cleanup headers (#5408)

* cleanup headers

* return issuer format errors

* go mod

authorize/evaluator/evaluator.go

@@ -295,12 +295,7 @@ func (e *Evaluator) evaluatePolicy(ctx context.Context, req *Request) (*PolicyRe
 }
 
 func (e *Evaluator) evaluateHeaders(ctx context.Context, req *Request) (*HeadersResponse, error) {
-	headersReq, err := NewHeadersRequestFromPolicy(req.Policy, req.HTTP)
-	if err != nil {
-		return nil, err
-	}
-	headersReq.Session = req.Session
-	res, err := e.headersEvaluators.Evaluate(ctx, headersReq)
+	res, err := e.headersEvaluators.Evaluate(ctx, req)
 	if err != nil {
 		return nil, err
 	}

authorize/evaluator/headers_evaluator.go

@@ -2,65 +2,15 @@ package evaluator
 
 import (
 	"context"
-	"fmt"
 	"net/http"
 	"time"
 
-	envoy_config_cluster_v3 "github.com/envoyproxy/go-control-plane/envoy/config/cluster/v3"
 	"github.com/open-policy-agent/opa/rego"
 
 	"github.com/pomerium/pomerium/authorize/internal/store"
-	"github.com/pomerium/pomerium/config"
 	"github.com/pomerium/pomerium/internal/telemetry/trace"
 )
 
-// HeadersRequest is the input to the headers.rego script.
-type HeadersRequest struct {
-	EnableGoogleCloudServerlessAuthentication bool                  `json:"enable_google_cloud_serverless_authentication"`
-	EnableRoutingKey                          bool                  `json:"enable_routing_key"`
-	Issuer                                    string                `json:"issuer"`
-	Audience                                  string                `json:"audience"`
-	KubernetesServiceAccountToken             string                `json:"kubernetes_service_account_token"`
-	ToAudience                                string                `json:"to_audience"`
-	Session                                   RequestSession        `json:"session"`
-	ClientCertificate                         ClientCertificateInfo `json:"client_certificate"`
-	SetRequestHeaders                         map[string]string     `json:"set_request_headers"`
-}
-
-// NewHeadersRequestFromPolicy creates a new HeadersRequest from a policy.
-func NewHeadersRequestFromPolicy(policy *config.Policy, http RequestHTTP) (*HeadersRequest, error) {
-	input := new(HeadersRequest)
-	input.Audience = http.Hostname
-	var issuerFormat string
-	if policy != nil {
-		issuerFormat = policy.JWTIssuerFormat
-	}
-	switch issuerFormat {
-	case "", "hostOnly":
-		input.Issuer = http.Hostname
-	case "uri":
-		input.Issuer = fmt.Sprintf("https://%s/", http.Hostname)
-	default:
-		return nil, fmt.Errorf("invalid issuer format: %q", policy.JWTIssuerFormat)
-	}
-	if policy != nil {
-		input.EnableGoogleCloudServerlessAuthentication = policy.EnableGoogleCloudServerlessAuthentication
-		input.EnableRoutingKey = policy.EnvoyOpts.GetLbPolicy() == envoy_config_cluster_v3.Cluster_RING_HASH ||
-			policy.EnvoyOpts.GetLbPolicy() == envoy_config_cluster_v3.Cluster_MAGLEV
-		var err error
-		input.KubernetesServiceAccountToken, err = policy.GetKubernetesServiceAccountToken()
-		if err != nil {
-			return nil, err
-		}
-		for _, wu := range policy.To {
-			input.ToAudience = "https://" + wu.URL.Hostname()
-		}
-		input.ClientCertificate = http.ClientCertificate
-		input.SetRequestHeaders = policy.SetRequestHeaders
-	}
-	return input, nil
-}
-
 // HeadersResponse is the output from the headers.rego script.
 type HeadersResponse struct {
 	Headers http.Header
@@ -79,7 +29,7 @@ func NewHeadersEvaluator(store *store.Store) *HeadersEvaluator {
 }
 
