[B.A.T.M.A.N.] [PATCHv2 2/2] batman-adv: check for tt_reponse real length

Antonio Quartulli
2011-10-12T13:10:58Z

Before accessing the TT_RESPONSE message payload, we have to ensure that the
real length of the packet reflect the claimed one (contained in
tt_response->tt_data field)

Reported-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
---

corrected skb length check

routing.c | 13 +++++++++++++
1 files changed, 13 insertions(+), 0 deletions(-)

diff --git a/routing.c b/routing.c
index 20804f4..af55cf7 100644
--- a/routing.c
+++ b/routing.c
@@ -578,6 +578,7 @@ int recv_tt_query(struct sk_buff *skb, struct hard_iface *recv_if)
{
struct bat_priv *bat_priv = netdev_priv(recv_if->soft_iface);
struct tt_query_packet *tt_query;
+ uint16_t tt_len;
struct ethhdr *ethhdr;

/* drop packet if it has not necessary minimum size */
@@ -622,6 +623,18 @@ int recv_tt_query(struct sk_buff *skb, struct hard_iface *recv_if)
if (skb_linearize(skb) < 0)
goto out;

+ if (tt_query->flags & TT_FULL_TABLE)
+ tt_len = tt_query->tt_data * ETH_ALEN;
+ else
+ tt_len = tt_query->tt_data *
+ sizeof(struct tt_change);
+
+ /* Ensure we have all the claimed data */
+ if (unlikely(skb_headlen(skb) <
+ sizeof(struct tt_query_packet) +
+ tt_len))
+ goto out;
+
handle_tt_response(bat_priv, tt_query);
} else {
bat_dbg(DBG_TT, bat_priv,
--
1.7.3.4