make enforcement configurable with default to false

auth/token_issuer.go

@@ -1,26 +1,30 @@
 package auth
 
 import (
+	"fmt"
 	"net/http"
 
 	"encoding/json"
+	"strings"
+	"time"
+
 	goldap "github.com/go-ldap/ldap"
 	"github.com/golang/glog"
 	"github.com/prometheus/client_golang/prometheus"
+	"github.com/proofpoint/kubernetes-ldap/client"
 	"github.com/proofpoint/kubernetes-ldap/ldap"
 	"github.com/proofpoint/kubernetes-ldap/token"
-	"strings"
-	"time"
 )
 
 // LDAPTokenIssuer issues cryptographically secure tokens after authenticating the
 // user against a backing LDAP directory.
 type LDAPTokenIssuer struct {
-	LDAPServer        string
-	LDAPAuthenticator ldap.Authenticator
-	TokenSigner       token.Signer
-	TTL               time.Duration
-	UsernameAttribute string
+	LDAPServer            string
+	LDAPAuthenticator     ldap.Authenticator
+	TokenSigner           token.Signer
+	TTL                   time.Duration
+	UsernameAttribute     string
+	EnforceClientVersions bool
 }
 
 var (
@@ -75,6 +79,24 @@ func (lti *LDAPTokenIssuer) ServeHTTP(resp http.ResponseWriter, req *http.Reques
 		return
 	}
 
+	if lti.EnforceClientVersions {
+		pluginVersion := req.Header.Get("x-pfpt-k8sldapctl-version")
+		kubectlVersion := req.Header.Get("x-pfpt-kubectl-version")
+
+		if pluginVersion == "" || kubectlVersion == "" {
+			resp.WriteHeader(http.StatusBadRequest)
+			resp.Write([]byte(fmt.Sprintf("\nError: you are using an old version of k8sldapctl plugin. Please upgrade to minimum of %q", client.MinimumPluginVersion)))
+			return
+		}
+
+		err := client.Validate(pluginVersion, kubectlVersion)
+		if err != nil {
+			resp.WriteHeader(http.StatusBadRequest)
+			resp.Write([]byte(fmt.Sprintf("\nError: %s", err.Error())))
+			return
+		}
+	}
+
 	// Authenticate the user via LDAP
 	ldapEntry, err := lti.LDAPAuthenticator.Authenticate(user, password)
 	if err != nil {

cmd/serve.go

@@ -21,6 +21,8 @@ import (
 	"net/http"
 	"os"
 
+	"time"
+
 	"github.com/golang/glog"
 	"github.com/mitchellh/go-homedir"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
@@ -30,7 +32,6 @@ import (
 	"github.com/spf13/cast"
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
-	"time"
 )
 
 //different flags supported by serve command
@@ -58,6 +59,8 @@ var (
 
 	keypairDir string
 	genKeypair bool
+
+	enforceClientVersions bool
 )
 
 // RootCmd represents the serve command
@@ -120,6 +123,8 @@ func init() {
 	RootCmd.Flags().DurationVar(&tokenTtl, "token-ttl", 24*time.Hour, "TTL for the token")
 	RootCmd.Flags().BoolVar(&genKeypair, "gen-keypair", false, "generate new keypair while starting server")
 
+	RootCmd.Flags().BoolVar(&enforceClientVersions, "enforce-client-versions", false, "if true enforces minimum version of k8sldapctl and kubectl")
+
 	viper.BindPFlags(RootCmd.Flags())
 	flag.CommandLine.Parse([]string{})
 }
@@ -233,10 +238,11 @@ func serve() error {
 	webhook := auth.NewTokenWebhook(tokenVerifier)
 
 	ldapTokenIssuer := &auth.LDAPTokenIssuer{
-		LDAPAuthenticator: ldapClient,
-		TokenSigner:       tokenSigner,
-		TTL:               tokenTtl,
-		UsernameAttribute: usernameAttribute,
+		LDAPAuthenticator:     ldapClient,
+		TokenSigner:           tokenSigner,
+		TTL:                   tokenTtl,
+		UsernameAttribute:     usernameAttribute,
+		EnforceClientVersions: enforceClientVersions,
 	}
 
 	// Endpoint for authenticating with token