From: Alexey Budankov <alexey.budankov@linux.intel.com>
To: Jonathan Corbet <corbet@lwn.net>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Kees Cook <keescook@chromium.org>, Jann Horn <jannh@google.com>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Andi Kleen <ak@linux.intel.com>,
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"
<kernel-hardening@lists.openwall.com>,
"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>
Subject: Re: [PATCH v2 1/2] Documentation/admin-guide: introduce perf-security.rst file
Date: Mon, 26 Nov 2018 11:57:21 +0300 [thread overview]
Message-ID: <02dbd6dc-86b5-2307-4122-b716c51b9eaa@linux.intel.com> (raw)
In-Reply-To: <20181125124732.6c1807de@lwn.net>
Hello Jon,
On 25.11.2018 22:47, Jonathan Corbet wrote:
> On Wed, 21 Nov 2018 12:14:14 +0300
> Alexey Budankov <alexey.budankov@linux.intel.com> wrote:
>
>> +For the purpose of performing security checks Linux implementation splits
>> +processes into two categories [6]_ : a) privileged processes (whose effective
>> +user ID is 0, referred to as superuser or root), and b) unprivileged processes
>> +(whose effective UID is nonzero).
>
> Is that really what's going on here? If I understand things correctly,
> it's looking for CAP_SYS_PTRACE rather than a specific UID; am I missing
> something here?
You are right regarding CAP_SYS_PTRACE but this capability is not the only
one which is used by perf_events for security checks, so the capabilities
clarification is kept aside of these patches, because patches initial intention
is to clarify security specifics of sysctl_perf_even_paranoid settings.
I agree that the document can be extended with details clarifying capabilities
used by perf_events for security checks.
>
> (Also, you would want "*the* Linux implementation" in the first sentence
> above).
Accepted.
>
> One other thing:
>
>> +(whose effective UID is nonzero). Privileged processes bypass all kernel
>> +security permission checks so perf_events performance monitoring is fully
>> +available to privileged processes without *access*, *scope* and *resource*
>> +restrictions.
>
> Could I ask for a slight toning down of the markup here? There's a lot of
> *emphasis* here that isn't really needed and tends to get in the way.
Accepted.
Thanks,
Alexey
>
> Thanks,
>
> jon
>
next prev parent reply other threads:[~2018-11-26 8:57 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-21 8:57 [PATCH v2 0/2] Documentation/admin-guide: introduce perf-security.rst file and extend perf_event_paranoid documentation Alexey Budankov
2018-11-21 9:14 ` [PATCH v2 1/2] Documentation/admin-guide: introduce perf-security.rst file Alexey Budankov
2018-11-25 19:47 ` Jonathan Corbet
2018-11-26 8:57 ` Alexey Budankov [this message]
2018-11-26 20:28 ` Jonathan Corbet
2018-11-27 6:55 ` Alexey Budankov
2018-11-21 9:15 ` [PATCH v2 2/2] Documentation/admin-guide: update admin-guide index.rst Alexey Budankov
-- strict thread matches above, loose matches on Subject: below --
2018-11-20 9:21 [PATCH v2 0/2]: Documentation/admin-guide: introduce perf-security.rst file and extend perf_event_paranoid documentation Alexey Budankov
2018-11-20 9:27 ` [PATCH v2 1/2] Documentation/admin-guide: introduce perf-security.rst file Alexey Budankov
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