batman-adv; branch, master, updated. v2010.1.0-174-g16506a6 - commits - lists.open-mesh.org

18 Sep 2010

The following commit has been merged in the master branch:
commit 31cffc13fd68ae5e38740e35b210f2119534a35e
Author: Sven Eckelmann sven.eckelmann@gmx.de
Date:   Sat Sep 18 15:35:44 2010 +0000
batman-adv: count batman_if list queries as reference
The return of get_batman_if_by_netdev and get_active_batman_if leaks a
    pointer from the rcu protected list of interfaces. We must protect it to
    prevent a too early release of the memory. Those functions must increase
    the reference counter before rcu_read_unlock or it may be to late to
    prevent a free.
hardif_add_interface must also increase the reference count for the
    returned batman_if to make the behaviour consistent.
Reported-by: Paul E. McKenney paulmck@linux.vnet.ibm.com
    Signed-off-by: Sven Eckelmann sven.eckelmann@gmx.de

diff --git a/bat_sysfs.c b/bat_sysfs.c
index 8e180ba..9ab2bfe 100644
--- a/bat_sysfs.c
+++ b/bat_sysfs.c
@@ -453,13 +453,17 @@ static ssize_t show_mesh_iface(struct kobject *kobj, struct attribute *attr,
    struct device *dev = to_dev(kobj->parent);
    struct net_device *net_dev = to_net_dev(dev);
    struct batman_if *batman_if = get_batman_if_by_netdev(net_dev);
+	ssize_t length;
if (!batman_if)
    	return 0;
-	return sprintf(buff, "%s\n",
-		       batman_if->if_status == IF_NOT_IN_USE ?
-					"none" : batman_if->soft_iface->name);
+	length = sprintf(buff, "%s\n", batman_if->if_status == IF_NOT_IN_USE ?
+			 "none" : batman_if->soft_iface->name);
+
+	hardif_put(batman_if);
+
+	return length;
 }
static ssize_t store_mesh_iface(struct kobject *kobj, struct attribute *attr,
@@ -469,6 +473,7 @@ static ssize_t store_mesh_iface(struct kobject *kobj, struct attribute *attr,
    struct net_device *net_dev = to_net_dev(dev);
    struct batman_if *batman_if = get_batman_if_by_netdev(net_dev);
    int status_tmp = -1;
+	int ret;
if (!batman_if)
    	return count;
@@ -479,6 +484,7 @@ static ssize_t store_mesh_iface(struct kobject *kobj, struct attribute *attr,
    if (strlen(buff) >= IFNAMSIZ) {
    	pr_err("Invalid parameter for 'mesh_iface' setting received: "
    	       "interface name too long '%s'\n", buff);
+		hardif_put(batman_if);
    	return -EINVAL;
    }
@@ -488,13 +494,16 @@ static ssize_t store_mesh_iface(struct kobject *kobj, struct attribute *attr,
    	status_tmp = IF_I_WANT_YOU;
if ((batman_if->if_status == status_tmp) || ((batman_if->soft_iface) &&
-	    (strncmp(batman_if->soft_iface->name, buff, IFNAMSIZ) == 0)))
+	    (strncmp(batman_if->soft_iface->name, buff, IFNAMSIZ) == 0))) {
+		hardif_put(batman_if);
    	return count;
+	}
if (status_tmp == IF_NOT_IN_USE) {
    	rtnl_lock();
    	hardif_disable_interface(batman_if);
    	rtnl_unlock();
+		hardif_put(batman_if);
    	return count;
    }
@@ -505,7 +514,10 @@ static ssize_t store_mesh_iface(struct kobject *kobj, struct attribute *attr,
    	rtnl_unlock();
    }
-	return hardif_enable_interface(batman_if, buff);
+	ret = hardif_enable_interface(batman_if, buff);
+	hardif_put(batman_if);
+
+	return ret;
 }
static ssize_t show_iface_status(struct kobject *kobj, struct attribute *attr,
@@ -514,23 +526,33 @@ static ssize_t show_iface_status(struct kobject *kobj, struct attribute *attr,
    struct device *dev = to_dev(kobj->parent);
    struct net_device *net_dev = to_net_dev(dev);
    struct batman_if *batman_if = get_batman_if_by_netdev(net_dev);
+	ssize_t length;
if (!batman_if)
    	return 0;
