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ipv6: Plug sk_buff leak in ipv6_rcv (net/ipv6/ip6_input.c)

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Commit 778d80be52699596bf70e0eb0761cf5e1e46088d
(ipv6: Add disable_ipv6 sysctl to disable IPv6 operaion on specific interface)
seems to have introduced a leak of sk_buff's for ipv6 traffic,
at least in some configurations where idev is NULL, or when ipv6
is disabled via sysctl.

The problem is that if the first condition of the if-statement
returns non-NULL, it returns an skb with only one reference,
and when the other conditions apply, execution jumps to the "out"
label, which does not call kfree_skb for it.

To plug this leak, change to use the "drop" label instead.
(this relies on it being ok to call kfree_skb on NULL)
This also allows us to avoid calling rcu_read_unlock here,
and removes the only user of the "out" label.

Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jesper Nilsson 2009-03-27 00:17:45 -07:00 committed by David S. Miller
parent a170285772
commit 71f6f6dfdf
1 changed files with 1 additions and 3 deletions
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4
net/ipv6/ip6_input.c
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@ -75,8 +75,7 @@ int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt
if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL || if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL ||
!idev || unlikely(idev->cnf.disable_ipv6)) { !idev || unlikely(idev->cnf.disable_ipv6)) {
IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDISCARDS); IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDISCARDS);
rcu_read_unlock(); goto drop;
goto out;
} }
memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm)); memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
@ -147,7 +146,6 @@ err:
drop: drop:
rcu_read_unlock(); rcu_read_unlock();
kfree_skb(skb); kfree_skb(skb);
out:
return 0; return 0;
} }