The following commit has been merged in the batadv/net-next branch: commit 7308dc953fe0aac1e737288d347f659132ece46c Author: Remi Pommarel repk@triplefau.lt Date: Wed Nov 20 18:47:15 2024 +0100

TODO: REMOVE: batman-adv: Remove uninitialized data in full table TT response

The number of entries filled by batadv_tt_tvlv_generate() can be less than initially expected in batadv_tt_prepare_tvlv_{global,local}_data() (changes can be removed by batadv_tt_local_event() in ADD+DEL sequence in the meantime as the lock held during the whole tvlv global/local data generation).

Thus tvlv_len could be bigger than the actual TT entry size that need to be sent so full table TT_RESPONSE could hold invalid TT entries such as below.

* 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)

Remove the extra allocated space to avoid sending uninitialized entries for full table TT_RESPONSE in both batadv_send_other_tt_response() and batadv_send_my_tt_response().

Fixes: 7ea7b4a14275 ("batman-adv: make the TT CRC logic VLAN specific") Signed-off-by: Remi Pommarel repk@triplefau.lt 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 996d1f01171ad..f5201738628ce 100644 --- a/net/batman-adv/translation-table.c +++ b/net/batman-adv/translation-table.c @@ -2712,14 +2712,16 @@ static bool batadv_tt_global_valid(const void *entry_ptr, * * Fills the tvlv buff with the tt entries from the specified hash. If valid_cb * is not provided then this becomes a no-op. + * + * Return: Remaining unused length in tvlv_buff. */ -static void batadv_tt_tvlv_generate(struct batadv_priv *bat_priv, - struct batadv_hashtable *hash, - void *tvlv_buff, u16 tt_len, - bool (*valid_cb)(const void *, - const void *, - u8 *flags), - void *cb_data) +static u16 batadv_tt_tvlv_generate(struct batadv_priv *bat_priv, + struct batadv_hashtable *hash, + void *tvlv_buff, u16 tt_len, + bool (*valid_cb)(const void *, + const void *, + u8 *flags), + void *cb_data) { struct batadv_tt_common_entry *tt_common_entry; struct batadv_tvlv_tt_change *tt_change; @@ -2733,7 +2735,7 @@ static void batadv_tt_tvlv_generate(struct batadv_priv *bat_priv, tt_change = tvlv_buff;

if (!valid_cb) - return; + return tt_len;

rcu_read_lock(); for (i = 0; i < hash->size; i++) { @@ -2759,6 +2761,8 @@ static void batadv_tt_tvlv_generate(struct batadv_priv *bat_priv, } } rcu_read_unlock(); + + return batadv_tt_len(tt_tot - tt_num_entries); }

/** @@ -3029,10 +3033,11 @@ static bool batadv_send_other_tt_response(struct batadv_priv *bat_priv, goto out;

/* fill the rest of the tvlv with the real TT entries */ - batadv_tt_tvlv_generate(bat_priv, bat_priv->tt.global_hash, - tt_change, tt_len, - batadv_tt_global_valid, - req_dst_orig_node); + tvlv_len -= batadv_tt_tvlv_generate(bat_priv, + bat_priv->tt.global_hash, + tt_change, tt_len, + batadv_tt_global_valid, + req_dst_orig_node); }

/* Don't send the response, if larger than fragmented packet. */ @@ -3156,9 +3161,11 @@ static bool batadv_send_my_tt_response(struct batadv_priv *bat_priv, goto out;

/* fill the rest of the tvlv with the real TT entries */ - batadv_tt_tvlv_generate(bat_priv, bat_priv->tt.local_hash, - tt_change, tt_len, - batadv_tt_local_valid, NULL); + tvlv_len -= batadv_tt_tvlv_generate(bat_priv, + bat_priv->tt.local_hash, + tt_change, tt_len, + batadv_tt_local_valid, + NULL); }

tvlv_tt_data->flags = BATADV_TT_RESPONSE;