Subject: [PATCH 24/46] net: sched: use temporary variable for actions indexes

From: Dmytro Linkin <[email-masked]>
Date: Thu, 1 Aug 2019 13:02:51 +0000

[ Upstream commit 7be8ef2cdbfe41a2e524b7c6cc3f8e6cfaa906e4 ]

Currently init call of all actions (except ipt) init their 'parm'
structure as a direct pointer to nla data in skb. This leads to race
condition when some of the filter actions were initialized successfully
(and were assigned with idr action index that was written directly
into nla data), but then were deleted and retried (due to following
action module missing or classifier-initiated retry), in which case
action init code tries to insert action to idr with index that was
assigned on previous iteration. During retry the index can be reused
by another action that was inserted concurrently, which causes
unintended action sharing between filters.
To fix described race condition, save action idr index to temporary
stack-allocated variable instead on nla data.

Fixes: 0190c1d452a9 ("net: sched: atomically check-allocate action")
Signed-off-by: Dmytro Linkin <[email-masked]>
Signed-off-by: Vlad Buslov <[email-masked]>
Acked-by: Cong Wang <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 net/sched/act_bpf.c        |  9 +++++----
 net/sched/act_connmark.c   |  9 +++++----
 net/sched/act_csum.c       |  9 +++++----
 net/sched/act_gact.c       |  8 +++++---
 net/sched/act_ife.c        |  8 +++++---
 net/sched/act_mirred.c     | 13 +++++++------
 net/sched/act_nat.c        |  9 +++++----
 net/sched/act_pedit.c      | 10 ++++++----
 net/sched/act_police.c     |  8 +++++---
 net/sched/act_sample.c     | 10 +++++-----
 net/sched/act_simple.c     | 10 ++++++----
 net/sched/act_skbedit.c    | 11 ++++++-----
 net/sched/act_skbmod.c     | 11 ++++++-----
 net/sched/act_tunnel_key.c |  8 +++++---
 net/sched/act_vlan.c       | 16 +++++++++-------
 15 files changed, 85 insertions(+), 64 deletions(-)

diff --git a/net/sched/act_bpf.c b/net/sched/act_bpf.c
index 8126b26f125e..fd1f7e799e23 100644
--- a/net/sched/act_bpf.c
+++ b/net/sched/act_bpf.c
@@ -285,6 +285,7 @@ static int tcf_bpf_init(struct net *net, struct nlattr *nla,
 	struct tcf_bpf *prog;
 	bool is_bpf, is_ebpf;
 	int ret, res = 0;
+	u32 index;
 
 	if (!nla)
 		return -EINVAL;
@@ -298,13 +299,13 @@ static int tcf_bpf_init(struct net *net, struct nlattr *nla,
 		return -EINVAL;
 
 	parm = nla_data(tb[TCA_ACT_BPF_PARMS]);
-
-	ret = tcf_idr_check_alloc(tn, &parm->index, act, bind);
+	index = parm->index;
+	ret = tcf_idr_check_alloc(tn, &index, act, bind);
 	if (!ret) {
-		ret = tcf_idr_create(tn, parm->index, est, act,
+		ret = tcf_idr_create(tn, index, est, act,
 				     &act_bpf_ops, bind, true);
 		if (ret < 0) {
-			tcf_idr_cleanup(tn, parm->index);
+			tcf_idr_cleanup(tn, index);
 			return ret;
 		}
 
diff --git a/net/sched/act_connmark.c b/net/sched/act_connmark.c
index ce36b0f7e1dc..32ac04d77a45 100644
--- a/net/sched/act_connmark.c
+++ b/net/sched/act_connmark.c
@@ -103,6 +103,7 @@ static int tcf_connmark_init(struct net *net, struct nlattr *nla,
 	struct tcf_connmark_info *ci;
 	struct tc_connmark *parm;
 	int ret = 0, err;
+	u32 index;
 
 	if (!nla)
 		return -EINVAL;
@@ -116,13 +117,13 @@ static int tcf_connmark_init(struct net *net, struct nlattr *nla,
 		return -EINVAL;
 
 	parm = nla_data(tb[TCA_CONNMARK_PARMS]);
-
-	ret = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	index = parm->index;
+	ret = tcf_idr_check_alloc(tn, &index, a, bind);
 	if (!ret) {
-		ret = tcf_idr_create(tn, parm->index, est, a,
+		ret = tcf_idr_create(tn, index, est, a,
 				     &act_connmark_ops, bind, false);
 		if (ret) {
-			tcf_idr_cleanup(tn, parm->index);
+			tcf_idr_cleanup(tn, index);
 			return ret;
 		}
 
