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 <bp@suse.de>
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Link: https://lkml.kernel.org/r/20190405045711.30339-1-bp@alien8.de
This commit is contained in:
Rasmus Villemoes 2019-04-10 22:27:25 +02:00 committed by Borislav Petkov
parent 79a3aaa7b8
commit e0478542cf
1 changed files with 6 additions and 2 deletions

View File

@ -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;