Merge tag 'batadv-net-for-davem-20191025' of git://git.open-mesh.org/linux-merge

Simon Wunderlich says:

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

 * Fix free/alloc race for OGM and OGMv2, by Sven Eckelmann (2 patches)
====================

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

4 files changed, 94 insertions, 17 deletions

diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c
index d78938e3e008..5b0b20e6da95 100644
--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -22,6 +22,8 @@
 #include <linux/kernel.h>
 #include <linux/kref.h>
 #include <linux/list.h>
+#include <linux/lockdep.h>
+#include <linux/mutex.h>
 #include <linux/netdevice.h>
 #include <linux/netlink.h>
 #include <linux/pkt_sched.h>
@@ -193,14 +195,18 @@ static int batadv_iv_ogm_iface_enable(struct batadv_hard_iface *hard_iface)
 	unsigned char *ogm_buff;
 	u32 random_seqno;
 
+	mutex_lock(&hard_iface->bat_iv.ogm_buff_mutex);
+
 	/* randomize initial seqno to avoid collision */
 	get_random_bytes(&random_seqno, sizeof(random_seqno));
 	atomic_set(&hard_iface->bat_iv.ogm_seqno, random_seqno);
 
 	hard_iface->bat_iv.ogm_buff_len = BATADV_OGM_HLEN;
 	ogm_buff = kmalloc(hard_iface->bat_iv.ogm_buff_len, GFP_ATOMIC);
-	if (!ogm_buff)
+	if (!ogm_buff) {
+		mutex_unlock(&hard_iface->bat_iv.ogm_buff_mutex);
 		return -ENOMEM;
+	}
 
 	hard_iface->bat_iv.ogm_buff = ogm_buff;
 
@@ -212,35 +218,59 @@ static int batadv_iv_ogm_iface_enable(struct batadv_hard_iface *hard_iface)
 	batadv_ogm_packet->reserved = 0;
 	batadv_ogm_packet->tq = BATADV_TQ_MAX_VALUE;
 
+	mutex_unlock(&hard_iface->bat_iv.ogm_buff_mutex);
+
 	return 0;
 }
 
 static void batadv_iv_ogm_iface_disable(struct batadv_hard_iface *hard_iface)
 {
+	mutex_lock(&hard_iface->bat_iv.ogm_buff_mutex);
+
 	kfree(hard_iface->bat_iv.ogm_buff);
 	hard_iface->bat_iv.ogm_buff = NULL;
+
+	mutex_unlock(&hard_iface->bat_iv.ogm_buff_mutex);
 }
 
 static void batadv_iv_ogm_iface_update_mac(struct batadv_hard_iface *hard_iface)
 {
 	struct batadv_ogm_packet *batadv_ogm_packet;
-	unsigned char *ogm_buff = hard_iface->bat_iv.ogm_buff;
+	void *ogm_buff;
 
-	batadv_ogm_packet = (struct batadv_ogm_packet *)ogm_buff;
+	mutex_lock(&hard_iface->bat_iv.ogm_buff_mutex);
+
+	ogm_buff = hard_iface->bat_iv.ogm_buff;
+	if (!ogm_buff)
+		goto unlock;
+
+	batadv_ogm_packet = ogm_buff;
 	ether_addr_copy(batadv_ogm_packet->orig,
 			hard_iface->net_dev->dev_addr);
 	ether_addr_copy(batadv_ogm_packet->prev_sender,
 			hard_iface->net_dev->dev_addr);
+
+unlock:
+	mutex_unlock(&hard_iface->bat_iv.ogm_buff_mutex);
 }
 
 static void
 batadv_iv_ogm_primary_iface_set(struct batadv_hard_iface *hard_iface)
 {
 	struct batadv_ogm_packet *batadv_ogm_packet;
-	unsigned char *ogm_buff = hard_iface->bat_iv.ogm_buff;
+	void *ogm_buff;
 
-	batadv_ogm_packet = (struct batadv_ogm_packet *)ogm_buff;
+	mutex_lock(&hard_iface->bat_iv.ogm_buff_mutex);
+
+	ogm_buff = hard_iface->bat_iv.ogm_buff;
+	if (!ogm_buff)
+		goto unlock;
+
+	batadv_ogm_packet = ogm_buff;
 	batadv_ogm_packet->ttl = BATADV_TTL;
+
+unlock:
+	mutex_unlock(&hard_iface->bat_iv.ogm_buff_mutex);
 }
 
