feat: add end session endpoint (#232)

backend/internal/service/oidc_service.go

@@ -51,7 +51,7 @@ func (s *OidcService) Authorize(input dto.AuthorizeOidcClientRequestDto, userID,
 	}
 
 	// Get the callback URL of the client. Return an error if the provided callback URL is not allowed
-	callbackURL, err := s.getCallbackURL(client, input.CallbackURL)
+	callbackURL, err := s.getCallbackURL(client.CallbackURLs, input.CallbackURL)
 	if err != nil {
 		return "", "", err
 	}
@@ -228,11 +228,12 @@ func (s *OidcService) ListClients(searchTerm string, sortedPaginationRequest uti
 
 func (s *OidcService) CreateClient(input dto.OidcClientCreateDto, userID string) (model.OidcClient, error) {
 	client := model.OidcClient{
-		Name:         input.Name,
-		CallbackURLs: input.CallbackURLs,
-		CreatedByID:  userID,
-		IsPublic:     input.IsPublic,
-		PkceEnabled:  input.IsPublic || input.PkceEnabled,
+		Name:               input.Name,
+		CallbackURLs:       input.CallbackURLs,
+		LogoutCallbackURLs: input.LogoutCallbackURLs,
+		CreatedByID:        userID,
+		IsPublic:           input.IsPublic,
+		PkceEnabled:        input.IsPublic || input.PkceEnabled,
 	}
 
 	if err := s.db.Create(&client).Error; err != nil {
@@ -250,6 +251,7 @@ func (s *OidcService) UpdateClient(clientID string, input dto.OidcClientCreateDt
 
 	client.Name = input.Name
 	client.CallbackURLs = input.CallbackURLs
+	client.LogoutCallbackURLs = input.LogoutCallbackURLs
 	client.IsPublic = input.IsPublic
 	client.PkceEnabled = input.IsPublic || input.PkceEnabled
 
@@ -460,6 +462,46 @@ func (s *OidcService) UpdateAllowedUserGroups(id string, input dto.OidcUpdateAll
 	return client, nil
 }
 
+// ValidateEndSession returns the logout callback URL for the client if all the validations pass
+func (s *OidcService) ValidateEndSession(input dto.OidcLogoutDto, userID string) (string, error) {
+	// If no ID token hint is provided, return an error
+	if input.IdTokenHint == "" {
+		return "", &common.TokenInvalidError{}
+	}
+
+	// If the ID token hint is provided, verify the ID token
+	claims, err := s.jwtService.VerifyIdToken(input.IdTokenHint)
+	if err != nil {
+		return "", &common.TokenInvalidError{}
+	}
+
+	// If the client ID is provided check if the client ID in the ID token matches the client ID in the request
+	if input.ClientId != "" && claims.Audience[0] != input.ClientId {
+		return "", &common.OidcClientIdNotMatchingError{}
+	}
+
+	clientId := claims.Audience[0]
+
+	// Check if the user has authorized the client before
+	var userAuthorizedOIDCClient model.UserAuthorizedOidcClient
+	if err := s.db.Preload("Client").First(&userAuthorizedOIDCClient, "client_id = ? AND user_id = ?", clientId, userID).Error; err != nil {
+		return "", &common.OidcMissingAuthorizationError{}
+	}
+
+	// If the client has no logout callback URLs, return an error
+	if len(userAuthorizedOIDCClient.Client.LogoutCallbackURLs) == 0 {
+		return "", &common.OidcNoCallbackURLError{}
+	}
+
+	callbackURL, err := s.getCallbackURL(userAuthorizedOIDCClient.Client.LogoutCallbackURLs, input.PostLogoutRedirectUri)
+	if err != nil {
+		return "", err
+	}
+
+	return callbackURL, nil
+
+}
+
 func (s *OidcService) createAuthorizationCode(clientID string, userID string, scope string, nonce string, codeChallenge string, codeChallengeMethod string) (string, error) {
 	randomString, err := utils.GenerateRandomAlphanumericString(32)
 	if err != nil {
@@ -506,12 +548,12 @@ func (s *OidcService) validateCodeVerifier(codeVerifier, codeChallenge string, c
 	return encodedVerifierHash == codeChallenge
 }
 
-func (s *OidcService) getCallbackURL(client model.OidcClient, inputCallbackURL string) (callbackURL string, err error) {
+func (s *OidcService) getCallbackURL(urls []string, inputCallbackURL string) (callbackURL string, err error) {
 	if inputCallbackURL == "" {
-		return client.CallbackURLs[0], nil
+		return urls[0], nil
 	}
 
-	for _, callbackPattern := range client.CallbackURLs {
+	for _, callbackPattern := range urls {
 		regexPattern := strings.ReplaceAll(regexp.QuoteMeta(callbackPattern), `\*`, ".*") + "$"
 		matched, err := regexp.MatchString(regexPattern, inputCallbackURL)
 		if err != nil {