mac80211: Drop frames from invalid MAC address in ad-hoc mode

WARNING: CPU: 1 PID: 9 at net/mac80211/sta_info.c:554
sta_info_insert_rcu+0x121/0x12a0
Modules linked in:
CPU: 1 PID: 9 Comm: kworker/u8:1 Not tainted 5.14.0-rc7+ rockchip-linux#253
Workqueue: phy3 ieee80211_iface_work
RIP: 0010:sta_info_insert_rcu+0x121/0x12a0
...
Call Trace:
 ieee80211_ibss_finish_sta+0xbc/0x170
 ieee80211_ibss_work+0x13f/0x7d0
 ieee80211_iface_work+0x37a/0x500
 process_one_work+0x357/0x850
 worker_thread+0x41/0x4d0

If an Ad-Hoc node receives packets with invalid source MAC address,
it hits a WARN_ON in sta_info_insert_check(), this can spam the log.

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20210827144230.39944-1-yuehaibing@huawei.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/rx.c

@@ -4131,7 +4131,8 @@ static bool ieee80211_accept_frame(struct ieee80211_rx_data *rx)
 		if (!bssid)
 			return false;
 		if (ether_addr_equal(sdata->vif.addr, hdr->addr2) ||
-		    ether_addr_equal(sdata->u.ibss.bssid, hdr->addr2))
+		    ether_addr_equal(sdata->u.ibss.bssid, hdr->addr2) ||
+		    !is_valid_ether_addr(hdr->addr2))
 			return false;
 		if (ieee80211_is_beacon(hdr->frame_control))
 			return true;