Fix response_type missing param

This commit fix problem with response_type param, which is required according to OIDC spec, when it is missing.
 At now, when connector_id url query param is not set, connector view use response_type that client request instead of default "code".

Fixes #370

server/http.go

@@ -255,7 +255,7 @@ func renderLoginPage(w http.ResponseWriter, r *http.Request, srv OIDCServer, idp
 
 		v := r.URL.Query()
 		v.Set("connector_id", idpc.ID())
-		v.Set("response_type", "code")
+		v.Set("response_type", q.Get("response_type"))
 		link.URL = httpPathAuth + "?" + v.Encode()
 		td.Links = append(td.Links, link)
 	}
@@ -273,77 +273,92 @@ func handleAuthFunc(srv OIDCServer, idpcs []connector.Connector, tpl *template.T
 		}
 
 		q := r.URL.Query()
-		register := q.Get("register") == "1" && registrationEnabled
-		e := q.Get("error")
-		if e != "" {
-			sessionKey := q.Get("state")
-			if err := srv.KillSession(sessionKey); err != nil {
-				log.Errorf("Failed killing sessionKey %q: %v", sessionKey, err)
-			}
-			renderLoginPage(w, r, srv, idpcs, register, tpl)
-			return
-		}
 
-		connectorID := q.Get("connector_id")
-		idpc, ok := idx[connectorID]
-		if !ok {
-			renderLoginPage(w, r, srv, idpcs, register, tpl)
+		// Retrieve client id
+		clientid := q.Get("client_id")
+
+		// Retrieve state
+		state := q.Get("state")
+
+		// Retrieve response_type
+		responseType := q.Get("response_type")
+
+		// Retrieve scopes
+		qscope := strings.Fields(q.Get("scope"))
+
+		// Check client ID param
+		if clientid == "" {
+			log.Errorf("Invalid auth request: no client_id received")
+			writeAuthError(w, oauth2.NewError(oauth2.ErrorInvalidRequest), state)
 			return
 		}
 
-		acr, err := oauth2.ParseAuthCodeRequest(q)
-		if err != nil {
-			log.Errorf("Invalid auth request: %v", err)
-			writeAuthError(w, err, acr.State)
-			return
+		// Check redirect_uri param, but if it's empty we don't return any error here
+		qru := q.Get("redirect_uri")
+		var rURL *url.URL
+		if qru != "" {
+			ru, err := url.Parse(qru)
+			if err != nil {
+				log.Errorf("Invalid auth request: %v", err)
+				writeAuthError(w, oauth2.NewError(oauth2.ErrorInvalidRequest), state)
+				return
+			}
+			rURL = ru
 		}
 
-		cm, err := srv.ClientMetadata(acr.ClientID)
+		cm, err := srv.ClientMetadata(clientid)
 		if err != nil {
-			log.Errorf("Failed fetching client %q from repo: %v", acr.ClientID, err)
-			writeAuthError(w, oauth2.NewError(oauth2.ErrorServerError), acr.State)
+			log.Errorf("Failed fetching client %q from repo: %v", clientid, err)
+			writeAuthError(w, oauth2.NewError(oauth2.ErrorServerError), state)
 			return
 		}
 		if cm == nil {
-			log.Errorf("Client %q not found", acr.ClientID)
-			writeAuthError(w, oauth2.NewError(oauth2.ErrorInvalidRequest), acr.State)
+			log.Errorf("Client %q not found", clientid)
+			writeAuthError(w, oauth2.NewError(oauth2.ErrorInvalidRequest), state)
 			return
 		}
 
 		if len(cm.RedirectURIs) == 0 {
-			log.Errorf("Client %q has no redirect URLs", acr.ClientID)
-			writeAuthError(w, oauth2.NewError(oauth2.ErrorServerError), acr.State)
+			log.Errorf("Client %q has no redirect URLs", clientid)
+			writeAuthError(w, oauth2.NewError(oauth2.ErrorServerError), state)
 			return
 		}
 
