batman-adv: update data pointers after skb_cow()

commit bc44b78157f621ff2a2618fe287a827bcb094ac4 upstream.

batadv_check_unicast_ttvn() calls skb_cow(), so pointers into the SKB data
must be (re)set after calling it. The ethhdr variable is dropped
altogether.

Fixes: 78fc6bbe0aca ("batman-adv: add UNICAST_4ADDR packet type")
Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c
index f9ffb18..19059ae 100644 (file)
--- a/net/batman-adv/routing.c
+++ b/net/batman-adv/routing.c
@@ -930,7 +930,6 @@ int batadv_recv_unicast_packet(struct sk_buff *skb,
        bool is4addr;
 
        unicast_packet = (struct batadv_unicast_packet *)skb->data;
-       unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
 
        is4addr = unicast_packet->packet_type == BATADV_UNICAST_4ADDR;
        /* the caller function should have already pulled 2 bytes */
@@ -951,9 +950,13 @@ int batadv_recv_unicast_packet(struct sk_buff *skb,
        if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size))
                return NET_RX_DROP;
 
+       unicast_packet = (struct batadv_unicast_packet *)skb->data;
+
        /* packet for me */
        if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
                if (is4addr) {
+                       unicast_4addr_packet =
+                               (struct batadv_unicast_4addr_packet *)skb->data;
                        subtype = unicast_4addr_packet->subtype;
                        batadv_dat_inc_counter(bat_priv, subtype);