[PATCH] openvswitch: add sanity check in queue_userspace_packet.

[Haishuang Yan]

kernel will crash in oops if genlmsg_put return NULL,
so add the sanity check.

Signed-off-by: Haishuang Yan <yanhaishuang@xxxxxxxxxxxxxxxxxxxx>
---
 net/openvswitch/datapath.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index 2d4c4d3..ceb1b1e 100644
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -474,6 +474,10 @@ static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb,
 
 	upcall = genlmsg_put(user_skb, 0, 0, &dp_packet_genl_family,
 			     0, upcall_info->cmd);
+	if (!upcall) {
+		err = -EMSGSIZE;
+		goto out;
+	}
 	upcall->dp_ifindex = dp_ifindex;
 
 	err = ovs_nla_put_key(key, key, OVS_PACKET_ATTR_KEY, false, user_skb);
-- 
1.8.3.1