Reset column information after running migrations

[#50179803]
[SeeRM rapid7#7967]
[SeeRM rapid7#7870]

Because metasploit-framework runs migrations with the same process and
with the same connection as it later accesses the database, the column
information can become cached prematurely and be incorrect by the end of
the migrations.  Fix the bad cache by automatically resetting the column
information for all model classes after the migrations have run.

Author: limhoff-r7

lib/msf/core/db_manager/migration.rb

@@ -26,13 +26,33 @@ def migrate(verbose=false)
 					end
 				end
 
+				# Since the connections that existed before the migrations ran could
+				# have outdated column information, reset column information for all
+				# ActiveRecord::Base descendents to prevent missing method errors for
+				# column methods for columns created in migrations after the column
+				# information was cached.
+				reset_column_information
+
 				return ran
 			end
 
 			# Flag to indicate database migration has completed
 			#
 			# @return [Boolean]
 			attr_accessor :migrated
+
+			private
+
+			# Resets the column information for all descendants of ActiveRecord::Base
+			# since some of the migrations may have cached column information that
+			# has been updated by later migrations.
+			#
+			# @return [void]
+			def reset_column_information
+				ActiveRecord::Base.descendants.each do |descendant|
+					descendant.reset_column_information
+				end
+			end
 		end
 	end
 end

spec/support/shared/examples/msf/db_manager/migration.rb

@@ -27,6 +27,12 @@ def migrate
 			migrate.should == migrations
 		end
 
+		it 'should reset the column information' do
+			db_manager.should_receive(:reset_column_information)
+
+			migrate
+		end
+
 		context 'with StandardError from ActiveRecord::Migration.migrate' do
 			let(:error) do
 				StandardError.new(message)
@@ -106,4 +112,32 @@ def migrate
 		it { should respond_to :migrated }
 		it { should respond_to :migrated= }
 	end
+
+	context '#reset_column_information' do
+		def reset_column_information
+			db_manager.send(:reset_column_information)
+		end
+
+		it 'should use ActiveRecord::Base.descendants to find both direct and indirect subclasses' do
+			ActiveRecord::Base.should_receive(:descendants).and_return([])
+
+			reset_column_information
+		end
+
+		it 'should reset column information on each descendant of ActiveRecord::Base' do
+			descendants = []
+
+			1.upto(2) do |i|
+				descendants << mock("Descendant #{i}")
+			end
+
+			ActiveRecord::Base.stub(:descendants => descendants)
+
+			descendants.each do |descendant|
+				descendant.should_receive(:reset_column_information)
+			end
+
+			reset_column_information
+		end
+	end
 end