 // Evaluate evaluates the headers.rego script.
-func (e *HeadersEvaluator) Evaluate(ctx context.Context, req *HeadersRequest, options ...rego.EvalOption) (*HeadersResponse, error) {
+func (e *HeadersEvaluator) Evaluate(ctx context.Context, req *Request, options ...rego.EvalOption) (*HeadersResponse, error) {
 	ctx, span := trace.StartSpan(ctx, "authorize.HeadersEvaluator.Evaluate")
 	defer span.End()
 

authorize/evaluator/headers_evaluator_evaluation.go

@@ -12,6 +12,7 @@ import (
 	"strings"
 	"time"
 
+	envoy_config_cluster_v3 "github.com/envoyproxy/go-control-plane/envoy/config/cluster/v3"
 	"github.com/go-jose/go-jose/v3"
 	"github.com/google/uuid"
 	"google.golang.org/protobuf/types/known/structpb"
@@ -26,7 +27,7 @@ import (
 // A headersEvaluatorEvaluation is a single evaluation of the headers evaluator.
 type headersEvaluatorEvaluation struct {
 	evaluator *HeadersEvaluator
-	request   *HeadersRequest
+	request   *Request
 	response  *HeadersResponse
 	now       time.Time
 
@@ -50,7 +51,7 @@ type headersEvaluatorEvaluation struct {
 	cachedSignedJWT string
 }
 
-func newHeadersEvaluatorEvaluation(evaluator *HeadersEvaluator, request *HeadersRequest, now time.Time) *headersEvaluatorEvaluation {
+func newHeadersEvaluatorEvaluation(evaluator *HeadersEvaluator, request *Request, now time.Time) *headersEvaluatorEvaluation {
 	return &headersEvaluatorEvaluation{
 		evaluator: evaluator,
 		request:   request,
@@ -60,16 +61,19 @@ func newHeadersEvaluatorEvaluation(evaluator *HeadersEvaluator, request *Headers
 }
 
 func (e *headersEvaluatorEvaluation) execute(ctx context.Context) (*HeadersResponse, error) {
-	e.fillHeaders(ctx)
-	return e.response, nil
+	err := e.fillHeaders(ctx)
+	return e.response, err
 }
 
 func (e *headersEvaluatorEvaluation) fillJWTAssertionHeader(ctx context.Context) {
 	e.response.Headers.Add("x-pomerium-jwt-assertion", e.getSignedJWT(ctx))
 }
 
-func (e *headersEvaluatorEvaluation) fillJWTClaimHeaders(ctx context.Context) {
-	claims := e.getJWTPayload(ctx)
+func (e *headersEvaluatorEvaluation) fillJWTClaimHeaders(ctx context.Context) error {
+	claims, err := e.getJWTPayload(ctx)
+	if err != nil {
+		return err
+	}
 	for headerName, claimKey := range e.evaluator.store.GetJWTClaimHeaders() {
 		claim, ok := claims[claimKey]
 		if !ok {
@@ -78,14 +82,20 @@ func (e *headersEvaluatorEvaluation) fillJWTClaimHeaders(ctx context.Context) {
 		}
 		e.response.Headers.Add(headerName, getHeaderStringValue(claim))
 	}
+	return nil
 }
 
 func (e *headersEvaluatorEvaluation) fillKubernetesHeaders(ctx context.Context) {
-	if e.request.KubernetesServiceAccountToken == "" {
+	if e.request.Policy == nil {
 		return
 	}
 