 /* when do we schedule our own ogm to be sent */
@@ -742,7 +772,11 @@ batadv_iv_ogm_slide_own_bcast_window(struct batadv_hard_iface *hard_iface)
 	}
 }
 
-static void batadv_iv_ogm_schedule(struct batadv_hard_iface *hard_iface)
+/**
+ * batadv_iv_ogm_schedule_buff() - schedule submission of hardif ogm buffer
+ * @hard_iface: interface whose ogm buffer should be transmitted
+ */
+static void batadv_iv_ogm_schedule_buff(struct batadv_hard_iface *hard_iface)
 {
 	struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 	unsigned char **ogm_buff = &hard_iface->bat_iv.ogm_buff;
@@ -753,9 +787,7 @@ static void batadv_iv_ogm_schedule(struct batadv_hard_iface *hard_iface)
 	u16 tvlv_len = 0;
 	unsigned long send_time;
 
-	if (hard_iface->if_status == BATADV_IF_NOT_IN_USE ||
-	    hard_iface->if_status == BATADV_IF_TO_BE_REMOVED)
-		return;
+	lockdep_assert_held(&hard_iface->bat_iv.ogm_buff_mutex);
 
 	/* the interface gets activated here to avoid race conditions between
 	 * the moment of activating the interface in
@@ -823,6 +855,17 @@ out:
 		batadv_hardif_put(primary_if);
 }
 
+static void batadv_iv_ogm_schedule(struct batadv_hard_iface *hard_iface)
+{
+	if (hard_iface->if_status == BATADV_IF_NOT_IN_USE ||
+	    hard_iface->if_status == BATADV_IF_TO_BE_REMOVED)
+		return;
+
+	mutex_lock(&hard_iface->bat_iv.ogm_buff_mutex);
+	batadv_iv_ogm_schedule_buff(hard_iface);
+	mutex_unlock(&hard_iface->bat_iv.ogm_buff_mutex);
+}
+
 /**
  * batadv_iv_orig_ifinfo_sum() - Get bcast_own sum for originator over iterface
  * @orig_node: originator which reproadcasted the OGMs directly
diff --git a/net/batman-adv/bat_v_ogm.c b/net/batman-adv/bat_v_ogm.c
index dc4f7430cb5a..8033f24f506c 100644
--- a/net/batman-adv/bat_v_ogm.c
+++ b/net/batman-adv/bat_v_ogm.c
@@ -18,6 +18,7 @@
 #include <linux/kref.h>
 #include <linux/list.h>
 #include <linux/lockdep.h>
+#include <linux/mutex.h>
 #include <linux/netdevice.h>
 #include <linux/random.h>
 #include <linux/rculist.h>
@@ -256,14 +257,12 @@ static void batadv_v_ogm_queue_on_if(struct sk_buff *skb,
 }
 
 /**
- * batadv_v_ogm_send() - periodic worker broadcasting the own OGM
- * @work: work queue item
+ * batadv_v_ogm_send_softif() - periodic worker broadcasting the own OGM
+ * @bat_priv: the bat priv with all the soft interface information
  */
-static void batadv_v_ogm_send(struct work_struct *work)
+static void batadv_v_ogm_send_softif(struct batadv_priv *bat_priv)
 {
 	struct batadv_hard_iface *hard_iface;
-	struct batadv_priv_bat_v *bat_v;
-	struct batadv_priv *bat_priv;
 	struct batadv_ogm2_packet *ogm_packet;
 	struct sk_buff *skb, *skb_tmp;
 	unsigned char *ogm_buff;
@@ -271,8 +270,7 @@ static void batadv_v_ogm_send(struct work_struct *work)
 	u16 tvlv_len = 0;
 	int ret;
 
-	bat_v = container_of(work, struct batadv_priv_bat_v, ogm_wq.work);
-	bat_priv = container_of(bat_v, struct batadv_priv, bat_v);
+	lockdep_assert_held(&bat_priv->bat_v.ogm_buff_mutex);
 
 	if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 		goto out;
@@ -364,6 +362,23 @@ out:
 }
 
