commit 88d0895d0ea9d4431507d576c963f2ff9918144d upstream.
The probe ELPs for WiFi interfaces are expanded to contain at least BATADV_ELP_MIN_PROBE_SIZE bytes. This is usually a lot more than the number of bytes which the template ELP packet requires.
These extra padding bytes were not initialized and thus could contain data which were previously stored at the same location. It is therefore required to set it to some predefined or random values to avoid leaking private information from the system transmitting these kind of packets.
Fixes: e4623c913508 ("batman-adv: Avoid probe ELP information leak") Signed-off-by: Sven Eckelmann sven@narfation.org Acked-by: Antonio Quartulli a@unstable.cc Signed-off-by: Simon Wunderlich sw@simonwunderlich.de --- net/batman-adv/bat_v_elp.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/net/batman-adv/bat_v_elp.c b/net/batman-adv/bat_v_elp.c index 3ff0dc83d04b..11e1a28ff526 100644 --- a/net/batman-adv/bat_v_elp.c +++ b/net/batman-adv/bat_v_elp.c @@ -191,6 +191,7 @@ batadv_v_elp_wifi_neigh_probe(struct batadv_hardif_neigh_node *neigh) struct sk_buff *skb; int probe_len, i; int elp_skb_len; + void *tmp;
/* this probing routine is for Wifi neighbours only */ if (!batadv_is_wifi_netdev(hard_iface->net_dev)) @@ -222,7 +223,8 @@ batadv_v_elp_wifi_neigh_probe(struct batadv_hardif_neigh_node *neigh) * the packet to be exactly of that size to make the link * throughput estimation effective. */ - skb_put(skb, probe_len - hard_iface->bat_v.elp_skb->len); + tmp = skb_put(skb, probe_len - hard_iface->bat_v.elp_skb->len); + memset(tmp, 0, probe_len - hard_iface->bat_v.elp_skb->len);
batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "Sending unicast (probe) ELP packet on interface %s to %pM\n",