Stop converting UDP and IP header values from network endianness to host

endianness for convenience reasons.  Especially in code pathes like TFTP
where the source port is read from the received UDP packet and used as
destination port in a new UDP packet this can be very harmful.  Luckily
this issue has had no effect on our architectures since they never use
any of the code paths that could be harmful.

ok visa@

1 files changed, 7 insertions, 10 deletions

diff --git a/sys/lib/libsa/netudp.c b/sys/lib/libsa/netudp.c
index 0199caaede5..fcf6351d6c4 100644
--- a/sys/lib/libsa/netudp.c
+++ b/sys/lib/libsa/netudp.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: netudp.c,v 1.3 2015/07/16 16:12:15 mpi Exp $	*/
+/*	$OpenBSD: netudp.c,v 1.4 2018/03/31 17:09:56 patrick Exp $	*/
 /*	$NetBSD: net.c,v 1.14 1996/10/13 02:29:02 christos Exp $	*/
 
 /*
@@ -183,11 +183,11 @@ readudp(struct iodesc *d, void *pkt, size_t len, time_t tleft)
 #endif
 		return -1;
 	}
-	ip->ip_len = ntohs(ip->ip_len);
-	if (n < ip->ip_len) {
+	if (n < ntohs(ip->ip_len)) {
 #ifdef NET_DEBUG
 		if (debug)
-			printf("readudp: bad length %d < %d.\n", n, ip->ip_len);
+			printf("readudp: bad length %d < %d.\n",
+			    n, ntohs(ip->ip_len));
 #endif
 		return -1;
 	}
@@ -204,7 +204,7 @@ readudp(struct iodesc *d, void *pkt, size_t len, time_t tleft)
 	/* If there were ip options, make them go away */
 	if (hlen != sizeof(*ip)) {
 		bcopy(((u_char *)ip) + hlen, uh, len - hlen);
-		ip->ip_len = sizeof(*ip);
+		ip->ip_len = htons(sizeof(*ip));
 		n -= hlen - sizeof(*ip);
 	}
 	if (uh->uh_dport != d->myport) {
@@ -238,14 +238,11 @@ readudp(struct iodesc *d, void *pkt, size_t len, time_t tleft)
 		}
 		*ip = tip;
 	}
-	uh->uh_dport = ntohs(uh->uh_dport);
-	uh->uh_sport = ntohs(uh->uh_sport);
-	uh->uh_ulen = ntohs(uh->uh_ulen);
-	if (uh->uh_ulen < sizeof(*uh)) {
+	if (ntohs(uh->uh_ulen) < sizeof(*uh)) {
 #ifdef NET_DEBUG
 		if (debug)
 			printf("readudp: bad udp len %d < %d\n",
-				uh->uh_ulen, sizeof(*uh));
+			    ntohs(uh->uh_ulen), sizeof(*uh));
 #endif
 		return -1;
 	}