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dex/storage/kubernetes/client.go
Eng Zer Jun f0186ff265
refactor: move from io/ioutil to io and os package
The io/ioutil package has been deprecated as of Go 1.16, see
https://golang.org/doc/go1.16#ioutil. This commit replaces the existing
io/ioutil functions with their new definitions in io and os packages.

Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>
2021-09-17 14:12:39 +08:00

543 lines
15 KiB
Go

package kubernetes
import (
"bytes"
"context"
"crypto/tls"
"crypto/x509"
"encoding/base32"
"encoding/base64"
"encoding/json"
"errors"
"fmt"
"hash"
"hash/fnv"
"io"
"net"
"net/http"
"os"
"path"
"strconv"
"strings"
"time"
"github.com/Masterminds/semver"
"github.com/ghodss/yaml"
"golang.org/x/net/http2"
"github.com/dexidp/dex/pkg/log"
"github.com/dexidp/dex/storage"
"github.com/dexidp/dex/storage/kubernetes/k8sapi"
)
type client struct {
client *http.Client
baseURL string
namespace string
logger log.Logger
// Hash function to map IDs (which could span a large range) to Kubernetes names.
// While this is not currently upgradable, it could be in the future.
//
// The default hash is a non-cryptographic hash, because cryptographic hashes
// always produce sums too long to fit into a Kubernetes name. Because of this,
// gets, updates, and deletes are _always_ checked for collisions.
hash func() hash.Hash
// API version of the oidc resources. For example "oidc.coreos.com". This is
// currently not configurable, but could be in the future.
apiVersion string
// API version of the custom resource definitions.
// Different Kubernetes version requires to create CRD in certain API. It will be discovered automatically on
// storage opening.
crdAPIVersion string
// This is called once the client's Close method is called to signal goroutines,
// such as the one creating third party resources, to stop.
cancel context.CancelFunc
}
// idToName maps an arbitrary ID, such as an email or client ID to a Kubernetes object name.
func (cli *client) idToName(s string) string {
return idToName(s, cli.hash)
}
// offlineTokenName maps two arbitrary IDs, to a single Kubernetes object name.
// This is used when more than one field is used to uniquely identify the object.
func (cli *client) offlineTokenName(userID string, connID string) string {
return offlineTokenName(userID, connID, cli.hash)
}
// Kubernetes names must match the regexp '[a-z0-9]([-a-z0-9]*[a-z0-9])?'.
var encoding = base32.NewEncoding("abcdefghijklmnopqrstuvwxyz234567")
func idToName(s string, h func() hash.Hash) string {
return strings.TrimRight(encoding.EncodeToString(h().Sum([]byte(s))), "=")
}
func offlineTokenName(userID string, connID string, h func() hash.Hash) string {
hash := h()
hash.Write([]byte(userID))
hash.Write([]byte(connID))
return strings.TrimRight(encoding.EncodeToString(hash.Sum(nil)), "=")
}
func (cli *client) urlFor(apiVersion, namespace, resource, name string) string {
basePath := "apis/"
if apiVersion == "v1" {
basePath = "api/"
}
var p string
if namespace != "" {
p = path.Join(basePath, apiVersion, "namespaces", namespace, resource, name)
} else {
p = path.Join(basePath, apiVersion, resource, name)
}
if strings.HasSuffix(cli.baseURL, "/") {
return cli.baseURL + p
}
return cli.baseURL + "/" + p
}
// Define an error interface so we can get at the underlying status code if it's
// absolutely necessary. For instance when we need to see if an error indicates
// a resource already exists.
type httpError interface {
StatusCode() int
}
var _ httpError = (*httpErr)(nil)
type httpErr struct {
method string
url string
status int
body []byte
}
func (e *httpErr) StatusCode() int {
return e.status
}
func (e *httpErr) Error() string {
return fmt.Sprintf("%s %s %s: response from server \"%s\"", e.method, e.url, http.StatusText(e.status), bytes.TrimSpace(e.body))
}
func checkHTTPErr(r *http.Response, validStatusCodes ...int) error {
for _, status := range validStatusCodes {
if r.StatusCode == status {
return nil
}
}
body, err := io.ReadAll(io.LimitReader(r.Body, 2<<15)) // 64 KiB
if err != nil {
return fmt.Errorf("read response body: %v", err)
}
// Check this case after we read the body so the connection can be reused.
