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| 1 | +package openshift |
| 2 | + |
| 3 | +import ( |
| 4 | + "context" |
| 5 | + "fmt" |
| 6 | + "net/http" |
| 7 | + "os" |
| 8 | + "os/user" |
| 9 | + "path" |
| 10 | + "strings" |
| 11 | + |
| 12 | + "github.com/go-kit/log" |
| 13 | + "github.com/go-kit/log/level" |
| 14 | + |
| 15 | + authenticationv1 "k8s.io/api/authentication/v1" |
| 16 | + metav1 "k8s.io/apimachinery/pkg/apis/meta/v1" |
| 17 | + "k8s.io/apiserver/pkg/authentication/authenticator" |
| 18 | + k8suser "k8s.io/apiserver/pkg/authentication/user" |
| 19 | + "k8s.io/client-go/kubernetes" |
| 20 | + "k8s.io/client-go/rest" |
| 21 | + "k8s.io/client-go/tools/clientcmd" |
| 22 | +) |
| 23 | + |
| 24 | +// SelfSubjectReview is a struct that implements the Token and Request interfaces. |
| 25 | +type SelfSubjectReview struct { |
| 26 | + logger log.Logger |
| 27 | + // RemoteKubeConfigFile is the file to use to connect to a "normal" kube API server which hosts the |
| 28 | + // TokenAccessReview.authentication.k8s.io endpoint for checking tokens. |
| 29 | + RemoteKubeConfigFile string |
| 30 | +} |
| 31 | + |
| 32 | +// NewSelfSubjectReview creates a new instance of SelfSubjectReview. |
| 33 | +func NewSelfSubjectReview(kubeCfgFile string, logger log.Logger) authenticator.Request { |
| 34 | + return &SelfSubjectReview{ |
| 35 | + logger: logger, |
| 36 | + RemoteKubeConfigFile: kubeCfgFile, |
| 37 | + } |
| 38 | +} |
| 39 | + |
| 40 | +// AuthenticateRequest implements the authenticator.Request interface. |
| 41 | +func (s *SelfSubjectReview) AuthenticateRequest(req *http.Request) (*authenticator.Response, bool, error) { |
| 42 | + authHeader := req.Header.Get("Authorization") |
| 43 | + level.Debug(s.logger).Log("msg", "Extracting token from Authorization header", "header", authHeader) |
| 44 | + if authHeader == "" { |
| 45 | + return nil, false, nil |
| 46 | + } |
| 47 | + |
| 48 | + const bearerPrefix = "Bearer " |
| 49 | + if !strings.HasPrefix(authHeader, bearerPrefix) { |
| 50 | + return nil, false, fmt.Errorf("invalid authorization header format") |
| 51 | + } |
| 52 | + |
| 53 | + token := strings.TrimPrefix(authHeader, bearerPrefix) |
| 54 | + cfg, err := getConfig(s.RemoteKubeConfigFile) |
| 55 | + if err != nil { |
| 56 | + return nil, false, err |
| 57 | + } |
| 58 | + |
| 59 | + cfg = rest.AnonymousClientConfig(cfg) |
| 60 | + cfg.BearerToken = token |
| 61 | + clientset, err := kubernetes.NewForConfig(cfg) |
| 62 | + if err != nil { |
| 63 | + return nil, false, err |
| 64 | + } |
| 65 | + |
| 66 | + ssr, err := clientset.AuthenticationV1().SelfSubjectReviews().Create(context.Background(), &authenticationv1.SelfSubjectReview{}, metav1.CreateOptions{}) |
| 67 | + if err != nil { |
| 68 | + return nil, false, err |
| 69 | + } |
| 70 | + |
| 71 | + level.Debug(s.logger).Log("msg", "SelfSubjectReview", |
| 72 | + "username", ssr.Status.UserInfo.Username, |
| 73 | + "uid", ssr.Status.UserInfo.UID, |
| 74 | + "groups", fmt.Sprintf("%v", ssr.Status.UserInfo.Groups), |
| 75 | + "extra", fmt.Sprintf("%v", ssr.Status.UserInfo.Extra)) |
| 76 | + |
| 77 | + extra := make(map[string][]string) |
| 78 | + for k, v := range ssr.Status.UserInfo.Extra { |
| 79 | + extra[k] = v |
| 80 | + } |
| 81 | + return &authenticator.Response{ |
| 82 | + User: &k8suser.DefaultInfo{ |
| 83 | + Name: ssr.Status.UserInfo.Username, |
| 84 | + UID: ssr.Status.UserInfo.UID, |
| 85 | + Groups: ssr.Status.UserInfo.Groups, |
| 86 | + Extra: extra, |
| 87 | + }, |
| 88 | + }, true, nil |
| 89 | +} |
| 90 | + |
| 91 | +func getConfig(kubeconfig string) (*rest.Config, error) { |
| 92 | + if len(kubeconfig) > 0 { |
| 93 | + loader := &clientcmd.ClientConfigLoadingRules{ExplicitPath: kubeconfig} |
| 94 | + return loadConfig(loader) |
| 95 | + } |
| 96 | + kubeconfigPath := os.Getenv(clientcmd.RecommendedConfigPathEnvVar) |
| 97 | + if len(kubeconfigPath) == 0 { |
| 98 | + return rest.InClusterConfig() //nolint:wrapcheck |
| 99 | + } |
| 100 | + loadingRules := clientcmd.NewDefaultClientConfigLoadingRules() |
| 101 | + if _, ok := os.LookupEnv("HOME"); !ok { |
| 102 | + u, err := user.Current() |
| 103 | + if err != nil { |
| 104 | + return nil, fmt.Errorf("could not get current user: %w", err) |
| 105 | + } |
| 106 | + p := path.Join(u.HomeDir, clientcmd.RecommendedHomeDir, clientcmd.RecommendedFileName) |
| 107 | + loadingRules.Precedence = append(loadingRules.Precedence, p) |
| 108 | + } |
| 109 | + return loadConfig(loadingRules) |
| 110 | +} |
| 111 | + |
| 112 | +func loadConfig(loader clientcmd.ClientConfigLoader) (*rest.Config, error) { |
| 113 | + return clientcmd.NewNonInteractiveDeferredLoadingClientConfig(loader, nil).ClientConfig() //nolint:wrapcheck |
| 114 | +} |
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