diff options
| author | Florian Westphal <fw@strlen.de> | 2014-06-08 11:41:23 +0200 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2014-06-16 12:51:36 +0200 |
| commit | cd5f336f1780cb20e83146cde64d3d5779e175e6 (patch) | |
| tree | 1256bde8377eda4f1ca29a232eaaa0e8a3d13e22 | |
| parent | netfilter: ctnetlink: fix dumping of dying/unconfirmed conntracks (diff) | |
| download | linux-cd5f336f1780cb20e83146cde64d3d5779e175e6.tar.xz linux-cd5f336f1780cb20e83146cde64d3d5779e175e6.zip | |
netfilter: ctnetlink: fix refcnt leak in dying/unconfirmed list dumper
'last' keeps track of the ct that had its refcnt bumped during previous
dump cycle. Thus it must not be overwritten until end-of-function.
Another (unrelated, theoretical) issue: Don't attempt to bump refcnt of a conntrack
whose reference count is already 0. Such conntrack is being destroyed
right now, its memory is freed once we release the percpu dying spinlock.
Fixes: b7779d06 ('netfilter: conntrack: spinlock per cpu to protect special lists.')
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
| -rw-r--r-- | net/netfilter/nf_conntrack_netlink.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index ef0eedd70541..70123f48b6c9 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -1150,7 +1150,7 @@ static int ctnetlink_done_list(struct netlink_callback *cb) static int ctnetlink_dump_list(struct sk_buff *skb, struct netlink_callback *cb, bool dying) { - struct nf_conn *ct, *last = NULL; + struct nf_conn *ct, *last; struct nf_conntrack_tuple_hash *h; struct hlist_nulls_node *n; struct nfgenmsg *nfmsg = nlmsg_data(cb->nlh); @@ -1163,6 +1163,8 @@ ctnetlink_dump_list(struct sk_buff *skb, struct netlink_callback *cb, bool dying if (cb->args[2]) return 0; + last = (struct nf_conn *)cb->args[1]; + for (cpu = cb->args[0]; cpu < nr_cpu_ids; cpu++) { struct ct_pcpu *pcpu; @@ -1171,7 +1173,6 @@ ctnetlink_dump_list(struct sk_buff *skb, struct netlink_callback *cb, bool dying pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu); spin_lock_bh(&pcpu->lock); - last = (struct nf_conn *)cb->args[1]; list = dying ? &pcpu->dying : &pcpu->unconfirmed; restart: hlist_nulls_for_each_entry(h, n, list, hnnode) { @@ -1190,7 +1191,8 @@ restart: ct); rcu_read_unlock(); if (res < 0) { - nf_conntrack_get(&ct->ct_general); + if (!atomic_inc_not_zero(&ct->ct_general.use)) + continue; cb->args[0] = cpu; cb->args[1] = (unsigned long)ct; spin_unlock_bh(&pcpu->lock); |