fix: grant_types_supported in discovery

pkg/oidc/token_request.go

@@ -9,8 +9,12 @@ import (
 const (
 	//GrantTypeCode defines the grant_type `authorization_code` used for the Token Request in the Authorization Code Flow
 	GrantTypeCode GrantType = "authorization_code"
-	//GrantTypeBearer define the grant_type `urn:ietf:params:oauth:grant-type:jwt-bearer` used for the JWT Authorization Grant
+
+	//GrantTypeBearer defines the grant_type `urn:ietf:params:oauth:grant-type:jwt-bearer` used for the JWT Authorization Grant
 	GrantTypeBearer GrantType = "urn:ietf:params:oauth:grant-type:jwt-bearer"
+
+	//GrantTypeTokenExchange defines the grant_type `urn:ietf:params:oauth:grant-type:token-exchange` used for the OAuth Token Exchange Grant
+	GrantTypeTokenExchange GrantType = "urn:ietf:params:oauth:grant-type:token-exchange"
 )
 
 type GrantType string

pkg/op/config.go

@@ -19,6 +19,8 @@ type Configuration interface {
 
 	AuthMethodPostSupported() bool
 	CodeMethodS256Supported() bool
+	GrantTypeTokenExchangeSupported() bool
+	GrantTypeJWTAuthorizationSupported() bool
 }
 
 func ValidateIssuer(issuer string) error {

pkg/op/discovery.go

@@ -52,22 +52,23 @@ func Scopes(c Configuration) []string {
 
 func ResponseTypes(c Configuration) []string {
 	return []string{
-		"code",
+		string(oidc.ResponseTypeCode),
-		"id_token",
+		string(oidc.ResponseTypeIDTokenOnly),
-		// "code token",
+		string(oidc.ResponseTypeIDToken),
-		// "code id_token",
+	} //TODO: ok for now, check later if dynamic needed
-		"id_token token",
-		// "code id_token token"
-	}
 }
 
 func GrantTypes(c Configuration) []string {
-	return []string{
+	grantTypes := []string{
-		"client_credentials",
+		string(oidc.GrantTypeCode),
-		"authorization_code",
-		// "password",
-		"urn:ietf:params:oauth:grant-type:token-exchange",
 	}
+	if c.GrantTypeTokenExchangeSupported() {
+		grantTypes = append(grantTypes, string(oidc.GrantTypeTokenExchange))
+	}
+	if c.GrantTypeJWTAuthorizationSupported() {
+		grantTypes = append(grantTypes, string(oidc.GrantTypeBearer))
+	}
+	return grantTypes
 }
 
 func SupportedClaims(c Configuration) []string {

pkg/op/op.go

@@ -50,7 +50,6 @@ type OpenIDProvider interface {
 	Decoder() utils.Decoder
 	Encoder() utils.Encoder
 	IDTokenHintVerifier() IDTokenHintVerifier
-	JWTProfileVerifier() JWTProfileVerifier
 	AccessTokenVerifier() AccessTokenVerifier
 	Crypto() Crypto
 	DefaultLogoutRedirectURI() string
@@ -90,15 +89,6 @@ type Config struct {
 	CryptoKey                [32]byte
 	DefaultLogoutRedirectURI string
 	CodeMethodS256           bool
-
-	//TODO: add to config after updating Configuration interface for DiscoveryConfig
-	// ScopesSupported:                   oidc.SupportedScopes,
-	// ResponseTypesSupported:            responseTypes,
-	// GrantTypesSupported:               oidc.SupportedGrantTypes,
-	// ClaimsSupported:                   oidc.SupportedClaims,
-	// IdTokenSigningAlgValuesSupported:  []string{keys.SigningAlgorithm},
-	// SubjectTypesSupported:             []string{"public"},
-	// TokenEndpointAuthMethodsSupported:
 }
 
 type endpoints struct {
@@ -196,6 +186,14 @@ func (o *openidProvider) CodeMethodS256Supported() bool {
 	return o.config.CodeMethodS256
 }
 
+func (o *openidProvider) GrantTypeTokenExchangeSupported() bool {
+	return false
+}
+
+func (o *openidProvider) GrantTypeJWTAuthorizationSupported() bool {
+	return true
+}
+
 func (o *openidProvider) Storage() Storage {
 	return o.storage
 }

pkg/op/tokenrequest.go

@@ -17,6 +17,12 @@ type Exchanger interface {
 	Signer() Signer
 	Crypto() Crypto
 	AuthMethodPostSupported() bool
+	GrantTypeTokenExchangeSupported() bool
+	GrantTypeJWTAuthorizationSupported() bool
+}
+
+type JWTAuthorizationGrantExchanger interface {
+	Exchanger
 	JWTProfileVerifier() JWTProfileVerifier
 }
 
@@ -27,17 +33,20 @@ func tokenHandler(exchanger Exchanger) func(w http.ResponseWriter, r *http.Reque
 			CodeExchange(w, r, exchanger)
 			return
 		case string(oidc.GrantTypeBearer):
-			JWTProfile(w, r, exchanger)
+			if ex, ok := exchanger.(JWTAuthorizationGrantExchanger); ok && exchanger.GrantTypeJWTAuthorizationSupported() {
+				JWTProfile(w, r, ex)
 				return
-		case "exchange":
+			}
+		case string(oidc.GrantTypeTokenExchange):
+			if exchanger.GrantTypeTokenExchangeSupported() {
 				TokenExchange(w, r, exchanger)
+				return
+			}
 		case "":
 			RequestError(w, r, ErrInvalidRequest("grant_type missing"))
 			return
-		default:
-			RequestError(w, r, ErrInvalidRequest("grant_type not supported"))
-			return
 		}
+		RequestError(w, r, ErrInvalidRequest("grant_type not supported"))
 	}
 }
 
@@ -137,7 +146,7 @@ func AuthorizeCodeChallenge(ctx context.Context, tokenReq *oidc.AccessTokenReque
 	return authReq, nil
 }
 
-func JWTProfile(w http.ResponseWriter, r *http.Request, exchanger Exchanger) {
+func JWTProfile(w http.ResponseWriter, r *http.Request, exchanger JWTAuthorizationGrantExchanger) {
 	profileRequest, err := ParseJWTProfileRequest(r, exchanger.Decoder())
 	if err != nil {
 		RequestError(w, r, err)