K8s: remove standalone authenticator in favor of providing one through the factory (#85901)

contribute/ISSUE_TRIAGE.md

@@ -180,7 +180,7 @@ If it's not perfectly clear that it's an actual bug, quickly try to reproduce it
 
 1. Add a comment describing detailed steps for how to reproduce it, if applicable.
 2. Label the issue `type/bug` and at least one `area/*` or `datasource/*` label.
-3. If you know that maintainers wont be able to put any resources into it for some time then label the issue with `help wanted` and optionally `beginner friendly` together with pointers on which code to update to fix the bug. This should signal to the community that we would appreciate any help we can get to resolve this.
+3. If you know that maintainers won't be able to put any resources into it for some time then label the issue with `help wanted` and optionally `beginner friendly` together with pointers on which code to update to fix the bug. This should signal to the community that we would appreciate any help we can get to resolve this.
 4. Move on to [prioritizing the issue](#4-prioritization-of-issues).
 
 **It can't be reproduced:**

pkg/cmd/grafana/apiserver/auth/tokenAuthenticator.go

@@ -1,71 +0,0 @@
-package auth
-
-import (
-	"net/http"
-	"strings"
-
-	"github.com/grafana/authlib/authn"
-	"k8s.io/apiserver/pkg/authentication/authenticator"
-	"k8s.io/apiserver/pkg/authentication/user"
-)
-
-const (
-	headerKeyAccessToken = "X-Access-Token"
-	headerKeyGrafanaID   = "X-Grafana-Id"
-
-	extraKeyAccessToken = "access-token"
-	extraKeyGrafanaID   = "id-token"
-	extraKeyGLSA        = "glsa"
-)
-
-func NewAccessTokenAuthenticator(config *authn.IDVerifierConfig) authenticator.RequestFunc {
-	verifier := authn.NewVerifier[CustomClaims](authn.IDVerifierConfig{
-		SigningKeysURL:   config.SigningKeysURL,
-		AllowedAudiences: config.AllowedAudiences,
-	})
-	return getAccessTokenAuthenticatorFunc(&TokenValidator{verifier})
-}
-
-func getAccessTokenAuthenticatorFunc(validator *TokenValidator) authenticator.RequestFunc {
-	return func(req *http.Request) (*authenticator.Response, bool, error) {
-		accessToken := req.Header.Get(headerKeyAccessToken)
-		if accessToken == "" {
-			return nil, false, nil
-		}
-
-		// While the authn token system is in development, we can temporarily use
-		// service account tokens.  Note this does not grant any real permissions/verification,
-		// it simply allows forwarding the token to the next request
-		if strings.HasPrefix(accessToken, "glsa_") {
-			return &authenticator.Response{
-				Audiences: authenticator.Audiences([]string{}),
-				User: &user.DefaultInfo{
-					Name:   "glsa-forwarding-request",
-					UID:    "",
-					Groups: []string{},
-					Extra: map[string][]string{
-						extraKeyGLSA: {accessToken},
-					},
-				},
-			}, true, nil
-		}
-
-		result, err := validator.Validate(req.Context(), accessToken)
-		if err != nil {
-			return nil, false, err
-		}
-
-		return &authenticator.Response{
-			Audiences: authenticator.Audiences(result.Claims.Audience),
-			User: &user.DefaultInfo{
-				Name:   result.Subject,
-				UID:    "",
-				Groups: []string{},
-				Extra: map[string][]string{
-					extraKeyAccessToken: {accessToken},
-					extraKeyGrafanaID:   {req.Header.Get("X-Grafana-Id")}, // this may exist if starting with a user
-				},
-			},
-		}, true, nil
-	}
-}

