Hi, In preparation for gaining instrumentation for signed[1], unsigned[2], and pointer[3] wrap-around, expand the overflow header to include wrap-around helpers that can be used to annotate arithmetic where wrapped calculations are expected (e.g. atomics).
After spending time getting the unsigned integer wrap-around sanitizer running warning-free on a basic x86_64 boot[4], I think the *_wrap() helpers first argument being the output type makes the most sense (as suggested by Rasmus). -Kees Link: https://github.com/KSPP/linux/issues/26 [1] Link: https://github.com/KSPP/linux/issues/27 [2] Link: https://github.com/KSPP/linux/issues/344 [3] Link: https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git/log/?h=devel/overflow/enable-unsigned-sanitizer [4] Kees Cook (5): overflow: Adjust check_*_overflow() kern-doc to reflect results overflow: Expand check_add_overflow() for pointer addition overflow: Introduce add_would_overflow() overflow: Introduce add_wrap(), sub_wrap(), and mul_wrap() overflow: Introduce inc_wrap() and dec_wrap() include/linux/compiler_types.h | 10 ++ include/linux/overflow.h | 164 ++++++++++++++++++++++++++++++--- lib/overflow_kunit.c | 77 ++++++++++++++-- 3 files changed, 228 insertions(+), 23 deletions(-) -- 2.34.1
