From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <8ef1669cdfbcc6114eebc30c610c91c191c7cc7a.camel@russell.cc> Subject: Re: [PATCH 0/7] Kernel Userspace Protection for radix From: Russell Currey Date: Fri, 22 Feb 2019 11:09:22 +1100 In-Reply-To: References: <20190221093601.27920-1-ruscur@russell.cc> Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit To: Kees Cook Cc: PowerPC , Michael Ellerman , Nick Piggin , Christophe Leroy , Kernel Hardening List-ID: On Thu, 2019-02-21 at 08:07 -0800, Kees Cook wrote: > On Thu, Feb 21, 2019 at 1:36 AM Russell Currey > wrote: > > The first three patches of these series are from Christophe's work > > and are > > the bare minimum framework needed to implement the support for > > radix. > > > > In patch 3, I have removed from Christophe's patch my > > implementation of > > the 64-bit exception handling code, since we don't have an answer > > for > > making nested exceptions work yet. This is mentioned in the final > > KUAP > > patch. Regardless, this is still a significant security > > improvement > > and greatly narrows the attack surface. > > Nice! Am I understanding correctly that with this series powerpc9 and > later, using radix, will pass the lkdtm tests for KUAP and KUEP (i.e. > EXEC_USERSPACE and ACCESS_USERSPACE)? Yes! We've had execution prevention for a while on radix (which is default on POWER9) since 3b10d0095a1e, the only functional thing this series does is allow disabling it with nosmep. This series adds access prevention.