batman-adv: check for more space before accessing the skb

In batadv_check_unicast_ttvn() the code accesses both the unicast header and the
Ethernet header in the payload. For this reason pskb_may_pull() must be invoked
to check for the required space.

Signed-off-by: Antonio Quartulli <ordex@autistici.org>
This commit is contained in:
Antonio Quartulli 2012-08-26 23:25:59 +02:00
parent 60c39c7584
commit b8fcfa42e4
1 changed files with 6 additions and 2 deletions

View File

@ -908,8 +908,12 @@ static int batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
bool tt_poss_change; bool tt_poss_change;
int is_old_ttvn; int is_old_ttvn;
/* I could need to modify it */ /* check if there is enough data before accessing it */
if (skb_cow(skb, sizeof(struct batadv_unicast_packet)) < 0) if (pskb_may_pull(skb, sizeof(*unicast_packet) + ETH_HLEN) < 0)
return 0;
/* create a copy of the skb (in case of for re-routing) to modify it. */
if (skb_cow(skb, sizeof(*unicast_packet)) < 0)
return 0; return 0;
unicast_packet = (struct batadv_unicast_packet *)skb->data; unicast_packet = (struct batadv_unicast_packet *)skb->data;