During the Wireless Battle Mesh v9 in Porto (PT) at the beginning of

May, we managed to uncover and fix some important bugs in our
 new B.A.T.M.A.N. V algorithm. These are the fixes we came up with
 together with others that I collected in the past weeks:
 - avoid potential crash due to NULL pointer dereference in
   B.A.T.M.A.N. V routine when a neigh_ifinfo object is not found, by
   Sven Eckelmann
 - avoid use-after-free of skb when counting outgoing bytes, by Florian
   Westphal
 - fix neigh_ifinfo object reference counting imbalance when using
   B.A.T.M.A.N. V, by Sven Eckelmann. Such imbalance may lead to the
   impossibility of releasing the related netdev object on shutdown
 - avoid invalid memory access in case of error while allocating
   bcast_own_sum when a new hard-interface is added, by Sven Eckelmann
 - ensure originator address is updated in OMG/ELP packet content upon
   primary interface address change, by Antonio Quartulli
 - fix integer overflow when computing TQ metric (B.A.T.M.A.N. IV), by
   Sven Eckelmann
 - avoid race condition while adding new neigh_node which would result
   in having two objects mapping to the same physical neighbour, by
   Linus Lüssing
 - ensure originator address is initialized in ELP packet content on
   secondary interfaces, by Marek Lindner
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v2
 
 iQIcBAABCAAGBQJXO+ZsAAoJEJ4aZjxxc6bK7UEQALxcPqv2YtQhQCexHAPlmTxg
 73uXuXpo0eWPxJh2FElcsHTHSt/l0/m/G8MEWCOfqI8MTeg+UTY5lXCY4iThtiY6
 n08nl/CLkPNLuDGzAd7CpCM2jJ1iAzgJEVpUGQ6qoO5ekFvO09U/J/o6E8gDTX4I
 yc1kR3hcJeLbF6EUXEfTX/2THdFhkYSgHgZoGyM3eu43Zhv/6v454iEpqNxA/Ubr
 UngJTGSfqf20FidUt+xjbfptltTzj25Cp+VQ2DQ/LOuit0ChECjXwMfk0UkDHlKX
 bYPm1tcUJ0dzbR7cILMlzzzCSzH00leUk5GYYo59rAxBQiJ2j+92c2K0dcnv8cJJ
 q+GsZapyQFBIgPWS/TLtG1II3u8YWYvl+nEQXBDtPeRAjGoO4VwSbuatsf+enM8K
 i0c622iEc0b3cVe5H8reUh7SZMfMT/cQkEgpX5/psf8FWvEzeDv4HI3aUfVuSpck
 mEZAy59HeLWrF+KTScougv14vyoMmKfUcr5E1Oe4X1Ke9dpVvHGiI9wlqb/J0lfl
 rIc/5WI3ae/QAXkcPybanPEO8O0pBMP+Y4oCYpWmDu1qYfwZzDaSMqqEALQVVW2I
 8Ta1gbzamgZDslf7YDSWOR0iyFAFcnMhT0qU6gv2+RGbcfwD+AGRLu5ufY/th0N3
 L6AuFhvT/bxW6jN+iuAS
 =IACg
 -----END PGP SIGNATURE-----

Merge tag 'batman-adv-fix-for-davem' of git://git.open-mesh.org/linux-merge

Antonio Quartulli says:

====================
During the Wireless Battle Mesh v9 in Porto (PT) at the beginning of
May, we managed to uncover and fix some important bugs in our
new B.A.T.M.A.N. V algorithm. These are the fixes we came up with
together with others that I collected in the past weeks:
- avoid potential crash due to NULL pointer dereference in
  B.A.T.M.A.N. V routine when a neigh_ifinfo object is not found, by
  Sven Eckelmann
- avoid use-after-free of skb when counting outgoing bytes, by Florian
  Westphal
- fix neigh_ifinfo object reference counting imbalance when using
  B.A.T.M.A.N. V, by Sven Eckelmann. Such imbalance may lead to the
  impossibility of releasing the related netdev object on shutdown
- avoid invalid memory access in case of error while allocating
  bcast_own_sum when a new hard-interface is added, by Sven Eckelmann
- ensure originator address is updated in OMG/ELP packet content upon
  primary interface address change, by Antonio Quartulli
- fix integer overflow when computing TQ metric (B.A.T.M.A.N. IV), by
  Sven Eckelmann
- avoid race condition while adding new neigh_node which would result
  in having two objects mapping to the same physical neighbour, by
  Linus Lüssing
- ensure originator address is initialized in ELP packet content on
  secondary interfaces, by Marek Lindner
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

