From afac8096bde4948e3caa7e4dd733867cfbd3018e Mon Sep 17 00:00:00 2001 From: Sven Eckelmann Date: Sun, 28 Jun 2026 08:45:41 +0200 Subject: [PATCH] batman-adv: gw: acquire ethernet header only after skb realloc commit 77880a3be88d378d60cc1e8f8ec70430e2ed0518 upstream. The pskb_may_pull() called by batadv_get_vid() could reallocate the buffer behind the skb. Variables which were pointing to the old buffer need to be reassigned to avoid an use-after-free. Cc: stable@vger.kernel.org Fixes: 6c413b1c22a2 ("batman-adv: send every DHCP packet as bat-unicast") Signed-off-by: Sven Eckelmann Signed-off-by: Greg Kroah-Hartman --- net/batman-adv/gateway_client.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c index 003b03ca31b4..f62797b441e9 100644 --- a/net/batman-adv/gateway_client.c +++ b/net/batman-adv/gateway_client.c @@ -693,12 +693,13 @@ bool batadv_gw_out_of_range(struct batadv_priv *bat_priv, struct batadv_gw_node *gw_node = NULL; struct batadv_gw_node *curr_gw = NULL; struct batadv_neigh_ifinfo *curr_ifinfo, *old_ifinfo; - struct ethhdr *ethhdr = (struct ethhdr *)skb->data; + struct ethhdr *ethhdr; bool out_of_range = false; u8 curr_tq_avg; unsigned short vid; vid = batadv_get_vid(skb, 0); + ethhdr = (struct ethhdr *)skb->data; if (is_multicast_ether_addr(ethhdr->h_dest)) goto out;