目錄

• identityserver4源碼解析_1_項目結構
• identityserver4源碼解析_2_元數據介面
• identityserver4源碼解析_3_認證介面
• identityserver4源碼解析_4_令牌發放介面
• identityserver4源碼解析_5_查詢用戶信息介面
• identityserver4源碼解析_6_結束會話介面
• identityserver4源碼解析_7_查詢令牌信息介面
• identityserver4源碼解析_8_撤銷令牌介面

協議

這一系列我們都採用這樣的方式，先大概看下協議，也就是需求描述，然後看idsv4怎麼實現的，這樣可以加深理解。
元數據介面的協議地址如下：

https://openid.net/specs/openid-connect-discovery-1_0.html

摘要

該協議定義了一套標準，用戶能夠獲取到oidc服務的基本信息，包括OAuth2.0相關介面地址。

Webfinger - 網路指紋

先瞭解一下Webfinger這個概念。

WebFinger可以翻譯成網路指紋，它定義了一套標準，描述如何通過標準的HTTP方法去獲取網路實體的資料信息。WebFinger使用JSON來描述實體信息。

https://tools.ietf.org/html/rfc7033

查詢oidc服務元數據 - OpenID Provider Issuer Discovery

可選協議。
定義瞭如何獲取oidc服務元數據。如果客戶端明確知道oidc服務的地址，可以跳過此部分。
個人理解是存在多個oidc服務的情況，可以部署一個webfinger服務，根據資源請求，路由到不同的oidc服務。
通常來說，我們只有一個oidc服務，我看了一下idsv4也沒有實現這一部分協議，這裡瞭解一下就可以了。

查詢oidc服務配置信息 - OpenID Provider Configuration Request

必選協議。
用於描述oidc服務各介面地址及其他配置信息。

  GET /.well-known/openid-configuration HTTP/1.1
  Host: example.com

必須校驗issuer與請求地址是否一致

啟個idsrv服務調用試一下，返回結果如圖

詳細信息如下。

{
    "issuer": "https://localhost:10000", //頒發者地址
    "jwks_uri": "https://localhost:10000/.well-known/openid-configuration/jwks", //jwks介面地址，查詢密鑰
    "authorization_endpoint": "https://localhost:10000/connect/authorize", //認證介面地址
    "token_endpoint": "https://localhost:10000/connect/token", //令牌發放介面
    "userinfo_endpoint": "https://localhost:10000/connect/userinfo", //查詢用戶信息介面
    "end_session_endpoint": "https://localhost:10000/connect/endsession", //結束會話介面
    "check_session_iframe": "https://localhost:10000/connect/checksession", //檢查會話介面
    "revocation_endpoint": "https://localhost:10000/connect/revocation", //撤銷令牌介面
    "introspection_endpoint": "https://localhost:10000/connect/introspect", //查詢令牌詳情介面
    "device_authorization_endpoint": "https://localhost:10000/connect/deviceauthorization", //設備認證介面
    "frontchannel_logout_supported": true, //是否支持前端登出
    "frontchannel_logout_session_supported": true, //是否支持前端結束會話
    "backchannel_logout_supported": true, //是否支持後端登出
    "backchannel_logout_session_supported": true, //是否支持後端結束會話
    "scopes_supported": [ //支持的授權範圍,scope
        "openid",
        "profile",
        "userid",
        "username",
        "email",
        "mobile",
        "api",
        "offline_access" //token過期可用refresh_token刷新換取新token
    ],
    "claims_supported": [ //支持的聲明
        "sub",
        "updated_at",
        "locale",
        "zoneinfo",
        "birthdate",
        "gender",
        "preferred_username",
        "picture",
        "profile",
        "nickname",
        "middle_name",
        "given_name",
        "family_name",
        "website",
        "name",
        "userid",
        "username",
        "email",
        "mobile"
    ],
    "grant_types_supported": [ //支持的認證類型
        "authorization_code", //授權碼模式
        "client_credentials", //客戶端密鑰模式
        "refresh_token", //刷新token
        "implicit", //隱式流程, 一般用於單頁應用javascript客戶端
        "password", //用戶名密碼模式
        "urn:ietf:params:oauth:grant-type:device_code" //設備授權碼
    ],
    "response_types_supported": [ //支持的返回類型
        "code", //授權碼 
        "token", //通行令牌
        "id_token", //身份令牌
        "id_token token", //身份令牌+統通行令牌
        "code id_token", //授權碼+身份令牌
        "code token", //授權碼+通行令牌
        "code id_token token" //授權碼+身份令牌+通行令牌
    ],
    "response_modes_supported": [ //支持的響應方法
        "form_post", //form-post提交
        "query", //get提交
        "fragment" //fragment提交
    ],
    "token_endpoint_auth_methods_supported": [ //發放令牌介面支持的認證方式
        "client_secret_basic", //basic
        "client_secret_post" //post
    ],
    "id_token_signing_alg_values_supported": [ //身份令牌加密演算法
        "RS256"
    ],
    "subject_types_supported": [
        "public"
    ],
    "code_challenge_methods_supported": [
        "plain",
        "S256"
    ],
    "request_parameter_supported": true
}

