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[02/19] batman-adv: fix skb->data assignment

Message ID 1340051963-14836-3-git-send-email-ordex@autistici.org
State Accepted, archived
Delegated to: David Miller
Headers show

Commit Message

Antonio Quartulli June 18, 2012, 8:39 p.m. UTC 
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 poisoned memory. The packet is then dropped but the
translation-table mechanism is corrupted.

Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
 net/batman-adv/routing.c |    2 ++
 1 file changed, 2 insertions(+)
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Patch

diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c
index 840e2c6..015471d 100644
--- a/net/batman-adv/routing.c
+++ b/net/batman-adv/routing.c
@@ -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);