netfilter: ctnetlink: fix reliable event delivery if message building fails

[ Upstream commit 37b7ef7203240b3aba577bb1ff6765fe15225976 ]

This patch fixes a bug that allows to lose events when reliable
event delivery mode is used, ie. if NETLINK_BROADCAST_SEND_ERROR
and NETLINK_RECV_NO_ENOBUFS socket options are set.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 4 insertions, 3 deletions

diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 0ffe689dfe97..eeac97fcef79 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -571,7 +571,8 @@ nla_put_failure:
 nlmsg_failure:
         kfree_skb(skb);
 errout:
-        nfnetlink_set_err(0, group, -ENOBUFS);
+        if (nfnetlink_set_err(0, group, -ENOBUFS) > 0)
+                return -ENOBUFS;
         return 0;
 }
 #endif /* CONFIG_NF_CONNTRACK_EVENTS */
diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
index eedc0c1ac7a4..35fe185316e7 100644
--- a/net/netfilter/nfnetlink.c
+++ b/net/netfilter/nfnetlink.c
@@ -114,9 +114,9 @@ int nfnetlink_send(struct sk_buff *skb, u32 pid,
 }
 EXPORT_SYMBOL_GPL(nfnetlink_send);
 
-void nfnetlink_set_err(u32 pid, u32 group, int error)
+int nfnetlink_set_err(u32 pid, u32 group, int error)
 {
-        netlink_set_err(nfnl, pid, group, error);
+        return netlink_set_err(nfnl, pid, group, error);
 }
 EXPORT_SYMBOL_GPL(nfnetlink_set_err);