netfilter: ipt_recent: fix race between recent_mt_destroy and proc manipulations The thing is that recent_mt_destroy first flushes the entries from table with the recent_table_flush and only *after* this removes the proc file, corresponding to that table. Thus, if we manage to write to this file the '+XXX' command we will leak some entries. If we manage to write there a 'clean' command we'll race in two recent_table_flush flows, since the recent_mt_destroy calls this outside the recent_lock. The proper solution as I see it is to remove the proc file first and then go on with flushing the table. This flushing becomes safe w/o the lock, since the table is already inaccessible from the outside. Signed-off-by: Pavel Emelyanov <xemul@xxxxxxxxxx> Signed-off-by: Patrick McHardy <kaber@xxxxxxxxx> --- commit 728845f8c11ec11be4a3725a70389a3013cd4e48 tree c6dfca9346769ab48550ba27c28a3ba2af94e30b parent 827768d3835412f6ba386c9fc2d6fdbde0c2c0ee author Pavel Emelyanov <xemul@xxxxxxxxxx> Wed, 30 Jul 2008 12:52:38 +0200 committer Patrick McHardy <kaber@xxxxxxxxx> Wed, 30 Jul 2008 12:52:38 +0200 net/ipv4/netfilter/ipt_recent.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/net/ipv4/netfilter/ipt_recent.c b/net/ipv4/netfilter/ipt_recent.c index 21cb053..3974d7c 100644 --- a/net/ipv4/netfilter/ipt_recent.c +++ b/net/ipv4/netfilter/ipt_recent.c @@ -305,10 +305,10 @@ static void recent_mt_destroy(const struct xt_match *match, void *matchinfo) spin_lock_bh(&recent_lock); list_del(&t->list); spin_unlock_bh(&recent_lock); - recent_table_flush(t); #ifdef CONFIG_PROC_FS remove_proc_entry(t->name, proc_dir); #endif + recent_table_flush(t); kfree(t); } mutex_unlock(&recent_mutex); -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
