On 21/12/2025 21:19, Marc Suñé wrote:

  
  /*
+ *	For Ethernet devices, Broadcast/Multicast and zero MAC addresses should
+ *	never be announced and accepted as sender HW address (prevent BCAST MAC
+ *	and NULL ARP poisoning attack).
+ */
+	if (dev->addr_len == ETH_ALEN &&

dev_type == ARPHRD_ETHER ?

+	    (is_broadcast_ether_addr(sha) || is_zero_ether_addr(sha)))

RFC says that neither broadcast, nor multicast must be believed. You
check for broadcast only. The better check would be:

!is_unicast_ether_addr(sha)

+		goto out_free_skb;
+
+ /*
   *     Special case: We must set Frame Relay source Q.922 address
   */
  	if (dev_type == ARPHRD_DLCI)