[PATCH wpan 2/2] net: mac802154: tx: expand tailroom if necessary

[Alexander Aring]

This patch is necessary if case of AF_PACKET or other socket interface
which I am aware of it and didn't allocated the necessary room.

Reported-by: David Palma <david.pa...@ntnu.no>
Reported-by: Rabi Narayan Sahoo <rabinarayans0...@gmail.com>
Signed-off-by: Alexander Aring <ar...@mojatatu.com>
---
 net/mac802154/tx.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/net/mac802154/tx.c b/net/mac802154/tx.c
index 7e253455f9dd..bcd1a5e6ebf4 100644
--- a/net/mac802154/tx.c
+++ b/net/mac802154/tx.c
@@ -63,8 +63,21 @@ ieee802154_tx(struct ieee802154_local *local, struct sk_buff 
*skb)
        int ret;
 
        if (!(local->hw.flags & IEEE802154_HW_TX_OMIT_CKSUM)) {
-               u16 crc = crc_ccitt(0, skb->data, skb->len);
+               struct sk_buff *nskb;
+               u16 crc;
+
+               if (unlikely(skb_tailroom(skb) < IEEE802154_FCS_LEN)) {
+                       nskb = skb_copy_expand(skb, 0, IEEE802154_FCS_LEN,
+                                              GFP_ATOMIC);
+                       if (likely(nskb)) {
+                               consume_skb(skb);
+                               skb = nskb;
+                       } else {
+                               goto err_tx;
+                       }
+               }
 
+               crc = crc_ccitt(0, skb->data, skb->len);
                put_unaligned_le16(crc, skb_put(skb, 2));
        }
 
-- 
2.11.0