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From: Ingo Molnar <mingo@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>,
	LKML <linux-kernel@vger.kernel.org>,
	"mingo@elte.hu" <mingo@elte.hu>,
	"ak@linux.intel.com" <ak@linux.intel.com>,
	Arnaldo Carvalho de Melo <acme@redhat.com>,
	David Ahern <dsahern@gmail.com>, Jiri Olsa <jolsa@redhat.com>,
	Hugh Dickins <hughd@google.com>,
	Kees Cook <keescook@chromium.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [RFC] perf: mmap2 not covering VM_CLONE regions
Date: Wed, 2 Oct 2013 17:22:10 +0200	[thread overview]
Message-ID: <20131002152210.GA15757@gmail.com> (raw)
In-Reply-To: <20131002124610.GD28601@twins.programming.kicks-ass.net>


* Peter Zijlstra <peterz@infradead.org> wrote:

> On Wed, Oct 02, 2013 at 02:39:53PM +0200, Ingo Molnar wrote:
> >  - then there are timing attacks, and someone having access to a PMU
> >    context and who can trigger this SHA1 computation arbitrarily in task 
> >    local context can run very accurate and low noise timing attacks...
> > 
> >    I don't think the kernel's sha_transform() is hardened against timing 
> >    attacks, it's performance optimized so it has variable execution time
> >    highly dependent on plaintext input - which leaks information about the 
> >    plaintext.
> 
> Typical user doesn't have enough priv to profile kernel space; once you 
> do you also have enough priv to see kernel addresses outright (ie. 
> kallsyms etc..).

I didn't mean profiling - that's not a 'timing attack'.

A simple RDTSC done around repeated calls to sha_transform() using kernel 
functionality is.

Thanks,

	Ingo

  parent reply	other threads:[~2013-10-02 15:22 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-09-30 15:44 [RFC] perf: mmap2 not covering VM_CLONE regions Stephane Eranian
2013-09-30 16:15 ` Peter Zijlstra
2013-09-30 16:48   ` Stephane Eranian
2013-09-30 16:54     ` Peter Zijlstra
2013-10-01 11:22       ` Stephane Eranian
2013-10-02 11:23         ` Peter Zijlstra
2013-10-02 11:58           ` Peter Zijlstra
2013-10-02 12:39             ` Ingo Molnar
2013-10-02 12:46               ` Peter Zijlstra
2013-10-02 12:59                 ` Stephane Eranian
2013-10-02 13:01                   ` Peter Zijlstra
2013-10-02 13:13                     ` Stephane Eranian
2013-10-02 13:37                       ` Peter Zijlstra
2013-10-02 17:14                         ` Kees Cook
2013-10-02 17:20                           ` Stephane Eranian
2013-10-02 17:29                             ` Kees Cook
2013-10-02 17:49                               ` Stephane Eranian
2013-10-02 18:10                                 ` Kees Cook
2013-10-02 19:00                                   ` Peter Zijlstra
2013-10-02 19:38                                     ` Kees Cook
2013-10-02 20:31                                       ` Peter Zijlstra
2013-10-03  8:55                                         ` Stephane Eranian
2013-10-03  9:03                                           ` Peter Zijlstra
2013-10-03  9:13                                             ` Stephane Eranian
2013-10-03 15:34                                               ` Kees Cook
2013-10-07 21:04                                             ` Stephane Eranian
2013-10-08  6:54                                               ` Peter Zijlstra
2013-10-08  7:15                                                 ` Stephane Eranian
2013-10-08  9:36                                                   ` Peter Zijlstra
2013-10-08  9:42                                                     ` Stephane Eranian
2013-10-08  9:54                                                       ` Peter Zijlstra
2013-10-03 18:32                                           ` Andi Kleen
2013-10-07 11:16                     ` Stephane Eranian
2013-10-07 11:32                       ` Peter Zijlstra
2013-10-02 15:22                 ` Ingo Molnar [this message]
2013-10-08 14:23 ` David Ahern
2013-10-08 19:41   ` Ingo Molnar
2013-10-08 19:54     ` Stephane Eranian
2013-10-08 19:57       ` David Ahern
2013-10-09  9:54         ` Ingo Molnar
2013-10-09  9:59       ` Ingo Molnar
2013-10-09 10:39         ` Peter Zijlstra

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