Land #10788, Clarify "NameError: wrong constant name" message on invalid module name

lib/msf/core/exceptions.rb

@@ -48,10 +48,22 @@ class ValidationError < ArgumentError
   end
 end
 
+
 ###
 #
-# This exception is raised when the module cache is invalidated.  It is
-# handled internally by the ModuleManager.
+# This exception is raised when a module fails to load.
+#
+# It is used by Msf::Modules::Loader::Base.
+#
+###
+class ModuleLoadError < RuntimeError
+end
+
+###
+#
+# This exception is raised when the module cache is invalidated.
+#
+# It is handled internally by the ModuleManager.
 #
 ###
 class ModuleCacheInvalidated < RuntimeError

lib/msf/core/modules/loader/base.rb

@@ -362,17 +362,24 @@ class Msf::Modules::Loader::Base
   # @return [nil] if any module name along the chain does not exist.
   def current_module(module_names)
     # Don't want to trigger ActiveSupport's const_missing, so can't use constantize.
-    named_module = module_names.inject(Object) { |parent, module_name|
+    named_module = module_names.reduce(Object) do |parent, module_name|
       # Since we're searching parent namespaces first anyway, this is
       # semantically equivalent to providing false for the 1.9-only
       # "inherit" parameter to const_defined?. If we ever drop 1.8
       # support, we can save a few cycles here by adding it back.
-      if parent.const_defined?(module_name)
-        parent.const_get(module_name)
-      else
-        break
+      begin
+        if parent.const_defined?(module_name)
+          parent.const_get(module_name)
+        else
+          break
+        end
+      # HACK: This doesn't slow load time as much as checking proactively
+      rescue NameError
+        reversed_name = self.class.reverse_relative_name(module_name)
+        # TODO: Consolidate this with Msftidy#check_snake_case_filename ?
+        raise Msf::ModuleLoadError, "#{reversed_name} must be lowercase alphanumeric snake case"
       end
-    }
+    end
 
     named_module
   end
@@ -522,7 +529,7 @@ class Msf::Modules::Loader::Base
   # @return [String] The module full name
   #
   # @see namespace_module_names
-  def reverse_relative_name(relative_name)
+  def self.reverse_relative_name(relative_name)
     relative_name.split('__').map(&:downcase).join('/')
   end
 

spec/lib/msf/core/modules/loader/base_spec.rb

@@ -738,7 +738,7 @@ RSpec.describe Msf::Modules::Loader::Base do
       it 'should be reversible' do
         namespace_module_name = subject.send(:namespace_module_name, module_full_name)
         relative_name = namespace_module_name.gsub(/^.*::/, '')
-        reversed_name = subject.send(:reverse_relative_name, relative_name)
+        reversed_name = described_class.reverse_relative_name(relative_name)
 
         expect(reversed_name).to eq module_full_name
       end
@@ -752,7 +752,7 @@ RSpec.describe Msf::Modules::Loader::Base do
       it 'should be reversible' do
         namespace_module_names = subject.send(:namespace_module_names, module_full_name)
         relative_name = namespace_module_names.last
-        reversed_name = subject.send(:reverse_relative_name, relative_name)
+        reversed_name = described_class.reverse_relative_name(relative_name)
 
         expect(reversed_name).to eq module_full_name
       end

tools/dev/msftidy.rb

@@ -257,7 +257,7 @@ class Msftidy
   # This check also enforces namespace module name reversibility
   def check_snake_case_filename
     if @name !~ /^[a-z0-9]+(?:_[a-z0-9]+)*\.rb$/
-      warn('Filenames should be lowercase alphanumeric snake case.')
+      warn('Filenames must be lowercase alphanumeric snake case.')
     end
   end