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

Included changes:
- fix soft-interface MTU computation
- fix bogus pointer mangling when parsing the TT-TVLV
  container. This bug led to a wrong memory access.
- fix memory leak by properly releasing the VLAN object
  after CRC check
- properly check pskb_may_pull() return value
- avoid potential race condition while adding new neighbour
- fix potential memory leak by removing all the references
  to the orig_node object in case of initialization failure
- fix the TT CRC computation by ensuring that every node uses
  the same byte order when hosts with different endianess are
  part of the same network
- fix severe memory leak by freeing skb after a successful
  TVLV parsing
- avoid potential double free when orig_node initialization
  fails
- fix potential kernel paging error caused by the usage of
  the old value of skb->data after skb reallocation

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

1 files changed, 14 insertions, 8 deletions

diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c
index 3d417d3..b851cc5 100644
--- a/net/batman-adv/hard-interface.c
+++ b/net/batman-adv/hard-interface.c
@@ -241,7 +241,7 @@ int batadv_hardif_min_mtu(struct net_device *soft_iface)
 {
 	struct batadv_priv *bat_priv = netdev_priv(soft_iface);
 	const struct batadv_hard_iface *hard_iface;
-	int min_mtu = ETH_DATA_LEN;
+	int min_mtu = INT_MAX;
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
@@ -256,8 +256,6 @@ int batadv_hardif_min_mtu(struct net_device *soft_iface)
 	}
 	rcu_read_unlock();
 
-	atomic_set(&bat_priv->packet_size_max, min_mtu);
-
 	if (atomic_read(&bat_priv->fragmentation) == 0)
 		goto out;
 
@@ -268,13 +266,21 @@ int batadv_hardif_min_mtu(struct net_device *soft_iface)
 	min_mtu = min_t(int, min_mtu, BATADV_FRAG_MAX_FRAG_SIZE);
 	min_mtu -= sizeof(struct batadv_frag_packet);
 	min_mtu *= BATADV_FRAG_MAX_FRAGMENTS;
-	atomic_set(&bat_priv->packet_size_max, min_mtu);
-
-	/* with fragmentation enabled we can fragment external packets easily */
-	min_mtu = min_t(int, min_mtu, ETH_DATA_LEN);
 
 out:
-	return min_mtu - batadv_max_header_len();
+	/* report to the other components the maximum amount of bytes that
+	 * batman-adv can send over the wire (without considering the payload
+	 * overhead). For example, this value is used by TT to compute the
+	 * maximum local table table size
+	 */
+	atomic_set(&bat_priv->packet_size_max, min_mtu);
+
+	/* the real soft-interface MTU is computed by removing the payload
+	 * overhead from the maximum amount of bytes that was just computed.
+	 *
+	 * However batman-adv does not support MTUs bigger than ETH_DATA_LEN
+	 */
+	return min_t(int, min_mtu - batadv_max_header_len(), ETH_DATA_LEN);
 }
 
 /* adjusts the MTU if a new interface with a smaller MTU appeared. */