net/batman-adv/bat_iv_ogm.c

@@ -157,10 +157,8 @@ static int batadv_iv_ogm_orig_add_if(struct batadv_orig_node *orig_node,
 	orig_node->bat_iv.bcast_own = data_ptr;
 
 	data_ptr = kmalloc_array(max_if_num, sizeof(u8), GFP_ATOMIC);
-	if (!data_ptr) {
-		kfree(orig_node->bat_iv.bcast_own);
+	if (!data_ptr)
 		goto unlock;
-	}
 
 	memcpy(data_ptr, orig_node->bat_iv.bcast_own_sum,
 	       (max_if_num - 1) * sizeof(u8));
@@ -1182,9 +1180,10 @@ static bool batadv_iv_ogm_calc_tq(struct batadv_orig_node *orig_node,
 	u8 total_count;
 	u8 orig_eq_count, neigh_rq_count, neigh_rq_inv, tq_own;
 	unsigned int neigh_rq_inv_cube, neigh_rq_max_cube;
-	int tq_asym_penalty, inv_asym_penalty, if_num;
+	int if_num;
+	unsigned int tq_asym_penalty, inv_asym_penalty;
 	unsigned int combined_tq;
-	int tq_iface_penalty;
+	unsigned int tq_iface_penalty;
 	bool ret = false;
 
 	/* find corresponding one hop neighbor */

net/batman-adv/bat_v.c

@@ -27,6 +27,7 @@
 #include <linux/rculist.h>
 #include <linux/rcupdate.h>
 #include <linux/seq_file.h>
+#include <linux/stddef.h>
 #include <linux/types.h>
 #include <linux/workqueue.h>
 
@@ -39,6 +40,16 @@
 
 static void batadv_v_iface_activate(struct batadv_hard_iface *hard_iface)
 {
+	struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
+	struct batadv_hard_iface *primary_if;
+
+	primary_if = batadv_primary_if_get_selected(bat_priv);
+
+	if (primary_if) {
+		batadv_v_elp_iface_activate(primary_if, hard_iface);
+		batadv_hardif_put(primary_if);
+	}
+
 	/* B.A.T.M.A.N. V does not use any queuing mechanism, therefore it can
 	 * set the interface as ACTIVE right away, without any risk of race
 	 * condition
@@ -72,16 +83,34 @@ static void batadv_v_iface_disable(struct batadv_hard_iface *hard_iface)
 	batadv_v_elp_iface_disable(hard_iface);
 }
 
-static void batadv_v_iface_update_mac(struct batadv_hard_iface *hard_iface)
-{
-}
-
 static void batadv_v_primary_iface_set(struct batadv_hard_iface *hard_iface)
 {
 	batadv_v_elp_primary_iface_set(hard_iface);
 	batadv_v_ogm_primary_iface_set(hard_iface);
 }
 
+/**
+ * batadv_v_iface_update_mac - react to hard-interface MAC address change
+ * @hard_iface: the modified interface
+ *
+ * If the modified interface is the primary one, update the originator
+ * address in the ELP and OGM messages to reflect the new MAC address.
+ */
+static void batadv_v_iface_update_mac(struct batadv_hard_iface *hard_iface)
+{
+	struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
+	struct batadv_hard_iface *primary_if;
+
+	primary_if = batadv_primary_if_get_selected(bat_priv);
+	if (primary_if != hard_iface)
+		goto out;
+
+	batadv_v_primary_iface_set(hard_iface);
+out:
+	if (primary_if)
+		batadv_hardif_put(primary_if);
+}
+
 static void
 batadv_v_hardif_neigh_init(struct batadv_hardif_neigh_node *hardif_neigh)
 {
@@ -255,14 +284,23 @@ static int batadv_v_neigh_cmp(struct batadv_neigh_node *neigh1,
 			      struct batadv_hard_iface *if_outgoing2)
 {
 	struct batadv_neigh_ifinfo *ifinfo1, *ifinfo2;
+	int ret = 0;
 