-	e.response.Headers.Add("Authorization", "Bearer "+e.request.KubernetesServiceAccountToken)
+	token, err := e.request.Policy.GetKubernetesServiceAccountToken()
+	if err != nil || token == "" {
+		return
+	}
+
+	e.response.Headers.Add("Authorization", "Bearer "+token)
 	impersonateUser := e.getJWTPayloadEmail(ctx)
 	if impersonateUser != "" {
 		e.response.Headers.Add("Impersonate-User", impersonateUser)
@@ -97,26 +107,42 @@ func (e *headersEvaluatorEvaluation) fillKubernetesHeaders(ctx context.Context)
 }
 
 func (e *headersEvaluatorEvaluation) fillGoogleCloudServerlessHeaders(ctx context.Context) {
-	if e.request.EnableGoogleCloudServerlessAuthentication {
-		h, err := getGoogleCloudServerlessHeaders(e.evaluator.store.GetGoogleCloudServerlessAuthenticationServiceAccount(), e.request.ToAudience)
-		if err != nil {
-			log.Ctx(ctx).Error().Err(err).Msg("authorize/header-evaluator: error retrieving google cloud serverless headers")
-			return
-		}
-		for k, v := range h {
-			e.response.Headers.Add(k, v)
-		}
+	if e.request.Policy == nil || !e.request.Policy.EnableGoogleCloudServerlessAuthentication {
+		return
+	}
+
+	var toAudience string
+	for _, wu := range e.request.Policy.To {
+		toAudience = "https://" + wu.URL.Hostname()
+	}
+
+	h, err := getGoogleCloudServerlessHeaders(e.evaluator.store.GetGoogleCloudServerlessAuthenticationServiceAccount(), toAudience)
+	if err != nil {
+		log.Ctx(ctx).Error().Err(err).Msg("authorize/header-evaluator: error retrieving google cloud serverless headers")
+		return
+	}
+	for k, v := range h {
+		e.response.Headers.Add(k, v)
 	}
 }
 
 func (e *headersEvaluatorEvaluation) fillRoutingKeyHeaders() {
-	if e.request.EnableRoutingKey {
+	if e.request.Policy == nil {
+		return
+	}
+
+	if e.request.Policy.EnvoyOpts.GetLbPolicy() == envoy_config_cluster_v3.Cluster_RING_HASH ||
+		e.request.Policy.EnvoyOpts.GetLbPolicy() == envoy_config_cluster_v3.Cluster_MAGLEV {
 		e.response.Headers.Add("x-pomerium-routing-key", cryptoSHA256(e.request.Session.ID))
 	}
 }
 
 func (e *headersEvaluatorEvaluation) fillSetRequestHeaders(ctx context.Context) {
-	for k, v := range e.request.SetRequestHeaders {
+	if e.request.Policy == nil {
+		return
+	}
+
+	for k, v := range e.request.Policy.SetRequestHeaders {
 		e.response.Headers.Add(k, os.Expand(v, func(name string) string {
 			switch name {
 			case "$":
@@ -138,13 +164,16 @@ func (e *headersEvaluatorEvaluation) fillSetRequestHeaders(ctx context.Context)
 	}
 }
 
-func (e *headersEvaluatorEvaluation) fillHeaders(ctx context.Context) {
+func (e *headersEvaluatorEvaluation) fillHeaders(ctx context.Context) error {
 	e.fillJWTAssertionHeader(ctx)
-	e.fillJWTClaimHeaders(ctx)
+	if err := e.fillJWTClaimHeaders(ctx); err != nil {
+		return err
+	}
 	e.fillKubernetesHeaders(ctx)
 	e.fillGoogleCloudServerlessHeaders(ctx)
 	e.fillRoutingKeyHeaders()
 	e.fillSetRequestHeaders(ctx)
+	return nil
 }
 
 func (e *headersEvaluatorEvaluation) getSessionOrServiceAccount(ctx context.Context) (*session.Session, *user.ServiceAccount) {
@@ -182,7 +211,7 @@ func (e *headersEvaluatorEvaluation) getUser(ctx context.Context) *user.User {
 }
 
 func (e *headersEvaluatorEvaluation) getClientCertFingerprint() string {
-	cert, err := cryptutil.ParsePEMCertificate([]byte(e.request.ClientCertificate.Leaf))
+	cert, err := cryptutil.ParsePEMCertificate([]byte(e.request.HTTP.ClientCertificate.Leaf))
 	if err != nil {
 		return ""
 	}
@@ -212,12 +241,23 @@ func (e *headersEvaluatorEvaluation) getGroupIDs(ctx context.Context) []string {
 	return make([]string, 0)
 }
 
