pppoe: Lacks DST MAC address check

A pppoe session is identified by its session ID and MAC address.
Currently pppoe does not check if the received pkg has the correct
MAC address. This is a problem when the eth I/F is in promisc mode
as then any DST MAC address is accepted.

Signed-off-by: Joakim Tjernlund <joakim.tjernlund@transmode.se>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/net/ppp/pppoe.c b/drivers/net/ppp/pppoe.c
index ff059e1d8ac6..aa1dd926623a 100644
--- a/drivers/net/ppp/pppoe.c
+++ b/drivers/net/ppp/pppoe.c
@@ -380,6 +380,9 @@ static int pppoe_rcv_core(struct sock *sk, struct sk_buff *skb)
          * can't change.
          */
 
+        if (skb->pkt_type == PACKET_OTHERHOST)
+                goto abort_kfree;
+
         if (sk->sk_state & PPPOX_BOUND) {
                 ppp_input(&po->chan, skb);
         } else if (sk->sk_state & PPPOX_RELAY) {