netfilter: ctnetlink: fix loop in ctnetlink_get_conntrack()
This patch fixes a loop in ctnetlink_get_conntrack() that can be
triggered if you use the same socket to receive events and to
perform a GET operation. Under heavy load, netlink_unicast()
may return -EAGAIN, this error code is reserved in nfnetlink for
the module load-on-demand. Instead, we return -ENOBUFS which is
the appropriate error code that has to be propagated to
user-space.
Reported-by: Holger Eitzenberger <holger@eitzenberger.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 5cb8d30..2b7eef3 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -972,7 +972,8 @@
free:
kfree_skb(skb2);
out:
- return err;
+ /* this avoids a loop in nfnetlink. */
+ return err == -EAGAIN ? -ENOBUFS : err;
}
#ifdef CONFIG_NF_NAT_NEEDED