-func (e *headersEvaluatorEvaluation) getJWTPayloadIss() string {
-	return e.request.Issuer
+func (e *headersEvaluatorEvaluation) getJWTPayloadIss() (string, error) {
+	var issuerFormat string
+	if e.request.Policy != nil {
+		issuerFormat = e.request.Policy.JWTIssuerFormat
+	}
+	switch issuerFormat {
+	case "uri":
+		return fmt.Sprintf("https://%s/", e.request.HTTP.Hostname), nil
+	case "", "hostOnly":
+		return e.request.HTTP.Hostname, nil
+	default:
+		return "", fmt.Errorf("unsupported JWT issuer format: %s", issuerFormat)
+	}
 }
 
 func (e *headersEvaluatorEvaluation) getJWTPayloadAud() string {
-	return e.request.Audience
+	return e.request.HTTP.Hostname
 }
 
 func (e *headersEvaluatorEvaluation) getJWTPayloadJTI() string {
@@ -307,14 +347,19 @@ func (e *headersEvaluatorEvaluation) getJWTPayloadName(ctx context.Context) stri
 	return ""
 }
 
-func (e *headersEvaluatorEvaluation) getJWTPayload(ctx context.Context) map[string]any {
+func (e *headersEvaluatorEvaluation) getJWTPayload(ctx context.Context) (map[string]any, error) {
 	if e.gotJWTPayload {
-		return e.cachedJWTPayload
+		return e.cachedJWTPayload, nil
+	}
+
+	iss, err := e.getJWTPayloadIss()
+	if err != nil {
+		return nil, err
 	}
 
 	e.gotJWTPayload = true
 	e.cachedJWTPayload = map[string]any{
-		"iss":    e.getJWTPayloadIss(),
+		"iss":    iss,
 		"aud":    e.getJWTPayloadAud(),
 		"jti":    e.getJWTPayloadJTI(),
 		"iat":    e.getJWTPayloadIAT(),
@@ -342,7 +387,7 @@ func (e *headersEvaluatorEvaluation) getJWTPayload(ctx context.Context) map[stri
 			e.cachedJWTPayload[claimKey] = strings.Join(vs, ",")
 		}
 	}
-	return e.cachedJWTPayload
+	return e.cachedJWTPayload, nil
 }
 
 func (e *headersEvaluatorEvaluation) getSignedJWT(ctx context.Context) string {
@@ -371,7 +416,11 @@ func (e *headersEvaluatorEvaluation) getSignedJWT(ctx context.Context) string {
 		return ""
 	}
 
-	jwtPayload := e.getJWTPayload(ctx)
+	jwtPayload, err := e.getJWTPayload(ctx)
+	if err != nil {
+		log.Ctx(ctx).Error().Err(err).Msg("authorize/header-evaluator: error creating JWT payload")
+		return ""
+	}
 	bs, err := json.Marshal(jwtPayload)
 	if err != nil {
 		log.Ctx(ctx).Error().Err(err).Msg("authorize/header-evaluator: error marshaling JWT payload")

authorize/evaluator/headers_evaluator_test.go

@@ -7,10 +7,12 @@ import (
 	"encoding/json"
 	"fmt"
 	"math"
+	"net/http"
 	"strings"
 	"testing"
 	"time"
 
+	envoy_config_cluster_v3 "github.com/envoyproxy/go-control-plane/envoy/config/cluster/v3"
 	"github.com/go-jose/go-jose/v3/jwt"
 	"github.com/open-policy-agent/opa/rego"
 	"github.com/stretchr/testify/assert"
@@ -62,22 +64,23 @@ func BenchmarkHeadersEvaluator(b *testing.B) {
 
 	e := NewHeadersEvaluator(s)
 
