batman-adv: properly check pskb_may_pull return value

pskb_may_pull() returns 1 on success and 0 in case of failure,
therefore checking for the return value being negative does
not make sense at all.

This way if the function fails we will probably read beyond the current
skb data buffer. Fix this by doing the proper check.

Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>

diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c
index 1ed9f7c9ecea4108f00d7beb6c2cb056f5ff87ed..c26f07368849b86bd0dacec984dcc88a59725d12 100644 (file)
--- a/net/batman-adv/routing.c
+++ b/net/batman-adv/routing.c
@@ -688,7 +688,7 @@ static int batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
        int is_old_ttvn;
 
        /* check if there is enough data before accessing it */
-       if (pskb_may_pull(skb, hdr_len + ETH_HLEN) < 0)
+       if (!pskb_may_pull(skb, hdr_len + ETH_HLEN))
                return 0;
 
        /* create a copy of the skb (in case of for re-routing) to modify it. */