Here are some batman-adv bugfixes:

- Fix issues with adjusted MTUs (2 patches), by Sven Eckelmann
 
  - Fix header access for memory reallocation case, by Remi Pommarel
 
  - Fix two memory leaks (2 patches), by Remi Pommarel
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Merge tag 'batadv-net-pullrequest-20230816' of git://git.open-mesh.org/linux-merge

Simon Wunderlich says:

====================
Here are some batman-adv bugfixes:

 - Fix issues with adjusted MTUs (2 patches), by Sven Eckelmann

 - Fix header access for memory reallocation case, by Remi Pommarel

 - Fix two memory leaks (2 patches), by Remi Pommarel

* tag 'batadv-net-pullrequest-20230816' of git://git.open-mesh.org/linux-merge:
  batman-adv: Fix batadv_v_ogm_aggr_send memory leak
  batman-adv: Fix TT global entry leak when client roamed back
  batman-adv: Do not get eth header before batadv_check_management_packet
  batman-adv: Don't increase MTU when set by user
  batman-adv: Trigger events for auto adjusted MTU
====================

Link: https://lore.kernel.org/r/20230816163318.189996-1-sw@simonwunderlich.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/batman-adv/bat_v_elp.c

@@ -505,7 +505,7 @@ int batadv_v_elp_packet_recv(struct sk_buff *skb,
 	struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 	struct batadv_elp_packet *elp_packet;
 	struct batadv_hard_iface *primary_if;
-	struct ethhdr *ethhdr = (struct ethhdr *)skb_mac_header(skb);
+	struct ethhdr *ethhdr;
 	bool res;
 	int ret = NET_RX_DROP;
 
@@ -513,6 +513,7 @@ int batadv_v_elp_packet_recv(struct sk_buff *skb,
 	if (!res)
 		goto free_skb;
 
+	ethhdr = eth_hdr(skb);
 	if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
 		goto free_skb;
 

net/batman-adv/bat_v_ogm.c

@@ -123,8 +123,10 @@ static void batadv_v_ogm_send_to_if(struct sk_buff *skb,
 {
 	struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 
-	if (hard_iface->if_status != BATADV_IF_ACTIVE)
+	if (hard_iface->if_status != BATADV_IF_ACTIVE) {
+		kfree_skb(skb);
 		return;
+	}
 
 	batadv_inc_counter(bat_priv, BATADV_CNT_MGMT_TX);
 	batadv_add_counter(bat_priv, BATADV_CNT_MGMT_TX_BYTES,
@@ -985,7 +987,7 @@ int batadv_v_ogm_packet_recv(struct sk_buff *skb,
 {
 	struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 	struct batadv_ogm2_packet *ogm_packet;
-	struct ethhdr *ethhdr = eth_hdr(skb);
+	struct ethhdr *ethhdr;
 	int ogm_offset;
 	u8 *packet_pos;
 	int ret = NET_RX_DROP;
@@ -999,6 +1001,7 @@ int batadv_v_ogm_packet_recv(struct sk_buff *skb,
 	if (!batadv_check_management_packet(skb, if_incoming, BATADV_OGM2_HLEN))
 		goto free_skb;
 
+	ethhdr = eth_hdr(skb);
 	if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
 		goto free_skb;
 

net/batman-adv/hard-interface.c

@@ -630,7 +630,19 @@ out:
  */
 void batadv_update_min_mtu(struct net_device *soft_iface)
 {
-	soft_iface->mtu = batadv_hardif_min_mtu(soft_iface);
+	struct batadv_priv *bat_priv = netdev_priv(soft_iface);
+	int limit_mtu;
+	int mtu;
+
+	mtu = batadv_hardif_min_mtu(soft_iface);
+
+	if (bat_priv->mtu_set_by_user)
+		limit_mtu = bat_priv->mtu_set_by_user;
+	else
+		limit_mtu = ETH_DATA_LEN;
+
+	mtu = min(mtu, limit_mtu);
+	dev_set_mtu(soft_iface, mtu);
 
 	/* Check if the local translate table should be cleaned up to match a
 	 * new (and smaller) MTU.

net/batman-adv/soft-interface.c

@@ -153,11 +153,14 @@ static int batadv_interface_set_mac_addr(struct net_device *dev, void *p)
 
 static int batadv_interface_change_mtu(struct net_device *dev, int new_mtu)
 {
+	struct batadv_priv *bat_priv = netdev_priv(dev);
+
 	/* check ranges */
 	if (new_mtu < 68 || new_mtu > batadv_hardif_min_mtu(dev))
 		return -EINVAL;
 
 	dev->mtu = new_mtu;
+	bat_priv->mtu_set_by_user = new_mtu;
 
 	return 0;
 }

net/batman-adv/translation-table.c

@@ -774,7 +774,6 @@ check_roaming:
 		if (roamed_back) {
 			batadv_tt_global_free(bat_priv, tt_global,
 					      "Roaming canceled");
-			tt_global = NULL;
 		} else {
 			/* The global entry has to be marked as ROAMING and
 			 * has to be kept for consistency purpose

net/batman-adv/types.h

@@ -1546,6 +1546,12 @@ struct batadv_priv {
 	/** @soft_iface: net device which holds this struct as private data */
 	struct net_device *soft_iface;
 
+	/**
+	 * @mtu_set_by_user: MTU was set once by user
+	 * protected by rtnl_lock
+	 */
+	int mtu_set_by_user;
+
 	/**
 	 * @bat_counters: mesh internal traffic statistic counters (see
 	 *  batadv_counters)