BGP: Fix length in decode_prefix4()

When decode_prefix4() gets called with more prefixes the length of
proto_tree_add_subtree_format() should not be the total length.

As the "Withdrawn route" part was the only one where decode_prefix4() has
been called with a tlen not equal 0 we can eliminate the tlen parameter.

Bug: 13146
Change-Id: I708dec2cecbed6054b60190104b82c72d54e8037
Reviewed-on: https://code.wireshark.org/review/18852
Reviewed-by: Michael Mann <mmann78@netscape.net>
Petri-Dish: Michael Mann <mmann78@netscape.net>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Alexis La Goutte <alexis.lagoutte@gmail.com>

1 files changed, 9 insertions, 10 deletions

diff --git a/epan/dissectors/packet-bgp.c b/epan/dissectors/packet-bgp.c
index e8526d617c..512a41bb8c 100644
--- a/epan/dissectors/packet-bgp.c
+++ b/epan/dissectors/packet-bgp.c
@@ -2199,7 +2199,7 @@ decode_path_prefix4(proto_tree *tree, packet_info *pinfo, int hf_path_id, int hf
  */
 static int
 decode_prefix4(proto_tree *tree, packet_info *pinfo, proto_item *parent_item, int hf_addr, tvbuff_t *tvb, gint offset,
-               guint16 tlen, const char *tag)
+               const char *tag)
 {
     proto_tree *prefix_tree;
     union {
@@ -2222,7 +2222,7 @@ decode_prefix4(proto_tree *tree, packet_info *pinfo, proto_item *parent_item, in
     /* put prefix into protocol tree */
     set_address(&addr, AT_IPv4, 4, ip_addr.addr_bytes);
     prefix_tree = proto_tree_add_subtree_format(tree, tvb, offset,
-            tlen != 0 ? tlen : 1 + length, ett_bgp_prefix, NULL,
+            1 + length, ett_bgp_prefix, NULL,
             "%s/%u", address_to_str(wmem_packet_scope(), &addr), plen);
 
     proto_item_append_text(parent_item, " (%s/%u)",
@@ -2748,7 +2748,7 @@ decode_flowspec_nlri(proto_tree *tree, tvbuff_t *tvb, gint offset, guint16 afi,
             cursor_fspec++;
             if (afi == AFNUM_INET)
                 filter_len = decode_prefix4(filter_tree, pinfo, filter_item, hf_bgp_flowspec_nlri_dst_pref_ipv4,
-                                            tvb, offset+cursor_fspec, 0, "Destination IP filter");
+                                            tvb, offset+cursor_fspec, "Destination IP filter");
             else /* AFNUM_INET6 */
                 filter_len = decode_fspec_match_prefix6(filter_tree, filter_item, hf_bgp_flowspec_nlri_dst_ipv6_pref,
                                                         tvb, offset+cursor_fspec, 0, pinfo);
@@ -2759,7 +2759,7 @@ decode_flowspec_nlri(proto_tree *tree, tvbuff_t *tvb, gint offset, guint16 afi,
             cursor_fspec++;
             if (afi == AFNUM_INET)
                 filter_len = decode_prefix4(filter_tree, pinfo, filter_item, hf_bgp_flowspec_nlri_src_pref_ipv4,
-                                            tvb, offset+cursor_fspec, 0, "Source IP filter");
+                                            tvb, offset+cursor_fspec, "Source IP filter");
             else /* AFNUM_INET6 */
                 filter_len = decode_fspec_match_prefix6(filter_tree, filter_item, hf_bgp_flowspec_nlri_src_ipv6_pref,
                                                         tvb, offset+cursor_fspec, 0, pinfo);
@@ -3642,7 +3642,7 @@ static int decode_bgp_link_nlri_prefix_descriptors(tvbuff_t *tvb,
 
             case BGP_NLRI_TLV_IP_REACHABILITY_INFORMATION:
                 if (decode_prefix4(tlv_sub_tree, pinfo, tlv_sub_item, hf_bgp_ls_nlri_ip_reachability_prefix_ip,
-                               tvb, offset + 4, 0, "Reachability") == -1)
+                               tvb, offset + 4, "Reachability") == -1)
                     return diss_length;
             break;
         }
@@ -4747,7 +4747,7 @@ decode_prefix_MP(proto_tree *tree, int hf_addr4, int hf_addr6,
             case SAFNUM_UNICAST:
             case SAFNUM_MULCAST:
             case SAFNUM_UNIMULC:
-                total_length = decode_prefix4(tree, pinfo, NULL,hf_addr4, tvb, offset, 0, tag);
+                total_length = decode_prefix4(tree, pinfo, NULL,hf_addr4, tvb, offset, tag);
                 if (total_length < 0)
                     return -1;
                 break;
@@ -7374,7 +7374,7 @@ dissect_bgp_update(tvbuff_t *tvb, proto_tree *tree, packet_info *pinfo)
             }
         } else {
             while (o < end) {
-                i = decode_prefix4(subtree, pinfo, NULL, hf_bgp_withdrawn_prefix, tvb, o, len,
+                i = decode_prefix4(subtree, pinfo, NULL, hf_bgp_withdrawn_prefix, tvb, o,
                     "Withdrawn route");
                 if (i < 0)
                     return;
@@ -7417,8 +7417,7 @@ dissect_bgp_update(tvbuff_t *tvb, proto_tree *tree, packet_info *pinfo)
             } else {
                 /* Standard prefixes */
                 while (o < end) {
-                    i = decode_prefix4(subtree, pinfo, NULL, hf_bgp_nlri_prefix, tvb, o, 0,
-                           "NLRI");
+                    i = decode_prefix4(subtree, pinfo, NULL, hf_bgp_nlri_prefix, tvb, o, "NLRI");
                     if (i < 0)
                         return;
                     o += i;
@@ -7585,7 +7584,7 @@ example 2
             proto_tree_add_item(subtree1, hf_bgp_route_refresh_orf_entry_prefixmask_upper, tvb, p, 1, ENC_BIG_ENDIAN);
             p++;
 
-            advance = decode_prefix4(subtree1, pinfo, NULL, hf_bgp_route_refresh_orf_entry_ip, tvb, p, 0, "ORF");
+            advance = decode_prefix4(subtree1, pinfo, NULL, hf_bgp_route_refresh_orf_entry_ip, tvb, p, "ORF");
             if (advance < 0)
                     break;
             entrylen = 7 + 1 + advance;