From: Mark Rutland <mark.rutland@arm.com>
To: kernel-hardening@lists.openwall.com
Cc: peterz@infradead.org, mingo@redhat.com, acme@kernel.org,
alexander.shishkin@linux.intel.com, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org,
Jeff Vander Stoep <jeffv@google.com>
Subject: Re: [kernel-hardening] [PATCH 1/2] security, perf: allow further restriction of perf_event_open
Date: Mon, 17 Oct 2016 14:44:14 +0100 [thread overview]
Message-ID: <20161017134413.GK29095@leverpostej> (raw)
In-Reply-To: <1469630746-32279-1-git-send-email-jeffv@google.com>
Hi,
Attempt to revive discussions below...
On Wed, Jul 27, 2016 at 07:45:46AM -0700, Jeff Vander Stoep wrote:
> When kernel.perf_event_paranoid is set to 3 (or greater), disallow
> all access to performance events by users without CAP_SYS_ADMIN.
>
> This new level of restriction is intended to reduce the attack
> surface of the kernel. Perf is a valuable tool for developers but
> is generally unnecessary and unused on production systems. Perf may
> open up an attack vector to vulnerable device-specific drivers as
> recently demonstrated in CVE-2016-0805, CVE-2016-0819,
> CVE-2016-0843, CVE-2016-3768, and CVE-2016-3843. This new level of
> restriction allows for a safe default to be set on production systems
> while leaving a simple means for developers to grant access [1].
>
> This feature is derived from CONFIG_GRKERNSEC_PERF_HARDEN by Brad
> Spengler. It is based on a patch by Ben Hutchings [2]. Ben's patches
> have been modified and split up to address on-list feedback.
>
> kernel.perf_event_paranoid=3 is the default on both Debian [2] and
> Android [3].
While people weren't particularly happy with this global toggle
approach, my understanding from face-to-face discussions at LSS2016 was
that people were happy with a more scoped restriction (e.g. using
capabilities or some other access control mechanism), but no-one had the
time to work on that.
Does that match everyone's understanding, or am I mistaken?
It's also my understanding that for Android, perf_event_paranoid is
lowered when the user enables developer mode (rather than only when an
external debugger is attached); is that correct?
Thanks,
Mark.
next prev parent reply other threads:[~2016-10-17 13:44 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-27 14:45 [kernel-hardening] [PATCH 1/2] security, perf: allow further restriction of perf_event_open Jeff Vander Stoep
2016-07-27 20:43 ` Kees Cook
2016-08-02 9:52 ` [kernel-hardening] " Peter Zijlstra
2016-08-02 13:04 ` Arnaldo Carvalho de Melo
2016-08-02 13:10 ` Daniel Micay
2016-08-02 13:16 ` Daniel Micay
2016-08-02 19:04 ` Kees Cook
2016-08-02 20:30 ` Peter Zijlstra
2016-08-02 20:51 ` Kees Cook
2016-08-02 21:06 ` Jeffrey Vander Stoep
2016-08-03 8:28 ` Ingo Molnar
2016-08-03 12:28 ` Daniel Micay
2016-08-03 12:53 ` Daniel Micay
2016-08-03 13:36 ` Peter Zijlstra
2016-08-03 14:41 ` Peter Zijlstra
2016-08-03 15:42 ` Schaufler, Casey
2016-08-03 17:25 ` Eric W. Biederman
2016-08-03 18:53 ` Kees Cook
2016-08-03 21:44 ` Peter Zijlstra
2016-08-04 2:50 ` Eric W. Biederman
2016-08-04 9:11 ` Peter Zijlstra
2016-08-04 15:13 ` Eric W. Biederman
2016-08-04 15:37 ` Peter Zijlstra
2016-08-03 19:36 ` Daniel Micay
2016-08-04 10:28 ` Mark Rutland
2016-08-04 13:45 ` Daniel Micay
2016-08-04 14:11 ` Peter Zijlstra
2016-08-04 15:44 ` Daniel Micay
2016-08-04 15:55 ` Peter Zijlstra
2016-08-04 16:10 ` Mark Rutland
2016-08-04 16:32 ` Daniel Micay
2016-08-04 17:09 ` Mark Rutland
2016-08-04 17:36 ` Daniel Micay
2016-08-02 21:16 ` Jeffrey Vander Stoep
2016-10-17 13:44 ` Mark Rutland [this message]
2016-10-17 14:54 ` [kernel-hardening] " Daniel Micay
2016-10-19 9:41 ` Mark Rutland
2016-10-19 15:16 ` Daniel Micay
2016-10-18 20:48 ` Kees Cook
2016-10-18 21:15 ` Daniel Micay
2016-10-19 9:56 ` Mark Rutland
2016-10-19 10:01 ` Peter Zijlstra
2016-10-19 10:26 ` Arnaldo Carvalho de Melo
2016-10-19 10:40 ` Peter Zijlstra
2016-10-19 15:39 ` Daniel Micay
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