 	ifinfo1 = batadv_neigh_ifinfo_get(neigh1, if_outgoing1);
+	if (WARN_ON(!ifinfo1))
+		goto err_ifinfo1;
+
 	ifinfo2 = batadv_neigh_ifinfo_get(neigh2, if_outgoing2);
+	if (WARN_ON(!ifinfo2))
+		goto err_ifinfo2;
 
-	if (WARN_ON(!ifinfo1 || !ifinfo2))
-		return 0;
+	ret = ifinfo1->bat_v.throughput - ifinfo2->bat_v.throughput;
 
-	return ifinfo1->bat_v.throughput - ifinfo2->bat_v.throughput;
+	batadv_neigh_ifinfo_put(ifinfo2);
+err_ifinfo2:
+	batadv_neigh_ifinfo_put(ifinfo1);
+err_ifinfo1:
+	return ret;
 }
 
 static bool batadv_v_neigh_is_sob(struct batadv_neigh_node *neigh1,
@@ -272,14 +310,26 @@ static bool batadv_v_neigh_is_sob(struct batadv_neigh_node *neigh1,
 {
 	struct batadv_neigh_ifinfo *ifinfo1, *ifinfo2;
 	u32 threshold;
+	bool ret = false;
 
 	ifinfo1 = batadv_neigh_ifinfo_get(neigh1, if_outgoing1);
+	if (WARN_ON(!ifinfo1))
+		goto err_ifinfo1;
+
 	ifinfo2 = batadv_neigh_ifinfo_get(neigh2, if_outgoing2);
+	if (WARN_ON(!ifinfo2))
+		goto err_ifinfo2;
 
 	threshold = ifinfo1->bat_v.throughput / 4;
 	threshold = ifinfo1->bat_v.throughput - threshold;
 
-	return ifinfo2->bat_v.throughput > threshold;
+	ret = ifinfo2->bat_v.throughput > threshold;
+
+	batadv_neigh_ifinfo_put(ifinfo2);
+err_ifinfo2:
+	batadv_neigh_ifinfo_put(ifinfo1);
+err_ifinfo1:
+	return ret;
 }
 
 static struct batadv_algo_ops batadv_batman_v __read_mostly = {

net/batman-adv/bat_v_elp.c

@@ -376,6 +376,27 @@ void batadv_v_elp_iface_disable(struct batadv_hard_iface *hard_iface)
 	hard_iface->bat_v.elp_skb = NULL;
 }
 
+/**
+ * batadv_v_elp_iface_activate - update the ELP buffer belonging to the given
+ *  hard-interface
+ * @primary_iface: the new primary interface
+ * @hard_iface: interface holding the to-be-updated buffer
+ */
+void batadv_v_elp_iface_activate(struct batadv_hard_iface *primary_iface,
+				 struct batadv_hard_iface *hard_iface)
+{
+	struct batadv_elp_packet *elp_packet;
+	struct sk_buff *skb;
+
+	if (!hard_iface->bat_v.elp_skb)
+		return;
+
+	skb = hard_iface->bat_v.elp_skb;
+	elp_packet = (struct batadv_elp_packet *)skb->data;
+	ether_addr_copy(elp_packet->orig,
+			primary_iface->net_dev->dev_addr);
+}
+
 /**
  * batadv_v_elp_primary_iface_set - change internal data to reflect the new
  *  primary interface
@@ -384,8 +405,6 @@ void batadv_v_elp_iface_disable(struct batadv_hard_iface *hard_iface)
 void batadv_v_elp_primary_iface_set(struct batadv_hard_iface *primary_iface)
 {
 	struct batadv_hard_iface *hard_iface;
-	struct batadv_elp_packet *elp_packet;
-	struct sk_buff *skb;
 