diff --git a/net/sched/act_csum.c b/net/sched/act_csum.c
index 621fb22ce2a9..9b9288267a54 100644
--- a/net/sched/act_csum.c
+++ b/net/sched/act_csum.c
@@ -52,6 +52,7 @@ static int tcf_csum_init(struct net *net, struct nlattr *nla,
 	struct tc_csum *parm;
 	struct tcf_csum *p;
 	int ret = 0, err;
+	u32 index;
 
 	if (nla == NULL)
 		return -EINVAL;
@@ -64,13 +65,13 @@ static int tcf_csum_init(struct net *net, struct nlattr *nla,
 	if (tb[TCA_CSUM_PARMS] == NULL)
 		return -EINVAL;
 	parm = nla_data(tb[TCA_CSUM_PARMS]);
-
-	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	index = parm->index;
+	err = tcf_idr_check_alloc(tn, &index, a, bind);
 	if (!err) {
-		ret = tcf_idr_create(tn, parm->index, est, a,
+		ret = tcf_idr_create(tn, index, est, a,
 				     &act_csum_ops, bind, true);
 		if (ret) {
-			tcf_idr_cleanup(tn, parm->index);
+			tcf_idr_cleanup(tn, index);
 			return ret;
 		}
 		ret = ACT_P_CREATED;
diff --git a/net/sched/act_gact.c b/net/sched/act_gact.c
index b2380c5284e6..8f0140c6ca58 100644
--- a/net/sched/act_gact.c
+++ b/net/sched/act_gact.c
@@ -61,6 +61,7 @@ static int tcf_gact_init(struct net *net, struct nlattr *nla,
 	struct tc_gact *parm;
 	struct tcf_gact *gact;
 	int ret = 0;
+	u32 index;
 	int err;
 #ifdef CONFIG_GACT_PROB
 	struct tc_gact_p *p_parm = NULL;
@@ -77,6 +78,7 @@ static int tcf_gact_init(struct net *net, struct nlattr *nla,
 	if (tb[TCA_GACT_PARMS] == NULL)
 		return -EINVAL;
 	parm = nla_data(tb[TCA_GACT_PARMS]);
+	index = parm->index;
 
 #ifndef CONFIG_GACT_PROB
 	if (tb[TCA_GACT_PROB] != NULL)
@@ -94,12 +96,12 @@ static int tcf_gact_init(struct net *net, struct nlattr *nla,
 	}
 #endif
 
-	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	err = tcf_idr_check_alloc(tn, &index, a, bind);
 	if (!err) {
-		ret = tcf_idr_create(tn, parm->index, est, a,
+		ret = tcf_idr_create(tn, index, est, a,
 				     &act_gact_ops, bind, true);
 		if (ret) {
-			tcf_idr_cleanup(tn, parm->index);
+			tcf_idr_cleanup(tn, index);
 			return ret;
 		}
 		ret = ACT_P_CREATED;
diff --git a/net/sched/act_ife.c b/net/sched/act_ife.c
index 3578196d1600..92ee853d43e6 100644
--- a/net/sched/act_ife.c
+++ b/net/sched/act_ife.c
@@ -479,6 +479,7 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla,
 	u8 *saddr = NULL;
 	bool exists = false;
 	int ret = 0;
+	u32 index;
 	int err;
 
 	if (!nla) {
@@ -507,7 +508,8 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla,
 	if (!p)
 		return -ENOMEM;
 
-	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	index = parm->index;
+	err = tcf_idr_check_alloc(tn, &index, a, bind);
 	if (err < 0) {
 		kfree(p);
 		return err;
@@ -519,10 +521,10 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla,
 	}
 
 	if (!exists) {
-		ret = tcf_idr_create(tn, parm->index, est, a, &act_ife_ops,
+		ret = tcf_idr_create(tn, index, est, a, &act_ife_ops,
 				     bind, true);
 		if (ret) {
-			tcf_idr_cleanup(tn, parm->index);
+			tcf_idr_cleanup(tn, index);
 			kfree(p);
 			return ret;
 		}
diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c
index 58e7573dded4..d10dca7a13e1 100644
--- a/net/sched/act_mirred.c
+++ b/net/sched/act_mirred.c
@@ -101,6 +101,7 @@ static int tcf_mirred_init(struct net *net, struct nlattr *nla,
 	struct net_device *dev;
 	bool exists = false;
 	int ret, err;
+	u32 index;
 