pkg/cmd/grafana/apiserver/auth/util.go

@@ -1,57 +0,0 @@
-package auth
-
-import (
-	"context"
-	"fmt"
-
-	"k8s.io/apiserver/pkg/authentication/authenticator"
-	"k8s.io/apiserver/pkg/authentication/request/union"
-	"k8s.io/apiserver/pkg/endpoints/request"
-)
-
-func AppendToAuthenticators(newAuthenticator authenticator.RequestFunc, authRequestHandlers ...authenticator.Request) authenticator.Request {
-	handlers := append([]authenticator.Request{newAuthenticator}, authRequestHandlers...)
-	return union.New(handlers...)
-}
-
-// Get tokens that can be forwarded to the next service
-// In the future this will need to create new tokens with a new audience
-func GetIDForwardingAuthHeaders(ctx context.Context) (map[string]string, error) {
-	user, ok := request.UserFrom(ctx)
-	if !ok {
-		return nil, fmt.Errorf("missing user")
-	}
-
-	getter := func(key string) string {
-		vals, ok := user.GetExtra()[key]
-		if ok && len(vals) == 1 {
-			return vals[0]
-		}
-		return ""
-	}
-
-	token := getter(extraKeyGLSA)
-	if token != "" {
-		// Service account tokens get forwarded as auth tokens
-		// this lets us keep testing the workflows while the ID token system is in dev
-		return map[string]string{
-			"Authorization": "Bearer " + token,
-		}, nil
-	}
-
-	accessToken := getter(extraKeyAccessToken)
-	if accessToken == "" {
-		return nil, fmt.Errorf("missing access token in user info")
-	}
-
-	idToken := getter(extraKeyGrafanaID)
-	if idToken != "" {
-		return map[string]string{
-			headerKeyAccessToken: accessToken,
-			headerKeyGrafanaID:   idToken,
-		}, nil
-	}
-	return map[string]string{
-		headerKeyAccessToken: accessToken,
-	}, nil
-}

pkg/cmd/grafana/apiserver/auth/validator.go

@@ -1,24 +0,0 @@
-package auth
-
-import (
-	"context"
-
-	"github.com/grafana/authlib/authn"
-)
-
-type CustomClaims struct {
-	// Nothing yet
-}
-
-type TokenValidator struct {
-	verifier authn.Verifier[CustomClaims]
-}
-
-func (v *TokenValidator) Validate(ctx context.Context, token string) (*authn.Claims[CustomClaims], error) {
-	customClaims, err := v.verifier.Verify(ctx, token)
-	if err != nil {
-		return nil, err
-	}
-
-	return customClaims, nil
-}

pkg/cmd/grafana/apiserver/server.go

@@ -14,7 +14,6 @@ import (
 	netutils "k8s.io/utils/net"
 
 	"github.com/grafana/grafana/pkg/apiserver/builder"
-	"github.com/grafana/grafana/pkg/cmd/grafana/apiserver/auth"
 	"github.com/grafana/grafana/pkg/infra/log"
 	"github.com/grafana/grafana/pkg/infra/tracing"
 	grafanaAPIServer "github.com/grafana/grafana/pkg/services/apiserver"
@@ -101,12 +100,11 @@ func (o *APIServerOptions) Config() (*genericapiserver.RecommendedConfig, error)
 		return nil, fmt.Errorf("failed to apply options to server config: %w", err)
 	}
 
-	// When the ID signing key exists, configure access-token support
-	if len(o.Options.AuthnOptions.IDVerifierConfig.SigningKeysURL) > 0 {
-		serverConfig.Authentication.Authenticator = auth.AppendToAuthenticators(
-			auth.NewAccessTokenAuthenticator(o.Options.AuthnOptions.IDVerifierConfig),
-			serverConfig.Authentication.Authenticator,
-		)
+	if factoryOptions := o.factory.GetOptions(); factoryOptions != nil {
+		err := factoryOptions.ApplyTo(serverConfig)
+		if err != nil {
+			return nil, fmt.Errorf("factory's applyTo func failed: %s", err.Error())
+		}
 	}
 
 	serverConfig.DisabledPostStartHooks = serverConfig.DisabledPostStartHooks.Insert("generic-apiserver-start-informers")

pkg/services/apiserver/options/options.go

@@ -12,6 +12,7 @@ import (
 
 type OptionsProvider interface {
 	AddFlags(fs *pflag.FlagSet)
+	ApplyTo(config *genericapiserver.RecommendedConfig) error
 	ValidateOptions() []error
 }
 

pkg/services/apiserver/standalone/factory.go

@@ -8,6 +8,7 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime/schema"
+	genericapiserver "k8s.io/apiserver/pkg/server"
 
