Merge tag 'nf-23-05-17' of https://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf

Florian Westphal says:

====================
Netfilter fixes for net

1. Silence warning about unused variable when CONFIG_NF_NAT=n, from Tom Rix.
2. nftables: Fix possible out-of-bounds access, from myself.
3. nftables: fix null deref+UAF during element insertion into rbtree,
   also from myself.

* tag 'nf-23-05-17' of https://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf:
  netfilter: nft_set_rbtree: fix null deref on element insertion
  netfilter: nf_tables: fix nft_trans type confusion
  netfilter: conntrack: define variables exp_nat_nla_policy and any_addr with CONFIG_NF_NAT
====================

Link: https://lore.kernel.org/r/20230517123756.7353-1-fw@strlen.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: kuba-moo

net/netfilter/nf_conntrack_netlink.c

@@ -2976,7 +2976,9 @@ static int ctnetlink_exp_dump_mask(struct sk_buff *skb,
 	return -1;
 }
 
+#if IS_ENABLED(CONFIG_NF_NAT)
 static const union nf_inet_addr any_addr;
+#endif
 
 static __be32 nf_expect_get_id(const struct nf_conntrack_expect *exp)
 {
@@ -3460,10 +3462,12 @@ ctnetlink_change_expect(struct nf_conntrack_expect *x,
 	return 0;
 }
 
+#if IS_ENABLED(CONFIG_NF_NAT)
 static const struct nla_policy exp_nat_nla_policy[CTA_EXPECT_NAT_MAX+1] = {
 	[CTA_EXPECT_NAT_DIR]	= { .type = NLA_U32 },
 	[CTA_EXPECT_NAT_TUPLE]	= { .type = NLA_NESTED },
 };
+#endif
 
 static int
 ctnetlink_parse_expect_nat(const struct nlattr *attr,

net/netfilter/nf_tables_api.c

@@ -3865,12 +3865,10 @@ static struct nft_rule *nft_rule_lookup_byid(const struct net *net,
 	struct nft_trans *trans;
 
 	list_for_each_entry(trans, &nft_net->commit_list, list) {
-		struct nft_rule *rule = nft_trans_rule(trans);
-
 		if (trans->msg_type == NFT_MSG_NEWRULE &&
 		    trans->ctx.chain == chain &&
 		    id == nft_trans_rule_id(trans))
-			return rule;
+			return nft_trans_rule(trans);
 	}
 	return ERR_PTR(-ENOENT);
 }

net/netfilter/nft_set_rbtree.c

@@ -221,25 +221,29 @@ static int nft_rbtree_gc_elem(const struct nft_set *__set,
 {
 	struct nft_set *set = (struct nft_set *)__set;
 	struct rb_node *prev = rb_prev(&rbe->node);
-	struct nft_rbtree_elem *rbe_prev;
+	struct nft_rbtree_elem *rbe_prev = NULL;
 	struct nft_set_gc_batch *gcb;
 
 	gcb = nft_set_gc_batch_check(set, NULL, GFP_ATOMIC);
 	if (!gcb)
 		return -ENOMEM;
 
 	/* search for expired end interval coming before this element. */
-	do {
+	while (prev) {
 		rbe_prev = rb_entry(prev, struct nft_rbtree_elem, node);
 		if (nft_rbtree_interval_end(rbe_prev))
 			break;
 
 		prev = rb_prev(prev);
-	} while (prev != NULL);
+	}
+
+	if (rbe_prev) {
+		rb_erase(&rbe_prev->node, &priv->root);
+		atomic_dec(&set->nelems);
+	}
 
-	rb_erase(&rbe_prev->node, &priv->root);
 	rb_erase(&rbe->node, &priv->root);
-	atomic_sub(2, &set->nelems);
+	atomic_dec(&set->nelems);
 
 	nft_set_gc_batch_add(gcb, rbe);
 	nft_set_gc_batch_complete(gcb);
@@ -268,7 +272,7 @@ static int __nft_rbtree_insert(const struct net *net, const struct nft_set *set,
 			       struct nft_set_ext **ext)
 {
 	struct nft_rbtree_elem *rbe, *rbe_le = NULL, *rbe_ge = NULL;
-	struct rb_node *node, *parent, **p, *first = NULL;
+	struct rb_node *node, *next, *parent, **p, *first = NULL;
 	struct nft_rbtree *priv = nft_set_priv(set);
 	u8 genmask = nft_genmask_next(net);
 	int d, err;
@@ -307,7 +311,9 @@ static int __nft_rbtree_insert(const struct net *net, const struct nft_set *set,
 	 * Values stored in the tree are in reversed order, starting from
 	 * highest to lowest value.
 	 */
-	for (node = first; node != NULL; node = rb_next(node)) {
+	for (node = first; node != NULL; node = next) {
+		next = rb_next(node);
+
 		rbe = rb_entry(node, struct nft_rbtree_elem, node);
 
 		if (!nft_set_elem_active(&rbe->ext, genmask))