Adding the missing generic method to support multiple vendor-defined ext types

The current EAP dissector assumes that all vendor-defined extended types are
WPS. This does not allow for adding new vendor-defined payloads. This codes
cleans up the limitation. The Vendor-ID can be registered using a dissector
table, while the Vendor-Type is passed as data.

Change-Id: Idc75108fd42b9b2153089db503b137c6eeefe274
Signed-off-by: Dr. Lars Voelker <lars-github@larsvoelker.de>
Reviewed-on: https://code.wireshark.org/review/32888
Petri-Dish: Graham Bloice <graham.bloice@trihedral.com>
Tested-by: Petri Dish Buildbot
Reviewed-by: Anders Broman <a.broman58@gmail.com>

3 files changed, 47 insertions, 20 deletions

diff --git a/epan/dissectors/packet-eap.c b/epan/dissectors/packet-eap.c
index 946a7e600e..b00d0add41 100644
--- a/epan/dissectors/packet-eap.c
+++ b/epan/dissectors/packet-eap.c
@@ -98,6 +98,8 @@ static expert_field ei_eap_md5_value_size_overflow = EI_INIT;
 static expert_field ei_eap_dictionary_attacks = EI_INIT;
 static expert_field ei_eap_identity_invalid = EI_INIT;
 
+static dissector_table_t eap_expanded_type_dissector_table;
+
 static dissector_handle_t eap_handle;
 
 static dissector_handle_t tls_handle;
@@ -395,10 +397,6 @@ static const fragment_items eap_tls_frag_items = {
 static int   hf_eap_ext_vendor_id   = -1;
 static int   hf_eap_ext_vendor_type = -1;
 
-/* Vendor-Type and Vendor-id */
-#define WFA_VENDOR_ID         0x00372A
-#define WFA_SIMPLECONFIG_TYPE 0x1
-
 static const value_string eap_ext_vendor_id_vals[] = {
   { WFA_VENDOR_ID, "WFA" },
   { 0, NULL }
@@ -413,17 +411,28 @@ static void
 dissect_exteap(proto_tree *eap_tree, tvbuff_t *tvb, int offset,
                gint size, packet_info* pinfo)
 {
+  tvbuff_t   *next_tvb;
+  guint32    vendor_id;
+  guint32    *vendor_type;
 
-  proto_tree_add_item(eap_tree, hf_eap_ext_vendor_id,   tvb, offset, 3, ENC_BIG_ENDIAN);
+  vendor_type = (guint32 *)g_malloc(sizeof(guint32));
+
+  proto_tree_add_item_ret_uint(eap_tree, hf_eap_ext_vendor_id, tvb, offset, 3, ENC_BIG_ENDIAN, &vendor_id);
   offset += 3;
   size   -= 3;
 
-  proto_tree_add_item(eap_tree, hf_eap_ext_vendor_type, tvb, offset, 4, ENC_BIG_ENDIAN);
+  proto_tree_add_item_ret_uint(eap_tree, hf_eap_ext_vendor_type, tvb, offset, 4, ENC_BIG_ENDIAN, vendor_type);
   offset += 4;
   size   -= 4;
 
-  /* Generic method to support multiple vendor-defined extended types goes here :-) */
-  dissect_exteap_wps(eap_tree, tvb, offset, size, pinfo);
+  next_tvb = tvb_new_subset_remaining(tvb, offset);
+  if (!dissector_try_uint_new(eap_expanded_type_dissector_table,
+    vendor_id, next_tvb, pinfo, eap_tree,
+    FALSE, vendor_type)) {
+    call_data_dissector(next_tvb, pinfo, eap_tree);
+  }
+
+  g_free(vendor_type);
 }
 /* *********************************************************************
 ********************************************************************* */
@@ -1712,6 +1721,12 @@ proto_register_eap(void)
 
   reassembly_table_register(&eap_tls_reassembly_table,
                         &addresses_reassembly_table_functions);
+
+  eap_expanded_type_dissector_table = register_dissector_table("eap.ext.vendor_id",
+    "EAP-EXT Vendor Id",
+    proto_eap, FT_UINT24,
+    BASE_HEX);
+
 }
 
 void
diff --git a/epan/dissectors/packet-wps.c b/epan/dissectors/packet-wps.c
index 26888cdcec..2231904044 100644
--- a/epan/dissectors/packet-wps.c
+++ b/epan/dissectors/packet-wps.c
@@ -45,6 +45,8 @@ static expert_field ei_eapwps_packet_too_short = EI_INIT;
 static expert_field ei_eapwps_fmt_warn_too_long = EI_INIT;
 static expert_field ei_eapwps_fmt_length_warn = EI_INIT;
 
