Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf

Pablo Neira Ayuso says:

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

The following patchset contains Netfilter fixes for your net tree:

1) Fix list corruption in device notifier in the masquerade
   infrastructure, from Florian Westphal.

2) Fix double-free of sets and use-after-free when deleting elements.

3) Don't bogusly return EBUSY when removing a set after flush command.

4) Use-after-free in dynamically allocate operations.

5) Don't report a new ruleset generation to userspace if transaction
   list is empty, this invalidates the userspace cache innecessarily.
   From Florian Westphal.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/netfilter/nf_tables.h

@@ -382,6 +382,7 @@ void nft_unregister_set(struct nft_set_type *type);
  * 	@dtype: data type (verdict or numeric type defined by userspace)
  * 	@objtype: object type (see NFT_OBJECT_* definitions)
  * 	@size: maximum set size
+ *	@use: number of rules references to this set
  * 	@nelems: number of elements
  * 	@ndeact: number of deactivated elements queued for removal
  *	@timeout: default timeout value in jiffies
@@ -407,6 +408,7 @@ struct nft_set {
 	u32				dtype;
 	u32				objtype;
 	u32				size;
+	u32				use;
 	atomic_t			nelems;
 	u32				ndeact;
 	u64				timeout;
@@ -416,7 +418,8 @@ struct nft_set {
 	unsigned char			*udata;
 	/* runtime data below here */
 	const struct nft_set_ops	*ops ____cacheline_aligned;
-	u16				flags:14,
+	u16				flags:13,
+					bound:1,
 					genmask:2;
 	u8				klen;
 	u8				dlen;
@@ -466,6 +469,10 @@ struct nft_set_binding {
 	u32				flags;
 };
 
+enum nft_trans_phase;
+void nf_tables_deactivate_set(const struct nft_ctx *ctx, struct nft_set *set,
+			      struct nft_set_binding *binding,
+			      enum nft_trans_phase phase);
 int nf_tables_bind_set(const struct nft_ctx *ctx, struct nft_set *set,
 		       struct nft_set_binding *binding);
 void nf_tables_unbind_set(const struct nft_ctx *ctx, struct nft_set *set,
@@ -1344,15 +1351,12 @@ struct nft_trans_rule {
 struct nft_trans_set {
 	struct nft_set			*set;
 	u32				set_id;
-	bool				bound;
 };
 
 #define nft_trans_set(trans)	\
 	(((struct nft_trans_set *)trans->data)->set)
 #define nft_trans_set_id(trans)	\
 	(((struct nft_trans_set *)trans->data)->set_id)
-#define nft_trans_set_bound(trans)	\
-	(((struct nft_trans_set *)trans->data)->bound)
 
 struct nft_trans_chain {
 	bool				update;

net/netfilter/nf_nat_masquerade.c

@@ -11,7 +11,8 @@
 #include <net/netfilter/ipv6/nf_nat_masquerade.h>
 
 static DEFINE_MUTEX(masq_mutex);
-static unsigned int masq_refcnt __read_mostly;
+static unsigned int masq_refcnt4 __read_mostly;
+static unsigned int masq_refcnt6 __read_mostly;
 
 unsigned int
 nf_nat_masquerade_ipv4(struct sk_buff *skb, unsigned int hooknum,
@@ -141,8 +142,13 @@ int nf_nat_masquerade_ipv4_register_notifier(void)
 	int ret = 0;
 
 	mutex_lock(&masq_mutex);
+	if (WARN_ON_ONCE(masq_refcnt4 == UINT_MAX)) {
+		ret = -EOVERFLOW;
+		goto out_unlock;
+	}
+
 	/* check if the notifier was already set */
-	if (++masq_refcnt > 1)
+	if (++masq_refcnt4 > 1)
 		goto out_unlock;
 
