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routing/batman-adv/patches/0020-batman-adv-fix-duplicate-MAC-address-check.patch
Sven Eckelmann e1c8557017 batman-adv: Merge bugfixes from 2025.2
* fix duplicate MAC address check

Signed-off-by: Sven Eckelmann <sven@narfation.org>
2025-06-18 23:35:54 +02:00

106 lines
3.9 KiB
Diff

From: Matthias Schiffer <mschiffer@universe-factory.net>
Date: Wed, 16 Apr 2025 20:37:56 +0200
Subject: 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: c7560658b16b ("[batman-adv] print a warning when an existing mac address is added again")
Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
(cherry picked from commit 4a2b85600c38876b6c76eb7e75d76aef2c60a055)
--- a/net/batman-adv/hard-interface.c
+++ b/net/batman-adv/hard-interface.c
@@ -504,28 +504,32 @@ batadv_hardif_is_iface_up(const struct b
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 *soft_iface = hard_iface->soft_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 (!soft_iface)
+ return;
+
+ list_for_each_entry(tmp_hard_iface, &batadv_hardif_list, list) {
+ if (tmp_hard_iface == hard_iface)
+ continue;
+
+ if (tmp_hard_iface->soft_iface != soft_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();
}
/**
@@ -758,6 +762,8 @@ int batadv_hardif_enable_interface(struc
hard_iface->net_dev->name, hard_iface->net_dev->mtu,
ETH_DATA_LEN + max_header_len);
+ batadv_check_known_mac_addr(hard_iface);
+
if (batadv_hardif_is_iface_up(hard_iface))
batadv_hardif_activate_interface(hard_iface);
else
@@ -896,7 +902,6 @@ batadv_hardif_add_interface(struct net_d
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++;
@@ -988,7 +993,7 @@ static int batadv_hard_if_event(struct n
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->soft_iface);
bat_priv->algo_ops->iface.update_mac(hard_iface);