ipvlan: fix leak in ipvlan_rcv_frame

Pass a **skb to ipvlan_rcv_frame so that if skb_share_check returns a
new skb, we actually use it during further processing.

It's safe to ignore the new skb in the ipvlan_xmit_* functions, because
they call ipvlan_rcv_frame with local == true, so that dev_forward_skb
is called and always takes ownership of the skb.

Fixes: 2ad7bf363841 ("ipvlan: Initial check-in of the IPVLAN driver.")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 5 deletions

diff --git a/drivers/net/ipvlan/ipvlan_core.c b/drivers/net/ipvlan/ipvlan_core.c
index d50887e3df6d..a9148e46dad0 100644
--- a/drivers/net/ipvlan/ipvlan_core.c
+++ b/drivers/net/ipvlan/ipvlan_core.c
@@ -254,7 +254,7 @@ acct:
         }
 }
 
-static int ipvlan_rcv_frame(struct ipvl_addr *addr, struct sk_buff *skb,
+static int ipvlan_rcv_frame(struct ipvl_addr *addr, struct sk_buff **pskb,
                             bool local)
 {
         struct ipvl_dev *ipvlan = addr->master;
@@ -262,6 +262,7 @@ static int ipvlan_rcv_frame(struct ipvl_addr *addr, struct sk_buff *skb,
         unsigned int len;
         rx_handler_result_t ret = RX_HANDLER_CONSUMED;
         bool success = false;
+        struct sk_buff *skb = *pskb;
 
         len = skb->len + ETH_HLEN;
         if (unlikely(!(dev->flags & IFF_UP))) {
@@ -273,6 +274,7 @@ static int ipvlan_rcv_frame(struct ipvl_addr *addr, struct sk_buff *skb,
         if (!skb)
                 goto out;
 
+        *pskb = skb;
         skb->dev = dev;
         skb->pkt_type = PACKET_HOST;
 
@@ -486,7 +488,7 @@ static int ipvlan_xmit_mode_l3(struct sk_buff *skb, struct net_device *dev)
 
         addr = ipvlan_addr_lookup(ipvlan->port, lyr3h, addr_type, true);
         if (addr)
-                return ipvlan_rcv_frame(addr, skb, true);
+                return ipvlan_rcv_frame(addr, &skb, true);
 
 out:
         skb->dev = ipvlan->phy_dev;
@@ -506,7 +508,7 @@ static int ipvlan_xmit_mode_l2(struct sk_buff *skb, struct net_device *dev)
                 if (lyr3h) {
                         addr = ipvlan_addr_lookup(ipvlan->port, lyr3h, addr_type, true);
                         if (addr)
-                                return ipvlan_rcv_frame(addr, skb, true);
+                                return ipvlan_rcv_frame(addr, &skb, true);
                 }
                 skb = skb_share_check(skb, GFP_ATOMIC);
                 if (!skb)
@@ -589,7 +591,7 @@ static rx_handler_result_t ipvlan_handle_mode_l3(struct sk_buff **pskb,
 
         addr = ipvlan_addr_lookup(port, lyr3h, addr_type, true);
         if (addr)
-                ret = ipvlan_rcv_frame(addr, skb, false);
+                ret = ipvlan_rcv_frame(addr, pskb, false);
 
 out:
         return ret;
@@ -626,7 +628,7 @@ static rx_handler_result_t ipvlan_handle_mode_l2(struct sk_buff **pskb,
 
                 addr = ipvlan_addr_lookup(port, lyr3h, addr_type, true);
                 if (addr)
-                        ret = ipvlan_rcv_frame(addr, skb, false);
+                        ret = ipvlan_rcv_frame(addr, pskb, false);
         }
 
         return ret;