 	/* update orig field of every elp iface belonging to this mesh */
 	rcu_read_lock();
@@ -393,13 +412,7 @@ void batadv_v_elp_primary_iface_set(struct batadv_hard_iface *primary_iface)
 		if (primary_iface->soft_iface != hard_iface->soft_iface)
 			continue;
 
-		if (!hard_iface->bat_v.elp_skb)
-			continue;
-
-		skb = hard_iface->bat_v.elp_skb;
-		elp_packet = (struct batadv_elp_packet *)skb->data;
-		ether_addr_copy(elp_packet->orig,
-				primary_iface->net_dev->dev_addr);
+		batadv_v_elp_iface_activate(primary_iface, hard_iface);
 	}
 	rcu_read_unlock();
 }

net/batman-adv/bat_v_elp.h

@@ -25,6 +25,8 @@ struct work_struct;
 
 int batadv_v_elp_iface_enable(struct batadv_hard_iface *hard_iface);
 void batadv_v_elp_iface_disable(struct batadv_hard_iface *hard_iface);
+void batadv_v_elp_iface_activate(struct batadv_hard_iface *primary_iface,
+				 struct batadv_hard_iface *hard_iface);
 void batadv_v_elp_primary_iface_set(struct batadv_hard_iface *primary_iface);
 int batadv_v_elp_packet_recv(struct sk_buff *skb,
 			     struct batadv_hard_iface *if_incoming);

net/batman-adv/originator.c

@@ -619,6 +619,8 @@ batadv_neigh_node_new(struct batadv_orig_node *orig_node,
 	struct batadv_neigh_node *neigh_node;
 	struct batadv_hardif_neigh_node *hardif_neigh = NULL;
 
+	spin_lock_bh(&orig_node->neigh_list_lock);
+
 	neigh_node = batadv_neigh_node_get(orig_node, hard_iface, neigh_addr);
 	if (neigh_node)
 		goto out;
@@ -650,15 +652,15 @@ batadv_neigh_node_new(struct batadv_orig_node *orig_node,
 	kref_init(&neigh_node->refcount);
 	kref_get(&neigh_node->refcount);
 
-	spin_lock_bh(&orig_node->neigh_list_lock);
 	hlist_add_head_rcu(&neigh_node->list, &orig_node->neigh_list);
-	spin_unlock_bh(&orig_node->neigh_list_lock);
 
 	batadv_dbg(BATADV_DBG_BATMAN, orig_node->bat_priv,
 		   "Creating new neighbor %pM for orig_node %pM on interface %s\n",
 		   neigh_addr, orig_node->orig, hard_iface->net_dev->name);
 
 out:
+	spin_unlock_bh(&orig_node->neigh_list_lock);
+
 	if (hardif_neigh)
 		batadv_hardif_neigh_put(hardif_neigh);
 	return neigh_node;

net/batman-adv/routing.c

@@ -601,6 +601,7 @@ static int batadv_route_unicast_packet(struct sk_buff *skb,
 	struct batadv_unicast_packet *unicast_packet;
 	struct ethhdr *ethhdr = eth_hdr(skb);
 	int res, hdr_len, ret = NET_RX_DROP;
+	unsigned int len;
 
 	unicast_packet = (struct batadv_unicast_packet *)skb->data;
 
@@ -641,6 +642,7 @@ static int batadv_route_unicast_packet(struct sk_buff *skb,
 	if (hdr_len > 0)
 		batadv_skb_set_priority(skb, hdr_len);
 
+	len = skb->len;
 	res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
 
 	/* translate transmit result into receive result */
@@ -648,7 +650,7 @@ static int batadv_route_unicast_packet(struct sk_buff *skb,
 		/* skb was transmitted and consumed */
 		batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
 		batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
-				   skb->len + ETH_HLEN);
+				   len + ETH_HLEN);
 
 		ret = NET_RX_SUCCESS;
 	} else if (res == NET_XMIT_POLICED) {