 	if (!nla) {
 		NL_SET_ERR_MSG_MOD(extack, "Mirred requires attributes to be passed");
@@ -115,8 +116,8 @@ static int tcf_mirred_init(struct net *net, struct nlattr *nla,
 		return -EINVAL;
 	}
 	parm = nla_data(tb[TCA_MIRRED_PARMS]);
-
-	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	index = parm->index;
+	err = tcf_idr_check_alloc(tn, &index, a, bind);
 	if (err < 0)
 		return err;
 	exists = err;
@@ -133,21 +134,21 @@ static int tcf_mirred_init(struct net *net, struct nlattr *nla,
 		if (exists)
 			tcf_idr_release(*a, bind);
 		else
-			tcf_idr_cleanup(tn, parm->index);
+			tcf_idr_cleanup(tn, index);
 		NL_SET_ERR_MSG_MOD(extack, "Unknown mirred option");
 		return -EINVAL;
 	}
 
 	if (!exists) {
 		if (!parm->ifindex) {
-			tcf_idr_cleanup(tn, parm->index);
+			tcf_idr_cleanup(tn, index);
 			NL_SET_ERR_MSG_MOD(extack, "Specified device does not exist");
 			return -EINVAL;
 		}
-		ret = tcf_idr_create(tn, parm->index, est, a,
+		ret = tcf_idr_create(tn, index, est, a,
 				     &act_mirred_ops, bind, true);
 		if (ret) {
-			tcf_idr_cleanup(tn, parm->index);
+			tcf_idr_cleanup(tn, index);
 			return ret;
 		}
 		ret = ACT_P_CREATED;
diff --git a/net/sched/act_nat.c b/net/sched/act_nat.c
index 45923ebb7a4f..7b858c11b1b5 100644
--- a/net/sched/act_nat.c
+++ b/net/sched/act_nat.c
@@ -44,6 +44,7 @@ static int tcf_nat_init(struct net *net, struct nlattr *nla, struct nlattr *est,
 	struct tc_nat *parm;
 	int ret = 0, err;
 	struct tcf_nat *p;
+	u32 index;
 
 	if (nla == NULL)
 		return -EINVAL;
@@ -56,13 +57,13 @@ static int tcf_nat_init(struct net *net, struct nlattr *nla, struct nlattr *est,
 	if (tb[TCA_NAT_PARMS] == NULL)
 		return -EINVAL;
 	parm = nla_data(tb[TCA_NAT_PARMS]);
-
-	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	index = parm->index;
+	err = tcf_idr_check_alloc(tn, &index, a, bind);
 	if (!err) {
-		ret = tcf_idr_create(tn, parm->index, est, a,
+		ret = tcf_idr_create(tn, index, est, a,
 				     &act_nat_ops, bind, false);
 		if (ret) {
-			tcf_idr_cleanup(tn, parm->index);
+			tcf_idr_cleanup(tn, index);
 			return ret;
 		}
 		ret = ACT_P_CREATED;
diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c
index 45e9d6bfddb3..17360c6faeaa 100644
--- a/net/sched/act_pedit.c
+++ b/net/sched/act_pedit.c
@@ -149,6 +149,7 @@ static int tcf_pedit_init(struct net *net, struct nlattr *nla,
 	struct tcf_pedit *p;
 	int ret = 0, err;
 	int ksize;
+	u32 index;
 
 	if (!nla) {
 		NL_SET_ERR_MSG_MOD(extack, "Pedit requires attributes to be passed");
@@ -179,18 +180,19 @@ static int tcf_pedit_init(struct net *net, struct nlattr *nla,
 	if (IS_ERR(keys_ex))
 		return PTR_ERR(keys_ex);
 
