fix: unsupported request parameter error

server/oauth2.go

@@ -95,6 +95,7 @@ const (
 	errUnauthorizedClient      = "unauthorized_client"
 	errAccessDenied            = "access_denied"
 	errUnsupportedResponseType = "unsupported_response_type"
+	errRequestNotSupported     = "request_not_supported"
 	errInvalidScope            = "invalid_scope"
 	errServerError             = "server_error"
 	errTemporarilyUnavailable  = "temporarily_unavailable"
@@ -453,6 +454,12 @@ func (s *Server) parseAuthorizationRequest(r *http.Request) (*storage.AuthReques
 		return &authErr{state, redirectURI, typ, fmt.Sprintf(format, a...)}
 	}
 
+	// dex doesn't support request parameter and must return request_not_supported error
+	// https://openid.net/specs/openid-connect-core-1_0.html#6.1
+	if q.Get("request") != "" {
+		return nil, newErr(errRequestNotSupported, "Server does not support request parameter.")
+	}
+
 	if codeChallengeMethod != CodeChallengeMethodS256 && codeChallengeMethod != CodeChallengeMethodPlain {
 		description := fmt.Sprintf("Unsupported PKCE challenge method (%q).", codeChallengeMethod)
 		return nil, newErr(errInvalidRequest, description)

server/server_test.go

@@ -25,6 +25,7 @@ import (
 	"github.com/kylelemons/godebug/pretty"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/sirupsen/logrus"
+	"github.com/stretchr/testify/require"
 	"golang.org/x/crypto/bcrypt"
 	"golang.org/x/oauth2"
 	jose "gopkg.in/square/go-jose.v2"
@@ -223,6 +224,9 @@ type test struct {
 	// extra parameters to pass when retrieving id token
 	retrieveTokenOptions []oauth2.AuthCodeOption
 
+	// define an error response, when the test expects an error on the auth endpoint
+	authError *OAuth2ErrorResponse
+
 	// define an error response, when the test expects an error on the token endpoint
 	tokenError ErrorResponse
 }
@@ -607,6 +611,19 @@ func makeOAuth2Tests(clientID string, clientSecret string, now func() time.Time)
 					StatusCode: http.StatusBadRequest,
 				},
 			},
+			{
+				name: "Request parameter in authorization query",
+				authCodeOptions: []oauth2.AuthCodeOption{
+					oauth2.SetAuthURLParam("request", "anything"),
+				},
+				authError: &OAuth2ErrorResponse{
+					Error:            errRequestNotSupported,
+					ErrorDescription: "Server does not support request parameter.",
+				},
+				handleToken: func(ctx context.Context, p *oidc.Provider, config *oauth2.Config, token *oauth2.Token, conn *mock.Callback) error {
+					return nil
+				},
+			},
 		},
 	}
 }
@@ -665,7 +682,7 @@ func TestOAuth2CodeFlow(t *testing.T) {
 				state             = "a_state"
 			)
 			defer func() {
-				if !gotCode {
+				if !gotCode && tc.authError == nil {
 					t.Errorf("never got a code in callback\n%s\n%s", reqDump, respDump)
 				}
 			}()
@@ -684,12 +701,18 @@ func TestOAuth2CodeFlow(t *testing.T) {
 
 				// Did dex return an error?
 				if errType := q.Get("error"); errType != "" {
-					if desc := q.Get("error_description"); desc != "" {
-						t.Errorf("got error from server %s: %s", errType, desc)
-					} else {
-						t.Errorf("got error from server %s", errType)
+					description := q.Get("error_description")
+
+					if tc.authError == nil {
+						if description != "" {
+							t.Errorf("got error from server %s: %s", errType, description)
+						} else {
+							t.Errorf("got error from server %s", errType)
+						}
+						w.WriteHeader(http.StatusInternalServerError)
+						return
 					}
-					w.WriteHeader(http.StatusInternalServerError)
+					require.Equal(t, *tc.authError, OAuth2ErrorResponse{Error: errType, ErrorDescription: description})
 					return
 				}