netfilter: evict stale entries when user reads /proc/net/nf_conntrack

Fabian reports a possible conntrack memory leak (could not reproduce so
far), however, one minor issue can be easily resolved:

> cat /proc/net/nf_conntrack | wc -l = 5
> 4 minutes required to clean up the table.

We should not report those timed-out entries to the user in first place.
And instead of just skipping those timed-out entries while iterating over
the table we can also zap them (we already do this during ctnetlink
walks, but I forgot about the /proc interface).

Fixes: f330a7fdbe ("netfilter: conntrack: get rid of conntrack timer")
Reported-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal 2016-09-22 23:49:17 +02:00 committed by Pablo Neira Ayuso
parent 11d5f15723
commit 58e207e498

View File

@ -212,6 +212,11 @@ static int ct_seq_show(struct seq_file *s, void *v)
if (unlikely(!atomic_inc_not_zero(&ct->ct_general.use)))
return 0;
if (nf_ct_should_gc(ct)) {
nf_ct_kill(ct);
goto release;
}
/* we only want to print DIR_ORIGINAL */
if (NF_CT_DIRECTION(hash))
goto release;