-	req := &HeadersRequest{
-		EnableRoutingKey:              true,
-		Issuer:                        "from.example.com",
-		Audience:                      "from.example.com",
-		KubernetesServiceAccountToken: "KUBERNETES_SERVICE_ACCOUNT_TOKEN",
-		ToAudience:                    "to.example.com",
+	req := &Request{
+		HTTP: RequestHTTP{
+			Method:   "GET",
+			Hostname: "from.example.com",
+		},
+		Policy: &config.Policy{
+			SetRequestHeaders: map[string]string{
+				"X-Custom-Header":         "CUSTOM_VALUE",
+				"X-ID-Token":              "${pomerium.id_token}",
+				"X-Access-Token":          "${pomerium.access_token}",
+				"Client-Cert-Fingerprint": "${pomerium.client_cert_fingerprint}",
+				"Authorization":           "Bearer ${pomerium.jwt}",
+			},
+		},
 		Session: RequestSession{
 			ID: "s1",
 		},
-		SetRequestHeaders: map[string]string{
-			"X-Custom-Header":         "CUSTOM_VALUE",
-			"X-ID-Token":              "${pomerium.id_token}",
-			"X-Access-Token":          "${pomerium.access_token}",
-			"Client-Cert-Fingerprint": "${pomerium.client_cert_fingerprint}",
-			"Authorization":           "Bearer ${pomerium.jwt}",
-		},
 	}
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
@@ -87,99 +90,6 @@ func BenchmarkHeadersEvaluator(b *testing.B) {
 	}
 }
 
-func TestNewHeadersRequestFromPolicy(t *testing.T) {
-	req, _ := NewHeadersRequestFromPolicy(&config.Policy{
-		EnableGoogleCloudServerlessAuthentication: true,
-		From: "https://*.example.com",
-		To: config.WeightedURLs{
-			{
-				URL: *mustParseURL("http://to.example.com"),
-			},
-		},
-	}, RequestHTTP{
-		Hostname: "from.example.com",
-		ClientCertificate: ClientCertificateInfo{
-			Leaf: "--- FAKE CERTIFICATE ---",
-		},
-	})
-	assert.Equal(t, &HeadersRequest{
-		EnableGoogleCloudServerlessAuthentication: true,
-		Issuer:     "from.example.com",
-		Audience:   "from.example.com",
-		ToAudience: "https://to.example.com",
-		ClientCertificate: ClientCertificateInfo{
-			Leaf: "--- FAKE CERTIFICATE ---",
-		},
-	}, req)
-}
-
-func TestNewHeadersRequestFromPolicy_IssuerFormat(t *testing.T) {
-	policy := &config.Policy{
-		EnableGoogleCloudServerlessAuthentication: true,
-		From: "https://*.example.com",
-		To: config.WeightedURLs{
-			{
-				URL: *mustParseURL("http://to.example.com"),
-			},
-		},
-	}
-	for _, tc := range []struct {
-		format           string
-		expectedIssuer   string
-		expectedAudience string
-		err              string
-	}{
-		{
-			format:           "",
-			expectedIssuer:   "from.example.com",
-			expectedAudience: "from.example.com",
-		},
-		{
-			format:           "hostOnly",
-			expectedIssuer:   "from.example.com",
-			expectedAudience: "from.example.com",
-		},
-		{
-			format:           "uri",
-			expectedIssuer:   "https://from.example.com/",
-			expectedAudience: "from.example.com",
-		},
-		{
-			format: "foo",
-			err:    `invalid issuer format: "foo"`,
-		},
-	} {
-		policy.JWTIssuerFormat = tc.format
-		req, err := NewHeadersRequestFromPolicy(policy, RequestHTTP{
-			Hostname: "from.example.com",
-			ClientCertificate: ClientCertificateInfo{
-				Leaf: "--- FAKE CERTIFICATE ---",
-			},
-		})
-		if tc.err != "" {
-			assert.ErrorContains(t, err, tc.err)
-		} else {
-			assert.Equal(t, &HeadersRequest{
-				EnableGoogleCloudServerlessAuthentication: true,
-				Issuer:     tc.expectedIssuer,
-				Audience:   tc.expectedAudience,
-				ToAudience: "https://to.example.com",
-				ClientCertificate: ClientCertificateInfo{
-					Leaf: "--- FAKE CERTIFICATE ---",
-				},
-			}, req)
-		}
-	}
-}
-
-func TestNewHeadersRequestFromPolicy_nil(t *testing.T) {
-	req, _ := NewHeadersRequestFromPolicy(nil, RequestHTTP{Hostname: "from.example.com"})
-	assert.Equal(t, &HeadersRequest{
-		Issuer:   "from.example.com",
-		Audience: "from.example.com",
-	}, req)
-}
-
 func TestHeadersEvaluator(t *testing.T) {
 	t.Parallel()
 
