure mode since allowed monitored *scope* is
>> + maximized and no PCL specific limits are imposed on *resources*
>> + allocated for performance monitoring.
>> +
>> +**>=0**:
>> + *scope* includes per-process and system wide performance monitoring
>> + but excludes raw tracepoints and ftrace function tracepoints monitoring.
>> + CPU and system events happened when executing either in user or
>> + in kernel space can be monitored and captured for later analysis.
>> + Per-user per-cpu perf_event_mlock_kb locking limit is imposed but
>> + ignored for unprivileged processes with CAP_IPC_LOCK [6]_ capability.
>> +
>> +**>=1**:
>> + *scope* includes per-process performance monitoring only and excludes
>> + system wide performance monitoring. CPU and system events happened when
>> + executing either in user or in kernel space can be monitored and
>> + captured for later analysis. Per-user per-cpu perf_event_mlock_kb
>> + locking limit is imposed but ignored for unprivileged processes with
>> + CAP_IPC_LOCK capability.
>> +
>> +**>=2**:
>> + *scope* includes per-process performance monitoring only. CPU and system
>> + events happened when executing in user space only can be monitored and
>> + captured for later analysis. Per-user per-cpu perf_event_mlock_kb
>> + locking limit is imposed but ignored for unprivileged processes with
>> + CAP_IPC_LOCK capability.
>> +
>> +**>=3**:
>> + Restrict *access* to PCL performance monitoring for unprivileged processes.
>> + This is the default on Debian and Android [7]_ , [8]_ .
>
> that ** crud is unreadable.
It can be avoided without missing the sense.
"two asterisks: **text** for strong emphasis (boldface)".
Thanks,
Alexey
>
> http://lkml.kernel.org/r/094556ca-ea87-9c4a-2115-600d2833fb2a@darmarit.de
>
next prev parent reply other threads:[~2018-11-19 15:13 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-19 5:37 [PATCH v1 0/2]: Documentation/admin-guide: introduce perf-security.rst file and extend perf_event_paranoid documentation Alexey Budankov
2018-11-19 5:41 ` [PATCH v1 1/2]: Documentation/admin-guide: update admin-guide index.rst Alexey Budankov
2018-11-19 10:03 ` Greg KH
2018-11-19 15:12 ` Alexey Budankov
2018-11-19 5:42 ` [PATCH v1 2/2]: Documentation/admin-guide: introduce perf-security.rst file Alexey Budankov
2018-11-19 10:33 ` Peter Zijlstra
2018-11-19 15:13 ` Alexey Budankov [this message]
2018-11-27 8:17 ` Alexey Budankov
2018-11-19 10:35 ` Jordan Glover
2018-11-19 10:46 ` Peter Zijlstra
2018-11-19 10:49 ` Jordan Glover
2018-11-19 15:19 ` Alexey Budankov
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