close massive file overwrite hole with TempDir

helper/common/shared_state.go

@@ -7,11 +7,16 @@ import (
 	"path/filepath"
 )
 
+var	sharedStateDir := ioutil.TempDir(packer.ConfigTmpDir(), "state")
+
 // Used to set variables which we need to access later in the build, where
 // state bag and config information won't work
 func sharedStateFilename(suffix string, buildName string) string {
 	uuid := os.Getenv("PACKER_RUN_UUID")
-	return filepath.Join(os.TempDir(), fmt.Sprintf("packer-%s-%s-%s", uuid, suffix, buildName))
+	if uuid == "" {
+		uuid="none"
+	}
+	return filepath.Join(sharedStateDir, fmt.Sprintf("%s-%s-%s", uuid, suffix, buildName))
 }
 
 func SetSharedState(key string, value string, buildName string) error {