@@ -197,7 +107,7 @@ func TestHeadersEvaluator(t *testing.T) {
 
 	iat := time.Unix(1686870680, 0)
 
-	eval := func(_ *testing.T, data []proto.Message, input *HeadersRequest) (*HeadersResponse, error) {
+	eval := func(_ *testing.T, data []proto.Message, input *Request) (*HeadersResponse, error) {
 		ctx := context.Background()
 		ctx = storage.WithQuerier(ctx, storage.NewStaticQuerier(data...))
 		store := store.New()
@@ -232,10 +142,11 @@ func TestHeadersEvaluator(t *testing.T) {
 				newDirectoryGroupRecord(directory.Group{ID: "g3", Name: "GROUP3", Email: "g3@example.com"}),
 				newDirectoryGroupRecord(directory.Group{ID: "g4", Name: "GROUP4", Email: "g4@example.com"}),
 			},
-			&HeadersRequest{
-				Issuer:     "from.example.com",
-				Audience:   "from.example.com",
-				ToAudience: "to.example.com",
+			&Request{
+				HTTP: RequestHTTP{
+					Hostname: "from.example.com",
+				},
+				Policy: &config.Policy{},
 				Session: RequestSession{
 					ID: "s1",
 				},
@@ -292,7 +203,7 @@ func TestHeadersEvaluator(t *testing.T) {
 					}},
 				}},
 			},
-			&HeadersRequest{
+			&Request{
 				Session: RequestSession{ID: "s1"},
 			})
 		require.NoError(t, err)
@@ -312,20 +223,22 @@ func TestHeadersEvaluator(t *testing.T) {
 					AccessToken: "ACCESS_TOKEN",
 				}},
 			},
-			&HeadersRequest{
-				Issuer:     "from.example.com",
-				Audience:   "from.example.com",
-				ToAudience: "to.example.com",
-				Session:    RequestSession{ID: "s1"},
-				SetRequestHeaders: map[string]string{
-					"X-Custom-Header":         "CUSTOM_VALUE",
-					"X-ID-Token":              "${pomerium.id_token}",
-					"X-Access-Token":          "${pomerium.access_token}",
-					"Client-Cert-Fingerprint": "${pomerium.client_cert_fingerprint}",
-					"Authorization":           "Bearer ${pomerium.jwt}",
-					"Foo":                     "escaped $$dollar sign",
+			&Request{
+				HTTP: RequestHTTP{
+					Hostname:          "from.example.com",
+					ClientCertificate: ClientCertificateInfo{Leaf: testValidCert},
 				},
-				ClientCertificate: ClientCertificateInfo{Leaf: testValidCert},
+				Policy: &config.Policy{
+					SetRequestHeaders: map[string]string{
+						"X-Custom-Header":         "CUSTOM_VALUE",
+						"X-ID-Token":              "${pomerium.id_token}",
+						"X-Access-Token":          "${pomerium.access_token}",
+						"Client-Cert-Fingerprint": "${pomerium.client_cert_fingerprint}",
+						"Authorization":           "Bearer ${pomerium.jwt}",
+						"Foo":                     "escaped $$dollar sign",
+					},
+				},
+				Session: RequestSession{ID: "s1"},
 			})
 		require.NoError(t, err)
 
