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