openvswitch: Fix vport_send double free

Today vport-send has complex error handling because it involves
freeing skb and updating stats depending on return value from
vport send implementation.
This can be simplified by delegating responsibility of freeing
skb to the vport implementation for all cases. So that
vport-send needs just update stats.

Fixes: 91b7514cdf ("openvswitch: Unify vport error stats
handling")
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 18 insertions, 10 deletions

diff --git a/net/openvswitch/vport-geneve.c b/net/openvswitch/vport-geneve.c
index 347fa2325b226..484864dd0e689 100644
--- a/net/openvswitch/vport-geneve.c
+++ b/net/openvswitch/vport-geneve.c
@@ -219,7 +219,10 @@ static int geneve_tnl_send(struct vport *vport, struct sk_buff *skb)
 			      false);
 	if (err < 0)
 		ip_rt_put(rt);
+	return err;
+
 error:
+	kfree_skb(skb);
 	return err;
 }
 
diff --git a/net/openvswitch/vport-gre.c b/net/openvswitch/vport-gre.c
index 6b69df545b1da..28f54e9a6b806 100644
--- a/net/openvswitch/vport-gre.c
+++ b/net/openvswitch/vport-gre.c
@@ -73,7 +73,7 @@ static struct sk_buff *__build_header(struct sk_buff *skb,
 
 	skb = gre_handle_offloads(skb, !!(tun_key->tun_flags & TUNNEL_CSUM));
 	if (IS_ERR(skb))
-		return NULL;
+		return skb;
 
 	tpi.flags = filter_tnl_flags(tun_key->tun_flags);
 	tpi.proto = htons(ETH_P_TEB);
@@ -144,7 +144,7 @@ static int gre_tnl_send(struct vport *vport, struct sk_buff *skb)
 
 	if (unlikely(!OVS_CB(skb)->egress_tun_info)) {
 		err = -EINVAL;
-		goto error;
+		goto err_free_skb;
 	}
 
 	tun_key = &OVS_CB(skb)->egress_tun_info->tunnel;
@@ -157,8 +157,10 @@ static int gre_tnl_send(struct vport *vport, struct sk_buff *skb)
 	fl.flowi4_proto = IPPROTO_GRE;
 
 	rt = ip_route_output_key(net, &fl);
-	if (IS_ERR(rt))
-		return PTR_ERR(rt);
+	if (IS_ERR(rt)) {
+		err = PTR_ERR(rt);
+		goto err_free_skb;
+	}
 
 	tunnel_hlen = ip_gre_calc_hlen(tun_key->tun_flags);
 
@@ -183,8 +185,9 @@ static int gre_tnl_send(struct vport *vport, struct sk_buff *skb)
 
 	/* Push Tunnel header. */
 	skb = __build_header(skb, tunnel_hlen);
-	if (unlikely(!skb)) {
-		err = 0;
+	if (IS_ERR(skb)) {
+		err = PTR_ERR(rt);
+		skb = NULL;
 		goto err_free_rt;
 	}
 
@@ -198,7 +201,8 @@ static int gre_tnl_send(struct vport *vport, struct sk_buff *skb)
 			     tun_key->ipv4_tos, tun_key->ipv4_ttl, df, false);
 err_free_rt:
 	ip_rt_put(rt);
-error:
+err_free_skb:
+	kfree_skb(skb);
 	return err;
 }
 
diff --git a/net/openvswitch/vport-vxlan.c b/net/openvswitch/vport-vxlan.c
index 38f95a52241bd..d7c46b3010249 100644
--- a/net/openvswitch/vport-vxlan.c
+++ b/net/openvswitch/vport-vxlan.c
@@ -187,7 +187,9 @@ static int vxlan_tnl_send(struct vport *vport, struct sk_buff *skb)
 			     false);
 	if (err < 0)
 		ip_rt_put(rt);
+	return err;
 error:
+	kfree_skb(skb);
 	return err;
 }
 
diff --git a/net/openvswitch/vport.c b/net/openvswitch/vport.c
index 9584526c07780..53f3ebbfceabc 100644
--- a/net/openvswitch/vport.c
+++ b/net/openvswitch/vport.c
@@ -519,10 +519,9 @@ int ovs_vport_send(struct vport *vport, struct sk_buff *skb)
 		u64_stats_update_end(&stats->syncp);
 	} else if (sent < 0) {
 		ovs_vport_record_error(vport, VPORT_E_TX_ERROR);
-		kfree_skb(skb);
-	} else
+	} else {
 		ovs_vport_record_error(vport, VPORT_E_TX_DROPPED);
-
+	}
 	return sent;
 }