pppoe: Unshare skb before anything else
We need to unshare the skb first as otherwise pskb_may_pull may
write to a shared skb which could be bad.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/pppoe.c b/drivers/net/pppoe.c
index d89ccfd..bafb69b 100644
--- a/drivers/net/pppoe.c
+++ b/drivers/net/pppoe.c
@@ -432,12 +432,12 @@
if (dev_net(dev) != &init_net)
goto abort;
- if (!pskb_may_pull(skb, sizeof(struct pppoe_hdr)))
- goto abort;
-
if (!(skb = skb_share_check(skb, GFP_ATOMIC)))
goto out;
+ if (!pskb_may_pull(skb, sizeof(struct pppoe_hdr)))
+ goto abort;
+
ph = pppoe_hdr(skb);
if (ph->code != PADT_CODE)
goto abort;
