From: Matthias Schiffer <mschiffer@xxxxxxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Sven Eckelmann <sven@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/batman-adv/routing.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/net/batman-adv/routing.c +++ b/net/batman-adv/routing.c @@ -930,7 +930,6 @@ int batadv_recv_unicast_packet(struct sk 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 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);