netfilter: ipset: fixes possible oops in mtype_resize

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@virtuozzo.com>
Signed-off-by: Jozsef Kadlecsik <kadlec@netfilter.org>

diff --git a/kernel/net/netfilter/ipset/ip_set_hash_gen.h b/kernel/net/netfilter/ipset/ip_set_hash_gen.h
index acfe0c89974981bf4387694975e7ff93b58691ac..4a4062e7a2fcecbc24c2d003050bd62cd35ea05f 100644 (file)
--- a/kernel/net/netfilter/ipset/ip_set_hash_gen.h
+++ b/kernel/net/netfilter/ipset/ip_set_hash_gen.h
@@ -149,6 +149,10 @@ htable_bits(u32 hashsize)
        /* Assume that hashsize == 2^htable_bits */
        u8 bits = fls(hashsize - 1);
 
+       /* We must fit both into u32 in jhash and size_t */
+       if (bits >= 31)
+               return 31;
+
        if (jhash_size(bits) != hashsize)
                /* Round up to the first 2^n value */
                bits = fls(hashsize);
@@ -640,7 +644,7 @@ mtype_resize(struct ip_set *set, bool retried)
        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;
@@ -664,14 +668,12 @@ mtype_resize(struct ip_set *set, bool retried)
 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;
@@ -813,6 +815,12 @@ cleanup:
        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  */