Kees Cook <keesc...@chromium.org> writes: > In an effort to separate intentional arithmetic wrap-around from > unexpected wrap-around, we need to refactor places that depend on this > kind of math. One of the most common code patterns of this is: > > VAR + value < VAR > > Notably, this is considered "undefined behavior" for signed and pointer > types, which the kernel works around by using the -fno-strict-overflow > option in the build[1] (which used to just be -fwrapv). Regardless, we > want to get the kernel source to the position where we can meaningfully > instrument arithmetic wrap-around conditions and catch them when they > are unexpected, regardless of whether they are signed[2], unsigned[3], > or pointer[4] types. > > Refactor open-coded wrap-around addition test to use add_would_overflow(). > This paves the way to enabling the wrap-around sanitizers in the future. > > Link: https://git.kernel.org/linus/68df3755e383e6fecf2354a67b08f92f18536594 > [1] > Link: https://github.com/KSPP/linux/issues/26 [2] > Link: https://github.com/KSPP/linux/issues/27 [3] > Link: https://github.com/KSPP/linux/issues/344 [4] > Cc: Michael Ellerman <m...@ellerman.id.au> > Cc: Nicholas Piggin <npig...@gmail.com> > Cc: Christophe Leroy <christophe.le...@csgroup.eu> > Cc: "Aneesh Kumar K.V" <aneesh.ku...@kernel.org> > Cc: "Naveen N. Rao" <naveen.n....@linux.ibm.com> > Cc: Mahesh Salgaonkar <mah...@linux.ibm.com> > Cc: Vasant Hegde <hegdevas...@linux.vnet.ibm.com> > Cc: dingsenjie <dingsen...@yulong.com> > Cc: linuxppc-dev@lists.ozlabs.org > Cc: Aneesh Kumar K.V <aneesh.ku...@kernel.org> > Cc: Naveen N. Rao <naveen.n....@linux.ibm.com> > Signed-off-by: Kees Cook <keesc...@chromium.org> > --- > arch/powerpc/platforms/powernv/opal-prd.c | 2 +- > arch/powerpc/xmon/xmon.c | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-)
Acked-by: Michael Ellerman <m...@ellerman.id.au> (powerpc) cheers