if r.StatusCode == http.StatusNotFound {
return storage.ErrNotFound
}
if r.Request.Method == http.MethodPost && r.StatusCode == http.StatusConflict {
return storage.ErrAlreadyExists
}
var url, method string
if r.Request != nil {
method = r.Request.Method
url = r.Request.URL.String()
}
return &httpErr{method, url, r.StatusCode, body}
}
// Close the response body. The initial request is drained so the connection can
// be reused.
func closeResp(r *http.Response) {
io.Copy(io.Discard, r.Body)
r.Body.Close()
}
func (cli *client) get(resource, name string, v interface{}) error {
return cli.getResource(cli.apiVersion, cli.namespace, resource, name, v)
}
func (cli *client) getResource(apiVersion, namespace, resource, name string, v interface{}) error {
url := cli.urlFor(apiVersion, namespace, resource, name)
resp, err := cli.client.Get(url)
if err != nil {
return err
}
defer closeResp(resp)
if err := checkHTTPErr(resp, http.StatusOK); err != nil {
return err
}
return json.NewDecoder(resp.Body).Decode(v)
}
func (cli *client) list(resource string, v interface{}) error {
return cli.get(resource, "", v)
}
func (cli *client) post(resource string, v interface{}) error {
return cli.postResource(cli.apiVersion, cli.namespace, resource, v)
}
func (cli *client) postResource(apiVersion, namespace, resource string, v interface{}) error {
body, err := json.Marshal(v)
if err != nil {
return fmt.Errorf("marshal object: %v", err)
}
url := cli.urlFor(apiVersion, namespace, resource, "")
resp, err := cli.client.Post(url, "application/json", bytes.NewReader(body))
if err != nil {
return err
}
defer closeResp(resp)
return checkHTTPErr(resp, http.StatusCreated)
}
func (cli *client) detectKubernetesVersion() error {
var version struct{ GitVersion string }
url := cli.baseURL + "/version"
resp, err := cli.client.Get(url)
if err != nil {
return err
}
defer closeResp(resp)
if err := checkHTTPErr(resp, http.StatusOK); err != nil {
return err
}
if err := json.NewDecoder(resp.Body).Decode(&version); err != nil {
return err
}
clusterVersion, err := semver.NewVersion(version.GitVersion)
if err != nil {
cli.logger.Warnf("cannot detect Kubernetes version (%s): %v", clusterVersion, err)
return nil
}
if clusterVersion.LessThan(semver.MustParse("v1.16.0")) {
cli.crdAPIVersion = legacyCRDAPIVersion
}
return nil
}
func (cli *client) delete(resource, name string) error {
url := cli.urlFor(cli.apiVersion, cli.namespace, resource, name)
req, err := http.NewRequest("DELETE", url, nil)
if err != nil {
return fmt.Errorf("create delete request: %v", err)
}
resp, err := cli.client.Do(req)
if err != nil {
return fmt.Errorf("delete request: %v", err)
}
defer closeResp(resp)
return checkHTTPErr(resp, http.StatusOK)
}
func (cli *client) deleteAll(resource string) error {
var list struct {
k8sapi.TypeMeta `json:",inline"`
k8sapi.ListMeta `json:"metadata,omitempty"`
Items []struct {
k8sapi.TypeMeta `json:",inline"`
k8sapi.ObjectMeta `json:"metadata,omitempty"`
} `json:"items"`
}
if err := cli.list(resource, &list); err != nil {
return err
}
for _, item := range list.Items {
if err := cli.delete(resource, item.Name); err != nil {
return err
}
}
return nil
}
func (cli *client) put(resource, name string, v interface{}) error {
body, err := json.Marshal(v)
if err != nil {
return fmt.Errorf("marshal object: %v", err)
}
url := cli.urlFor(cli.apiVersion, cli.namespace, resource, name)
req, err := http.NewRequest("PUT", url, bytes.NewReader(body))
if err != nil {
return fmt.Errorf("create patch request: %v", err)
}
req.Header.Set("Content-Length", strconv.Itoa(len(body)))
resp, err := cli.client.Do(req)
if err != nil {
return fmt.Errorf("patch request: %v", err)
}
defer closeResp(resp)
return checkHTTPErr(resp, http.StatusOK)
}
// Copied from https://github.com/gtank/cryptopasta
func defaultTLSConfig() *tls.Config {
return &tls.Config{
// Avoids most of the memorably-named TLS attacks
MinVersion: tls.VersionTLS12,
// Causes servers to use Go's default ciphersuite preferences,
// which are tuned to avoid attacks. Does nothing on clients.
