get_dns_name: fixup some missing change introduced with c397adda8a7

Following commit c397adda8a7 there was some missing change

* Some `cur_offset += name_len` instead of `cur_offset += used_bytes`
* Some missing format_text

I took a look at the code after observing a bug with RRSIG record.
The signature in RRSIG was dissecting with some strange offset.

You can easily generate some pcap with those commands

delv @1.1.1.1 A www.cloudflare.com
and/or
dig @1.1.1.1 +dnssec www.cloudflare.com

Change-Id: Ibd6a6248b7497b8409d7797dc320035c8c2d1ed8
Reviewed-on: https://code.wireshark.org/review/36080
Petri-Dish: Alexis La Goutte <alexis.lagoutte@gmail.com>
Tested-by: Petri Dish Buildbot
Reviewed-by: Dario Lombardo <lomato@gmail.com>
Reviewed-by: Anders Broman <a.broman58@gmail.com>

1 files changed, 8 insertions, 4 deletions

diff --git a/epan/dissectors/packet-dhcp.c b/epan/dissectors/packet-dhcp.c
index 2b79356c6e..c3f20804f0 100644
--- a/epan/dissectors/packet-dhcp.c
+++ b/epan/dissectors/packet-dhcp.c
@@ -2772,6 +2772,7 @@ static int
 dissect_dhcpopt_dhcp_domain_search(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree, void* data _U_)
 {
 	int length = tvb_reported_length(tvb);
+        gchar		*name_out;
 	const gchar	*dns_name;
 	guint		dns_name_len;
 
@@ -2808,12 +2809,13 @@ dissect_dhcpopt_dhcp_domain_search(tvbuff_t *tvb, packet_info *pinfo _U_, proto_
 			/* use the get_dns_name method that manages all techniques of RFC 1035 (compression pointer and so on) */
 			consumedx = get_dns_name(rfc3396_dns_domain_search_list.tvb_composite, composite_offset,
 				tvb_reported_length(rfc3396_dns_domain_search_list.tvb_composite), 0, &dns_name, &dns_name_len);
+                        name_out = format_text(wmem_packet_scope(), dns_name, dns_name_len);
 			if (rfc3396_dns_domain_search_list.total_number_of_block == 1) {
 				/* RFC 3396 is not used, so we can easily link the fqdn with v_tree. */
-				proto_tree_add_string(tree, hf_dhcp_option_dhcp_dns_domain_search_list_fqdn, tvb, composite_offset, consumedx, dns_name);
+				proto_tree_add_string(tree, hf_dhcp_option_dhcp_dns_domain_search_list_fqdn, tvb, composite_offset, consumedx, name_out);
 			} else {
 				/* RFC 3396 is used, so the option is split into several option 119. We don't link fqdn with v_tree. */
-				proto_tree_add_string(tree, hf_dhcp_option_dhcp_dns_domain_search_list_fqdn, tvb, 0, 0, dns_name);
+				proto_tree_add_string(tree, hf_dhcp_option_dhcp_dns_domain_search_list_fqdn, tvb, 0, 0, name_out);
 			}
 			composite_offset += consumedx;
 		}
@@ -2829,6 +2831,7 @@ dissect_dhcpopt_sip_servers(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
 	int length = tvb_reported_length(tvb);
 	const gchar	*dns_name;
 	guint		dns_name_len;
+        gchar           *name_out;
 
 	/* Encoding Long Options in the Dynamic Host Configuration Protocol (DHCPv4) (RFC 3396) */
 	/* Domain Names - Implementation And Specification (RFC 1035) */
@@ -2880,13 +2883,14 @@ dissect_dhcpopt_sip_servers(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
 				/* use the get_dns_name method that manages all techniques of RFC 1035 (compression pointer and so on) */
 				consumedx = get_dns_name(rfc3396_sip_server.tvb_composite, composite_offset, tvb_reported_length(rfc3396_sip_server.tvb_composite),
 					1 /* ignore enc */, &dns_name, &dns_name_len);
+                                name_out = format_text(wmem_packet_scope(), dns_name, dns_name_len);
 
 				if (rfc3396_sip_server.total_number_of_block == 1) {
 					/* RFC 3396 is not used, so we can easily link the fqdn with v_tree. */
-					proto_tree_add_string(tree, hf_dhcp_option_sip_server_name, tvb, composite_offset, consumedx, dns_name);
+					proto_tree_add_string(tree, hf_dhcp_option_sip_server_name, tvb, composite_offset, consumedx, name_out);
 				} else {
 					/* RFC 3396 is used, so the option is split into several option 120. We don't link fqdn with v_tree. */
-					proto_tree_add_string(tree, hf_dhcp_option_sip_server_name, tvb, 0, 0, format_text(wmem_packet_scope(), dns_name, dns_name_len));
+					proto_tree_add_string(tree, hf_dhcp_option_sip_server_name, tvb, 0, 0, name_out);
 				}
 				composite_offset += consumedx;
 			}