https://bugzilla.kernel.org/show_bug.cgi?id=216073 --- Comment #13 from willy@xxxxxxxxxxxxx --- On Sun, Jun 12, 2022 at 03:03:20PM +0200, Uladzislau Rezki wrote: > > @@ -181,8 +181,9 @@ static inline void check_heap_object(const void *ptr, > unsigned long n, > > return; > > } > > > > - offset = ptr - area->addr; > > - if (offset + n > get_vm_area_size(area)) > > + /* XXX: We should also abort for free vmap_areas */ > > + offset = (unsigned long)ptr - area->va_start; > > > I was a bit confused about "offset" and why it is needed here. It is always > zero. > So we can get rid of it to make it less confused. From the other hand a zero > offset > contributes to nothing. I don't think offset is necessarily zero. 'ptr' is a pointer somewhere in the object, not necessarily the start of the object. > > > > + if (offset + n >= area->va_end) > > > I think it is a bit wrong. As i see it, "n" is a size and what we would like > to do > here is boundary check: > > <snip> > if (n > va_size(area)) > usercopy_abort("vmalloc", NULL, to_user, 0, n); > <snip> Hmm ... we should probably be more careful about wrapping. if (n > area->va_end - addr) usercopy_abort("vmalloc", NULL, to_user, offset, n); ... and that goes for the whole function actually. I'll split that into a separate change. -- You may reply to this email to add a comment. You are receiving this mail because: You are watching someone on the CC list of the bug.