@@ -355,13 +268,12 @@ func TestHeadersEvaluator(t *testing.T) {
 					AccessToken: "ACCESS_TOKEN",
 				}},
 			},
-			&HeadersRequest{
-				Issuer:     "from.example.com",
-				Audience:   "from.example.com",
-				ToAudience: "to.example.com",
-				Session:    RequestSession{ID: "s1"},
-				SetRequestHeaders: map[string]string{
-					"X-ID-Token": "${pomerium.id_token}",
+			&Request{
+				Session: RequestSession{ID: "s1"},
+				Policy: &config.Policy{
+					SetRequestHeaders: map[string]string{
+						"X-ID-Token": "${pomerium.id_token}",
+					},
 				},
 			})
 		require.NoError(t, err)
@@ -378,14 +290,13 @@ func TestHeadersEvaluator(t *testing.T) {
 					AccessToken: "ACCESS_TOKEN",
 				}},
 			},
-			&HeadersRequest{
-				Issuer:     "from.example.com",
-				Audience:   "from.example.com",
-				ToAudience: "to.example.com",
-				Session:    RequestSession{ID: "s1"},
-				SetRequestHeaders: map[string]string{
-					"Authorization": "Bearer ${pomerium.id_token}",
+			&Request{
+				Policy: &config.Policy{
+					SetRequestHeaders: map[string]string{
+						"Authorization": "Bearer ${pomerium.id_token}",
+					},
 				},
+				Session: RequestSession{ID: "s1"},
 			})
 		require.NoError(t, err)
 
@@ -394,12 +305,11 @@ func TestHeadersEvaluator(t *testing.T) {
 
 	t.Run("set_request_headers no client cert", func(t *testing.T) {
 		output, err := eval(t, nil,
-			&HeadersRequest{
-				Issuer:     "from.example.com",
-				Audience:   "from.example.com",
-				ToAudience: "to.example.com",
-				SetRequestHeaders: map[string]string{
-					"fingerprint": "${pomerium.client_cert_fingerprint}",
+			&Request{
+				Policy: &config.Policy{
+					SetRequestHeaders: map[string]string{
+						"fingerprint": "${pomerium.client_cert_fingerprint}",
+					},
 				},
 			})
 		require.NoError(t, err)
@@ -427,12 +337,11 @@ func TestHeadersEvaluator(t *testing.T) {
 					Name: "GROUP2",
 				}),
 			},
-			&HeadersRequest{
-				Issuer:                        "from.example.com",
-				Audience:                      "from.example.com",
-				ToAudience:                    "to.example.com",
-				KubernetesServiceAccountToken: "TOKEN",
-				Session:                       RequestSession{ID: "s1"},
+			&Request{
+				Policy: &config.Policy{
+					KubernetesServiceAccountToken: "TOKEN",
+				},
+				Session: RequestSession{ID: "s1"},
 			})
 		require.NoError(t, err)
 		assert.Equal(t, "Bearer TOKEN", output.Headers.Get("Authorization"))
@@ -445,18 +354,21 @@ func TestHeadersEvaluator(t *testing.T) {
 
 		output, err := eval(t,
 			[]protoreflect.ProtoMessage{},
-			&HeadersRequest{
-				EnableRoutingKey: false,
-				Session:          RequestSession{ID: "s1"},
+			&Request{
+				Session: RequestSession{ID: "s1"},
 			})
 		require.NoError(t, err)
 		assert.Empty(t, output.Headers.Get("X-Pomerium-Routing-Key"))
 
