netem: fix possible skb leak

BugLink: http://bugs.launchpad.net/bugs/1002880

[ Upstream commit 116a0fc31c6c9b8fc821be5a96e5bf0b43260131 ]

skb_checksum_help(skb) can return an error, we must free skb in this
case. qdisc_drop(skb, sch) can also be feeded with a NULL skb (if
skb_unshare() failed), so lets use this generic helper.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

1 files changed, 2 insertions, 4 deletions

diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index 2f684593f35..945f3dd6c6f 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -350,10 +350,8 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch)
         if (q->corrupt && q->corrupt >= get_crandom(&q->corrupt_cor)) {
                 if (!(skb = skb_unshare(skb, GFP_ATOMIC)) ||
                     (skb->ip_summed == CHECKSUM_PARTIAL &&
-                     skb_checksum_help(skb))) {
-                        sch->qstats.drops++;
-                        return NET_XMIT_DROP;
-                }
+                     skb_checksum_help(skb)))
+                        return qdisc_drop(skb, sch);
 
                 skb->data[net_random() % skb_headlen(skb)] ^= 1<<(net_random() % 8);
         }