/// <summary> /// Called to create a new identity token. An application may use this context /// to replace the authentication ticket before it is serialized or to use its own token format /// and skip the default logic using <see cref="BaseContext{OpenIdConnectServerOptions}.HandleResponse"/>. /// </summary> /// <param name="context">The context of the event carries information in and results out.</param> /// <returns>Task to enable asynchronous execution</returns> public virtual Task CreateIdentityToken(CreateIdentityTokenContext context) => OnCreateIdentityToken(context);
private async Task <string> CreateIdentityTokenAsync( ClaimsPrincipal principal, AuthenticationProperties properties, OpenIdConnectMessage request, OpenIdConnectMessage response) { try { // properties.IssuedUtc and properties.ExpiresUtc // should always be preferred when explicitly set. if (properties.IssuedUtc == null) { properties.IssuedUtc = Options.SystemClock.UtcNow; } if (properties.ExpiresUtc == null) { properties.ExpiresUtc = properties.IssuedUtc + Options.IdentityTokenLifetime; } properties.SetUsage(OpenIdConnectConstants.Usages.IdToken); // Replace the principal by a new one containing only the filtered claims. // Actors identities are also filtered (delegation scenarios). principal = principal.Clone(claim => { // ClaimTypes.NameIdentifier and JwtRegisteredClaimNames.Sub are never excluded. if (string.Equals(claim.Type, ClaimTypes.NameIdentifier, StringComparison.Ordinal) || string.Equals(claim.Type, JwtRegisteredClaimNames.Sub, StringComparison.Ordinal)) { return(true); } // Claims whose destination is not explicitly referenced or // doesn't contain "id_token" are not included in the identity token. return(claim.HasDestination(OpenIdConnectConstants.ResponseTypes.IdToken)); }); var identity = (ClaimsIdentity)principal.Identity; identity.AddClaim(JwtRegisteredClaimNames.Iat, EpochTime.GetIntDate(properties.IssuedUtc.Value.UtcDateTime).ToString()); if (!string.IsNullOrEmpty(response.Code)) { using (var algorithm = SHA256.Create()) { // Create the c_hash using the authorization code returned by CreateAuthorizationCodeAsync. var hash = algorithm.ComputeHash(Encoding.ASCII.GetBytes(response.Code)); // Note: only the left-most half of the hash of the octets is used. // See http://openid.net/specs/openid-connect-core-1_0.html#HybridIDToken identity.AddClaim(JwtRegisteredClaimNames.CHash, Base64UrlEncoder.Encode(hash, 0, hash.Length / 2)); } } if (!string.IsNullOrEmpty(response.AccessToken)) { using (var algorithm = SHA256.Create()) { // Create the at_hash using the access token returned by CreateAccessTokenAsync. var hash = algorithm.ComputeHash(Encoding.ASCII.GetBytes(response.AccessToken)); // Note: only the left-most half of the hash of the octets is used. // See http://openid.net/specs/openid-connect-core-1_0.html#CodeIDToken identity.AddClaim(JwtRegisteredClaimNames.AtHash, Base64UrlEncoder.Encode(hash, 0, hash.Length / 2)); } } var nonce = request.Nonce; // If a nonce was present in the authorization request, it MUST // be included in the id_token generated by the token endpoint. // See http://openid.net/specs/openid-connect-core-1_0.html#IDTokenValidation if (request.IsAuthorizationCodeGrantType()) { // Restore the nonce stored in the authentication // ticket extracted from the authorization code. nonce = properties.GetNonce(); } if (!string.IsNullOrEmpty(nonce)) { identity.AddClaim(JwtRegisteredClaimNames.Nonce, nonce); } // While the 'sub' claim is declared mandatory by the OIDC specs, // it is not always issued as-is by the authorization servers. // When missing, the name identifier claim is used as a substitute. // See http://openid.net/specs/openid-connect-core-1_0.html#IDToken var subject = principal.FindFirst(JwtRegisteredClaimNames.Sub); if (subject == null) { var identifier = principal.FindFirst(ClaimTypes.NameIdentifier); if (identifier == null) { throw new InvalidOperationException( "A unique identifier cannot be found to generate a 'sub' claim. " + "Make sure to either add a 'sub' or a 'ClaimTypes.NameIdentifier' claim " + "in the returned ClaimsIdentity before calling SignIn."); } identity.AddClaim(JwtRegisteredClaimNames.Sub, identifier.Value); } // Remove the ClaimTypes.NameIdentifier claims to avoid getting duplicate claims. // Note: the "sub" claim is automatically mapped by JwtSecurityTokenHandler // to ClaimTypes.NameIdentifier when validating a JWT token. // Note: make sure to call ToArray() to avoid an InvalidOperationException // on old versions of Mono, where