From: Rasmus Villemoes Date: Wed, 10 Apr 2019 20:27:25 +0000 (+0200) Subject: overflow.h: Add comment documenting __ab_c_size() X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=e0478542cfd4d993e38d5f92a3f3ecd238805e96;p=openwrt%2Fstaging%2Fblogic.git overflow.h: Add comment documenting __ab_c_size() __ab_c_size() is a somewhat opaque name. Document its purpose, and while at it, rename the parameters to actually match the abc naming. [ bp: glued a complete patch from chunks on LKML. ] Reported-by: Borislav Petkov Signed-off-by: Rasmus Villemoes Signed-off-by: Borislav Petkov Acked-by: Kees Cook Cc: Matthew Wilcox Link: https://lkml.kernel.org/r/20190405045711.30339-1-bp@alien8.de --- diff --git a/include/linux/overflow.h b/include/linux/overflow.h index 40b48e2133cb..6534a727cadb 100644 --- a/include/linux/overflow.h +++ b/include/linux/overflow.h @@ -278,11 +278,15 @@ static inline __must_check size_t array3_size(size_t a, size_t b, size_t c) return bytes; } -static inline __must_check size_t __ab_c_size(size_t n, size_t size, size_t c) +/* + * Compute a*b+c, returning SIZE_MAX on overflow. Internal helper for + * struct_size() below. + */ +static inline __must_check size_t __ab_c_size(size_t a, size_t b, size_t c) { size_t bytes; - if (check_mul_overflow(n, size, &bytes)) + if (check_mul_overflow(a, b, &bytes)) return SIZE_MAX; if (check_add_overflow(bytes, c, &bytes)) return SIZE_MAX;