package cmd import ( "crypto/tls" "encoding/json" "encoding/pem" "fmt" "io/ioutil" "net/http" "os" "strings" "time" "github.com/golang/glog" ) type KubeVersion struct { Major string Minor string baseVersion string GitVersion string } func (k *KubeVersion) BaseVersion() string { if k.baseVersion != "" { return k.baseVersion } // Some provides return the minor version like "15+" minor := strings.Replace(k.Minor, "+", "", -1) ver := fmt.Sprintf("%s.%s", k.Major, minor) k.baseVersion = ver return ver } func getKubeVersionFromRESTAPI() (*KubeVersion, error) { glog.V(2).Info("Try to get version from Rest API") k8sVersionURL := getKubernetesURL() serviceaccount := "/var/run/secrets/kubernetes.io/serviceaccount" cacertfile := fmt.Sprintf("%s/ca.crt", serviceaccount) tokenfile := fmt.Sprintf("%s/token", serviceaccount) tlsCert, err := loadCertificate(cacertfile) if err != nil { glog.V(2).Infof("Failed loading certificate Error: %s", err) return nil, err } tb, err := ioutil.ReadFile(tokenfile) if err != nil { glog.V(2).Infof("Failed reading token file Error: %s", err) return nil, err } token := strings.TrimSpace(string(tb)) data, err := getWebDataWithRetry(k8sVersionURL, token, tlsCert) if err != nil { glog.V(2).Infof("Failed to get data Error: %s", err) return nil, err } k8sVersion, err := extractVersion(data) if err != nil { return nil, err } return k8sVersion, nil } // The idea of this function is so if Kubernetes DNS is not completely seetup and the // Container where kube-bench is running needs time for DNS configure. // Basically try 10 times, waiting 1 second until either it is successful or it fails. func getWebDataWithRetry(k8sVersionURL, token string, cacert *tls.Certificate) (data []byte, err error) { tries := 0 // We retry a few times in case the DNS service has not had time to come up for tries < 10 { data, err = getWebData(k8sVersionURL, token, cacert) if err == nil { return } tries++ time.Sleep(1 * time.Second) } return } type VersionResponse struct { Major string Minor string GitVersion string GitCommit string GitTreeState string BuildDate string GoVersion string Compiler string Platform string } func extractVersion(data []byte) (*KubeVersion, error) { vrObj := &VersionResponse{} glog.V(2).Info(fmt.Sprintf("vd: %s\n", string(data))) err := json.Unmarshal(data, vrObj) if err != nil { return nil, err } glog.V(2).Info(fmt.Sprintf("vrObj: %#v\n", vrObj)) return &KubeVersion{ Major: vrObj.Major, Minor: vrObj.Minor, GitVersion: vrObj.GitVersion, }, nil } func getWebData(srvURL, token string, cacert *tls.Certificate) ([]byte, error) { glog.V(2).Info(fmt.Sprintf("getWebData srvURL: %s\n", srvURL)) tlsConf := &tls.Config{ Certificates: []tls.Certificate{*cacert}, InsecureSkipVerify: true, } tr := &http.Transport{ TLSClientConfig: tlsConf, } client := &http.Client{Transport: tr} req, err := http.NewRequest(http.MethodGet, srvURL, nil) if err != nil { return nil, err } authToken := fmt.Sprintf("Bearer %s", token) req.Header.Set("Authorization", authToken) resp, err := client.Do(req) if err != nil { glog.V(2).Info(fmt.Sprintf("HTTP ERROR: %v\n", err)) return nil, err } defer resp.Body.Close() if resp.StatusCode != http.StatusOK { glog.V(2).Info(fmt.Sprintf("URL:[%s], StatusCode:[%d] \n Headers: %#v\n", srvURL, resp.StatusCode, resp.Header)) err = fmt.Errorf("URL:[%s], StatusCode:[%d]", srvURL, resp.StatusCode) return nil, err } return ioutil.ReadAll(resp.Body) } func loadCertificate(certFile string) (*tls.Certificate, error) { cacert, err := ioutil.ReadFile(certFile) if err != nil { return nil, err } var tlsCert tls.Certificate block, _ := pem.Decode(cacert) if block == nil { return nil, fmt.Errorf("unable to Decode certificate") } glog.V(2).Info("Loading CA certificate") tlsCert.Certificate = append(tlsCert.Certificate, block.Bytes) return &tlsCert, nil } func getKubernetesURL() string { k8sVersionURL := "https://kubernetes.default.svc/version" // The following provides flexibility to use // K8S provided variables is situations where // hostNetwork: true if !isEmpty(os.Getenv("KUBE_BENCH_K8S_ENV")) { k8sHost := os.Getenv("KUBERNETES_SERVICE_HOST") k8sPort := os.Getenv("KUBERNETES_SERVICE_PORT_HTTPS") if !isEmpty(k8sHost) && !isEmpty(k8sPort) { return fmt.Sprintf("https://%s:%s/version", k8sHost, k8sPort) } glog.V(2).Info("KUBE_BENCH_K8S_ENV is set, but environment variables KUBERNETES_SERVICE_HOST or KUBERNETES_SERVICE_PORT_HTTPS are not set") } return k8sVersionURL }