JWK - Json Web Keys

idsv還註入這樣一個介面：DiscoveryKeyEndpoint，嘗試發現返回了一組密鑰。協議內容如下。

https://tools.ietf.org/html/draft-ietf-jose-json-web-key-41

GET /.well-known/openid-configuration/jwks，返回結果如下

{
    "keys": [
        {
            "kty": "RSA",
            "use": "sig",
            "kid": "LS-EQOr-3BkalkkUVh8q7Q",
            "e": "AQAB",
            "n": "08BLLaTz4JrTYmE4bZ9c7oKVrZKLy3KfGT5mmnslhl41nk_EV_8OUdL8wMXunC2KERdnsy5XYk4aw3LlvxZDIvjxO9PEblPsoap-WErdi9GVyAv-NJ6eJQy3S7FRSkvzQYBsLnCKm5wu0kjdQBVUCFJ7wfiZ9ayY7pH7K10qN2Utvt-qsCLUy0cJ0StuP_rquefp7_XhUw3A8IIA8P6DjfZIbpwrVjOeVWoI_ZKIwfxShghOAKBDLyQuC2PhozsqZ7HvGEeAPm06YPMWQVbE9_LBn2j_Ul_VBUWc9KfBNOzk_BMQHyF2NUlwMtqMUEcwK_hpjEeo62O_aFT8EDkgcQ",
            "alg": "RS256"
        },
        {
            "kty": "RSA",
            "use": "sig",
            "kid": "LS-EQOr-3BkalkkUVh8q7Q",
            "e": "AQAB",
            "n": "08BLLaTz4JrTYmE4bZ9c7oKVrZKLy3KfGT5mmnslhl41nk_EV_8OUdL8wMXunC2KERdnsy5XYk4aw3LlvxZDIvjxO9PEblPsoap-WErdi9GVyAv-NJ6eJQy3S7FRSkvzQYBsLnCKm5wu0kjdQBVUCFJ7wfiZ9ayY7pH7K10qN2Utvt-qsCLUy0cJ0StuP_rquefp7_XhUw3A8IIA8P6DjfZIbpwrVjOeVWoI_ZKIwfxShghOAKBDLyQuC2PhozsqZ7HvGEeAPm06YPMWQVbE9_LBn2j_Ul_VBUWc9KfBNOzk_BMQHyF2NUlwMtqMUEcwK_hpjEeo62O_aFT8EDkgcQ",
            "alg": "RS256"
        }
    ]
}

源碼解析

介面地址都在Constants.cs這個文件，ProtocalRoutePaths這個類裡面定義的。現在知道為什麼介面地址是.well-known/openid-configuration這樣奇怪的一個路由了，這是oidc協議定的（對，都是產品的鍋）。

oidc服務配置信息介面 - DiscoveryEndpoint

代碼很長，但是邏輯很簡單，就是組裝協議規定的所有地址和信息。
需要註意的支持的claims、支持的scope等信息是遍歷所有IdentityResource、ApiResource動態獲取的。
基本上每個介面都可以配置是否顯示在元數據文檔中。

public async Task<IEndpointResult> ProcessAsync(HttpContext context)
{
    _logger.LogTrace("Processing discovery request.");

    // validate HTTP
    if (!HttpMethods.IsGet(context.Request.Method))
    {
        _logger.LogWarning("Discovery endpoint only supports GET requests");
        return new StatusCodeResult(HttpStatusCode.MethodNotAllowed);
    }

    _logger.LogDebug("Start discovery request");

    if (!_options.Endpoints.EnableDiscoveryEndpoint)
    {
        _logger.LogInformation("Discovery endpoint disabled. 404.");
        return new StatusCodeResult(HttpStatusCode.NotFound);
    }

    var baseUrl = context.GetIdentityServerBaseUrl().EnsureTrailingSlash();
    var issuerUri = context.GetIdentityServerIssuerUri();

    // generate response
    _logger.LogTrace("Calling into discovery response generator: {type}", _responseGenerator.GetType().FullName);
    var response = await _responseGenerator.CreateDiscoveryDocumentAsync(baseUrl, issuerUri);

    return new DiscoveryDocumentResult(response, _options.Discovery.ResponseCacheInterval);
}

