Am Donnerstag, dem 10.08.2023 um 13:59 +0000 schrieb Qing Zhao:
>
> > On Aug 10, 2023, at 2:58 AM, Martin Uecker <muec...@gwdg.de> wrote:
> >
> > Am Mittwoch, dem 09.08.2023 um 20:10 +0000 schrieb Qing Zhao:
> > >
> > > > On Aug 9, 2023, at 12:21 PM, Michael Matz <m...@suse.de> wrote:
> >
> > I am not sure for the reason given above. The following
> > code would not work:
> >
> > struct foo_flex { int a; short b; char t[]; } x;
> > x.a = 1;
> > struct foo_flex *p = malloc(sizeof(x) + x.a);
> > if (!p) abort();
> > memcpy(p, &x, sizeof(x)); // initialize struct
> >
> Okay.
> Then, the user still should use the sizeof(struct foo_flex) + N *
> sizeof(foo->t) for the allocation, even though this might allocate more bytes
> than necessary. (But this is safe)
>
> Let me know if I still miss anything.
The question is not only what the user should use to
allocate, but also what BDOS should return. In my
example the user uses the sizeof() + N * sizeof
formula and the memcpy is safe, but it would be flagged
as a buffer overrun if BDOS uses the offsetof formula.
Martin