 	/* Register for device down reports */
@@ -160,7 +166,7 @@ int nf_nat_masquerade_ipv4_register_notifier(void)
 err_unregister:
 	unregister_netdevice_notifier(&masq_dev_notifier);
 err_dec:
-	masq_refcnt--;
+	masq_refcnt4--;
 out_unlock:
 	mutex_unlock(&masq_mutex);
 	return ret;
@@ -171,7 +177,7 @@ void nf_nat_masquerade_ipv4_unregister_notifier(void)
 {
 	mutex_lock(&masq_mutex);
 	/* check if the notifier still has clients */
-	if (--masq_refcnt > 0)
+	if (--masq_refcnt4 > 0)
 		goto out_unlock;
 
 	unregister_netdevice_notifier(&masq_dev_notifier);
@@ -321,25 +327,23 @@ int nf_nat_masquerade_ipv6_register_notifier(void)
 	int ret = 0;
 
 	mutex_lock(&masq_mutex);
-	/* check if the notifier is already set */
-	if (++masq_refcnt > 1)
+	if (WARN_ON_ONCE(masq_refcnt6 == UINT_MAX)) {
+		ret = -EOVERFLOW;
 		goto out_unlock;
+	}
 
-	ret = register_netdevice_notifier(&masq_dev_notifier);
-	if (ret)
-		goto err_dec;
+	/* check if the notifier is already set */
+	if (++masq_refcnt6 > 1)
+		goto out_unlock;
 
 	ret = register_inet6addr_notifier(&masq_inet6_notifier);
 	if (ret)
-		goto err_unregister;
+		goto err_dec;
 
 	mutex_unlock(&masq_mutex);
 	return ret;
-
-err_unregister:
-	unregister_netdevice_notifier(&masq_dev_notifier);
 err_dec:
-	masq_refcnt--;
+	masq_refcnt6--;
 out_unlock:
 	mutex_unlock(&masq_mutex);
 	return ret;
@@ -350,11 +354,10 @@ void nf_nat_masquerade_ipv6_unregister_notifier(void)
 {
 	mutex_lock(&masq_mutex);
 	/* check if the notifier still has clients */
-	if (--masq_refcnt > 0)
+	if (--masq_refcnt6 > 0)
 		goto out_unlock;
 
 	unregister_inet6addr_notifier(&masq_inet6_notifier);
-	unregister_netdevice_notifier(&masq_dev_notifier);
 out_unlock:
 	mutex_unlock(&masq_mutex);
 }

net/netfilter/nf_tables_api.c

@@ -142,7 +142,7 @@ static void nft_set_trans_bind(const struct nft_ctx *ctx, struct nft_set *set)
 	list_for_each_entry_reverse(trans, &net->nft.commit_list, list) {
 		if (trans->msg_type == NFT_MSG_NEWSET &&
 		    nft_trans_set(trans) == set) {
-			nft_trans_set_bound(trans) = true;
+			set->bound = true;
 			break;
 		}
 	}
@@ -2162,9 +2162,11 @@ static int nf_tables_newexpr(const struct nft_ctx *ctx,
 static void nf_tables_expr_destroy(const struct nft_ctx *ctx,
 				   struct nft_expr *expr)
 {
+	const struct nft_expr_type *type = expr->ops->type;
+
 	if (expr->ops->destroy)
 		expr->ops->destroy(ctx, expr);
-	module_put(expr->ops->type->owner);
+	module_put(type->owner);
 }
 
 struct nft_expr *nft_expr_init(const struct nft_ctx *ctx,
@@ -3672,6 +3674,9 @@ static int nf_tables_newset(struct net *net, struct sock *nlsk,
 
