bonding: COW before overwriting the destination MAC address
When there is a ptype handler holding a clone of this skb, whose
destination MAC addresse is overwritten, the owner of this handler may
get a corrupted packet.
Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 912b416..7b7ca97 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1511,9 +1511,13 @@
if (bond_dev->priv_flags & IFF_MASTER_ALB &&
bond_dev->priv_flags & IFF_BRIDGE_PORT &&
skb->pkt_type == PACKET_HOST) {
- u16 *dest = (u16 *) eth_hdr(skb)->h_dest;
- memcpy(dest, bond_dev->dev_addr, ETH_ALEN);
+ if (unlikely(skb_cow_head(skb,
+ skb->data - skb_mac_header(skb)))) {
+ kfree_skb(skb);
+ return NULL;
+ }
+ memcpy(eth_hdr(skb)->h_dest, bond_dev->dev_addr, ETH_ALEN);
}
return skb;