Kees Cook <[email protected]> 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 <[email protected]> > Cc: Nicholas Piggin <[email protected]> > Cc: Christophe Leroy <[email protected]> > Cc: "Aneesh Kumar K.V" <[email protected]> > Cc: "Naveen N. Rao" <[email protected]> > Cc: Mahesh Salgaonkar <[email protected]> > Cc: Vasant Hegde <[email protected]> > Cc: dingsenjie <[email protected]> > Cc: [email protected] > Cc: Aneesh Kumar K.V <[email protected]> > Cc: Naveen N. Rao <[email protected]> > Signed-off-by: Kees Cook <[email protected]> > --- > 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 <[email protected]> (powerpc) cheers