/// <summary>
/// Creates the discovery document.
/// </summary>
/// <param name="baseUrl">The base URL.</param>
/// <param name="issuerUri">The issuer URI.</param>
public virtual async Task<Dictionary<string, object>> CreateDiscoveryDocumentAsync(string baseUrl, string issuerUri)
{
    var entries = new Dictionary<string, object>
    {
        { OidcConstants.Discovery.Issuer, issuerUri }
    };

    // jwks
    if (Options.Discovery.ShowKeySet)
    {
        if ((await Keys.GetValidationKeysAsync()).Any())
        {
            entries.Add(OidcConstants.Discovery.JwksUri, baseUrl + Constants.ProtocolRoutePaths.DiscoveryWebKeys);
        }
    }

    // endpoints
    if (Options.Discovery.ShowEndpoints)
    {
        if (Options.Endpoints.EnableAuthorizeEndpoint)
        {
            entries.Add(OidcConstants.Discovery.AuthorizationEndpoint, baseUrl + Constants.ProtocolRoutePaths.Authorize);
        }

        if (Options.Endpoints.EnableTokenEndpoint)
        {
            entries.Add(OidcConstants.Discovery.TokenEndpoint, baseUrl + Constants.ProtocolRoutePaths.Token);
        }

        if (Options.Endpoints.EnableUserInfoEndpoint)
        {
            entries.Add(OidcConstants.Discovery.UserInfoEndpoint, baseUrl + Constants.ProtocolRoutePaths.UserInfo);
        }

        if (Options.Endpoints.EnableEndSessionEndpoint)
        {
            entries.Add(OidcConstants.Discovery.EndSessionEndpoint, baseUrl + Constants.ProtocolRoutePaths.EndSession);
        }

        if (Options.Endpoints.EnableCheckSessionEndpoint)
        {
            entries.Add(OidcConstants.Discovery.CheckSessionIframe, baseUrl + Constants.ProtocolRoutePaths.CheckSession);
        }

        if (Options.Endpoints.EnableTokenRevocationEndpoint)
        {
            entries.Add(OidcConstants.Discovery.RevocationEndpoint, baseUrl + Constants.ProtocolRoutePaths.Revocation);
        }

        if (Options.Endpoints.EnableIntrospectionEndpoint)
        {
            entries.Add(OidcConstants.Discovery.IntrospectionEndpoint, baseUrl + Constants.ProtocolRoutePaths.Introspection);
        }

        if (Options.Endpoints.EnableDeviceAuthorizationEndpoint)
        {
            entries.Add(OidcConstants.Discovery.DeviceAuthorizationEndpoint, baseUrl + Constants.ProtocolRoutePaths.DeviceAuthorization);
        }

        if (Options.MutualTls.Enabled)
        {
            var mtlsEndpoints = new Dictionary<string, string>();

            if (Options.Endpoints.EnableTokenEndpoint)
            {
                mtlsEndpoints.Add(OidcConstants.Discovery.TokenEndpoint, baseUrl + Constants.ProtocolRoutePaths.MtlsToken);
            }
            if (Options.Endpoints.EnableTokenRevocationEndpoint)
            {
                mtlsEndpoints.Add(OidcConstants.Discovery.RevocationEndpoint, baseUrl + Constants.ProtocolRoutePaths.MtlsRevocation);
            }
            if (Options.Endpoints.EnableIntrospectionEndpoint)
            {
                mtlsEndpoints.Add(OidcConstants.Discovery.IntrospectionEndpoint, baseUrl + Constants.ProtocolRoutePaths.MtlsIntrospection);
            }
            if (Options.Endpoints.EnableDeviceAuthorizationEndpoint)
            {
                mtlsEndpoints.Add(OidcConstants.Discovery.DeviceAuthorizationEndpoint, baseUrl + Constants.ProtocolRoutePaths.MtlsDeviceAuthorization);
            }

            if (mtlsEndpoints.Any())
            {
                entries.Add(OidcConstants.Discovery.MtlsEndpointAliases, mtlsEndpoints);
            }
        }
    }

    // logout
    if (Options.Endpoints.EnableEndSessionEndpoint)
    {
        entries.Add(OidcConstants.Discovery.FrontChannelLogoutSupported, true);
        entries.Add(OidcConstants.Discovery.FrontChannelLogoutSessionSupported, true);
        entries.Add(OidcConstants.Discovery.BackChannelLogoutSupported, true);
        entries.Add(OidcConstants.Discovery.BackChannelLogoutSessionSupported, true);
    }

