Hi Vasily, Pablo,
On Thu, 17 Dec 2020, Vasily Averin wrote:
> currently mtype_resize() can cause oops
>
> t = ip_set_alloc(htable_size(htable_bits));
> if (!t) {
> ret = -ENOMEM;
> goto out;
> }
> t->hregion = ip_set_alloc(ahash_sizeof_regions(htable_bits));
>
> Increased htable_bits can force htable_size() to return 0.
> In own turn ip_set_alloc(0) returns not 0 but ZERO_SIZE_PTR,
> so follwoing access to t->hregion should trigger an OOPS.
>
> Signed-off-by: Vasily Averin <vvs@xxxxxxxxxxxxx>
Good catch, thank you Vasily.
Acked-by: Jozsef Kadlecsik <kadlec@xxxxxxxxxxxxx>
Best regards,
Jozsef
> ---
> net/netfilter/ipset/ip_set_hash_gen.h | 22 +++++++++++++---------
> 1 file changed, 13 insertions(+), 9 deletions(-)
>
> diff --git a/net/netfilter/ipset/ip_set_hash_gen.h b/net/netfilter/ipset/ip_set_hash_gen.h
> index 7d01086..7cd1d31 100644
> --- a/net/netfilter/ipset/ip_set_hash_gen.h
> +++ b/net/netfilter/ipset/ip_set_hash_gen.h
> @@ -630,7 +630,7 @@ struct mtype_resize_ad {
> struct htype *h = set->data;
> struct htable *t, *orig;
> u8 htable_bits;
> - size_t dsize = set->dsize;
> + size_t hsize, dsize = set->dsize;
> #ifdef IP_SET_HASH_WITH_NETS
> u8 flags;
> struct mtype_elem *tmp;
> @@ -654,14 +654,12 @@ struct mtype_resize_ad {
> retry:
> ret = 0;
> htable_bits++;
> - if (!htable_bits) {
> - /* In case we have plenty of memory :-) */
> - pr_warn("Cannot increase the hashsize of set %s further\n",
> - set->name);
> - ret = -IPSET_ERR_HASH_FULL;
> - goto out;
> - }
> - t = ip_set_alloc(htable_size(htable_bits));
> + if (!htable_bits)
> + goto hbwarn;
> + hsize = htable_size(htable_bits);
> + if (!hsize)
> + goto hbwarn;
> + t = ip_set_alloc(hsize);
> if (!t) {
> ret = -ENOMEM;
> goto out;
> @@ -803,6 +801,12 @@ struct mtype_resize_ad {
> if (ret == -EAGAIN)
> goto retry;
> goto out;
> +
> +hbwarn:
> + /* In case we have plenty of memory :-) */
> + pr_warn("Cannot increase the hashsize of set %s further\n", set->name);
> + ret = -IPSET_ERR_HASH_FULL;
> + goto out;
> }
>
> /* Get the current number of elements and ext_size in the set */
> --
> 1.8.3.1
>
>
-
E-mail : kadlec@xxxxxxxxxxxxxxxxx, kadlecsik.jozsef@xxxxxxxxx
PGP key : https://wigner.hu/~kadlec/pgp_public_key.txt
Address : Wigner Research Centre for Physics
H-1525 Budapest 114, POB. 49, Hungary
