packet: do not set TP_STATUS_CSUM_VALID on CHECKSUM_COMPLETE

CHECKSUM_COMPLETE signals that skb->csum stores the sum over the
entire packet. It does not imply that an embedded l4 checksum
field has been validated.

Fixes: 682f048b ("af_packet: pass checksum validation status to the user")
Signed-off-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20221128161812.640098-1-willemdebruijn.kernel@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/packet/af_packet.c

@@ -2293,8 +2293,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
 	if (skb->ip_summed == CHECKSUM_PARTIAL)
 		status |= TP_STATUS_CSUMNOTREADY;
 	else if (skb->pkt_type != PACKET_OUTGOING &&
-		 (skb->ip_summed == CHECKSUM_COMPLETE ||
-		  skb_csum_unnecessary(skb)))
+		 skb_csum_unnecessary(skb))
 		status |= TP_STATUS_CSUM_VALID;
 
 	if (snaplen > res)
@@ -3520,8 +3519,7 @@ static int packet_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
 		if (skb->ip_summed == CHECKSUM_PARTIAL)
 			aux.tp_status |= TP_STATUS_CSUMNOTREADY;
 		else if (skb->pkt_type != PACKET_OUTGOING &&
-			 (skb->ip_summed == CHECKSUM_COMPLETE ||
-			  skb_csum_unnecessary(skb)))
+			 skb_csum_unnecessary(skb))
 			aux.tp_status |= TP_STATUS_CSUM_VALID;
 
 		aux.tp_len = origlen;