diff mbox series

[nf,v2] netfilter: nf_tables: unbind set in rule from commit path

Message ID 20190201164904.30303-1-pablo@netfilter.org
State Changes Requested
Delegated to: Pablo Neira
Headers show
Series [nf,v2] netfilter: nf_tables: unbind set in rule from commit path | expand

Commit Message

Pablo Neira Ayuso Feb. 1, 2019, 4:49 p.m. UTC 
Anonymous sets that are bound to rules from the same transaction trigger
a kernel splat from the abort path due to double set list removal and
double free.

This patch updates the logic to search for the transaction that is
responsible for creating the set and disable the set list removal and
release, given the rule is now responsible for this.

Moreover, this patch adds the unbind step to deliver the event from the
commit path.  This should not be done from the worker thread, since we
have no guarantees of in-order delivery to the listener.

This patch removes the assumption that both activate and deactivate
callbacks need to be provided.

Fixes: cd5125d8f518 ("netfilter: nf_tables: split set destruction in deactivate and destroy phase")
Reported-by: Mikhail Morfikov <mmorfikov@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
v2: reuse the .deactivate callback, pass a parameter to specify the commit
    phase.

 include/net/netfilter/nf_tables.h | 17 ++++++--
 net/netfilter/nf_tables_api.c     | 85 +++++++++++++++++++--------------------
 net/netfilter/nft_dynset.c        | 18 ++++-----
 net/netfilter/nft_immediate.c     |  6 ++-
 net/netfilter/nft_lookup.c        | 18 ++++-----
 net/netfilter/nft_objref.c        | 18 ++++-----
 6 files changed, 80 insertions(+), 82 deletions(-)

Comments

Florian Westphal Feb. 1, 2019, 5:29 p.m. UTC | #1 
Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> Moreover, this patch adds the unbind step to deliver the event from the
> commit path.  This should not be done from the worker thread, since we
> have no guarantees of in-order delivery to the listener.

Right, they indeed should occur during finalization of commit phase, not
worker.

> This patch removes the assumption that both activate and deactivate
> callbacks need to be provided.

The assumption was that deactive has side effects that might need to
be undone in case another rule in the batch triggers an abort.

AFAICS after this patch .deactivate has no effect if we're still
in the preparation phase so no reactive needed either in case of abort.

IOW, looks good to me, thanks for fixing this.
Pablo Neira Ayuso Feb. 1, 2019, 8:14 p.m. UTC | #2 
On Fri, Feb 01, 2019 at 06:29:22PM +0100, Florian Westphal wrote:
> Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> > Moreover, this patch adds the unbind step to deliver the event from the
> > commit path.  This should not be done from the worker thread, since we
> > have no guarantees of in-order delivery to the listener.
> 
> Right, they indeed should occur during finalization of commit phase, not
> worker.
> 
> > This patch removes the assumption that both activate and deactivate
> > callbacks need to be provided.
> 
> The assumption was that deactive has side effects that might need to
> be undone in case another rule in the batch triggers an abort.
> 
> AFAICS after this patch .deactivate has no effect if we're still
> in the preparation phase so no reactive needed either in case of abort.
> 
> IOW, looks good to me, thanks for fixing this.

Thanks Florian, just noticed a small issue with event order (DELSET
should come after DELRULE for anonymous sets as it uses to be before
this patch) just sent a v3.
diff mbox series

Patch

diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
index 45eba7d7ab38..a66fcd316734 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -469,9 +469,7 @@  struct nft_set_binding {
 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,
-			  struct nft_set_binding *binding);
-void nf_tables_rebind_set(const struct nft_ctx *ctx, struct nft_set *set,
-			  struct nft_set_binding *binding);
+			  struct nft_set_binding *binding, bool commit);
 void nf_tables_destroy_set(const struct nft_ctx *ctx, struct nft_set *set);
 
 /**
@@ -721,6 +719,13 @@  struct nft_expr_type {
 #define NFT_EXPR_STATEFUL		0x1
 #define NFT_EXPR_GC			0x2
 
