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authorChangli Gao <xiaosuo@gmail.com>2011-03-02 21:07:14 +0000
committerDavid S. Miller <davem@davemloft.net>2011-03-07 15:45:08 -0800
commit541ac7c9b30ee2ff84ad87f27e0bc069e143afb5 (patch)
treebb1e2377bf33ecee73518b0c517980f5a33b8405 /drivers/net/bonding
parentcca134fe784a01cf4eb9f0621b0104591b7ddfba (diff)
downloadlinux-541ac7c9b30ee2ff84ad87f27e0bc069e143afb5.tar.gz
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>
Diffstat (limited to 'drivers/net/bonding')
-rw-r--r--drivers/net/bonding/bond_main.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 912b416b7573..7b7ca971672f 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1511,9 +1511,13 @@ static struct sk_buff *bond_handle_frame(struct sk_buff *skb)
 	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;