    // scopes and claims
    if (Options.Discovery.ShowIdentityScopes ||
        Options.Discovery.ShowApiScopes ||
        Options.Discovery.ShowClaims)
    {
        var resources = await ResourceStore.GetAllEnabledResourcesAsync();
        var scopes = new List<string>();

        // scopes
        if (Options.Discovery.ShowIdentityScopes)
        {
            scopes.AddRange(resources.IdentityResources.Where(x => x.ShowInDiscoveryDocument).Select(x => x.Name));
        }

        if (Options.Discovery.ShowApiScopes)
        {
            var apiScopes = from api in resources.ApiResources
                            from scope in api.Scopes
                            where scope.ShowInDiscoveryDocument
                            select scope.Name;

            scopes.AddRange(apiScopes);
            scopes.Add(IdentityServerConstants.StandardScopes.OfflineAccess);
        }

        if (scopes.Any())
        {
            entries.Add(OidcConstants.Discovery.ScopesSupported, scopes.ToArray());
        }

        // claims
        if (Options.Discovery.ShowClaims)
        {
            var claims = new List<string>();

            // add non-hidden identity scopes related claims
            claims.AddRange(resources.IdentityResources.Where(x => x.ShowInDiscoveryDocument).SelectMany(x => x.UserClaims));

            // add non-hidden api scopes related claims
            foreach (var resource in resources.ApiResources)
            {
                claims.AddRange(resource.UserClaims);

                foreach (var scope in resource.Scopes)
                {
                    if (scope.ShowInDiscoveryDocument)
                    {
                        claims.AddRange(scope.UserClaims);
                    }
                }
            }

            entries.Add(OidcConstants.Discovery.ClaimsSupported, claims.Distinct().ToArray());
        }
    }

    // grant types
    if (Options.Discovery.ShowGrantTypes)
    {
        var standardGrantTypes = new List<string>
        {
            OidcConstants.GrantTypes.AuthorizationCode,
            OidcConstants.GrantTypes.ClientCredentials,
            OidcConstants.GrantTypes.RefreshToken,
            OidcConstants.GrantTypes.Implicit
        };

        if (!(ResourceOwnerValidator is NotSupportedResourceOwnerPasswordValidator))
        {
            standardGrantTypes.Add(OidcConstants.GrantTypes.Password);
        }

        if (Options.Endpoints.EnableDeviceAuthorizationEndpoint)
        {
            standardGrantTypes.Add(OidcConstants.GrantTypes.DeviceCode);
        }

        var showGrantTypes = new List<string>(standardGrantTypes);

        if (Options.Discovery.ShowExtensionGrantTypes)
        {
            showGrantTypes.AddRange(ExtensionGrants.GetAvailableGrantTypes());
        }

        entries.Add(OidcConstants.Discovery.GrantTypesSupported, showGrantTypes.ToArray());
    }

    // response types
    if (Options.Discovery.ShowResponseTypes)
    {
        entries.Add(OidcConstants.Discovery.ResponseTypesSupported, Constants.SupportedResponseTypes.ToArray());
    }

    // response modes
    if (Options.Discovery.ShowResponseModes)
    {
        entries.Add(OidcConstants.Discovery.ResponseModesSupported, Constants.SupportedResponseModes.ToArray());
    }

    // misc
    if (Options.Discovery.ShowTokenEndpointAuthenticationMethods)
    {
        var types = SecretParsers.GetAvailableAuthenticationMethods().ToList();
        if (Options.MutualTls.Enabled)
        {
            types.Add(OidcConstants.EndpointAuthenticationMethods.TlsClientAuth);
            types.Add(OidcConstants.EndpointAuthenticationMethods.SelfSignedTlsClientAuth);
        }

        entries.Add(OidcConstants.Discovery.TokenEndpointAuthenticationMethodsSupported, types);
    }
    
    var signingCredentials = await Keys.GetSigningCredentialsAsync();
    if (signingCredentials != null)
    {
        var algorithm = signingCredentials.Algorithm;
        entries.Add(OidcConstants.Discovery.IdTokenSigningAlgorithmsSupported, new[] { algorithm });
    }

    entries.Add(OidcConstants.Discovery.SubjectTypesSupported, new[] { "public" });
    entries.Add(OidcConstants.Discovery.CodeChallengeMethodsSupported, new[] { OidcConstants.CodeChallengeMethods.Plain, OidcConstants.CodeChallengeMethods.Sha256 });

    if (Options.Endpoints.EnableAuthorizeEndpoint)
    {
        entries.Add(OidcConstants.Discovery.RequestParameterSupported, true);

        if (Options.Endpoints.EnableJwtRequestUri)
        {
            entries.Add(OidcConstants.Discovery.RequestUriParameterSupported, true);
        }
    }

    if (Options.MutualTls.Enabled)
    {
        entries.Add(OidcConstants.Discovery.TlsClientCertificateBoundAccessTokens, true);
    }

