Lua: Validate Proto() arguments

Check if description (protocol name) and short_name are used before
registering the protocol.  This because proto_register_protocol() makes
sure there's not already a protocol with any of the names registered
and duplicates will be reported with a g_error() which terminates the
Wireshark unexpectedly.

Also check if short_name contains valid characters.

Give appropriate error messages.

Bug: 11739
Change-Id: Ib9776a2a3406ae5278ce744defd61864ebed0282
Reviewed-on: https://code.wireshark.org/review/11995
Reviewed-by: Stig Bjørlykke <stig@bjorlykke.org>

debian/libwireshark0.symbols

@@ -989,6 +989,7 @@ libwireshark.so.0 libwireshark0 #MINVER#
  proto_item_set_end@Base 1.9.1
  proto_item_set_len@Base 1.9.1
  proto_item_set_text@Base 1.9.1
+ proto_name_already_registered@Base 2.0.1
  proto_register_field_array@Base 1.9.1
  proto_register_fields_manual@Base 1.12.0~rc1
  proto_register_fields_section@Base 1.12.0~rc1

epan/proto.c

@@ -5508,6 +5508,19 @@ proto_get_id(const protocol_t *protocol)
 	return protocol->proto_id;
 }
 
+gboolean
+proto_name_already_registered(const gchar *name)
+{
+	gint key;
+
+	DISSECTOR_ASSERT_HINT(name, "No name present");
+
+	key = wrs_str_hash(name);
+	if (g_hash_table_lookup(proto_names, &key) != NULL)
+		return TRUE;
+	return FALSE;
+}
+
 int
 proto_get_id_by_filter_name(const gchar *filter_name)
 {

epan/proto.h

@@ -2116,6 +2116,11 @@ WS_DLL_PUBLIC int proto_get_next_protocol(void **cookie);
 WS_DLL_PUBLIC header_field_info *proto_get_first_protocol_field(const int proto_id, void **cookie);
 WS_DLL_PUBLIC header_field_info *proto_get_next_protocol_field(const int proto_id, void **cookie);
 
+/** Check if a protocol name is already registered.
+ @param name the name to search for
+ @return proto_id */
+WS_DLL_PUBLIC int proto_name_already_registered(const gchar *name);
+
 /** Given a protocol's filter_name.
  @param filter_name the filter name to search for
  @return proto_id */

epan/wslua/wslua_proto.c

@@ -93,7 +93,6 @@ WSLUA_CONSTRUCTOR Proto_new(lua_State* L) {
     const gchar* desc = luaL_checkstring(L,WSLUA_ARG_Proto_new_DESC);
     Proto proto;
     gchar *loname, *hiname;
-    int proto_id;
 
     /* TODO: should really make a common function for all of wslua that does checkstring and non-empty at same time */
     if (!name[0]) {
@@ -106,17 +105,29 @@ WSLUA_CONSTRUCTOR Proto_new(lua_State* L) {
         return 0;
     }
 
-    loname = g_ascii_strdown(name, -1);
-    proto_id = proto_get_id_by_filter_name(loname);
+    if (proto_name_already_registered(desc)) {
+        WSLUA_ARG_ERROR(Proto_new,DESC,"there cannot be two protocols with the same description");
+        return 0;
+    }
 
-    if (proto_id > 0) {
-        WSLUA_ARG_ERROR(Proto_new,NAME,"there cannot be two protocols with the same name");
+    loname = g_ascii_strdown(name, -1);
+    if (proto_check_field_name(loname)) {
+        WSLUA_ARG_ERROR(Proto_new,NAME,"invalid character in name");
         g_free(loname);
         return 0;
     }
 
-    proto = (wslua_proto_t *)g_malloc(sizeof(wslua_proto_t));
     hiname = g_ascii_strup(name, -1);
+    if ((proto_get_id_by_short_name(hiname) != -1) ||
+        (proto_get_id_by_filter_name(loname) != -1))
+    {
+        WSLUA_ARG_ERROR(Proto_new,NAME,"there cannot be two protocols with the same name");
+        g_free(loname);
+        g_free(hiname);
+        return 0;
+    }
+
+    proto = (wslua_proto_t *)g_malloc(sizeof(wslua_proto_t));
 
     proto->name = hiname;
     proto->loname = loname;