 	"github.com/grafana/grafana/pkg/apis/datasource/v0alpha1"
 	"github.com/grafana/grafana/pkg/apiserver/builder"
@@ -62,6 +63,10 @@ func (p *DummyAPIFactory) GetEnabled(runtime []RuntimeConfig) ([]schema.GroupVer
 	return gv, nil
 }
 
+func (p *DummyAPIFactory) ApplyTo(config *genericapiserver.RecommendedConfig) error {
+	return nil
+}
+
 func (p *DummyAPIFactory) MakeAPIServer(tracer tracing.Tracer, gv schema.GroupVersion) (builder.APIGroupBuilder, error) {
 	if gv.Version != "v0alpha1" {
 		return nil, fmt.Errorf("only alpha supported now")

pkg/services/apiserver/standalone/options/authn.go

@@ -1,9 +0,0 @@
-package options
-
-import "github.com/grafana/authlib/authn"
-
-func NewAuthnOptions() *AuthnOptions {
-	return &AuthnOptions{
-		IDVerifierConfig: &authn.IDVerifierConfig{},
-	}
-}

pkg/services/apiserver/standalone/options/options.go

@@ -7,8 +7,6 @@ import (
 	"k8s.io/apimachinery/pkg/runtime"
 	genericapiserver "k8s.io/apiserver/pkg/server"
 	genericoptions "k8s.io/apiserver/pkg/server/options"
-
-	"github.com/grafana/authlib/authn"
 )
 
 type Options struct {
@@ -17,7 +15,6 @@ type Options struct {
 	RecommendedOptions *genericoptions.RecommendedOptions
 	TracingOptions     *TracingOptions
 	MetricsOptions     *MetricsOptions
-	AuthnOptions       *AuthnOptions
 }
 
 func New(logger log.Logger, codec runtime.Codec) *Options {
@@ -27,7 +24,6 @@ func New(logger log.Logger, codec runtime.Codec) *Options {
 		RecommendedOptions: options.NewRecommendedOptions(codec),
 		TracingOptions:     NewTracingOptions(logger),
 		MetricsOptions:     NewMetrcicsOptions(logger),
-		AuthnOptions:       NewAuthnOptions(),
 	}
 }
 
@@ -37,7 +33,6 @@ func (o *Options) AddFlags(fs *pflag.FlagSet) {
 	o.RecommendedOptions.AddFlags(fs)
 	o.TracingOptions.AddFlags(fs)
 	o.MetricsOptions.AddFlags(fs)
-	o.AuthnOptions.AddFlags(fs)
 }
 
 func (o *Options) Validate() []error {
@@ -162,15 +157,3 @@ func (o *Options) ApplyTo(serverConfig *genericapiserver.RecommendedConfig) erro
 
 	return nil
 }
-
-type AuthnOptions struct {
-	IDVerifierConfig *authn.IDVerifierConfig
-}
-
-func (authOpts *AuthnOptions) AddFlags(fs *pflag.FlagSet) {
-	prefix := "grafana.authn"
-	fs.StringVar(&authOpts.IDVerifierConfig.SigningKeysURL, prefix+".signing-keys-url", "", "URL to jwks endpoint")
-
-	audience := fs.StringSlice(prefix+".allowed-audiences", []string{}, "Specifies a comma-separated list of allowed audiences.")
-	authOpts.IDVerifierConfig.AllowedAudiences = *audience
-}