On Mon, Oct 10, 2022 at 04:00:39PM -0500, David Teigland wrote:
> On Sat, Oct 08, 2022 at 09:03:28PM -0700, Kees Cook wrote:
> > On Sun, Oct 09, 2022 at 03:05:17PM +1300, Paulo Miguel Almeida wrote:
> > > On Sat, Oct 08, 2022 at 05:18:35PM -0700, Kees Cook wrote:
> > > > This is allocating 1 more byte than before, since the struct size
> > > > didn't change. But this has always allocated too much space, due to the
> > > > struct padding. For a "no binary changes" patch, the above "+ 1" needs
> > > > to be left off.
> > >
> > > That's true. I agree that leaving "+ 1" would work and produce a
> > > no-binary-changes patch due to the existing padding that the structure
> > > has. OTOH, I thought that relying on that space could bite us in the
> > > future if anyone tweaks the struct again...so my reaction was to ensure
> > > that the NUL-terminator space was always guaranteed to be there.
> > > Hence, the change on c693 (objdump above).
> > >
> > > What do you think? Should we keep or leave the above
> > > "+ 1" after the rationale above?
> >
> > I think it depends on what's expected from this allocation. Christine or
> > David, can you speak to this?
>
> Hi, thanks for picking through that. Most likely the intention was to
> allow up to 64 (DLM_LOCKSPACE_LEN) character names, and then use the
> ls_name[1] for the terminating byte. I'd be happy to take the patch
Should this just use:
char ls_name[DLM_LOCKSPACE_LEN + 1];
instead, or is the byte savings worth keeping it dynamically sized?
--
Kees Cook
