The following commit has been merged in the next branch: commit ac96f464399058a2041cdf6736f2d73a3c1579f1 Author: Sven Eckelmann sven@narfation.org Date: Fri Mar 4 21:36:41 2011 +0000

batman-adv: Disallow regular interface as mesh device

When trying to associate a net_device with another net_device which already exists, batman-adv assumes that this interface is a fully initialized batman mesh interface without checking it. The behaviour when accessing data behind netdev_priv of a random net_device is undefined and potentially dangerous.

Reported-by: Linus Lüssing linus.luessing@ascom.ch Signed-off-by: Marek Lindner lindner_marek@yahoo.de

diff --git a/hard-interface.c b/hard-interface.c index 95a35b6..b3058e4 100644 --- a/hard-interface.c +++ b/hard-interface.c @@ -79,13 +79,8 @@ static int is_valid_iface(struct net_device *net_dev) return 0;

/* no batman over batman */ -#ifdef HAVE_NET_DEVICE_OPS - if (net_dev->netdev_ops->ndo_start_xmit == interface_tx) + if (softif_is_valid(net_dev)) return 0; -#else - if (net_dev->hard_start_xmit == interface_tx) - return 0; -#endif

/* Device is being bridged */ /* if (net_dev->priv_flags & IFF_BRIDGE_PORT) @@ -282,6 +277,8 @@ int hardif_enable_interface(struct hard_iface *hard_iface, char *iface_name) { struct bat_priv *bat_priv; struct batman_packet *batman_packet; + struct net_device *soft_iface; + int ret;

if (hard_iface->if_status != IF_NOT_IN_USE) goto out; @@ -289,18 +286,30 @@ int hardif_enable_interface(struct hard_iface *hard_iface, char *iface_name) if (!atomic_inc_not_zero(&hard_iface->refcount)) goto out;

- hard_iface->soft_iface = dev_get_by_name(&init_net, iface_name); + soft_iface = dev_get_by_name(&init_net, iface_name);

- if (!hard_iface->soft_iface) { - hard_iface->soft_iface = softif_create(iface_name); + if (!soft_iface) { + soft_iface = softif_create(iface_name);

- if (!hard_iface->soft_iface) + if (!soft_iface) { + ret = -ENOMEM; goto err; + }

/* dev_get_by_name() increases the reference counter for us */ - dev_hold(hard_iface->soft_iface); + dev_hold(soft_iface); + } + + if (!softif_is_valid(soft_iface)) { + pr_err("Can't create batman mesh interface %s: " + "already exists as regular interface\n", + soft_iface->name); + dev_put(soft_iface); + ret = -EINVAL; + goto err; }

+ hard_iface->soft_iface = soft_iface; bat_priv = netdev_priv(hard_iface->soft_iface); hard_iface->packet_len = BAT_PACKET_LEN; hard_iface->packet_buff = kmalloc(hard_iface->packet_len, GFP_ATOMIC); @@ -308,6 +317,7 @@ int hardif_enable_interface(struct hard_iface *hard_iface, char *iface_name) if (!hard_iface->packet_buff) { bat_err(hard_iface->soft_iface, "Can't add interface packet " "(%s): out of memory\n", hard_iface->net_dev->name); + ret = -ENOMEM; goto err; }

@@ -370,7 +380,7 @@ out:

err: hardif_free_ref(hard_iface); - return -ENOMEM; + return ret; }

void hardif_disable_interface(struct hard_iface *hard_iface) diff --git a/soft-interface.c b/soft-interface.c index 6b514ec..9ed2614 100644 --- a/soft-interface.c +++ b/soft-interface.c @@ -622,6 +622,19 @@ void softif_destroy(struct net_device *soft_iface) unregister_netdevice(soft_iface); }

+int softif_is_valid(struct net_device *net_dev) +{ +#ifdef HAVE_NET_DEVICE_OPS + if (net_dev->netdev_ops->ndo_start_xmit == interface_tx) + return 1; +#else + if (net_dev->hard_start_xmit == interface_tx) + return 1; +#endif + + return 0; +} + /* ethtool */ static int bat_get_settings(struct net_device *dev, struct ethtool_cmd *cmd) { diff --git a/soft-interface.h b/soft-interface.h index 80a3607..4789b6f 100644 --- a/soft-interface.h +++ b/soft-interface.h @@ -31,5 +31,6 @@ void interface_rx(struct net_device *soft_iface, int hdr_size); struct net_device *softif_create(char *name); void softif_destroy(struct net_device *soft_iface); +int softif_is_valid(struct net_device *net_dev);

#endif /* _NET_BATMAN_ADV_SOFT_INTERFACE_H_ */