[B.A.T.M.A.N.] [PATCH 09/14] batman-adv: fix kernel crash due to missing NULL checks

Antonio Quartulli
2015-08-04T16:35:29Z

From: Marek Lindner <mareklindner@neomailbox.ch>

batadv_softif_vlan_get() may return NULL which has to be verified
by the caller.

Fixes: 35df3b298fc8 ("batman-adv: fix TT VLAN inconsistency on VLAN re-add")
Reported-by: Ryan Thompson <ryan@eero.com>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
---
net/batman-adv/soft-interface.c | 3 +++
net/batman-adv/translation-table.c | 18 ++++++++++++++----
2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
index c002961..a2fc843 100644
--- a/net/batman-adv/soft-interface.c
+++ b/net/batman-adv/soft-interface.c
@@ -479,6 +479,9 @@ out:
*/
void batadv_softif_vlan_free_ref(struct batadv_softif_vlan *vlan)
{
+ if (!vlan)
+ return;
+
if (atomic_dec_and_test(&vlan->refcount)) {
spin_lock_bh(&vlan->bat_priv->softif_vlan_list_lock);
hlist_del_rcu(&vlan->list);
diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
index 1573489..2db3093 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -595,6 +595,9 @@ bool batadv_tt_local_add(struct net_device *soft_iface, const uint8_t *addr,

/* increase the refcounter of the related vlan */
vlan = batadv_softif_vlan_get(bat_priv, vid);
+ if (WARN(!vlan, "adding TT local entry %pM to non-existent VLAN %d",
+ addr, BATADV_PRINT_VID(vid)))
+ goto out;

batadv_dbg(BATADV_DBG_TT, bat_priv,
"Creating new local tt entry: %pM (vid: %d, ttvn: %d)\n",
@@ -1067,6 +1070,9 @@ uint16_t batadv_tt_local_remove(struct batadv_priv *bat_priv,

/* decrease the reference held for this vlan */
vlan = batadv_softif_vlan_get(bat_priv, vid);
+ if (!vlan)
+ goto out;
+
batadv_softif_vlan_free_ref(vlan);
batadv_softif_vlan_free_ref(vlan);

@@ -1167,8 +1173,10 @@ static void batadv_tt_local_table_free(struct batadv_priv *bat_priv)
/* decrease the reference held for this vlan */
vlan = batadv_softif_vlan_get(bat_priv,
tt_common_entry->vid);
- batadv_softif_vlan_free_ref(vlan);
- batadv_softif_vlan_free_ref(vlan);
+ if (vlan) {
+ batadv_softif_vlan_free_ref(vlan);
+ batadv_softif_vlan_free_ref(vlan);
+ }

batadv_tt_local_entry_free_ref(tt_local);
}
@@ -3208,8 +3216,10 @@ static void batadv_tt_local_purge_pending_clients(struct batadv_priv *bat_priv)

/* decrease the reference held for this vlan */
vlan = batadv_softif_vlan_get(bat_priv, tt_common->vid);
- batadv_softif_vlan_free_ref(vlan);
- batadv_softif_vlan_free_ref(vlan);
+ if (vlan) {
+ batadv_softif_vlan_free_ref(vlan);
+ batadv_softif_vlan_free_ref(vlan);
+ }

batadv_tt_local_entry_free_ref(tt_local);
}
--
2.5.0