switch (batman_if->if_status) {
    case IF_TO_BE_REMOVED:
-		return sprintf(buff, "disabling\n");
+		length = sprintf(buff, "disabling\n");
+		break;
    case IF_INACTIVE:
-		return sprintf(buff, "inactive\n");
+		length = sprintf(buff, "inactive\n");
+		break;
    case IF_ACTIVE:
-		return sprintf(buff, "active\n");
+		length = sprintf(buff, "active\n");
+		break;
    case IF_TO_BE_ACTIVATED:
-		return sprintf(buff, "enabling\n");
+		length = sprintf(buff, "enabling\n");
+		break;
    case IF_NOT_IN_USE:
    default:
-		return sprintf(buff, "not in use\n");
+		length = sprintf(buff, "not in use\n");
+		break;
    }
+
+	hardif_put(batman_if);
+
+	return length;
 }
static BAT_ATTR(mesh_iface, S_IRUGO | S_IWUSR,
diff --git a/hard-interface.c b/hard-interface.c
index 445498c..f519b4b 100644
--- a/hard-interface.c
+++ b/hard-interface.c
@@ -51,6 +51,9 @@ struct batman_if *get_batman_if_by_netdev(struct net_device *net_dev)
    batman_if = NULL;
out:
+	if (batman_if)
+		hardif_hold(batman_if);
+
    rcu_read_unlock();
    return batman_if;
 }
@@ -98,6 +101,9 @@ static struct batman_if *get_active_batman_if(struct net_device *soft_iface)
    batman_if = NULL;
out:
+	if (batman_if)
+		hardif_hold(batman_if);
+
    rcu_read_unlock();
    return batman_if;
 }
@@ -294,6 +300,7 @@ int hardif_enable_interface(struct batman_if *batman_if, char *iface_name)
    batman_if->batman_adv_ptype.type = __constant_htons(ETH_P_BATMAN);
    batman_if->batman_adv_ptype.func = batman_skb_recv;
    batman_if->batman_adv_ptype.dev = batman_if->net_dev;
+	hardif_hold(batman_if);
    dev_add_pack(&batman_if->batman_adv_ptype);
atomic_set(&batman_if->seqno, 1);
@@ -352,13 +359,20 @@ void hardif_disable_interface(struct batman_if *batman_if)
    bat_info(batman_if->soft_iface, "Removing interface: %s\n",
    	 batman_if->net_dev->name);
    dev_remove_pack(&batman_if->batman_adv_ptype);
+	hardif_put(batman_if);
bat_priv->num_ifaces--;
    orig_hash_del_if(batman_if, bat_priv->num_ifaces);
-	if (batman_if == bat_priv->primary_if)
-		set_primary_if(bat_priv,
-			       get_active_batman_if(batman_if->soft_iface));
+	if (batman_if == bat_priv->primary_if) {
+		struct batman_if *new_if;
+
+		new_if = get_active_batman_if(batman_if->soft_iface);
+		set_primary_if(bat_priv, new_if);
+
+		if (new_if)
+			hardif_put(new_if);
+	}
kfree(batman_if->packet_buff);
    batman_if->packet_buff = NULL;
@@ -412,6 +426,8 @@ static struct batman_if *hardif_add_interface(struct net_device *net_dev)
    list_add_tail_rcu(&batman_if->list, &if_list);
    spin_unlock(&if_list_lock);
+	/* extra reference for return */
+	hardif_hold(batman_if);
    return batman_if;
free_if:
@@ -461,7 +477,7 @@ static int hard_if_event(struct notifier_block *this,
    struct bat_priv *bat_priv;
if (!batman_if && event == NETDEV_REGISTER)
-			batman_if = hardif_add_interface(net_dev);
+		batman_if = hardif_add_interface(net_dev);
if (!batman_if)
    	goto out;
@@ -484,8 +500,10 @@ static int hard_if_event(struct notifier_block *this,
    		update_min_mtu(batman_if->soft_iface);
    	break;
    case NETDEV_CHANGEADDR:
-		if (batman_if->if_status == IF_NOT_IN_USE)
+		if (batman_if->if_status == IF_NOT_IN_USE) {
+			hardif_put(batman_if);
    		goto out;
+		}
check_known_mac_addr(batman_if->net_dev->dev_addr);
    	update_mac_addresses(batman_if);
@@ -497,6 +515,7 @@ static int hard_if_event(struct notifier_block *this,
    default:
    	break;
    };
+	hardif_put(batman_if);
out:
    return NOTIFY_DONE;
-- 
batman-adv

    