[PATCH 3.16.y-ckt 120/130] batman-adv: fix kernel crash due to missing NULL checks

From: Luis Henriques
Date: Fri Sep 04 2015 - 09:14:42 EST


3.16.7-ckt17 -stable review patch. If anyone has any objections, please let me know.

------------------

From: Marek Lindner <mareklindner@xxxxxxxxxxxxx>

commit 354136bcc3c4f40a2813bba8f57ca5267d812d15 upstream.

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@xxxxxxxx>
Signed-off-by: Marek Lindner <mareklindner@xxxxxxxxxxxxx>
Signed-off-by: Antonio Quartulli <antonio@xxxxxxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
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 cbd677f48c00..713498c378c7 100644
--- a/net/batman-adv/soft-interface.c
+++ b/net/batman-adv/soft-interface.c
@@ -450,6 +450,9 @@ 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 5f59e7f899a0..dc0a67fff85b 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -575,6 +575,9 @@ 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",
@@ -1047,6 +1050,9 @@ 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);

@@ -1147,8 +1153,10 @@ 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);
}
@@ -3190,8 +3198,10 @@ 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);
}
--
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