-	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	index = parm->index;
+	err = tcf_idr_check_alloc(tn, &index, a, bind);
 	if (!err) {
 		if (!parm->nkeys) {
-			tcf_idr_cleanup(tn, parm->index);
+			tcf_idr_cleanup(tn, index);
 			NL_SET_ERR_MSG_MOD(extack, "Pedit requires keys to be passed");
 			ret = -EINVAL;
 			goto out_free;
 		}
-		ret = tcf_idr_create(tn, parm->index, est, a,
+		ret = tcf_idr_create(tn, index, est, a,
 				     &act_pedit_ops, bind, false);
 		if (ret) {
-			tcf_idr_cleanup(tn, parm->index);
+			tcf_idr_cleanup(tn, index);
 			goto out_free;
 		}
 		ret = ACT_P_CREATED;
diff --git a/net/sched/act_police.c b/net/sched/act_police.c
index a065f62fa79c..49cec3e64a4d 100644
--- a/net/sched/act_police.c
+++ b/net/sched/act_police.c
@@ -57,6 +57,7 @@ static int tcf_police_init(struct net *net, struct nlattr *nla,
 	struct tc_action_net *tn = net_generic(net, police_net_id);
 	struct tcf_police_params *new;
 	bool exists = false;
+	u32 index;
 
 	if (nla == NULL)
 		return -EINVAL;
@@ -73,7 +74,8 @@ static int tcf_police_init(struct net *net, struct nlattr *nla,
 		return -EINVAL;
 
 	parm = nla_data(tb[TCA_POLICE_TBF]);
-	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	index = parm->index;
+	err = tcf_idr_check_alloc(tn, &index, a, bind);
 	if (err < 0)
 		return err;
 	exists = err;
@@ -81,10 +83,10 @@ static int tcf_police_init(struct net *net, struct nlattr *nla,
 		return 0;
 
 	if (!exists) {
-		ret = tcf_idr_create(tn, parm->index, NULL, a,
+		ret = tcf_idr_create(tn, index, NULL, a,
 				     &act_police_ops, bind, true);
 		if (ret) {
-			tcf_idr_cleanup(tn, parm->index);
+			tcf_idr_cleanup(tn, index);
 			return ret;
 		}
 		ret = ACT_P_CREATED;
diff --git a/net/sched/act_sample.c b/net/sched/act_sample.c
index 274d7a0c0e25..595308d60133 100644
--- a/net/sched/act_sample.c
+++ b/net/sched/act_sample.c
@@ -41,8 +41,8 @@ static int tcf_sample_init(struct net *net, struct nlattr *nla,
 	struct tc_action_net *tn = net_generic(net, sample_net_id);
 	struct nlattr *tb[TCA_SAMPLE_MAX + 1];
 	struct psample_group *psample_group;
+	u32 psample_group_num, rate, index;
 	struct tcf_chain *goto_ch = NULL;
-	u32 psample_group_num, rate;
 	struct tc_sample *parm;
 	struct tcf_sample *s;
 	bool exists = false;
@@ -59,8 +59,8 @@ static int tcf_sample_init(struct net *net, struct nlattr *nla,
 		return -EINVAL;
 
 	parm = nla_data(tb[TCA_SAMPLE_PARMS]);
-
-	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	index = parm->index;
+	err = tcf_idr_check_alloc(tn, &index, a, bind);
 	if (err < 0)
 		return err;
 	exists = err;
@@ -68,10 +68,10 @@ static int tcf_sample_init(struct net *net, struct nlattr *nla,
 		return 0;
 
 	if (!exists) {
-		ret = tcf_idr_create(tn, parm->index, est, a,
+		ret = tcf_idr_create(tn, index, est, a,
 				     &act_sample_ops, bind, true);
 		if (ret) {
-			tcf_idr_cleanup(tn, parm->index);
+			tcf_idr_cleanup(tn, index);
 			return ret;
 		}
 		ret = ACT_P_CREATED;
diff --git a/net/sched/act_simple.c b/net/sched/act_simple.c
index f28ddbabff76..33aefa25b545 100644
--- a/net/sched/act_simple.c
+++ b/net/sched/act_simple.c
@@ -95,6 +95,7 @@ static int tcf_simp_init(struct net *net, struct nlattr *nla,
 	struct tcf_defact *d;
 	bool exists = false;
 	int ret = 0, err;
+	u32 index;
 
 	if (nla == NULL)
 		return -EINVAL;
@@ -108,7 +109,8 @@ static int tcf_simp_init(struct net *net, struct nlattr *nla,
 		return -EINVAL;
 