+enum nft_trans_phase {
+	NFT_TRANS_PREPARE,
+	NFT_TRANS_ABORT,
+	NFT_TRANS_COMMIT,
+	NFT_TRANS_RELEASE
+};
+
 /**
  *	struct nft_expr_ops - nf_tables expression operations
  *
@@ -750,7 +755,8 @@  struct nft_expr_ops {
 	void				(*activate)(const struct nft_ctx *ctx,
 						    const struct nft_expr *expr);
 	void				(*deactivate)(const struct nft_ctx *ctx,
-						      const struct nft_expr *expr);
+						      const struct nft_expr *expr,
+						      enum nft_trans_phase phase);
 	void				(*destroy)(const struct nft_ctx *ctx,
 						   const struct nft_expr *expr);
 	void				(*destroy_clone)(const struct nft_ctx *ctx,
@@ -1335,12 +1341,15 @@  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;
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 7495f29d24e8..76c9724f4118 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -131,6 +131,23 @@  static void nft_trans_destroy(struct nft_trans *trans)
 	kfree(trans);
 }
 
+static void nft_set_trans_bind(const struct nft_ctx *ctx, struct nft_set *set)
+{
+	struct net *net = ctx->net;
+	struct nft_trans *trans;
+
+	if (!nft_set_is_anonymous(set))
+		return;
+
+	list_for_each_entry(trans, &net->nft.commit_list, list) {
+		if (trans->msg_type == NFT_MSG_NEWSET &&
+		    nft_trans_set(trans) == set) {
+			nft_trans_set_bound(trans) = true;
+			break;
+		}
+	}
+}
+
 static int nf_tables_register_hook(struct net *net,
 				   const struct nft_table *table,
 				   struct nft_chain *chain)
@@ -226,18 +243,6 @@  static int nft_delchain(struct nft_ctx *ctx)
 	return err;
 }
 
-/* either expr ops provide both activate/deactivate, or neither */
-static bool nft_expr_check_ops(const struct nft_expr_ops *ops)
-{
-	if (!ops)
-		return true;
-
-	if (WARN_ON_ONCE((!ops->activate ^ !ops->deactivate)))
-		return false;
-
-	return true;
-}
-
 static void nft_rule_expr_activate(const struct nft_ctx *ctx,
 				   struct nft_rule *rule)
 {
@@ -253,14 +258,15 @@  static void nft_rule_expr_activate(const struct nft_ctx *ctx,
 }
 
 static void nft_rule_expr_deactivate(const struct nft_ctx *ctx,
-				     struct nft_rule *rule)
+				     struct nft_rule *rule,
+				     enum nft_trans_phase phase)
 {
 	struct nft_expr *expr;
 
 	expr = nft_expr_first(rule);
 	while (expr != nft_expr_last(rule) && expr->ops) {
 		if (expr->ops->deactivate)
-			expr->ops->deactivate(ctx, expr);
+			expr->ops->deactivate(ctx, expr, phase);
 
 		expr = nft_expr_next(expr);
 	}
@@ -311,7 +317,7 @@  static int nft_delrule(struct nft_ctx *ctx, struct nft_rule *rule)
 		nft_trans_destroy(trans);
 		return err;
 	}
-	nft_rule_expr_deactivate(ctx, rule);
+	nft_rule_expr_deactivate(ctx, rule, NFT_TRANS_PREPARE);
 
 	return 0;
 }
@@ -1972,9 +1978,6 @@  static int nf_tables_delchain(struct net *net, struct sock *nlsk,
  */
 int nft_register_expr(struct nft_expr_type *type)
 {
-	if (!nft_expr_check_ops(type->ops))
-		return -EINVAL;
-
 	nfnl_lock(NFNL_SUBSYS_NFTABLES);
 	if (type->family == NFPROTO_UNSPEC)
 		list_add_tail_rcu(&type->list, &nf_tables_expressions);
@@ -2122,10 +2125,6 @@  static int nf_tables_expr_parse(const struct nft_ctx *ctx,
 			err = PTR_ERR(ops);
 			goto err1;
 		}
-		if (!nft_expr_check_ops(ops)) {
-			err = -EINVAL;
-			goto err1;
-		}
 	} else
 		ops = type->ops;
 
@@ -2555,7 +2554,7 @@  static void nf_tables_rule_destroy(const struct nft_ctx *ctx,
 static void nf_tables_rule_release(const struct nft_ctx *ctx,
 				   struct nft_rule *rule)
 {
-	nft_rule_expr_deactivate(ctx, rule);
+	nft_rule_expr_deactivate(ctx, rule, NFT_TRANS_RELEASE);
 	nf_tables_rule_destroy(ctx, rule);
 }
 
