Commit f4c9c2cc authored Jan 28, 2025 by Remi Pommarel Committed by Simon Wunderlich Jan 28, 2025

batman-adv: Fix incorrect offset in batadv_tt_tvlv_ogm_handler_v1()



Since commit 4436df47 ("batman-adv: Add flex array to struct
batadv_tvlv_tt_data"), the introduction of batadv_tvlv_tt_data's flex
array member in batadv_tt_tvlv_ogm_handler_v1() put tt_changes at
invalid offset. Those TT changes are supposed to be filled from the end
of batadv_tvlv_tt_data structure (including vlan_data flexible array),
but only the flex array size is taken into account missing completely
the size of the fixed part of the structure itself.

Fix the tt_change offset computation by using struct_size() instead of
flex_array_size() so both flex array member and its container structure
sizes are taken into account.

Cc: stable@vger.kernel.org
Fixes: 4436df47 ("batman-adv: Add flex array to struct batadv_tvlv_tt_data")
Signed-off-by: Remi Pommarel <repk@triplefau.lt>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

parent 8c8ecc98

net/batman-adv/translation-table.c

+5 −7

Original line number	Diff line number	Diff line
		@@ -3959,23 +3959,21 @@ static void batadv_tt_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
		struct batadv_tvlv_tt_change *tt_change;
		struct batadv_tvlv_tt_data *tt_data;
		u16 num_entries, num_vlan;
		size_t flex_size;
		size_t tt_data_sz;

		if (tvlv_value_len < sizeof(*tt_data))
		return;

		tt_data = tvlv_value;
		tvlv_value_len -= sizeof(*tt_data);

		num_vlan = ntohs(tt_data->num_vlan);

		flex_size = flex_array_size(tt_data, vlan_data, num_vlan);
		if (tvlv_value_len < flex_size)
		tt_data_sz = struct_size(tt_data, vlan_data, num_vlan);
		if (tvlv_value_len < tt_data_sz)
		return;

		tt_change = (struct batadv_tvlv_tt_change )((void )tt_data
		+ flex_size);
		tvlv_value_len -= flex_size;
		+ tt_data_sz);
		tvlv_value_len -= tt_data_sz;

		num_entries = batadv_tt_entries(tvlv_value_len);