The functions batadv_tt_prepare_tvlv_local_data and
batadv_tt_prepare_tvlv_global_data are responsible for preparing a buffer
which can be used to store the TVLV container for TT and add the VLAN
information to it.
This will be done in three phases:
1. count the number of VLANs and their entries
2. allocate the buffer using the counters from the previous step and limits
from the caller (parameter tt_len)
3. insert the VLAN information to the buffer
The step 1 and 3 operate on a list which contains the VLANs. The access to
these lists must be protected with an appropriate lock or otherwise they
might operate on on different entries. This could for example happen when
another context is adding VLAN entries to this list.
This could lead to a buffer overflow in these functions when enough entries
are added to the VLAN lists that the extra buffer for the entries is
smaller then the now required extra buffer for new VLAN entries. Or the
buffer overflow can happen when the caller now does no longer gets its
requested extra buffer size tt_len.
Fixes: 21a57f6e7a3b ("batman-adv: make the TT CRC logic VLAN specific")
Signed-off-by: Sven Eckelmann <s...@narfation.org>
---
This change is completely untested. The issue for this problem can be found
in https://www.open-mesh.org/issues/354
net/batman-adv/translation-table.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/net/batman-adv/translation-table.c
b/net/batman-adv/translation-table.c
index 0225616d..7fa3a0a0 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -862,7 +862,7 @@ batadv_tt_prepare_tvlv_global_data(struct batadv_orig_node
*orig_node,
struct batadv_orig_node_vlan *vlan;
u8 *tt_change_ptr;
- rcu_read_lock();
+ spin_lock_bh(&orig_node->vlan_list_lock);
hlist_for_each_entry_rcu(vlan, &orig_node->vlan_list, list) {
num_vlan++;
num_entries += atomic_read(&vlan->tt.num_entries);
@@ -900,7 +900,7 @@ batadv_tt_prepare_tvlv_global_data(struct batadv_orig_node
*orig_node,
*tt_change = (struct batadv_tvlv_tt_change *)tt_change_ptr;
out:
- rcu_read_unlock();
+ spin_unlock_bh(&orig_node->vlan_list_lock);
return tvlv_len;
}
@@ -936,7 +936,7 @@ batadv_tt_prepare_tvlv_local_data(struct batadv_priv
*bat_priv,
u8 *tt_change_ptr;
int change_offset;
- rcu_read_lock();
+ spin_lock_bh(&bat_priv->softif_vlan_list_lock);
hlist_for_each_entry_rcu(vlan, &bat_priv->softif_vlan_list, list) {
num_vlan++;
num_entries += atomic_read(&vlan->tt.num_entries);
@@ -974,7 +974,7 @@ batadv_tt_prepare_tvlv_local_data(struct batadv_priv
*bat_priv,
*tt_change = (struct batadv_tvlv_tt_change *)tt_change_ptr;
out:
- rcu_read_unlock();
+ spin_unlock_bh(&bat_priv->softif_vlan_list_lock);
return tvlv_len;
}
--
2.17.0
