[PATCH] CIPSO: Fix unaligned memory access in cipso_v4_gentag_hdr

[Paul Moore]

On Thu, Mar 4, 2021 at 4:17 PM Ondrej Mosnacek <omosnace at redhat.com> wrote:
> On Thu, Mar 4, 2021 at 10:09 PM Seergey Nazarov <s-nazarov at yandex.ru> wrote:
> > We need to use put_unaligned when writing 32-bit DOI value
> > in cipso_v4_gentag_hdr to avoid unaligned memory access.
> >
> > Signed-off-by: Sergey Nazarov <s-nazarov at yandex.ru>
> > ---
> >  net/ipv4/cipso_ipv4.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
> > index 471d33a..28dfe40 100644
> > --- a/net/ipv4/cipso_ipv4.c
> > +++ b/net/ipv4/cipso_ipv4.c
> > @@ -1162,7 +1162,7 @@ static void cipso_v4_gentag_hdr(const struct
> > cipso_v4_doi *doi_def,
> >  {
> >         buf[0] = IPOPT_CIPSO;
> >         buf[1] = CIPSO_V4_HDR_LEN + len;
> > -       *(__be32 *)&buf[2] = htonl(doi_def->doi);
> > +       put_unaligned_be32(doi_def->doi, (__be32 *)&buf[2]);
>
> I think you can now also drop the cast, since put_unaligned_be32()
> expects a void *.

Yes, it shouldn't be necessary.

You should also send this to netdev as NetLabel code lives under net/
and goes to Linus via the netdev tree.

Also, looking at the code, there are a few similar spots you should
probably fix while you are revising this patch:

* the short/__be16 assignment in cipso_v4_map_cat_enum_hton()
* the short/__be16 assignments in cipso_v4_map_cat_rng_hton()
* the long/__be32 assignment in calipso_genopt()

-- 
paul moore
www.paul-moore.com