On Wed, Oct 2, 2013 at 2:46 PM, 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 was going to say just that. But that's not the default, paranoid level is at 1 by default and not 2. So I supposedly can still do:
$ perf record -e cycles ...... In per-thread mode and collect kernel level addresses. -- 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/
