6lowpan: move skb_free from error paths in decompression

Currently we ensure that the skb is freed on every error path in IPHC
decompression which makes it easy to introduce skb leaks.  By centralising
the skb_free into the receive function it makes future decompression routines
easier to maintain.  It does come at the expense of ensuring that the skb
passed into the decompression routine must not be copied.

Signed-off-by: Martin Townsend <mtownsend1973@gmail.com>
Acked-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Acked-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This commit is contained in:
Martin Townsend
2014-11-06 19:15:13 +00:00
committed by Marcel Holtmann
parent 9645c76c7c
commit 56b2c3eea3
3 changed files with 25 additions and 37 deletions

View File

@@ -294,20 +294,20 @@ static int iphc_decompress(struct sk_buff *skb, struct net_device *netdev,
peer = __peer_lookup_chan(dev, chan);
rcu_read_unlock();
if (!peer)
goto drop;
return -EINVAL;
saddr = peer->eui64_addr;
daddr = dev->netdev->dev_addr;
/* at least two bytes will be used for the encoding */
if (skb->len < 2)
goto drop;
return -EINVAL;
if (lowpan_fetch_skb_u8(skb, &iphc0))
goto drop;
return -EINVAL;
if (lowpan_fetch_skb_u8(skb, &iphc1))
goto drop;
return -EINVAL;
return lowpan_header_decompress(skb, netdev,
saddr, IEEE802154_ADDR_LONG,
@@ -315,9 +315,6 @@ static int iphc_decompress(struct sk_buff *skb, struct net_device *netdev,
IEEE802154_ADDR_LONG, EUI64_ADDR_LEN,
iphc0, iphc1);
drop:
kfree_skb(skb);
return -EINVAL;
}
static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
@@ -370,8 +367,10 @@ static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
goto drop;
ret = iphc_decompress(local_skb, dev, chan);
if (ret < 0)
if (ret < 0) {
kfree_skb(local_skb);
goto drop;
}
local_skb->protocol = htons(ETH_P_IPV6);
local_skb->pkt_type = PACKET_HOST;