batman-adv: verify tt len does not exceed packet len

[ 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@yahoo.de>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c
index 7d02ebd11a7f1bd13b173cbe1eb0f54e623e0345..1ee94d08f93243179c64fea8393dc11ef91e94b7 100644 (file)
--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -1298,7 +1298,8 @@ 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,
@@ -1309,8 +1310,7 @@ static int batadv_iv_ogm_receive(struct sk_buff *skb,
 
                packet_pos = packet_buff + buff_pos;
                batadv_ogm_packet = (struct batadv_ogm_packet *)packet_pos;
-       } while (batadv_iv_ogm_aggr_packet(buff_pos, packet_len,
-                                          batadv_ogm_packet->tt_num_changes));
+       }
 
        kfree_skb(skb);
        return NET_RX_SUCCESS;