From: Greg KH <gregkh@linuxfoundation.org>
To: Andi Kleen <ak@linux.intel.com>
Cc: Julian Stecklina <jsteckli@amazon.de>,
linux-kernel@vger.kernel.org,
David Woodhouse <dwmw2@infradead.org>,
Liran Alon <liran.alon@oracle.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Linus Torvalds <torvalds@linux-foundation.org>,
x86@kernel.org,
Kernel Hardening <kernel-hardening@lists.openwall.com>
Subject: Re: [RFC] x86/speculation: add L1 Terminal Fault / Foreshadow demo
Date: Mon, 21 Jan 2019 20:15:41 +0100 [thread overview]
Message-ID: <20190121191541.GB4026@kroah.com> (raw)
In-Reply-To: <20190121183618.GP6118@tassilo.jf.intel.com>
On Mon, Jan 21, 2019 at 10:36:18AM -0800, Andi Kleen wrote:
> > + /* Check the start address: needs to be page-aligned.. */
> > +- if (start & ~PAGE_MASK)
> > ++ if (start & ~PAGE_MASK) {
> > ++
> > ++ /*
> > ++ * XXX Hack
> > ++ *
> > ++ * We re-use this error case to show case a cache load gadget:
> > ++ * There is a mispredicted branch, which leads to prefetching
> > ++ * the cache with attacker controlled data.
> > ++ */
> > ++ asm volatile (
>
> Obviously that can never be added to a standard kernel.
No, that's why it is a patch, right? People want to test things, it's
nice to have a way to easily do this.
> And I don't see much point in shipping test cases that require non
> standard kernel patching. The idea of shipping test cases is that
> you can easily test them, but in this form it can't.
It's better than having nothing at all, which is what we have today. So
I see no harm in it, only benefits.
thanks,
greg k-h
next prev parent reply other threads:[~2019-01-21 19:15 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-21 13:10 [RFC] x86/speculation: add L1 Terminal Fault / Foreshadow demo Julian Stecklina
2019-01-21 18:36 ` Andi Kleen
2019-01-21 19:15 ` Greg KH [this message]
2019-01-21 20:42 ` Kees Cook
2019-01-22 14:34 ` Julian Stecklina
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