@@ -3761,39 +3760,30 @@  int nf_tables_bind_set(const struct nft_ctx *ctx, struct nft_set *set,
 bind:
 	binding->chain = ctx->chain;
 	list_add_tail_rcu(&binding->list, &set->bindings);
+	nft_set_trans_bind(ctx, set);
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(nf_tables_bind_set);
 
-void nf_tables_rebind_set(const struct nft_ctx *ctx, struct nft_set *set,
-			  struct nft_set_binding *binding)
-{
-	if (list_empty(&set->bindings) && nft_set_is_anonymous(set) &&
-	    nft_is_active(ctx->net, set))
-		list_add_tail_rcu(&set->list, &ctx->table->sets);
-
-	list_add_tail_rcu(&binding->list, &set->bindings);
-}
-EXPORT_SYMBOL_GPL(nf_tables_rebind_set);
-
 void nf_tables_unbind_set(const struct nft_ctx *ctx, struct nft_set *set,
-		          struct nft_set_binding *binding)
+			  struct nft_set_binding *binding, bool event)
 {
 	list_del_rcu(&binding->list);
 
-	if (list_empty(&set->bindings) && nft_set_is_anonymous(set) &&
-	    nft_is_active(ctx->net, set))
+	if (list_empty(&set->bindings) && nft_set_is_anonymous(set)) {
 		list_del_rcu(&set->list);
+		if (event)
+			nf_tables_set_notify(ctx, set, NFT_MSG_DELSET,
+					     GFP_KERNEL);
+	}
 }
 EXPORT_SYMBOL_GPL(nf_tables_unbind_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) &&
-	    nft_is_active(ctx->net, set)) {
-		nf_tables_set_notify(ctx, set, NFT_MSG_DELSET, GFP_ATOMIC);
+	if (list_empty(&set->bindings) && nft_set_is_anonymous(set))
 		nft_set_destroy(set);
-	}
 }
 EXPORT_SYMBOL_GPL(nf_tables_destroy_set);
 
@@ -6618,6 +6608,9 @@  static int nf_tables_commit(struct net *net, struct sk_buff *skb)
 			nft_trans_destroy(trans);
 			break;
 		case NFT_MSG_DELRULE:
+			nft_rule_expr_deactivate(&trans->ctx,
+						 nft_trans_rule(trans),
+						 NFT_TRANS_COMMIT);
 			list_del_rcu(&nft_trans_rule(trans)->list);
 			nf_tables_rule_notify(&trans->ctx,
 					      nft_trans_rule(trans),
@@ -6708,7 +6701,8 @@  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:
-		nft_set_destroy(nft_trans_set(trans));
+		if (!nft_trans_set_bound(trans))
+			nft_set_destroy(nft_trans_set(trans));
 		break;
 	case NFT_MSG_NEWSETELEM:
 		nft_set_elem_destroy(nft_trans_elem_set(trans),
@@ -6769,7 +6763,9 @@  static int __nf_tables_abort(struct net *net)
 		case NFT_MSG_NEWRULE:
 			trans->ctx.chain->use--;
 			list_del_rcu(&nft_trans_rule(trans)->list);
-			nft_rule_expr_deactivate(&trans->ctx, nft_trans_rule(trans));
+			nft_rule_expr_deactivate(&trans->ctx,
+						 nft_trans_rule(trans),
+						 NFT_TRANS_ABORT);
 			break;
 		case NFT_MSG_DELRULE:
 			trans->ctx.chain->use++;
@@ -6779,7 +6775,8 @@  static int __nf_tables_abort(struct net *net)
 			break;
 		case NFT_MSG_NEWSET:
 			trans->ctx.table->use--;
-			list_del_rcu(&nft_trans_set(trans)->list);
+			if (!nft_trans_set_bound(trans))
+				list_del_rcu(&nft_trans_set(trans)->list);
 			break;
 		case NFT_MSG_DELSET:
 			trans->ctx.table->use++;
diff --git a/net/netfilter/nft_dynset.c b/net/netfilter/nft_dynset.c
index 9658493d37d4..a8a74a16f9c4 100644
--- a/net/netfilter/nft_dynset.c
+++ b/net/netfilter/nft_dynset.c
@@ -234,20 +234,17 @@  static int nft_dynset_init(const struct nft_ctx *ctx,
 	return err;
 }
 
