Re: [PATCH] perfcounters: allow sysadmin to restrict non-rootcounting of kernel events

[Peter Zijlstra]

On Wed, 2009-02-18 at 21:26 +1100, Paul Mackerras wrote:
> Impact: security feature
> 
> This allows the sysadmin to prevent non-root users from counting
> hardware events that occur in kernel or hypervisor mode via a sysfs file:
> 
> 	/sys/devices/system/cpu/perf_counters/restrict_kernel_events
> 
> This defaults to off (0), allowing users to count kernel and hypervisor
> events, but if the sysadmin writes 1 to that file, any new counters
> created by non-root users will automatically be set to ignore kernel
> and hypervisor events.
> 
> This could be useful if there is a concern that allowing non-root users
> to count kernel or hypervisor events might leak sensitive information.

I would expect it the other way around, don't allow users access to
kernel/hv events unless explicitly granted.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/