The following commit has been merged in the master branch:
commit 8772cc49e0b8ab782e475ce5ef659eedab601a09
Author: Matthias Schiffer <[email protected]>
Date: Wed Apr 16 20:37:56 2025 +0200
batman-adv: fix duplicate MAC address check
batadv_check_known_mac_addr() is both too lenient and too strict:
- It is called from batadv_hardif_add_interface(), which means that it
checked interfaces that are not used for batman-adv at all. Move it
to batadv_hardif_enable_interface(). Also, restrict it to hardifs of
the same mesh interface; different mesh interfaces should not interact
at all. The batadv_check_known_mac_addr() argument is changed from
`struct net_device` to `struct batadv_hard_iface` to achieve this.
- The check only cares about hardifs in BATADV_IF_ACTIVE and
BATADV_IF_TO_BE_ACTIVATED states, but interfaces in BATADV_IF_INACTIVE
state should be checked as well, or the following steps will not
result in a warning then they should:
- Add two interfaces in down state with different MAC addresses to
a mesh as hardifs
- Change the MAC addresses so they conflict
- Set interfaces to up state
Now there will be two active hardifs with the same MAC address, but no
warning. Fix by only ignoring hardifs in BATADV_IF_NOT_IN_USE state.
The RCU lock can be dropped, as we're holding RTNL anyways when the
function is called.
Fixes: c6c8fea29769 ("net: Add batman-adv meshing protocol")
Signed-off-by: Matthias Schiffer <[email protected]>
Signed-off-by: Simon Wunderlich <[email protected]>
diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c
index f145f96626531..d099434d3dfab 100644
--- a/net/batman-adv/hard-interface.c
+++ b/net/batman-adv/hard-interface.c
@@ -506,28 +506,32 @@ batadv_hardif_is_iface_up(const struct batadv_hard_iface
*hard_iface)
return false;
}
-static void batadv_check_known_mac_addr(const struct net_device *net_dev)
+static void batadv_check_known_mac_addr(const struct batadv_hard_iface
*hard_iface)
{
- const struct batadv_hard_iface *hard_iface;
+ const struct net_device *mesh_iface = hard_iface->mesh_iface;
+ const struct batadv_hard_iface *tmp_hard_iface;
- rcu_read_lock();
- list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
- if (hard_iface->if_status != BATADV_IF_ACTIVE &&
- hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED)
+ if (!mesh_iface)
+ return;
+
+ list_for_each_entry(tmp_hard_iface, &batadv_hardif_list, list) {
+ if (tmp_hard_iface == hard_iface)
+ continue;
+
+ if (tmp_hard_iface->mesh_iface != mesh_iface)
continue;
- if (hard_iface->net_dev == net_dev)
+ if (tmp_hard_iface->if_status == BATADV_IF_NOT_IN_USE)
continue;
- if (!batadv_compare_eth(hard_iface->net_dev->dev_addr,
- net_dev->dev_addr))
+ if (!batadv_compare_eth(tmp_hard_iface->net_dev->dev_addr,
+ hard_iface->net_dev->dev_addr))
continue;
pr_warn("The newly added mac address (%pM) already exists on:
%s\n",
- net_dev->dev_addr, hard_iface->net_dev->name);
+ hard_iface->net_dev->dev_addr,
tmp_hard_iface->net_dev->name);
pr_warn("It is strongly recommended to keep mac addresses
unique to avoid problems!\n");
}
- rcu_read_unlock();
}
/**
@@ -764,6 +768,8 @@ int batadv_hardif_enable_interface(struct batadv_hard_iface
*hard_iface,
hard_iface->net_dev->name, hardif_mtu,
required_mtu);
+ batadv_check_known_mac_addr(hard_iface);
+
if (batadv_hardif_is_iface_up(hard_iface))
batadv_hardif_activate_interface(hard_iface);
else
@@ -902,7 +908,6 @@ batadv_hardif_add_interface(struct net_device *net_dev)
batadv_v_hardif_init(hard_iface);
- batadv_check_known_mac_addr(hard_iface->net_dev);
kref_get(&hard_iface->refcount);
list_add_tail_rcu(&hard_iface->list, &batadv_hardif_list);
batadv_hardif_generation++;
@@ -989,7 +994,7 @@ static int batadv_hard_if_event(struct notifier_block *this,
if (hard_iface->if_status == BATADV_IF_NOT_IN_USE)
goto hardif_put;
- batadv_check_known_mac_addr(hard_iface->net_dev);
+ batadv_check_known_mac_addr(hard_iface);
bat_priv = netdev_priv(hard_iface->mesh_iface);
bat_priv->algo_ops->iface.update_mac(hard_iface);
--
LinuxNextTracking