 		output, err = eval(t,
 			[]protoreflect.ProtoMessage{},
-			&HeadersRequest{
-				EnableRoutingKey: true,
-				Session:          RequestSession{ID: "s1"},
+			&Request{
+				Policy: &config.Policy{
+					EnvoyOpts: &envoy_config_cluster_v3.Cluster{
+						LbPolicy: envoy_config_cluster_v3.Cluster_MAGLEV,
+					},
+				},
+				Session: RequestSession{ID: "s1"},
 			})
 		require.NoError(t, err)
 		assert.Equal(t, "e8bc163c82eee18733288c7d4ac636db3a6deb013ef2d37b68322be20edc45cc", output.Headers.Get("X-Pomerium-Routing-Key"))
@@ -470,7 +382,7 @@ func TestHeadersEvaluator(t *testing.T) {
 				&session.Session{Id: "s1", UserId: "u1"},
 				&user.User{Id: "u1", Email: "user@example.com"},
 			},
-			&HeadersRequest{
+			&Request{
 				Session: RequestSession{ID: "s1"},
 			})
 		require.NoError(t, err)
@@ -481,7 +393,7 @@ func TestHeadersEvaluator(t *testing.T) {
 				&session.Session{Id: "s1", UserId: "u1"},
 				newDirectoryUserRecord(directory.User{ID: "u1", Email: "directory-user@example.com"}),
 			},
-			&HeadersRequest{
+			&Request{
 				Session: RequestSession{ID: "s1"},
 			})
 		require.NoError(t, err)
@@ -498,7 +410,7 @@ func TestHeadersEvaluator(t *testing.T) {
 					}},
 				}},
 			},
-			&HeadersRequest{
+			&Request{
 				Session: RequestSession{ID: "s1"},
 			})
 		require.NoError(t, err)
@@ -513,7 +425,7 @@ func TestHeadersEvaluator(t *testing.T) {
 					}},
 				}},
 			},
-			&HeadersRequest{
+			&Request{
 				Session: RequestSession{ID: "s1"},
 			})
 		require.NoError(t, err)
@@ -528,12 +440,54 @@ func TestHeadersEvaluator(t *testing.T) {
 				&user.ServiceAccount{Id: "sa1", UserId: "u1"},
 				&user.User{Id: "u1", Email: "u1@example.com"},
 			},
-			&HeadersRequest{
+			&Request{
 				Session: RequestSession{ID: "sa1"},
 			})
 		require.NoError(t, err)
 		assert.Equal(t, "u1@example.com", output.Headers.Get("X-Pomerium-Claim-Email"))
 	})
+
+	t.Run("issuer format", func(t *testing.T) {
+		t.Parallel()
+
+		for _, tc := range []struct {
+			format string
+			input  string
+			output string
+		}{
+			{"", "example.com", "example.com"},
+			{"hostOnly", "host-only.example.com", "host-only.example.com"},
+			{"uri", "uri.example.com", "https://uri.example.com/"},
+		} {
+			output, err := eval(t,
+				nil,
+				&Request{
+					HTTP: RequestHTTP{
+						Hostname: tc.input,
+					},
+					Policy: &config.Policy{
+						JWTIssuerFormat: tc.format,
+					},
+				})
+			require.NoError(t, err)
+			m := decodeJWTAssertion(t, output.Headers)
+			assert.Equal(t, tc.output, m["iss"], "unexpected issuer for format=%s", tc.format)
+		}
+	})
+}
+
+func decodeJWTAssertion(t *testing.T, headers http.Header) map[string]any {
+	jwtHeader := headers.Get("X-Pomerium-Jwt-Assertion")
+	// Make sure the 'iat' and 'exp' claims can be parsed as an integer. We
+	// need to do some explicit decoding in order to be able to verify
+	// this, as by default json.Unmarshal() will make no distinction
+	// between numeric formats.
+	d := json.NewDecoder(bytes.NewReader(decodeJWSPayload(t, jwtHeader)))
+	d.UseNumber()
+	var m map[string]any
+	err := d.Decode(&m)
+	require.NoError(t, err)
+	return m
 }
 
 func decodeJWSPayload(t *testing.T, jws string) []byte {