 static void nft_set_destroy(struct nft_set *set)
 {
+	if (WARN_ON(set->use > 0))
+		return;
+
 	set->ops->destroy(set);
 	module_put(to_set_type(set->ops)->owner);
 	kfree(set->name);
@@ -3712,7 +3717,7 @@ static int nf_tables_delset(struct net *net, struct sock *nlsk,
 		NL_SET_BAD_ATTR(extack, attr);
 		return PTR_ERR(set);
 	}
-	if (!list_empty(&set->bindings) ||
+	if (set->use ||
 	    (nlh->nlmsg_flags & NLM_F_NONREC && atomic_read(&set->nelems) > 0)) {
 		NL_SET_BAD_ATTR(extack, attr);
 		return -EBUSY;
@@ -3742,6 +3747,9 @@ int nf_tables_bind_set(const struct nft_ctx *ctx, struct nft_set *set,
 	struct nft_set_binding *i;
 	struct nft_set_iter iter;
 
+	if (set->use == UINT_MAX)
+		return -EOVERFLOW;
+
 	if (!list_empty(&set->bindings) && nft_set_is_anonymous(set))
 		return -EBUSY;
 
@@ -3769,6 +3777,7 @@ int nf_tables_bind_set(const struct nft_ctx *ctx, struct nft_set *set,
 	binding->chain = ctx->chain;
 	list_add_tail_rcu(&binding->list, &set->bindings);
 	nft_set_trans_bind(ctx, set);
+	set->use++;
 
 	return 0;
 }
@@ -3788,6 +3797,25 @@ void nf_tables_unbind_set(const struct nft_ctx *ctx, struct nft_set *set,
 }
 EXPORT_SYMBOL_GPL(nf_tables_unbind_set);
 
+void nf_tables_deactivate_set(const struct nft_ctx *ctx, struct nft_set *set,
+			      struct nft_set_binding *binding,
+			      enum nft_trans_phase phase)
+{
+	switch (phase) {
+	case NFT_TRANS_PREPARE:
+		set->use--;
+		return;
+	case NFT_TRANS_ABORT:
+	case NFT_TRANS_RELEASE:
+		set->use--;
+		/* fall through */
+	default:
+		nf_tables_unbind_set(ctx, set, binding,
+				     phase == NFT_TRANS_COMMIT);
+	}
+}
+EXPORT_SYMBOL_GPL(nf_tables_deactivate_set);
+
 void nf_tables_destroy_set(const struct nft_ctx *ctx, struct nft_set *set)
 {
 	if (list_empty(&set->bindings) && nft_set_is_anonymous(set))
@@ -6536,6 +6564,11 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb)
 	struct nft_chain *chain;
 	struct nft_table *table;
 
+	if (list_empty(&net->nft.commit_list)) {
+		mutex_unlock(&net->nft.commit_mutex);
+		return 0;
+	}
+
 	/* 0. Validate ruleset, otherwise roll back for error reporting. */
 	if (nf_tables_validate(net) < 0)
 		return -EAGAIN;
@@ -6709,7 +6742,6 @@ static void nf_tables_abort_release(struct nft_trans *trans)
 		nf_tables_rule_destroy(&trans->ctx, nft_trans_rule(trans));
 		break;
 	case NFT_MSG_NEWSET:
-		if (!nft_trans_set_bound(trans))
 		nft_set_destroy(nft_trans_set(trans));
 		break;
 	case NFT_MSG_NEWSETELEM:
@@ -6783,7 +6815,10 @@ static int __nf_tables_abort(struct net *net)
 			break;
 		case NFT_MSG_NEWSET:
 			trans->ctx.table->use--;
-			if (!nft_trans_set_bound(trans))
+			if (nft_trans_set(trans)->bound) {
+				nft_trans_destroy(trans);
+				break;
+			}
 			list_del_rcu(&nft_trans_set(trans)->list);
 			break;
 		case NFT_MSG_DELSET:
@@ -6792,8 +6827,11 @@ static int __nf_tables_abort(struct net *net)
 			nft_trans_destroy(trans);
 			break;
 		case NFT_MSG_NEWSETELEM:
+			if (nft_trans_elem_set(trans)->bound) {
+				nft_trans_destroy(trans);
+				break;
+			}
 			te = (struct nft_trans_elem *)trans->data;
-
 			te->set->ops->remove(net, te->set, &te->elem);
 			atomic_dec(&te->set->nelems);
 			break;

net/netfilter/nft_dynset.c

@@ -240,11 +240,15 @@ static void nft_dynset_deactivate(const struct nft_ctx *ctx,
 {
 	struct nft_dynset *priv = nft_expr_priv(expr);
 