 	parm = nla_data(tb[TCA_DEF_PARMS]);
-	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	index = parm->index;
+	err = tcf_idr_check_alloc(tn, &index, a, bind);
 	if (err < 0)
 		return err;
 	exists = err;
@@ -119,15 +121,15 @@ static int tcf_simp_init(struct net *net, struct nlattr *nla,
 		if (exists)
 			tcf_idr_release(*a, bind);
 		else
-			tcf_idr_cleanup(tn, parm->index);
+			tcf_idr_cleanup(tn, index);
 		return -EINVAL;
 	}
 
 	if (!exists) {
-		ret = tcf_idr_create(tn, parm->index, est, a,
+		ret = tcf_idr_create(tn, index, est, a,
 				     &act_simp_ops, bind, false);
 		if (ret) {
-			tcf_idr_cleanup(tn, parm->index);
+			tcf_idr_cleanup(tn, index);
 			return ret;
 		}
 
diff --git a/net/sched/act_skbedit.c b/net/sched/act_skbedit.c
index 215a06705cef..b100870f02a6 100644
--- a/net/sched/act_skbedit.c
+++ b/net/sched/act_skbedit.c
@@ -99,6 +99,7 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla,
 	u16 *queue_mapping = NULL, *ptype = NULL;
 	bool exists = false;
 	int ret = 0, err;
+	u32 index;
 
 	if (nla == NULL)
 		return -EINVAL;
@@ -146,8 +147,8 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla,
 	}
 
 	parm = nla_data(tb[TCA_SKBEDIT_PARMS]);
-
-	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	index = parm->index;
+	err = tcf_idr_check_alloc(tn, &index, a, bind);
 	if (err < 0)
 		return err;
 	exists = err;
@@ -158,15 +159,15 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla,
 		if (exists)
 			tcf_idr_release(*a, bind);
 		else
-			tcf_idr_cleanup(tn, parm->index);
+			tcf_idr_cleanup(tn, index);
 		return -EINVAL;
 	}
 
 	if (!exists) {
-		ret = tcf_idr_create(tn, parm->index, est, a,
+		ret = tcf_idr_create(tn, index, est, a,
 				     &act_skbedit_ops, bind, true);
 		if (ret) {
-			tcf_idr_cleanup(tn, parm->index);
+			tcf_idr_cleanup(tn, index);
 			return ret;
 		}
 
diff --git a/net/sched/act_skbmod.c b/net/sched/act_skbmod.c
index 4f07706eff07..7da3518e18ef 100644
--- a/net/sched/act_skbmod.c
+++ b/net/sched/act_skbmod.c
@@ -87,12 +87,12 @@ static int tcf_skbmod_init(struct net *net, struct nlattr *nla,
 	struct tcf_skbmod_params *p, *p_old;
 	struct tcf_chain *goto_ch = NULL;
 	struct tc_skbmod *parm;
+	u32 lflags = 0, index;
 	struct tcf_skbmod *d;
 	bool exists = false;
 	u8 *daddr = NULL;
 	u8 *saddr = NULL;
 	u16 eth_type = 0;
-	u32 lflags = 0;
 	int ret = 0, err;
 
 	if (!nla)
@@ -122,10 +122,11 @@ static int tcf_skbmod_init(struct net *net, struct nlattr *nla,
 	}
 
 	parm = nla_data(tb[TCA_SKBMOD_PARMS]);
+	index = parm->index;
 	if (parm->flags & SKBMOD_F_SWAPMAC)
 		lflags = SKBMOD_F_SWAPMAC;
 
-	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	err = tcf_idr_check_alloc(tn, &index, a, bind);
 	if (err < 0)
 		return err;
 	exists = err;
@@ -136,15 +137,15 @@ static int tcf_skbmod_init(struct net *net, struct nlattr *nla,
 		if (exists)
 			tcf_idr_release(*a, bind);
 		else
-			tcf_idr_cleanup(tn, parm->index);
+			tcf_idr_cleanup(tn, index);
 		return -EINVAL;
 	}
 
 	if (!exists) {
-		ret = tcf_idr_create(tn, parm->index, est, a,
+		ret = tcf_idr_create(tn, index, est, a,
 				     &act_skbmod_ops, bind, true);
 		if (ret) {
-			tcf_idr_cleanup(tn, parm->index);
+			tcf_idr_cleanup(tn, index);
 			return ret;
 		}
 