-		redirectURL, err := client.ValidRedirectURL(acr.RedirectURL, cm.RedirectURIs)
+		redirectURL, err := client.ValidRedirectURL(rURL, cm.RedirectURIs)
 		if err != nil {
 			switch err {
 			case (client.ErrorCantChooseRedirectURL):
-				log.Errorf("Request must provide redirect URL as client %q has registered many", acr.ClientID)
-				writeAuthError(w, oauth2.NewError(oauth2.ErrorInvalidRequest), acr.State)
+				log.Errorf("Request must provide redirect URL as client %q has registered many", clientid)
+				writeAuthError(w, oauth2.NewError(oauth2.ErrorInvalidRequest), state)
 				return
 			case (client.ErrorInvalidRedirectURL):
-				log.Errorf("Request provided unregistered redirect URL: %s", acr.RedirectURL)
-				writeAuthError(w, oauth2.NewError(oauth2.ErrorInvalidRequest), acr.State)
+				log.Errorf("Request provided unregistered redirect URL: %s", rURL)
+				writeAuthError(w, oauth2.NewError(oauth2.ErrorInvalidRequest), state)
 				return
 			case (client.ErrorNoValidRedirectURLs):
-				log.Errorf("There are no registered URLs for the requested client: %s", acr.RedirectURL)
-				writeAuthError(w, oauth2.NewError(oauth2.ErrorInvalidRequest), acr.State)
+				log.Errorf("There are no registered URLs for the requested client: %s", rURL)
+				writeAuthError(w, oauth2.NewError(oauth2.ErrorInvalidRequest), state)
+				return
+			default:
+				log.Errorf("Unexpected error checking redirect URL for client %q: %v", clientid, err)
+				writeAuthError(w, oauth2.NewError(oauth2.ErrorServerError), state)
 				return
 			}
 		}
 
-		if acr.ResponseType != oauth2.ResponseTypeCode {
-			log.Errorf("unexpected ResponseType: %v: ", acr.ResponseType)
-			redirectAuthError(w, oauth2.NewError(oauth2.ErrorUnsupportedResponseType), acr.State, redirectURL)
+		// Response type check
+		switch responseType {
+		case "code": // Add more cases as we support more response types
+		default:
+			log.Errorf("Invalid auth request: unsupported response_type")
+			redirectAuthError(w, oauth2.NewError(oauth2.ErrorUnsupportedResponseType), state, redirectURL)
 			return
 		}
 
 		// Check scopes.
 		var scopes []string
 		foundOpenIDScope := false
-		for _, scope := range acr.Scope {
+		for _, scope := range qscope {
 			switch scope {
 			case "openid":
 				foundOpenIDScope = true
@@ -364,16 +379,33 @@ func handleAuthFunc(srv OIDCServer, idpcs []connector.Connector, tpl *template.T
 
 		if !foundOpenIDScope {
 			log.Errorf("Invalid auth request: missing 'openid' in 'scope'")
-			writeAuthError(w, oauth2.NewError(oauth2.ErrorInvalidRequest), acr.State)
+			writeAuthError(w, oauth2.NewError(oauth2.ErrorInvalidRequest), state)
+			return
+		}
+
+		register := q.Get("register") == "1" && registrationEnabled
+		e := q.Get("error")
+		if e != "" {
+			if err := srv.KillSession(state); err != nil {
+				log.Errorf("Failed killing sessionKey %q: %v", state, err)
+			}
+			renderLoginPage(w, r, srv, idpcs, register, tpl)
+			return
+		}
+
+		connectorID := q.Get("connector_id")
+		idpc, ok := idx[connectorID]
+		if !ok {
+			renderLoginPage(w, r, srv, idpcs, register, tpl)
 			return
 		}
 
 		nonce := q.Get("nonce")
 
-		key, err := srv.NewSession(connectorID, acr.ClientID, acr.State, redirectURL, nonce, register, acr.Scope)
+		key, err := srv.NewSession(connectorID, clientid, state, redirectURL, nonce, register, qscope)
 		if err != nil {
 			log.Errorf("Error creating new session: %v: ", err)
-			redirectAuthError(w, err, acr.State, redirectURL)
+			redirectAuthError(w, err, state, redirectURL)
 			return
 		}
 
@@ -399,7 +431,7 @@ func handleAuthFunc(srv OIDCServer, idpcs []connector.Connector, tpl *template.T
 		lu, err := idpc.LoginURL(key, p)
 		if err != nil {
 			log.Errorf("Connector.LoginURL failed: %v", err)
-			redirectAuthError(w, err, acr.State, redirectURL)
+			redirectAuthError(w, err, state, redirectURL)
 			return
 		}
 

server/http_test.go

@@ -175,6 +175,29 @@ func TestHandleAuthFuncResponsesSingleRedirectURL(t *testing.T) {
 			},
 			wantCode: http.StatusBadRequest,
 		},
+
+		// empty response_type
+		{
+			query: url.Values{
+				"redirect_uri": []string{"http://client.example.com/callback"},
+				"client_id":    []string{"XXX"},
+				"connector_id": []string{"fake"},
+				"scope":        []string{"openid"},
+			},
+			wantCode:     http.StatusFound,
+			wantLocation: "http://client.example.com/callback?error=unsupported_response_type&state=",
+		},
+
+		// empty client_id
+		{
+			query: url.Values{
+				"response_type": []string{"code"},
+				"redirect_uri":  []string{"http://unrecognized.example.com/callback"},
+				"connector_id":  []string{"fake"},
+				"scope":         []string{"openid"},
+			},
+			wantCode: http.StatusBadRequest,
+		},
 	}
 
 	for i, tt := range tests {