On Thu, Aug 03, 2023 at 07:55:54PM +0000, Qing Zhao wrote:
>
>
> > On Aug 3, 2023, at 1:51 PM, Kees Cook <k...@kernel.org> wrote:
> >
> > On August 3, 2023 10:34:24 AM PDT, Qing Zhao <qing.z...@oracle.com> wrote:
> >> One thing I need to point out first is, currently, even for regular fixed
> >> size array in the structure,
> >> We have this same issue, for example:
> >>
> >> #define LENGTH 10
> >>
> >> struct fix {
> >> size_t foo;
> >> int array[LENGTH];
> >> };
> >>
> >> …
> >> int main ()
> >> {
> >> struct fix *p;
> >> p = alloc_buf_more ();
> >>
> >> expect(__builtin_object_size(p->array, 1), LENGTH * sizeof(int));
> >> expect(__builtin_object_size(p->array, 0), -1);
> >> }
> >>
> >> Currently, for __builtin_object_size(p->array, 0), GCC return UNKNOWN for
> >> it.
> >> This is not a special issue for flexible array member.
> >
> > Is this true with -fstrict-flex-arrays=3 ?
>
> Yes.
Okay, right, I understand now -- it doesn't see the allocation, therefore
max size is unknown. Sounds good.
-Kees
--
Kees Cook
