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authorAntonio Quartulli <ordex@autistici.org>2012-08-26 23:25:59 +0200
committerAntonio Quartulli <ordex@autistici.org>2012-10-29 09:42:45 +0100
commitb8fcfa42e4ec5d55d4cccd5c728415e8bca0539d (patch)
treee4ebbf1372f4841b98b05276550db37b38f0abf7 /net/batman-adv
parent60c39c7584e1bb69cdce4e0a9ee1e78ba09c82b9 (diff)
downloadlinux-b8fcfa42e4ec5d55d4cccd5c728415e8bca0539d.tar.gz
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>
Diffstat (limited to 'net/batman-adv')
-rw-r--r--net/batman-adv/routing.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c
index 456a0a9f8831..46dd5b47ed29 100644
--- a/net/batman-adv/routing.c
+++ b/net/batman-adv/routing.c
@@ -908,8 +908,12 @@ static int batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
 	bool tt_poss_change;
 	int is_old_ttvn;
 
-	/* I could need to modify it */
-	if (skb_cow(skb, sizeof(struct batadv_unicast_packet)) < 0)
+	/* check if there is enough data before accessing it */
+	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;
 
 	unicast_packet = (struct batadv_unicast_packet *)skb->data;