 /**
+ * batadv_v_ogm_send() - periodic worker broadcasting the own OGM
+ * @work: work queue item
+ */
+static void batadv_v_ogm_send(struct work_struct *work)
+{
+	struct batadv_priv_bat_v *bat_v;
+	struct batadv_priv *bat_priv;
+
+	bat_v = container_of(work, struct batadv_priv_bat_v, ogm_wq.work);
+	bat_priv = container_of(bat_v, struct batadv_priv, bat_v);
+
+	mutex_lock(&bat_priv->bat_v.ogm_buff_mutex);
+	batadv_v_ogm_send_softif(bat_priv);
+	mutex_unlock(&bat_priv->bat_v.ogm_buff_mutex);
+}
+
+/**
  * batadv_v_ogm_aggr_work() - OGM queue periodic task per interface
  * @work: work queue item
  *
@@ -424,11 +439,15 @@ void batadv_v_ogm_primary_iface_set(struct batadv_hard_iface *primary_iface)
 	struct batadv_priv *bat_priv = netdev_priv(primary_iface->soft_iface);
 	struct batadv_ogm2_packet *ogm_packet;
 
+	mutex_lock(&bat_priv->bat_v.ogm_buff_mutex);
 	if (!bat_priv->bat_v.ogm_buff)
-		return;
+		goto unlock;
 
 	ogm_packet = (struct batadv_ogm2_packet *)bat_priv->bat_v.ogm_buff;
 	ether_addr_copy(ogm_packet->orig, primary_iface->net_dev->dev_addr);
+
+unlock:
+	mutex_unlock(&bat_priv->bat_v.ogm_buff_mutex);
 }
 
 /**
@@ -1050,6 +1069,8 @@ int batadv_v_ogm_init(struct batadv_priv *bat_priv)
 	atomic_set(&bat_priv->bat_v.ogm_seqno, random_seqno);
 	INIT_DELAYED_WORK(&bat_priv->bat_v.ogm_wq, batadv_v_ogm_send);
 
+	mutex_init(&bat_priv->bat_v.ogm_buff_mutex);
+
 	return 0;
 }
 
@@ -1061,7 +1082,11 @@ void batadv_v_ogm_free(struct batadv_priv *bat_priv)
 {
 	cancel_delayed_work_sync(&bat_priv->bat_v.ogm_wq);
 
+	mutex_lock(&bat_priv->bat_v.ogm_buff_mutex);
+
 	kfree(bat_priv->bat_v.ogm_buff);
 	bat_priv->bat_v.ogm_buff = NULL;
 	bat_priv->bat_v.ogm_buff_len = 0;
+
+	mutex_unlock(&bat_priv->bat_v.ogm_buff_mutex);
 }
diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c
index c90e47342bb0..afb52282d5bd 100644
--- a/net/batman-adv/hard-interface.c
+++ b/net/batman-adv/hard-interface.c
@@ -18,6 +18,7 @@
 #include <linux/kref.h>
 #include <linux/limits.h>
 #include <linux/list.h>
+#include <linux/mutex.h>
 #include <linux/netdevice.h>
 #include <linux/printk.h>
 #include <linux/rculist.h>
@@ -929,6 +930,7 @@ batadv_hardif_add_interface(struct net_device *net_dev)
 	INIT_LIST_HEAD(&hard_iface->list);
 	INIT_HLIST_HEAD(&hard_iface->neigh_list);
 
+	mutex_init(&hard_iface->bat_iv.ogm_buff_mutex);
 	spin_lock_init(&hard_iface->neigh_list_lock);
 	kref_init(&hard_iface->refcount);
 
diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index be7c02aa91e2..4d7f1baee7b7 100644
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -17,6 +17,7 @@
 #include <linux/if.h>
 #include <linux/if_ether.h>
 #include <linux/kref.h>
+#include <linux/mutex.h>
 #include <linux/netdevice.h>
 #include <linux/netlink.h>
 #include <linux/sched.h> /* for linux/wait.h */
@@ -81,6 +82,9 @@ struct batadv_hard_iface_bat_iv {
 
 	/** @ogm_seqno: OGM sequence number - used to identify each OGM */
 	atomic_t ogm_seqno;
+
+	/** @ogm_buff_mutex: lock protecting ogm_buff and ogm_buff_len */
+	struct mutex ogm_buff_mutex;
 };
 
 /**
@@ -1539,6 +1543,9 @@ struct batadv_priv_bat_v {
 	/** @ogm_seqno: OGM sequence number - used to identify each OGM */
 	atomic_t ogm_seqno;
 
+	/** @ogm_buff_mutex: lock protecting ogm_buff and ogm_buff_len */
+	struct mutex ogm_buff_mutex;
+
 	/** @ogm_wq: workqueue used to schedule OGM transmissions */
 	struct delayed_work ogm_wq;
 };