PreferServerCipherSuites: true,
// Only use curves which have constant-time implementations
CurvePreferences: []tls.CurveID{
tls.CurveP256,
},
}
}
func newClient(cluster k8sapi.Cluster, user k8sapi.AuthInfo, namespace string, logger log.Logger, inCluster bool) (*client, error) {
tlsConfig := defaultTLSConfig()
data := func(b string, file string) ([]byte, error) {
if b != "" {
return base64.StdEncoding.DecodeString(b)
}
if file == "" {
return nil, nil
}
return os.ReadFile(file)
}
if caData, err := data(cluster.CertificateAuthorityData, cluster.CertificateAuthority); err != nil {
return nil, err
} else if caData != nil {
tlsConfig.RootCAs = x509.NewCertPool()
if !tlsConfig.RootCAs.AppendCertsFromPEM(caData) {
return nil, fmt.Errorf("no certificate data found: %v", err)
}
}
clientCert, err := data(user.ClientCertificateData, user.ClientCertificate)
if err != nil {
return nil, err
}
clientKey, err := data(user.ClientKeyData, user.ClientKey)
if err != nil {
return nil, err
}
if clientCert != nil && clientKey != nil {
cert, err := tls.X509KeyPair(clientCert, clientKey)
if err != nil {
return nil, fmt.Errorf("failed to load client cert: %v", err)
}
tlsConfig.Certificates = []tls.Certificate{cert}
}
var t http.RoundTripper
httpTransport := &http.Transport{
Proxy: http.ProxyFromEnvironment,
DialContext: (&net.Dialer{
Timeout: 30 * time.Second,
KeepAlive: 30 * time.Second,
}).DialContext,
TLSClientConfig: tlsConfig,
TLSHandshakeTimeout: 10 * time.Second,
ExpectContinueTimeout: 1 * time.Second,
}
// Since we set a custom TLS client config we have to explicitly
// enable HTTP/2.
//
// https://github.com/golang/go/blob/go1.7.4/src/net/http/transport.go#L200-L206
if err := http2.ConfigureTransport(httpTransport); err != nil {
return nil, err
}
t = wrapRoundTripper(httpTransport, user, inCluster)
apiVersion := "dex.coreos.com/v1"
logger.Infof("kubernetes client apiVersion = %s", apiVersion)
return &client{
client: &http.Client{
Transport: t,
Timeout: 15 * time.Second,
},
baseURL: cluster.Server,
hash: func() hash.Hash { return fnv.New64() },
namespace: namespace,
apiVersion: apiVersion,
crdAPIVersion: crdAPIVersion,
logger: logger,
}, nil
}
func loadKubeConfig(kubeConfigPath string) (cluster k8sapi.Cluster, user k8sapi.AuthInfo, namespace string, err error) {
data, err := os.ReadFile(kubeConfigPath)
if err != nil {
err = fmt.Errorf("read %s: %v", kubeConfigPath, err)
return
}
var c k8sapi.Config
if err = yaml.Unmarshal(data, &c); err != nil {
err = fmt.Errorf("unmarshal %s: %v", kubeConfigPath, err)
return
}
cluster, user, namespace, err = currentContext(&c)
if namespace == "" {
namespace = "default"
}
return
}
func namespaceFromServiceAccountJWT(s string) (string, error) {
// The service account token is just a JWT. Parse it as such.
parts := strings.Split(s, ".")
if len(parts) < 2 {
// It's extremely important we don't log the actual service account token.
return "", fmt.Errorf("malformed service account token: expected 3 parts got %d", len(parts))
}
payload, err := base64.RawURLEncoding.DecodeString(parts[1])
if err != nil {
return "", fmt.Errorf("malformed service account token: %v", err)
}
var data struct {
// The claim Kubernetes uses to identify which namespace a service account belongs to.
