From: Sven Eckelmann <[email protected]> batadv_mcast_forw_mode_by_count() pushs the skb->data for BATADV_FORW_MCAST forwarding via batadv_mcast_forw_mcsend(). But the batadv_skb_set_priority() expects the ethernet header directly before (skb->data + offset). With the moved skb->data, just some random data would be accessed to get the priority data.
Move the batadv_skb_set_priority() before the decision about the handling multicast packets and potential header modifications. Cc: [email protected] Fixes: 90039133221e ("batman-adv: mcast: implement multicast packet generation") Signed-off-by: Sven Eckelmann <[email protected]> Signed-off-by: Simon Wunderlich <[email protected]> --- net/batman-adv/mesh-interface.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/net/batman-adv/mesh-interface.c b/net/batman-adv/mesh-interface.c index 1dc6cfae9e9ae..48bbb28d4576f 100644 --- a/net/batman-adv/mesh-interface.c +++ b/net/batman-adv/mesh-interface.c @@ -260,6 +260,8 @@ static netdev_tx_t batadv_interface_tx(struct sk_buff *skb, if (batadv_compare_eth(ethhdr->h_dest, ectp_addr)) goto dropped; + batadv_skb_set_priority(skb, 0); + gw_mode = READ_ONCE(bat_priv->gw.mode); if (is_multicast_ether_addr(ethhdr->h_dest)) { /* if gw mode is off, broadcast every packet */ @@ -293,6 +295,9 @@ static netdev_tx_t batadv_interface_tx(struct sk_buff *skb, send: if (do_bcast && !is_broadcast_ether_addr(ethhdr->h_dest)) { + /* WARNING batadv_mcast_forw_mode might add more headers + * in front of the skb. and might even reallocate the skb + */ forw_mode = batadv_mcast_forw_mode(bat_priv, skb, vid, &mcast_is_routable); switch (forw_mode) { @@ -310,8 +315,6 @@ static netdev_tx_t batadv_interface_tx(struct sk_buff *skb, } } - batadv_skb_set_priority(skb, 0); - /* ethernet packet should be broadcasted */ if (do_bcast) { primary_if = batadv_primary_if_get_selected(bat_priv); -- 2.47.3
