batman-adv: fix skb->data assignment

skb_linearize(skb) possibly rearranges the skb internal data and then changes
the skb->data pointer value. For this reason any other pointer in the code that
was assigned skb->data before invoking skb_linearise(skb) must be re-assigned.

In the current tt_query message handling code this is not done and therefore, in
case of skb linearization, the pointer used to handle the packet header ends up
in pointing to free'd memory.

This bug was introduced by a73105b8d4
(batman-adv: improved client announcement mechanism)

Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Antonio Quartulli 2012-06-19 09:26:39 +00:00 committed by David S. Miller
parent 48d7d0ad90
commit 2c995ff892

View File

@ -617,6 +617,8 @@ int recv_tt_query(struct sk_buff *skb, struct hard_iface *recv_if)
* changes */
if (skb_linearize(skb) < 0)
goto out;
/* skb_linearize() possibly changed skb->data */
tt_query = (struct tt_query_packet *)skb->data;
tt_len = tt_query->tt_data * sizeof(struct tt_change);