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>

5 files changed, 23 insertions, 11 deletions

diff --git a/net/ipv4/geneve.c b/net/ipv4/geneve.c
index 95e47c97585e..394a200f93c1 100644
--- a/net/ipv4/geneve.c
+++ b/net/ipv4/geneve.c
@@ -122,14 +122,18 @@ int geneve_xmit_skb(struct geneve_sock *gs, struct rtable *rt,
         int err;
 
         skb = udp_tunnel_handle_offloads(skb, !gs->sock->sk->sk_no_check_tx);
+        if (IS_ERR(skb))
+                return PTR_ERR(skb);
 
         min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len
                         + GENEVE_BASE_HLEN + opt_len + sizeof(struct iphdr)
                         + (vlan_tx_tag_present(skb) ? VLAN_HLEN : 0);
 
         err = skb_cow_head(skb, min_headroom);
-        if (unlikely(err))
+        if (unlikely(err)) {
+                kfree_skb(skb);
                 return err;
+        }
 
         skb = vlan_hwaccel_push_inside(skb);
         if (unlikely(!skb))
diff --git a/net/openvswitch/vport-geneve.c b/net/openvswitch/vport-geneve.c
index 347fa2325b22..484864dd0e68 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 6b69df545b1d..28f54e9a6b80 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 38f95a52241b..d7c46b301024 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 9584526c0778..53f3ebbfceab 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;
 }