net_sched: fix a NULL pointer deref in ipt action

[ Upstream commit 981471bd3a ]

The net pointer in struct xt_tgdtor_param is not explicitly
initialized therefore is still NULL when dereferencing it.
So we have to find a way to pass the correct net pointer to
ipt_destroy_target().

The best way I find is just saving the net pointer inside the per
netns struct tcf_idrinfo, which could make this patch smaller.

Fixes: 0c66dc1ea3 ("netfilter: conntrack: register hooks in netns when needed by ruleset")
Reported-and-tested-by: itugrok@yahoo.com
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/net/act_api.h

@@ -14,6 +14,7 @@
 struct tcf_idrinfo {
 	spinlock_t	lock;
 	struct idr	action_idr;
+	struct net	*net;
 };
 
 struct tc_action_ops;
@@ -104,7 +105,7 @@ struct tc_action_net {
 };
 
 static inline
-int tc_action_net_init(struct tc_action_net *tn,
+int tc_action_net_init(struct net *net, struct tc_action_net *tn,
 		       const struct tc_action_ops *ops)
 {
 	int err = 0;
@@ -113,6 +114,7 @@ int tc_action_net_init(struct tc_action_net *tn,
 	if (!tn->idrinfo)
 		return -ENOMEM;
 	tn->ops = ops;
+	tn->idrinfo->net = net;
 	spin_lock_init(&tn->idrinfo->lock);
 	idr_init(&tn->idrinfo->action_idr);
 	return err;

net/sched/act_bpf.c

@@ -402,7 +402,7 @@ static __net_init int bpf_init_net(struct net *net)
 {
 	struct tc_action_net *tn = net_generic(net, bpf_net_id);
 
-	return tc_action_net_init(tn, &act_bpf_ops);
+	return tc_action_net_init(net, tn, &act_bpf_ops);
 }
 
 static void __net_exit bpf_exit_net(struct net *net)

net/sched/act_connmark.c

@@ -206,7 +206,7 @@ static __net_init int connmark_init_net(struct net *net)
 {
 	struct tc_action_net *tn = net_generic(net, connmark_net_id);
 
-	return tc_action_net_init(tn, &act_connmark_ops);
+	return tc_action_net_init(net, tn, &act_connmark_ops);
 }
 
 static void __net_exit connmark_exit_net(struct net *net)

net/sched/act_csum.c

@@ -632,7 +632,7 @@ static __net_init int csum_init_net(struct net *net)
 {
 	struct tc_action_net *tn = net_generic(net, csum_net_id);
 
-	return tc_action_net_init(tn, &act_csum_ops);
+	return tc_action_net_init(net, tn, &act_csum_ops);
 }
 
 static void __net_exit csum_exit_net(struct net *net)

net/sched/act_gact.c

@@ -232,7 +232,7 @@ static __net_init int gact_init_net(struct net *net)
 {
 	struct tc_action_net *tn = net_generic(net, gact_net_id);
 
-	return tc_action_net_init(tn, &act_gact_ops);
+	return tc_action_net_init(net, tn, &act_gact_ops);
 }
 
 static void __net_exit gact_exit_net(struct net *net)

net/sched/act_ife.c

@@ -837,7 +837,7 @@ static __net_init int ife_init_net(struct net *net)
 {
 	struct tc_action_net *tn = net_generic(net, ife_net_id);
 
-	return tc_action_net_init(tn, &act_ife_ops);
+	return tc_action_net_init(net, tn, &act_ife_ops);
 }
 
 static void __net_exit ife_exit_net(struct net *net)

net/sched/act_ipt.c

@@ -65,12 +65,13 @@ static int ipt_init_target(struct net *net, struct xt_entry_target *t,
 	return 0;
 }
 
-static void ipt_destroy_target(struct xt_entry_target *t)
+static void ipt_destroy_target(struct xt_entry_target *t, struct net *net)
 {
 	struct xt_tgdtor_param par = {
 		.target   = t->u.kernel.target,
 		.targinfo = t->data,
 		.family   = NFPROTO_IPV4,
+		.net      = net,
 	};
 	if (par.target->destroy != NULL)
 		par.target->destroy(&par);
@@ -82,7 +83,7 @@ static void tcf_ipt_release(struct tc_action *a, int bind)
 	struct tcf_ipt *ipt = to_ipt(a);
 
 	if (ipt->tcfi_t) {
-		ipt_destroy_target(ipt->tcfi_t);
+		ipt_destroy_target(ipt->tcfi_t, a->idrinfo->net);
 		kfree(ipt->tcfi_t);
 	}
 	kfree(ipt->tcfi_tname);
@@ -172,7 +173,7 @@ static int __tcf_ipt_init(struct net *net, unsigned int id, struct nlattr *nla,
 
 	spin_lock_bh(&ipt->tcf_lock);
 	if (ret != ACT_P_CREATED) {
-		ipt_destroy_target(ipt->tcfi_t);
+		ipt_destroy_target(ipt->tcfi_t, net);
 		kfree(ipt->tcfi_tname);
 		kfree(ipt->tcfi_t);
 	}
@@ -337,7 +338,7 @@ static __net_init int ipt_init_net(struct net *net)
 {
 	struct tc_action_net *tn = net_generic(net, ipt_net_id);
 
