net: dns: Parse individual labels in CNAME properly

The ANCOUNT has nothing to do with label count so remove the
original while loop and just go through all the labels until
we have read all of them.

Signed-off-by: Jukka Rissanen <[email protected]>
Signed-off-by: Flavio Ceolin <[email protected]>

Author: jukkar

subsys/net/lib/dns/dns_pack.c

@@ -352,14 +352,10 @@ int dns_copy_qname(u8_t *buf, u16_t *len, u16_t size,
 	u8_t *msg = dns_msg->msg;
 	u16_t lb_size;
 	int rc = -EINVAL;
-	int i = 0;
 
 	*len = 0U;
 
-	/* Iterate ANCOUNT + 1 to allow the Query's QNAME to be parsed.
-	 * This is required to avoid 'alias loops'
-	 */
-	while (i++ < dns_header_ancount(dns_msg->msg) + 1) {
+	while (1) {
 		if (pos >= msg_size) {
 			rc = -ENOMEM;
 			break;