The following commit has been merged in the batadv/net branch: commit d55a75038b256f91dc476d3ad8fb2031586de394 Author: Remi Pommarel repk@triplefau.lt Date: Fri Nov 22 16:52:48 2024 +0100

batman-adv: Do not send uninitialized TT changes

The number of TT changes can be less than initially expected in batadv_tt_tvlv_container_update() (changes can be removed by batadv_tt_local_event() in ADD+DEL sequence between reading tt_diff_entries_num and actually iterating the change list under lock).

Thus tt_diff_len could be bigger than the actual changes size that need to be sent. Because batadv_send_my_tt_response sends the whole packet, uninitialized data can be interpreted as TT changes on other nodes leading to weird TT global entries on those nodes such as:

* 00:00:00:00:00:00 -1 [....] ( 0) 88:12:4e:ad:7e:ba (179) (0x45845380) * 00:00:00:00:78:79 4092 [.W..] ( 0) 88:12:4e:ad:7e:3c (145) (0x8ebadb8b)

All of the above also applies to OGM tvlv container buffer's tvlv_len.

Remove the extra allocated space to avoid sending uninitialized TT changes in batadv_send_my_tt_response() and batadv_v_ogm_send_softif().

Fixes: e1bf0c14096f ("batman-adv: tvlv - convert tt data sent within OGMs") Signed-off-by: Remi Pommarel repk@triplefau.lt Signed-off-by: Sven Eckelmann sven@narfation.org Signed-off-by: Simon Wunderlich sw@simonwunderlich.de

diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c index b44c382226a11..996d1f01171ad 100644 --- a/net/batman-adv/translation-table.c +++ b/net/batman-adv/translation-table.c @@ -948,6 +948,7 @@ static void batadv_tt_tvlv_container_update(struct batadv_priv *bat_priv) int tt_diff_len, tt_change_len = 0; int tt_diff_entries_num = 0; int tt_diff_entries_count = 0; + size_t tt_extra_len = 0; u16 tvlv_len;

tt_diff_entries_num = atomic_read(&bat_priv->tt.local_changes); @@ -985,6 +986,9 @@ static void batadv_tt_tvlv_container_update(struct batadv_priv *bat_priv) } spin_unlock_bh(&bat_priv->tt.changes_list_lock);

+ tt_extra_len = batadv_tt_len(tt_diff_entries_num - + tt_diff_entries_count); + /* Keep the buffer for possible tt_request */ spin_lock_bh(&bat_priv->tt.last_changeset_lock); kfree(bat_priv->tt.last_changeset); @@ -993,6 +997,7 @@ static void batadv_tt_tvlv_container_update(struct batadv_priv *bat_priv) tt_change_len = batadv_tt_len(tt_diff_entries_count); /* check whether this new OGM has no changes due to size problems */ if (tt_diff_entries_count > 0) { + tt_diff_len -= tt_extra_len; /* if kmalloc() fails we will reply with the full table * instead of providing the diff */ @@ -1005,6 +1010,8 @@ static void batadv_tt_tvlv_container_update(struct batadv_priv *bat_priv) } spin_unlock_bh(&bat_priv->tt.last_changeset_lock);

+ /* Remove extra packet space for OGM */ + tvlv_len -= tt_extra_len; container_register: batadv_tvlv_container_register(bat_priv, BATADV_TVLV_TT, 1, tt_data, tvlv_len);