-	if (phase == NFT_TRANS_PREPARE)
-		return;
+	nf_tables_deactivate_set(ctx, priv->set, &priv->binding, phase);
+}
+
+static void nft_dynset_activate(const struct nft_ctx *ctx,
+				const struct nft_expr *expr)
+{
+	struct nft_dynset *priv = nft_expr_priv(expr);
 
-	nf_tables_unbind_set(ctx, priv->set, &priv->binding,
-			     phase == NFT_TRANS_COMMIT);
+	priv->set->use++;
 }
 
 static void nft_dynset_destroy(const struct nft_ctx *ctx,
@@ -292,6 +296,7 @@ static const struct nft_expr_ops nft_dynset_ops = {
 	.eval		= nft_dynset_eval,
 	.init		= nft_dynset_init,
 	.destroy	= nft_dynset_destroy,
+	.activate	= nft_dynset_activate,
 	.deactivate	= nft_dynset_deactivate,
 	.dump		= nft_dynset_dump,
 };

net/netfilter/nft_lookup.c

@@ -127,11 +127,15 @@ static void nft_lookup_deactivate(const struct nft_ctx *ctx,
 {
 	struct nft_lookup *priv = nft_expr_priv(expr);
 
-	if (phase == NFT_TRANS_PREPARE)
-		return;
+	nf_tables_deactivate_set(ctx, priv->set, &priv->binding, phase);
+}
+
+static void nft_lookup_activate(const struct nft_ctx *ctx,
+				const struct nft_expr *expr)
+{
+	struct nft_lookup *priv = nft_expr_priv(expr);
 
-	nf_tables_unbind_set(ctx, priv->set, &priv->binding,
-			     phase == NFT_TRANS_COMMIT);
+	priv->set->use++;
 }
 
 static void nft_lookup_destroy(const struct nft_ctx *ctx,
@@ -222,6 +226,7 @@ static const struct nft_expr_ops nft_lookup_ops = {
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_lookup)),
 	.eval		= nft_lookup_eval,
 	.init		= nft_lookup_init,
+	.activate	= nft_lookup_activate,
 	.deactivate	= nft_lookup_deactivate,
 	.destroy	= nft_lookup_destroy,
 	.dump		= nft_lookup_dump,

net/netfilter/nft_objref.c

@@ -162,11 +162,15 @@ static void nft_objref_map_deactivate(const struct nft_ctx *ctx,
 {
 	struct nft_objref_map *priv = nft_expr_priv(expr);
 
-	if (phase == NFT_TRANS_PREPARE)
-		return;
+	nf_tables_deactivate_set(ctx, priv->set, &priv->binding, phase);
+}
+
+static void nft_objref_map_activate(const struct nft_ctx *ctx,
+				    const struct nft_expr *expr)
+{
+	struct nft_objref_map *priv = nft_expr_priv(expr);
 
-	nf_tables_unbind_set(ctx, priv->set, &priv->binding,
-			     phase == NFT_TRANS_COMMIT);
+	priv->set->use++;
 }
 
 static void nft_objref_map_destroy(const struct nft_ctx *ctx,
@@ -183,6 +187,7 @@ static const struct nft_expr_ops nft_objref_map_ops = {
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_objref_map)),
 	.eval		= nft_objref_map_eval,
 	.init		= nft_objref_map_init,
+	.activate	= nft_objref_map_activate,
 	.deactivate	= nft_objref_map_deactivate,
 	.destroy	= nft_objref_map_destroy,
 	.dump		= nft_objref_map_dump,