Re: [PATCH v2] selinux: check sidtab limit before adding a new entry

[Paul Moore <paul@paul-moore.com>]

On Tue, Jul 23, 2019 at 2:51 AM Ondrej Mosnacek <omosnace@redhat.com> wrote:
>
> We need to error out when trying to add an entry above SIDTAB_MAX in
> sidtab_reverse_lookup() to avoid overflow on the odd chance that this
> happens.
>
> Fixes: ee1a84fdfeed ("selinux: overhaul sidtab to fix bug and improve performance")
> Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
> ---
>  security/selinux/ss/sidtab.c | 5 +++++
>  1 file changed, 5 insertions(+)

Thanks.  This looks like -stable material to me so I've marked it as
such and merged it into selinux/stable-5.3; assuming it passes
testing, and as long as I don't hear any objections, I'll send it up
to Linus later this week.

> diff --git a/security/selinux/ss/sidtab.c b/security/selinux/ss/sidtab.c
> index e63a90ff2728..1f0a6eaa2d6a 100644
> --- a/security/selinux/ss/sidtab.c
> +++ b/security/selinux/ss/sidtab.c
> @@ -286,6 +286,11 @@ static int sidtab_reverse_lookup(struct sidtab *s, struct context *context,
>                 ++count;
>         }
>
> +       /* bail out if we already reached max entries */
> +       rc = -EOVERFLOW;
> +       if (count >= SIDTAB_MAX)
> +               goto out_unlock;
> +
>         /* insert context into new entry */
>         rc = -ENOMEM;
>         dst = sidtab_do_lookup(s, count, 1);
> --
> 2.21.0

-- 
paul moore
www.paul-moore.com