Re: [PATCH 07/12] perf_events: add LBR software filter support for Intel X86

[Andi Kleen]

On Thu, Oct 06, 2011 at 06:43:44PM +0200, Peter Zijlstra wrote:
> On Thu, 2011-10-06 at 17:32 +0200, Andi Kleen wrote:
> > > +	kernel_insn_init(&insn, kaddr);
> > > +	insn_get_opcode(&insn);
> > 
> > This makes me uncomfortable. AFAIK that's the first use of the opcode
> > decoder being used directly for user space. It has a quite large attack
> > surface. Who says it cannot be exploited?
> 
> You mean:
> arch/x86/kernel/cpu/perf_event_intel_ds.c:intel_pmu_pebs_fixup_ip()
> doesn't use the opcode decoder on user space code?

True it does. Ok the second.
I know uprobes is planning it too, so the problem has to be handled
eventually.

Still it makes me uncomfortable.

-Andi
-- 
ak@xxxxxxxxxxxxxxx -- Speaking for myself only.
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