[PATCH v2] Bluetooth: 6LoWPAN: Add missing check for skb_clone

[Jiasheng Jiang]

Add the check for the return value of skb_clone since it may return NULL
pointer and cause NULL pointer dereference in send_pkt.

Fixes: 18722c247023 ("Bluetooth: Enable 6LoWPAN support for BT LE devices")
Signed-off-by: Jiasheng Jiang <jiasheng@xxxxxxxxxxx>
---
Changelog:

v1 -> v2:

1. Modify the error handling in the loop.
---
 net/bluetooth/6lowpan.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
index 4eb1b3ced0d2..55ae2ff40efb 100644
--- a/net/bluetooth/6lowpan.c
+++ b/net/bluetooth/6lowpan.c
@@ -477,19 +477,25 @@ static int send_mcast_pkt(struct sk_buff *skb, struct net_device *netdev)
 			int ret;
 
 			local_skb = skb_clone(skb, GFP_ATOMIC);
+			if (!local_skb) {
+				err = -ENOMEM;
+				goto out;
+			}
 
 			BT_DBG("xmit %s to %pMR type %u IP %pI6c chan %p",
 			       netdev->name,
 			       &pentry->chan->dst, pentry->chan->dst_type,
 			       &pentry->peer_addr, pentry->chan);
 			ret = send_pkt(pentry->chan, local_skb, netdev);
-			if (ret < 0)
-				err = ret;
-
 			kfree_skb(local_skb);
+			if (ret < 0) {
+				err = ret;
+				goto out;
+			}
 		}
 	}
 
+out:
 	rcu_read_unlock();
 
 	return err;
-- 
2.25.1