18 Jul
2023
18 Jul
'23
1:55 p.m.
On Tue, Jul 18, 2023 at 10:10:04AM +0100, Szabolcs Nagy wrote:
uint64_t *p = map_shadow_stack(0, N*8, 0);
i'd expect p[N-1] to be the end token and p[N-2] to be the cap token, not p[PAGE_ALIGN(N*8)/8-2].
Yes, that probably would be more helpful.
if we allow misalligned size here (and in munmap) then i think it's better to not page align. size%8!=0 || size<16 can be an error.
Honestly I'd be a lot happier to just not allow misalignment but that raises the issue with binaries randomly not working when moved to a kernel with a different page size. I'll have a think but possibly the safest thing would be requiring a multiple of 4K then rounding up to our actual page size.