-	return tc_action_net_init(tn, &act_ipt_ops);
+	return tc_action_net_init(net, tn, &act_ipt_ops);
 }
 
 static void __net_exit ipt_exit_net(struct net *net)
@@ -387,7 +388,7 @@ static __net_init int xt_init_net(struct net *net)
 {
 	struct tc_action_net *tn = net_generic(net, xt_net_id);
 
-	return tc_action_net_init(tn, &act_xt_ops);
+	return tc_action_net_init(net, tn, &act_xt_ops);
 }
 
 static void __net_exit xt_exit_net(struct net *net)

net/sched/act_mirred.c

@@ -343,7 +343,7 @@ static __net_init int mirred_init_net(struct net *net)
 {
 	struct tc_action_net *tn = net_generic(net, mirred_net_id);
 
-	return tc_action_net_init(tn, &act_mirred_ops);
+	return tc_action_net_init(net, tn, &act_mirred_ops);
 }
 
 static void __net_exit mirred_exit_net(struct net *net)

net/sched/act_nat.c

@@ -307,7 +307,7 @@ static __net_init int nat_init_net(struct net *net)
 {
 	struct tc_action_net *tn = net_generic(net, nat_net_id);
 
-	return tc_action_net_init(tn, &act_nat_ops);
+	return tc_action_net_init(net, tn, &act_nat_ops);
 }
 
 static void __net_exit nat_exit_net(struct net *net)

net/sched/act_pedit.c

@@ -458,7 +458,7 @@ static __net_init int pedit_init_net(struct net *net)
 {
 	struct tc_action_net *tn = net_generic(net, pedit_net_id);
 
-	return tc_action_net_init(tn, &act_pedit_ops);
+	return tc_action_net_init(net, tn, &act_pedit_ops);
 }
 
 static void __net_exit pedit_exit_net(struct net *net)

net/sched/act_police.c

@@ -331,7 +331,7 @@ static __net_init int police_init_net(struct net *net)
 {
 	struct tc_action_net *tn = net_generic(net, police_net_id);
 
-	return tc_action_net_init(tn, &act_police_ops);
+	return tc_action_net_init(net, tn, &act_police_ops);
 }
 
 static void __net_exit police_exit_net(struct net *net)

net/sched/act_sample.c

@@ -249,7 +249,7 @@ static __net_init int sample_init_net(struct net *net)
 {
 	struct tc_action_net *tn = net_generic(net, sample_net_id);
 
-	return tc_action_net_init(tn, &act_sample_ops);
+	return tc_action_net_init(net, tn, &act_sample_ops);
 }
 
 static void __net_exit sample_exit_net(struct net *net)

net/sched/act_simple.c

@@ -198,7 +198,7 @@ static __net_init int simp_init_net(struct net *net)
 {
 	struct tc_action_net *tn = net_generic(net, simp_net_id);
 
-	return tc_action_net_init(tn, &act_simp_ops);
+	return tc_action_net_init(net, tn, &act_simp_ops);
 }
 
 static void __net_exit simp_exit_net(struct net *net)

net/sched/act_skbedit.c

@@ -239,7 +239,7 @@ static __net_init int skbedit_init_net(struct net *net)
 {
 	struct tc_action_net *tn = net_generic(net, skbedit_net_id);
 
-	return tc_action_net_init(tn, &act_skbedit_ops);
+	return tc_action_net_init(net, tn, &act_skbedit_ops);
 }
 
 static void __net_exit skbedit_exit_net(struct net *net)

net/sched/act_skbmod.c

@@ -267,7 +267,7 @@ static __net_init int skbmod_init_net(struct net *net)
 {
 	struct tc_action_net *tn = net_generic(net, skbmod_net_id);
 
-	return tc_action_net_init(tn, &act_skbmod_ops);
+	return tc_action_net_init(net, tn, &act_skbmod_ops);
 }
 
 static void __net_exit skbmod_exit_net(struct net *net)

net/sched/act_tunnel_key.c

@@ -324,7 +324,7 @@ static __net_init int tunnel_key_init_net(struct net *net)
 {
 	struct tc_action_net *tn = net_generic(net, tunnel_key_net_id);
 
-	return tc_action_net_init(tn, &act_tunnel_key_ops);
+	return tc_action_net_init(net, tn, &act_tunnel_key_ops);
 }
 
 static void __net_exit tunnel_key_exit_net(struct net *net)

net/sched/act_vlan.c

@@ -271,7 +271,7 @@ static __net_init int vlan_init_net(struct net *net)
 {
 	struct tc_action_net *tn = net_generic(net, vlan_net_id);
 
-	return tc_action_net_init(tn, &act_vlan_ops);
+	return tc_action_net_init(net, tn, &act_vlan_ops);
 }
 
 static void __net_exit vlan_exit_net(struct net *net)