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

Included changes:
- fix parsing of user typed protocol string to avoid random memory access in
  some cases
- check pskb_trim_rcsum() return value
- prevent DAT from sending ARP replies when not needed
- reorder the main clean up routine to prevent race conditions

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

3 files changed, 32 insertions, 7 deletions

diff --git a/net/batman-adv/distributed-arp-table.c b/net/batman-adv/distributed-arp-table.c
index 8e15d966d9b..239992021b1 100644
--- a/net/batman-adv/distributed-arp-table.c
+++ b/net/batman-adv/distributed-arp-table.c
@@ -837,6 +837,19 @@ bool batadv_dat_snoop_outgoing_arp_request(struct batadv_priv *bat_priv,
 
 	dat_entry = batadv_dat_entry_hash_find(bat_priv, ip_dst);
 	if (dat_entry) {
+		/* If the ARP request is destined for a local client the local
+		 * client will answer itself. DAT would only generate a
+		 * duplicate packet.
+		 *
+		 * Moreover, if the soft-interface is enslaved into a bridge, an
+		 * additional DAT answer may trigger kernel warnings about
+		 * a packet coming from the wrong port.
+		 */
+		if (batadv_is_my_client(bat_priv, dat_entry->mac_addr)) {
+			ret = true;
+			goto out;
+		}
+
 		skb_new = arp_create(ARPOP_REPLY, ETH_P_ARP, ip_src,
 				     bat_priv->soft_iface, ip_dst, hw_src,
 				     dat_entry->mac_addr, hw_src);
diff --git a/net/batman-adv/main.c b/net/batman-adv/main.c
index 3e30a0f1b90..1240f07ad31 100644
--- a/net/batman-adv/main.c
+++ b/net/batman-adv/main.c
@@ -163,14 +163,22 @@ void batadv_mesh_free(struct net_device *soft_iface)
 	batadv_vis_quit(bat_priv);
 
 	batadv_gw_node_purge(bat_priv);
-	batadv_originator_free(bat_priv);
 	batadv_nc_free(bat_priv);
+	batadv_dat_free(bat_priv);
+	batadv_bla_free(bat_priv);
 
+	/* Free the TT and the originator tables only after having terminated
+	 * all the other depending components which may use these structures for
+	 * their purposes.
+	 */
 	batadv_tt_free(bat_priv);
 
-	batadv_bla_free(bat_priv);
-
-	batadv_dat_free(bat_priv);
+	/* Since the originator table clean up routine is accessing the TT
+	 * tables as well, it has to be invoked after the TT tables have been
+	 * freed and marked as empty. This ensures that no cleanup RCU callbacks
+	 * accessing the TT data are scheduled for later execution.
+	 */
+	batadv_originator_free(bat_priv);
 
 	free_percpu(bat_priv->bat_counters);
 
@@ -475,7 +483,7 @@ static int batadv_param_set_ra(const char *val, const struct kernel_param *kp)
 	char *algo_name = (char *)val;
 	size_t name_len = strlen(algo_name);
 
-	if (algo_name[name_len - 1] == '\n')
+	if (name_len > 0 && algo_name[name_len - 1] == '\n')
 		algo_name[name_len - 1] = '\0';
 
 	bat_algo_ops = batadv_algo_get(algo_name);
diff --git a/net/batman-adv/network-coding.c b/net/batman-adv/network-coding.c
index f7c54305a91..e84629ece9b 100644
--- a/net/batman-adv/network-coding.c
+++ b/net/batman-adv/network-coding.c
@@ -1514,6 +1514,7 @@ batadv_nc_skb_decode_packet(struct batadv_priv *bat_priv, struct sk_buff *skb,
 	struct ethhdr *ethhdr, ethhdr_tmp;
 	uint8_t *orig_dest, ttl, ttvn;
 	unsigned int coding_len;
+	int err;
 
 	/* Save headers temporarily */
 	memcpy(&coded_packet_tmp, skb->data, sizeof(coded_packet_tmp));
@@ -1568,8 +1569,11 @@ batadv_nc_skb_decode_packet(struct batadv_priv *bat_priv, struct sk_buff *skb,
 			 coding_len);
 
 	/* Resize decoded skb if decoded with larger packet */
-	if (nc_packet->skb->len > coding_len + h_size)
-		pskb_trim_rcsum(skb, coding_len + h_size);
+	if (nc_packet->skb->len > coding_len + h_size) {
+		err = pskb_trim_rcsum(skb, coding_len + h_size);
+		if (err)
+			return NULL;
+	}
 
 	/* Create decoded unicast packet */
 	unicast_packet = (struct batadv_unicast_packet *)skb->data;