On 1/22/24 18:27, Kees Cook wrote:
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: Dinh Nguyen <dingu...@kernel.org> Cc: Jann Horn <ja...@google.com> Cc: Ley Foon Tan <ley.foon....@intel.com> Signed-off-by: Kees Cook <keesc...@chromium.org> --- arch/nios2/kernel/sys_nios2.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
Acked-by: Dinh Nguyen <dingu...@kernel.org>
