mac80211_hwsim: verify wmediumd socket

There can't be two wmediumd instances controlling hwsim,
so reject registration from a second one and verify in
the commands that it's the correct instance calling.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/mac80211_hwsim.c

@@ -2112,6 +2112,9 @@ static int hwsim_tx_info_frame_received_nl(struct sk_buff *skb_2,
 	int i;
 	bool found = false;
 
+	if (info->snd_portid != wmediumd_portid)
+		return -EINVAL;
+
 	if (!info->attrs[HWSIM_ATTR_ADDR_TRANSMITTER] ||
 	    !info->attrs[HWSIM_ATTR_FLAGS] ||
 	    !info->attrs[HWSIM_ATTR_COOKIE] ||
@@ -2185,6 +2188,9 @@ static int hwsim_cloned_frame_received_nl(struct sk_buff *skb_2,
 	void *frame_data;
 	struct sk_buff *skb = NULL;
 
+	if (info->snd_portid != wmediumd_portid)
+		return -EINVAL;
+
 	if (!info->attrs[HWSIM_ATTR_ADDR_RECEIVER] ||
 	    !info->attrs[HWSIM_ATTR_FRAME] ||
 	    !info->attrs[HWSIM_ATTR_RX_RATE] ||
@@ -2237,6 +2243,9 @@ static int hwsim_cloned_frame_received_nl(struct sk_buff *skb_2,
 static int hwsim_register_received_nl(struct sk_buff *skb_2,
 				      struct genl_info *info)
 {
+	if (wmediumd_portid)
+		return -EBUSY;
+
 	wmediumd_portid = info->snd_portid;
 
 	printk(KERN_DEBUG "mac80211_hwsim: received a REGISTER, "