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From: Daniel Micay <danielmicay@gmail.com>
To: kernel-hardening@lists.openwall.com
Cc: Peter Zijlstra <peterz@infradead.org>,
	Kees Cook <keescook@chromium.org>,
	Jeff Vander Stoep <jeffv@google.com>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Jonathan Corbet <corbet@lwn.net>
Subject: Re: [kernel-hardening] Re: [PATCH 1/2] security, perf: allow further restriction of perf_event_open
Date: Thu, 04 Aug 2016 12:32:32 -0400
Message-ID: <1470328352.22643.110.camel@gmail.com> (raw)
In-Reply-To: <20160804161000.GA11673@leverpostej>


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On Thu, 2016-08-04 at 17:10 +0100, Mark Rutland wrote:
> On Thu, Aug 04, 2016 at 11:44:28AM -0400, Daniel Micay wrote:
> > 
> > Qualcomm's drivers might be lower quality than core kernel code, but
> > they're way above the baseline set by mainline kernel drivers...
> 
> I don't think that's true for the arm/arm64 perf code.

The baseline architecture support is essentially core kernel code. I
agree it's much better than the SoC vendor code. You're spending a lot
of time auditing, fuzzing and improving the code in general, which is
not true for most drivers. They don't get that attention.

> I think we've done a reasonable job of testing and fixing those, along
> with core infrastructure issues. The perf fuzzer runs for a very long
> time on a mainline kernel without issues, while on my Nexus 5x I get a
> hard lockup after ~85 seconds (and prior to the last android update
> the
> lockup was instantaneous).
>
> From my personal experience (and as above), and talking specifically
> about PMU drivers, I think that the opposite is true. This is not to
> say
> there aren't issues; I would not be surprised if there are. But it's
> disingenuous to say that mainline code is worse than that which exists
> in a vendor kernel when the latter is demonstrably much easier to
> break
> than the former.

I wasn't talking specifically about perf.

> If there are issues you are aware of, please report them. If those
> issues only exist in non-upstream code, then the applicable concerns
> are
> somewhat different (though certainly still exist).

I'm not going to do volunteer work for a corporation. I've learned that
lesson after spending years doing it.

> But please, let's frame the argument to match reality.

The argument is framed in reality. Stating that it now often takes a few
hours to find a vulnerability with the unaltered, widely known public
perf fuzzer is not impressive. It's really an argument for claiming that
it's a significant security issue.

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  reply index

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-27 14:45 [kernel-hardening] " 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 [this message]
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 ` [kernel-hardening] " Mark Rutland
2016-10-17 14:54   ` 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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