//
// See: https://github.com/kubernetes/kubernetes/blob/v1.4.3/pkg/serviceaccount/jwt.go#L42
Namespace string `json:"kubernetes.io/serviceaccount/namespace"`
}
if err := json.Unmarshal(payload, &data); err != nil {
return "", fmt.Errorf("malformed service account token: %v", err)
}
if data.Namespace == "" {
return "", errors.New(`jwt claim "kubernetes.io/serviceaccount/namespace" not found`)
}
return data.Namespace, nil
}
func namespaceFromFile(path string) (string, error) {
data, err := os.ReadFile(path)
if err != nil {
return "", err
}
return string(data), nil
}
func getInClusterConfigNamespace(token, namespaceENV, namespacePath string) (string, error) {
namespace := os.Getenv(namespaceENV)
if namespace != "" {
return namespace, nil
}
namespace, err := namespaceFromServiceAccountJWT(token)
if err == nil {
return namespace, nil
}
err = fmt.Errorf("inspect service account token: %v", err)
namespace, fileErr := namespaceFromFile(namespacePath)
if fileErr == nil {
return namespace, nil
}
return "", fmt.Errorf("%v: trying to get namespace from file: %v", err, fileErr)
}
func inClusterConfig() (k8sapi.Cluster, k8sapi.AuthInfo, string, error) {
const (
serviceAccountPath = "/var/run/secrets/kubernetes.io/serviceaccount/"
serviceAccountTokenPath = serviceAccountPath + "token"
serviceAccountCAPath = serviceAccountPath + "ca.crt"
serviceAccountNamespacePath = serviceAccountPath + "namespace"
kubernetesServiceHostENV = "KUBERNETES_SERVICE_HOST"
kubernetesServicePortENV = "KUBERNETES_SERVICE_PORT"
kubernetesPodNamespaceENV = "KUBERNETES_POD_NAMESPACE"
)
host, port := os.Getenv(kubernetesServiceHostENV), os.Getenv(kubernetesServicePortENV)
if len(host) == 0 || len(port) == 0 {
return k8sapi.Cluster{}, k8sapi.AuthInfo{}, "", fmt.Errorf(
"unable to load in-cluster configuration, %s and %s must be defined",
kubernetesServiceHostENV,
kubernetesServicePortENV,
)
}
// we need to wrap IPv6 addresses in square brackets
// IPv4 also works with square brackets
host = "[" + host + "]"
cluster := k8sapi.Cluster{
Server: "https://" + host + ":" + port,
CertificateAuthority: serviceAccountCAPath,
}
token, err := os.ReadFile(serviceAccountTokenPath)
if err != nil {
return cluster, k8sapi.AuthInfo{}, "", err
}
user := k8sapi.AuthInfo{Token: string(token)}
namespace, err := getInClusterConfigNamespace(user.Token, kubernetesPodNamespaceENV, serviceAccountNamespacePath)
if err != nil {
return cluster, user, "", err
}
return cluster, user, namespace, nil
}
func currentContext(config *k8sapi.Config) (cluster k8sapi.Cluster, user k8sapi.AuthInfo, ns string, err error) {
if config.CurrentContext == "" {
if len(config.Contexts) == 1 {
config.CurrentContext = config.Contexts[0].Name
} else {
return cluster, user, "", errors.New("kubeconfig has no current context")
}
}
k8sContext, ok := func() (k8sapi.Context, bool) {
for _, namedContext := range config.Contexts {
if namedContext.Name == config.CurrentContext {
return namedContext.Context, true
}
}
return k8sapi.Context{}, false
}()
if !ok {
return cluster, user, "", fmt.Errorf("no context named %q found", config.CurrentContext)
}
cluster, ok = func() (k8sapi.Cluster, bool) {
for _, namedCluster := range config.Clusters {
if namedCluster.Name == k8sContext.Cluster {
return namedCluster.Cluster, true
}
}
return k8sapi.Cluster{}, false
}()
if !ok {
return cluster, user, "", fmt.Errorf("no cluster named %q found", k8sContext.Cluster)
}
user, ok = func() (k8sapi.AuthInfo, bool) {
for _, namedAuthInfo := range config.AuthInfos {
if namedAuthInfo.Name == k8sContext.AuthInfo {
return namedAuthInfo.AuthInfo, true
}
}
return k8sapi.AuthInfo{}, false
}()
if !ok {
return cluster, user, "", fmt.Errorf("no user named %q found", k8sContext.AuthInfo)
}
return cluster, user, k8sContext.Namespace, nil
}