New system for silent require errors. Use the new function

stdnse.silent_require. The Lua require function is back in its usual spot
(_G.require).

nse_main.lua

@@ -212,8 +212,7 @@ local function tcopy (t)
 end
 
 local REQUIRE_ERROR = {};
-stdnse.require = require; -- add real require to stdnse so it can be called if desired
-function _G.require (...)
+rawset(stdnse, "silent_require", function (...)
   local status, mod = pcall(require, ...);
   if not status then
     print_debug(1, "%s", traceback(mod));
@@ -222,7 +221,7 @@ function _G.require (...)
   else
     return mod;
   end
-end
+end);
 
 local Script = {}; -- The Script Class, its constructor is Script.new.
 local Thread = {}; -- The Thread Class, its constructor is Script:new_thread.

nselib/stdnse.lua

@@ -869,13 +869,15 @@ do end -- no function here, see nse_main.lua
 --@return coroutine Returns the base coroutine of the running script.
 do end -- no function here, see nse_main.lua
 
---- The (Unmodified) Lua Require Function.
+--- The Lua Require Function with errors silenced.
 --
--- See the Lua manual for description. NSE replaces the standard function
--- in the global namespace to improve error handling.
+-- See the Lua manual for description of the require function. This modified
+-- version allows the script to quietly fail at loading if a required
+-- library does not exist.
 --
---@name require
+--@name silent_require
 --@class function
+--@usage stdnse.silent_require "openssl"
 do end -- no function here, see nse_main.lua
 
 

scripts/http-cakephp-version.nse

@@ -27,6 +27,8 @@ categories = {"discovery","safe"}
 
 require "http"
 require "shortport"
+require "stdnse"
+stdnse.silent_require "openssl"
 
 portrule = shortport.http
 

scripts/http-favicon.nse

@@ -37,7 +37,8 @@ require "http"
 require "stdnse"
 require "datafiles"
 require "nsedebug"
-require "openssl"
+require "stdnse"
+stdnse.silent_require "openssl"
 
 portrule = shortport.http
 

scripts/http-php-version.nse

@@ -28,6 +28,8 @@ categories = {"discovery", "safe"}
 
 require "http"
 require "shortport"
+require "stdnse"
+stdnse.silent_require "openssl"
 
 portrule = shortport.http
 

scripts/mysql-brute.nse

@@ -17,7 +17,7 @@ require 'shortport'
 require 'stdnse'
 require 'mysql'
 require 'unpwdb'
-require 'openssl'
+stdnse.silent_require 'openssl'
 
 -- Version 0.3
 -- Created 01/15/2010 - v0.1 - created by Patrik Karlsson <patrik@cqure.net>

scripts/mysql-databases.nse

@@ -27,7 +27,7 @@ categories = {"discovery", "intrusive"}
 require 'shortport'
 require 'stdnse'
 require 'mysql'
-require 'openssl'
+stdnse.silent_require 'openssl'
 
 dependencies = {"mysql-brute", "mysql-empty-password"}
 

scripts/mysql-users.nse

@@ -30,7 +30,7 @@ categories = {"discovery", "intrusive"}
 require 'shortport'
 require 'stdnse'
 require 'mysql'
-require 'openssl'
+stdnse.silent_require 'openssl'
 
 dependencies = {"mysql-brute", "mysql-empty-password"}
 

scripts/mysql-variables.nse

@@ -38,7 +38,7 @@ categories = {"discovery", "intrusive"}
 require 'shortport'
 require 'stdnse'
 require 'mysql'
-require 'openssl'
+stdnse.silent_require 'openssl'
 
 dependencies = {"mysql-brute", "mysql-empty-password"}
 

scripts/oracle-brute.nse

@@ -37,7 +37,8 @@ categories = {"intrusive", "auth"}
 
 require 'shortport'
 require 'brute'
-require 'openssl'
+require 'stdnse'
+stdnse.silent_require 'openssl'
 require 'tns'
 
 portrule = shortport.port_or_service(1521, "oracle-tns", "tcp", "open")

scripts/oracle-enum-users.nse

@@ -34,7 +34,8 @@ categories = {"intrusive", "auth"}
 
 require 'shortport'
 require 'unpwdb'
-require 'openssl'
+require 'stdnse'
+stdnse.silent_require 'openssl'
 require 'tns'
 
 portrule = shortport.port_or_service(1521, 'oracle-tns' )

scripts/pgsql-brute.nse

@@ -29,7 +29,7 @@ categories = {"intrusive", "auth"}
 require 'shortport'
 require 'stdnse'
 require 'unpwdb'
-require 'openssl'
+stdnse.silent_require 'openssl'
 
 -- Version 0.3
 -- Created 01/15/2010 - v0.1 - created by Patrik Karlsson <patrik@cqure.net>

scripts/ssh-hostkey.nse

@@ -56,7 +56,7 @@ categories = {"safe","default","discovery"}
 
 require("shortport")
 require("stdnse")
-require("openssl")
+stdnse.silent_require("openssl")
 require("ssh1")
 require("ssh2")
 

scripts/ssh2-enum-algos.nse

@@ -57,7 +57,7 @@ categories = {"safe", "discovery"}
 
 require "shortport"
 require "stdnse"
-require "openssl"
+stdnse.silent_require "openssl"
 
 portrule = shortport.port_or_service(22, "ssh")