FindAll() is implemented using an iterator. foreach (var claim in identity.FindAll(ClaimTypes.NameIdentifier).ToArray()) { identity.RemoveClaim(claim); } // Create a new ticket containing the updated properties and the filtered principal. var ticket = new AuthenticationTicket(principal, properties, Options.AuthenticationScheme); var notification = new CreateIdentityTokenContext(Context, Options, request, response, ticket) { Issuer = Context.GetIssuer(Options), SecurityTokenHandler = Options.IdentityTokenHandler, SignatureProvider = Options.SignatureProvider, SigningCredentials = Options.SigningCredentials.FirstOrDefault() }; // Only add client_id in the audiences list if it is non-null. if (!string.IsNullOrEmpty(request.ClientId)) { notification.Audiences.Add(request.ClientId); } // Sets the default identity token serializer. notification.Serializer = payload => { if (notification.SecurityTokenHandler == null) { return(Task.FromResult <string>(null)); } // Extract the main identity from the principal. identity = (ClaimsIdentity)payload.Principal.Identity; // Store the "usage" property as a claim. identity.AddClaim(OpenIdConnectConstants.Extra.Usage, payload.Properties.GetUsage()); // If the ticket is marked as confidential, // add a new "conf" claim in the JWT token. if (payload.Properties.IsConfidential()) { identity.AddClaim(OpenIdConnectConstants.Extra.Confidential, "true"); } // Store the audiences as claims. foreach (var audience in notification.Audiences) { identity.AddClaim(JwtRegisteredClaimNames.Aud, audience); } var token = notification.SecurityTokenHandler.CreateToken( subject: identity, issuer: notification.Issuer, signatureProvider: notification.SignatureProvider, signingCredentials: notification.SigningCredentials, notBefore: payload.Properties.IssuedUtc.Value.UtcDateTime, expires: payload.Properties.ExpiresUtc.Value.UtcDateTime); if (notification.SigningCredentials != null) { var x509SecurityKey = notification.SigningCredentials.SigningKey as X509SecurityKey; if (x509SecurityKey != null) { // Note: unlike "kid", "x5t" is not automatically added by JwtHeader's constructor in IdentityModel for ASP.NET 5. // Though not required by the specifications, this property is needed for IdentityModel for Katana to work correctly. // See https://github.com/aspnet-contrib/AspNet.Security.OpenIdConnect.Server/issues/132 // and https://github.com/AzureAD/azure-activedirectory-identitymodel-extensions-for-dotnet/issues/181. token.Header[JwtHeaderParameterNames.X5t] = Base64UrlEncoder.Encode(x509SecurityKey.Certificate.GetCertHash()); } object identifier; if (!token.Header.TryGetValue(JwtHeaderParameterNames.Kid, out identifier) || identifier == null) { // When the token doesn't contain a "kid" parameter in the header, automatically add one // using the identifier specified in the signing credentials or in the security key. identifier = notification.SigningCredentials.Kid ?? notification.SigningCredentials.SigningKey.KeyId; if (identifier == null) { // When no key identifier has been explicitly added by the developer, a "kid" is automatically // inferred from the hexadecimal representation of the certificate thumbprint (SHA-1). if (x509SecurityKey != null) { identifier = x509SecurityKey.Certificate.Thumbprint; } // When no key identifier has been explicitly added by the developer, a "kid" // is automatically inferred from the modulus if the signing key is a RSA key. var rsaSecurityKey = notification.SigningCredentials.SigningKey as RsaSecurityKey; if (rsaSecurityKey != null) { // Only use the 40 first chars to match the identifier used by the JWKS endpoint. identifier = Base64UrlEncoder.Encode(rsaSecurityKey.Parameters.Modulus) .Substring(0, 40).ToUpperInvariant(); } } token.Header[JwtHeaderParameterNames.Kid] = identifier; } } return(Task.FromResult(notification.SecurityTokenHandler.WriteToken(token))); }; await Options.Provider.CreateIdentityToken(notification); // Treat a non-null identity token like an implicit HandleResponse call. if (notification.HandledResponse || !string.IsNullOrEmpty(notification.IdentityToken)) { return(notification.IdentityToken); } else if (notification.Skipped) { return(null); } // Allow the application to change the authentication // ticket from the CreateIdentityTokenAsync event. ticket = notification.AuthenticationTicket; ticket.Properties.CopyTo(properties); return(await notification.SerializeTicketAsync()); } catch (Exception exception) { Logger.LogWarning("An exception occured when serializing an identity token.", exception); return(null); } }