+static dissector_handle_t wps_handle;
+
 /* OPCodes */
 #define OPC_WSC_START    0x01   /* WPS OPCODE WSC_Start */
 #define OPC_WSC_ACK      0x02   /* WPS OPCODE WSC_ACK */
@@ -1677,15 +1679,20 @@ dissect_wps_tlvs(proto_tree *eap_tree, tvbuff_t *tvb, int offset,
 
 /********************************************************************** */
 /********************************************************************** */
-void
-dissect_exteap_wps(proto_tree *eap_tree, tvbuff_t *tvb, int offset,
-                   gint size, packet_info *pinfo)
+
+static int
+dissect_wps(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
 {
   proto_item *pi;
   proto_tree *pt;
   guint8      flags;
+  int         offset;
+  gint        size;
+
+  offset = 0;
+  size = tvb_captured_length(tvb);
 
-  pi = proto_tree_add_item(eap_tree, hf_eapwps_opcode,     tvb, offset, 1, ENC_BIG_ENDIAN);
+  pi = proto_tree_add_item(tree, hf_eapwps_opcode, tvb, offset, 1, ENC_BIG_ENDIAN);
   offset += 1; size -= 1;
 
   pi = proto_item_get_parent(pi);
@@ -1694,10 +1701,9 @@ dissect_exteap_wps(proto_tree *eap_tree, tvbuff_t *tvb, int offset,
   if (pinfo != NULL)
     col_append_str(pinfo->cinfo, COL_INFO, ", WPS");
 
-
   /* Flag field, if msg-len flag set, add appropriate field  */
   flags = tvb_get_guint8(tvb,offset);
-  pi = proto_tree_add_item(eap_tree, hf_eapwps_flags,      tvb, offset, 1, ENC_BIG_ENDIAN);
+  pi = proto_tree_add_item(tree, hf_eapwps_flags,      tvb, offset, 1, ENC_BIG_ENDIAN);
   pt = proto_item_add_subtree(pi, ett_eap_wps_flags);
 
   proto_tree_add_item(pt, hf_eapwps_flag_mf,    tvb, offset, 1, ENC_BIG_ENDIAN);
@@ -1706,11 +1712,13 @@ dissect_exteap_wps(proto_tree *eap_tree, tvbuff_t *tvb, int offset,
 
   if (flags & MASK_WSC_FLAG_LF) {
     /* length field is present in first eap-packet when msg is fragmented  */
-    proto_tree_add_item(eap_tree, hf_eapwps_msglen, tvb, offset, 2, ENC_BIG_ENDIAN);
+    proto_tree_add_item(tree, hf_eapwps_msglen, tvb, offset, 2, ENC_BIG_ENDIAN);
     offset += 2; size -= 2;
   }
 
-  dissect_wps_tlvs(eap_tree, tvb, offset, size, pinfo);
+  dissect_wps_tlvs(tree, tvb, offset, size, pinfo);
+
+  return size;
 }
 
 /********************************************************************** */
@@ -2539,12 +2547,15 @@ proto_register_wps(void)
   proto_register_subtree_array(ett, array_length(ett));
   expert_wps = expert_register_protocol(proto_wps);
   expert_register_field_array(expert_wps, ei, array_length(ei));
+
+  wps_handle = register_dissector("wps", dissect_wps, proto_wps);
 }
 
 void
 proto_reg_handoff_wps(void)
 {
   dissector_add_uint("wlan.ie.wifi_alliance.subtype", WFA_SUBTYPE_IEEE1905_MULTI_AP, create_dissector_handle(dissect_wps_wfa_ext_via_dt, -1));
+  dissector_add_uint("eap.ext.vendor_id", WFA_VENDOR_ID, wps_handle);
 }
 
 /*
diff --git a/epan/dissectors/packet-wps.h b/epan/dissectors/packet-wps.h
index f4ef6da00f..f80ada73a6 100644
--- a/epan/dissectors/packet-wps.h
+++ b/epan/dissectors/packet-wps.h
@@ -23,11 +23,12 @@
 #ifndef _packet_wps_h_
 #define _packet_wps_h_
 
-void
-dissect_exteap_wps(proto_tree *eap_tree, tvbuff_t *tvb, int offset,
-		   gint size, packet_info* pinfo);
+ /* Vendor-Type and Vendor-id */
+#define WFA_VENDOR_ID         0x00372A
+#define WFA_SIMPLECONFIG_TYPE 0x1
+
 void
 dissect_wps_tlvs(proto_tree *eap_tree, tvbuff_t *tvb, int offset,
 		 gint size, packet_info* pinfo);
 
-#endif
+#endif
\ No newline at end of file