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| author | Herbert Xu <herbert@gondor.apana.org.au> | 2007-08-21 09:06:37 +0200 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2007-08-22 05:58:13 +0200 |
| commit | d92a7db710c32db826a00ba9bc7a22e741d5041e (patch) | |
| tree | 800eeede84fea9ab9397b7a1a326629cf3c45bc8 | |
| parent | [DCCP]: Allocation in atomic context (diff) | |
| download | linux-d92a7db710c32db826a00ba9bc7a22e741d5041e.tar.xz linux-d92a7db710c32db826a00ba9bc7a22e741d5041e.zip | |
[SNAP]: Check packet length before reading
The snap_rcv code reads 5 bytes so we should make sure that
we have 5 bytes in the head before proceeding.
Based on diagnosis and fix by Evgeniy Polyakov, reported by
Alan J. Wylie.
Patch also kills the skb->sk assignment before kfree_skb
since it's redundant.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/802/psnap.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/net/802/psnap.c b/net/802/psnap.c index 04ee43e7538f..31128cb92a23 100644 --- a/net/802/psnap.c +++ b/net/802/psnap.c @@ -55,6 +55,9 @@ static int snap_rcv(struct sk_buff *skb, struct net_device *dev, .type = __constant_htons(ETH_P_SNAP), }; + if (unlikely(!pskb_may_pull(skb, 5))) + goto drop; + rcu_read_lock(); proto = find_snap_client(skb_transport_header(skb)); if (proto) { @@ -62,14 +65,18 @@ static int snap_rcv(struct sk_buff *skb, struct net_device *dev, skb->transport_header += 5; skb_pull_rcsum(skb, 5); rc = proto->rcvfunc(skb, dev, &snap_packet_type, orig_dev); - } else { - skb->sk = NULL; - kfree_skb(skb); - rc = 1; } - rcu_read_unlock(); + + if (unlikely(!proto)) + goto drop; + +out: return rc; + +drop: + kfree_skb(skb); + goto out; } /* |