diff --git a/net/sched/act_tunnel_key.c b/net/sched/act_tunnel_key.c
index 10dffda1d5cc..6d0debdc9b97 100644
--- a/net/sched/act_tunnel_key.c
+++ b/net/sched/act_tunnel_key.c
@@ -225,6 +225,7 @@ static int tunnel_key_init(struct net *net, struct nlattr *nla,
 	__be16 flags = 0;
 	u8 tos, ttl;
 	int ret = 0;
+	u32 index;
 	int err;
 
 	if (!nla) {
@@ -245,7 +246,8 @@ static int tunnel_key_init(struct net *net, struct nlattr *nla,
 	}
 
 	parm = nla_data(tb[TCA_TUNNEL_KEY_PARMS]);
-	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	index = parm->index;
+	err = tcf_idr_check_alloc(tn, &index, a, bind);
 	if (err < 0)
 		return err;
 	exists = err;
@@ -345,7 +347,7 @@ static int tunnel_key_init(struct net *net, struct nlattr *nla,
 	}
 
 	if (!exists) {
-		ret = tcf_idr_create(tn, parm->index, est, a,
+		ret = tcf_idr_create(tn, index, est, a,
 				     &act_tunnel_key_ops, bind, true);
 		if (ret) {
 			NL_SET_ERR_MSG(extack, "Cannot create TC IDR");
@@ -403,7 +405,7 @@ static int tunnel_key_init(struct net *net, struct nlattr *nla,
 	if (exists)
 		tcf_idr_release(*a, bind);
 	else
-		tcf_idr_cleanup(tn, parm->index);
+		tcf_idr_cleanup(tn, index);
 	return ret;
 }
 
diff --git a/net/sched/act_vlan.c b/net/sched/act_vlan.c
index e0c97267bccb..a3c9eea1ee8a 100644
--- a/net/sched/act_vlan.c
+++ b/net/sched/act_vlan.c
@@ -116,6 +116,7 @@ static int tcf_vlan_init(struct net *net, struct nlattr *nla,
 	u8 push_prio = 0;
 	bool exists = false;
 	int ret = 0, err;
+	u32 index;
 
 	if (!nla)
 		return -EINVAL;
@@ -128,7 +129,8 @@ static int tcf_vlan_init(struct net *net, struct nlattr *nla,
 	if (!tb[TCA_VLAN_PARMS])
 		return -EINVAL;
 	parm = nla_data(tb[TCA_VLAN_PARMS]);
-	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	index = parm->index;
+	err = tcf_idr_check_alloc(tn, &index, a, bind);
 	if (err < 0)
 		return err;
 	exists = err;
@@ -144,7 +146,7 @@ static int tcf_vlan_init(struct net *net, struct nlattr *nla,
 			if (exists)
 				tcf_idr_release(*a, bind);
 			else
-				tcf_idr_cleanup(tn, parm->index);
+				tcf_idr_cleanup(tn, index);
 			return -EINVAL;
 		}
 		push_vid = nla_get_u16(tb[TCA_VLAN_PUSH_VLAN_ID]);
@@ -152,7 +154,7 @@ static int tcf_vlan_init(struct net *net, struct nlattr *nla,
 			if (exists)
 				tcf_idr_release(*a, bind);
 			else
-				tcf_idr_cleanup(tn, parm->index);
+				tcf_idr_cleanup(tn, index);
 			return -ERANGE;
 		}
 
@@ -166,7 +168,7 @@ static int tcf_vlan_init(struct net *net, struct nlattr *nla,
 				if (exists)
 					tcf_idr_release(*a, bind);
 				else
-					tcf_idr_cleanup(tn, parm->index);
+					tcf_idr_cleanup(tn, index);
 				return -EPROTONOSUPPORT;
 			}
 		} else {
@@ -180,16 +182,16 @@ static int tcf_vlan_init(struct net *net, struct nlattr *nla,
 		if (exists)
 			tcf_idr_release(*a, bind);
 		else
-			tcf_idr_cleanup(tn, parm->index);
+			tcf_idr_cleanup(tn, index);
 		return -EINVAL;
 	}
 	action = parm->v_action;
 
 	if (!exists) {
-		ret = tcf_idr_create(tn, parm->index, est, a,
+		ret = tcf_idr_create(tn, index, est, a,
 				     &act_vlan_ops, bind, true);
 		if (ret) {
-			tcf_idr_cleanup(tn, parm->index);
+			tcf_idr_cleanup(tn, index);
 			return ret;
 		}
 
-- 
2.20.1