-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_rebind_set(ctx, priv->set, &priv->binding);
-}
-
 static void nft_dynset_deactivate(const struct nft_ctx *ctx,
-				  const struct nft_expr *expr)
+				  const struct nft_expr *expr,
+				  enum nft_trans_phase phase)
 {
 	struct nft_dynset *priv = nft_expr_priv(expr);
 
-	nf_tables_unbind_set(ctx, priv->set, &priv->binding);
+	if (phase == NFT_TRANS_PREPARE)
+		return;
+
+	nf_tables_unbind_set(ctx, priv->set, &priv->binding,
+			     phase == NFT_TRANS_COMMIT);
 }
 
 static void nft_dynset_destroy(const struct nft_ctx *ctx,
@@ -295,7 +292,6 @@  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,
 };
diff --git a/net/netfilter/nft_immediate.c b/net/netfilter/nft_immediate.c
index 3e5ed787b1d4..5ec43124cbca 100644
--- a/net/netfilter/nft_immediate.c
+++ b/net/netfilter/nft_immediate.c
@@ -72,10 +72,14 @@  static void nft_immediate_activate(const struct nft_ctx *ctx,
 }
 
 static void nft_immediate_deactivate(const struct nft_ctx *ctx,
-				     const struct nft_expr *expr)
+				     const struct nft_expr *expr,
+				     enum nft_trans_phase phase)
 {
 	const struct nft_immediate_expr *priv = nft_expr_priv(expr);
 
+	if (phase == NFT_TRANS_COMMIT)
+		return;
+
 	return nft_data_release(&priv->data, nft_dreg_to_type(priv->dreg));
 }
 
diff --git a/net/netfilter/nft_lookup.c b/net/netfilter/nft_lookup.c
index 227b2b15a19c..14496da5141d 100644
--- a/net/netfilter/nft_lookup.c
+++ b/net/netfilter/nft_lookup.c
@@ -121,20 +121,17 @@  static int nft_lookup_init(const struct nft_ctx *ctx,
 	return 0;
 }
 
-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_rebind_set(ctx, priv->set, &priv->binding);
-}
-
 static void nft_lookup_deactivate(const struct nft_ctx *ctx,
-				  const struct nft_expr *expr)
+				  const struct nft_expr *expr,
+				  enum nft_trans_phase phase)
 {
 	struct nft_lookup *priv = nft_expr_priv(expr);
 
-	nf_tables_unbind_set(ctx, priv->set, &priv->binding);
+	if (phase == NFT_TRANS_PREPARE)
+		return;
+
+	nf_tables_unbind_set(ctx, priv->set, &priv->binding,
+			     phase == NFT_TRANS_COMMIT);
 }
 
 static void nft_lookup_destroy(const struct nft_ctx *ctx,
@@ -225,7 +222,6 @@  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,
diff --git a/net/netfilter/nft_objref.c b/net/netfilter/nft_objref.c
index c1f2adf198a0..79ef074c18ca 100644
--- a/net/netfilter/nft_objref.c
+++ b/net/netfilter/nft_objref.c
@@ -156,20 +156,17 @@  static int nft_objref_map_dump(struct sk_buff *skb, const struct nft_expr *expr)
 	return -1;
 }
 
-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_rebind_set(ctx, priv->set, &priv->binding);
-}
-
 static void nft_objref_map_deactivate(const struct nft_ctx *ctx,
-				      const struct nft_expr *expr)
+				      const struct nft_expr *expr,
+				      enum nft_trans_phase phase)
 {
 	struct nft_objref_map *priv = nft_expr_priv(expr);
 
-	nf_tables_unbind_set(ctx, priv->set, &priv->binding);
+	if (phase == NFT_TRANS_PREPARE)
+		return;
+
+	nf_tables_unbind_set(ctx, priv->set, &priv->binding,
+			     phase == NFT_TRANS_COMMIT);
 }
 
 static void nft_objref_map_destroy(const struct nft_ctx *ctx,
@@ -186,7 +183,6 @@  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,