[ 007/171 ] batman-adv: verify tt len does not exceed packet len

[Steven Rostedt]

3.6.11.2 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Marek Lindner <lindner_marek@xxxxxxxx>

[ Upstream commit b47506d91259c29b9c75c404737eb6525556f9b4 ]

batadv_iv_ogm_process() accesses the packet using the tt_num_changes
attribute regardless of the real packet len (assuming the length check
was done before). Therefore a length check is needed to avoid reading
random memory.

Signed-off-by: Marek Lindner <lindner_marek@xxxxxxxx>
Signed-off-by: Antonio Quartulli <ordex@xxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
 net/batman-adv/bat_iv_ogm.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c
index 1476f26..aca451e 100644
--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -1273,7 +1273,8 @@ static int batadv_iv_ogm_receive(struct sk_buff *skb,
 	batadv_ogm_packet = (struct batadv_ogm_packet *)packet_buff;
 
 	/* unpack the aggregated packets and process them one by one */
-	do {
+	while (batadv_iv_ogm_aggr_packet(buff_pos, packet_len,
+					 batadv_ogm_packet->tt_num_changes)) {
 		tt_buff = packet_buff + buff_pos + BATADV_OGM_HLEN;
 
 		batadv_iv_ogm_process(ethhdr, batadv_ogm_packet, tt_buff,
@@ -1284,8 +1285,7 @@ static int batadv_iv_ogm_receive(struct sk_buff *skb,
 
 		batadv_ogm_packet = (struct batadv_ogm_packet *)
 						(packet_buff + buff_pos);
-	} while (batadv_iv_ogm_aggr_packet(buff_pos, packet_len,
-					   batadv_ogm_packet->tt_num_changes));
+	}
 
 	kfree_skb(skb);
 	return NET_RX_SUCCESS;
-- 
1.7.10.4


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