Re-enable host lookup for _failure

Again needed when called from exploit_driver because nothing is reported
yet at that point.

Also adds some yardoc

lib/msf/core/db_manager/exploit_attempt.rb

@@ -27,6 +27,11 @@ module Msf::DBManager::ExploitAttempt
   }
   end
 
+  # Create an `Mdm::ExploitAttempt` (and possibly an `Mdm::VulnAttempt`, if
+  # the `vuln` option is passed).
+  #
+  # @option (see #do_report_failure_or_success)
+  # @return (see #do_report_failure_or_success)
   def report_exploit_failure(opts)
     return unless opts.has_key?(:refs) && !opts[:refs].blank?
     host   = opts[:host] || return
@@ -39,14 +44,31 @@ module Msf::DBManager::ExploitAttempt
     # Look up the service as appropriate
     if port and svc.nil?
       opts[:proto] ||= prot
-      opts[:service] = get_service(wspace, host, prot, port)
+      svc = opts[:service] = get_service(wspace, host, prot, port)
     end
 
+    # Look up the host as appropriate
+    if !host || !host.kind_of?(::Mdm::Host)
+      if svc.kind_of? ::Mdm::Service
+        host = svc.host
+      else
+        host = get_host(workspace: wspace, address: host)
+      end
+    end
+
+    # Bail if we dont have a host object
+    return if not host
+    opts[:host] = host
+
     do_report_failure_or_success(opts)
   end
 
+  # Create an `Mdm::ExploitAttempt` (and possibly an `Mdm::VulnAttempt`, if
+  # the `vuln` option is passed).
+  #
+  # @return (see #do_report_failure_or_success)
   def report_exploit_success(opts)
-    opts[:refs] || return
+    return unless opts[:refs]
     host   = opts[:host] || return
 
     wspace = opts[:workspace] || workspace
@@ -67,6 +89,16 @@ module Msf::DBManager::ExploitAttempt
 
   private
 
+  # @option opts [Array<String>, Array<Msf::Module::Reference>] :refs
+  # @option opts [Mdm::Host] :host
+  # @option opts [Mdm::Service] :service
+  # @option opts [Integer] :port (nil)
+  # @option opts ["tcp","udp"] :proto (nil)
+  # @option opts [Mdm::Vuln] :vuln (nil)
+  # @option opts [Time] :timestamp (nil)
+  # @option opts [Mdm::Vuln] :timestamp (nil)
+  # @option opts [String] :module (nil)
+  # @return [void]
   def do_report_failure_or_success(opts)
     ::ActiveRecord::Base.connection_pool.with_connection {
       mrefs  = opts.delete(:refs) || return