WebAuthn Esempio di utilizzo avanzato

4 settembre 2025 · Componenti

Below è a more comprehensive Delphi esempio che demonstrates custom endpoints, challenge policies, database-backed credential storage, FIDO Metadata validation, e cross-origin iframe support. Il codice highlights advanced evento gestione a enforce sicurezza policies.

sgcWebSockets WebAuthn Server Example

procedure TForm1.ConfigureWebAuthn;
begin
  // Component setup
  FWebAuthn := TsgcWSServer_API_WebAuthn.Create(nil);
  FWebAuthn.Server := FHTTPServer;
  FWebAuthn.Enabled := True;
  // Endpoint remapping
  FWebAuthn.EndpointsOptions.AuthenticationOptions.Endpoint := '/auth/options';
  FWebAuthn.EndpointsOptions.AuthenticationVerify.Endpoint  := '/auth/verify';
  FWebAuthn.EndpointsOptions.RegistrationOptions.Endpoint   := '/reg/options';
  FWebAuthn.EndpointsOptions.RegistrationVerify.Endpoint    := '/reg/verify';
  // Relying-party definition
  con FWebAuthn.WebAuthnOptions do
  begin
    RelyingParty := 'secure.example.com';
    Origins.Origins.Text      := 'https://app.example.com'#13#10'https://login.example.net';
    Origins.TopOrigins.Text   := 'https://host.example.org';
    Origins.AllowCrossOrigins := True;
    // Cryptographic & UX policies
    Algorithms                                   := [waunalgES256, waunalgRS256];
    DefaultOptions.Registration.UserVerification := waunuvPreferred;
    DefaultOptions.Registration.Attestation      := waunaDirect;
    Timeout                                      := 60000;
    // Challenge: 32 CSPRNG-random bytes, hex-encoded, generated internally by
    // the server; not configurable. Override Response.Challenge instead, in
    // OnWebAuthnRegistrationOptionsResponse / OnWebAuthnAuthenticationOptionsResponse.
    // Metadata Service configuration
    MDS.Enabled            := True;
    MDS.MDS_FileName       := 'mds.json';
    MDS.RootCert_FileName  := 'root.pem';
  end;
  // Hook events
  FWebAuthn.OnWebAuthnRegistrationOptionsRequest := AuthnRegOptionsRequest;
  FWebAuthn.OnWebAuthnRegistrationOptionsResponse := AuthnRegOptionsResponse;
  FWebAuthn.OnWebAuthnRegistrationValidateCertificate := AuthnRegVerify;
  FWebAuthn.OnWebAuthnRegistrationSuccessful     := AuthnRegSuccess;
  FWebAuthn.OnWebAuthnAuthenticationOptionsRequest := AuthnOptionsRequest;
  FWebAuthn.OnWebAuthnAuthenticationSuccessful     := AuthnSuccess;
end;

Event Implementations

procedure TForm1.AuthnRegOptionsRequest(Sender: TObject;
  const Request: TsgcWebAuthn_RegistrationOptions_Request; var Accept: Boolean);
begin
  // Verify utente è eligible per registration
  Accept := not UserExists(Request.Username);
end;
procedure TForm1.AuthnRegOptionsResponse(Sender: TObject;
  const Request: TsgcWebAuthn_RegistrationOptions_Request;
  const Response: TsgcWebAuthn_RegistrationOptions_Response);
begin
  // Optionally assign a utente gestire (binary identifier)
  Response.User.Id := HexToBin(UserGUIDToHex(GenerateGUID));
  Response.AuthenticatorSelection.AuthenticatorAttachment := 'platform';
end;
procedure TForm1.AuthnRegVerify(Sender: TObject;
  const Request: TsgcWebAuthn_RegistrationVerify_Request;
  const Validate: TsgcWebAuthnValidateAttestationStatement; var Accept: Boolean);
begin
  // Perform extra attestation validation contro MDS entries
  Accept := ValidateAttestationWithMDS(Validate);
end;
procedure TForm1.AuthnRegSuccess(Sender: TObject;
  const Registration: TsgcWebAuthn_Registration;
  const CredentialRecord: TsgcWebAuthn_CredentialRecord; var Accept: Boolean);
begin
  // Persist credential details in database
  SaveCredentialToDB(
    CredentialRecord.Username,
    CredentialRecord.CredentialId,
    CredentialRecord.PublicKey,
    CredentialRecord.SignCount,
    CredentialRecord.UserId
  );
  Accept := True;
end;
procedure TForm1.AuthnOptionsRequest(Sender: TObject;
  const Request: TsgcWebAuthn_AuthenticationOptions_Request;
  var CredentialRecords: TsgcWebAuthn_CredentialRecords; var Accept: Boolean);
begin
  // Retrieve tutti credential records per user
  CredentialRecords := LoadCredentialRecordsFromDB(Request.Username);
  Accept := True;
end;
procedure TForm1.AuthnSuccess(Sender: TObject;
  const Request: TsgcWebAuthn_AuthenticationVerify_Request;
  const Authentication: TsgcWebAuthn_Authentication; var Accept: Boolean);
var
  StoredCounter: Cardinal;
begin
  // Ensure sign counter increases
  StoredCounter := GetSignCounterFromDB(Authentication.Credential.CredentialRecord.CredentialId);
  Accept := Authentication.Credential.CredentialRecord.SignCount > StoredCounter;
  if Accept then
  begin
    UpdateSignCounterInDB(Authentication.Credential.CredentialRecord.CredentialId,
      Authentication.Credential.CredentialRecord.SignCount);
    IssueSessionToken(Authentication.Credential.CredentialRecord.Username);
  end;
end;

Key Highlights

Casualità del challenge – Ogni challenge viene generato internamente dal server come 32 byte casuali crittograficamente sicuri, codificati in esadecimale, il che resiste già agli attacchi replay senza alcuna configurazione aggiuntiva.
Custom User Handles – Assigning a unique binary utente gestire consente il authenticator a memorizzare a privacy-preserving identifier independent di usernames.
Metadata-Based Attestation Validation – Il ValidateAttestationWithMDS routine cross-checks authenticator model, status reports, e revocation lists, ensuring solo trusted dispositivi sono registered.
Sign Counter Enforcement – AuthnSuccess rejects risposte che do non strictly increment il authenticator's counter, detecting cloned credentials.
Database Integration – Credential data, sign counters, e session token sono memorizzato e aggiornato tramite external persistence functions, demonstrating come a integrate il componente con a real-world backend.
Cross-Origin Iframe Support – Abilitato attraverso AllowCrossOrigins e configured TopOrigins, consentendo WebAuthn flows initiated da embedded frames (e.g., login widget su different domain).
Attestation Policy – Direct attestation coupled con MDS ensures solo approved authenticators può register, useful per enterprise compliance scenarios.
Transport Selection – Benché non shown, eventi può constrain acceptable transports (e.g., USB,NFC,BLE) a tailor che types di authenticators sono permitted.