    // custom entries
    if (!Options.Discovery.CustomEntries.IsNullOrEmpty())
    {
        foreach (var customEntry in Options.Discovery.CustomEntries)
        {
            if (entries.ContainsKey(customEntry.Key))
            {
                Logger.LogError("Discovery custom entry {key} cannot be added, because it already exists.", customEntry.Key);
            }
            else
            {
                if (customEntry.Value is string customValueString)
                {
                    if (customValueString.StartsWith("~/") && Options.Discovery.ExpandRelativePathsInCustomEntries)
                    {
                        entries.Add(customEntry.Key, baseUrl + customValueString.Substring(2));
                        continue;
                    }
                }

                entries.Add(customEntry.Key, customEntry.Value);
            }
        }
    }

    return entries;
}

然後是jwks描述信息的代碼。關於加密的信息也是根據配置的SecuritKey去動態返回的。

public virtual async Task<IEnumerable<Models.JsonWebKey>> CreateJwkDocumentAsync()
    {
        var webKeys = new List<Models.JsonWebKey>();
        
        foreach (var key in await Keys.GetValidationKeysAsync())
        {
            if (key.Key is X509SecurityKey x509Key)
            {
                var cert64 = Convert.ToBase64String(x509Key.Certificate.RawData);
                var thumbprint = Base64Url.Encode(x509Key.Certificate.GetCertHash());

                if (x509Key.PublicKey is RSA rsa)
                {
                    var parameters = rsa.ExportParameters(false);
                    var exponent = Base64Url.Encode(parameters.Exponent);
                    var modulus = Base64Url.Encode(parameters.Modulus);

                    var rsaJsonWebKey = new Models.JsonWebKey
                    {
                        kty = "RSA",
                        use = "sig",
                        kid = x509Key.KeyId,
                        x5t = thumbprint,
                        e = exponent,
                        n = modulus,
                        x5c = new[] { cert64 },
                        alg = key.SigningAlgorithm
                    };
                    webKeys.Add(rsaJsonWebKey);
                }
                else if (x509Key.PublicKey is ECDsa ecdsa)
                {
                    var parameters = ecdsa.ExportParameters(false);
                    var x = Base64Url.Encode(parameters.Q.X);
                    var y = Base64Url.Encode(parameters.Q.Y);

                    var ecdsaJsonWebKey = new Models.JsonWebKey
                    {
                        kty = "EC",
                        use = "sig",
                        kid = x509Key.KeyId,
                        x5t = thumbprint,
                        x = x,
                        y = y,
                        crv = CryptoHelper.GetCrvValueFromCurve(parameters.Curve),
                        x5c = new[] { cert64 },
                        alg = key.SigningAlgorithm
                    };
                    webKeys.Add(ecdsaJsonWebKey);
                }
                else
                {
                    throw new InvalidOperationException($"key type: {x509Key.PublicKey.GetType().Name} not supported.");
                }
            }
            else if (key.Key is RsaSecurityKey rsaKey)
            {
                var parameters = rsaKey.Rsa?.ExportParameters(false) ?? rsaKey.Parameters;
                var exponent = Base64Url.Encode(parameters.Exponent);
                var modulus = Base64Url.Encode(parameters.Modulus);

                var webKey = new Models.JsonWebKey
                {
                    kty = "RSA",
                    use = "sig",
                    kid = rsaKey.KeyId,
                    e = exponent,
                    n = modulus,
                    alg = key.SigningAlgorithm
                };

                webKeys.Add(webKey);
            }
            else if (key.Key is ECDsaSecurityKey ecdsaKey)
            {
                var parameters = ecdsaKey.ECDsa.ExportParameters(false);
                var x = Base64Url.Encode(parameters.Q.X);
                var y = Base64Url.Encode(parameters.Q.Y);

                var ecdsaJsonWebKey = new Models.JsonWebKey
                {
                    kty = "EC",
                    use = "sig",
                    kid = ecdsaKey.KeyId,
                    x = x,
                    y = y,
                    crv = CryptoHelper.GetCrvValueFromCurve(parameters.Curve),
                    alg = key.SigningAlgorithm
                };
                webKeys.Add(ecdsaJsonWebKey);
            }
            else if (key.Key is JsonWebKey jsonWebKey)
            {
                var webKey = new Models.JsonWebKey
                {
                    kty = jsonWebKey.Kty,
                    use = jsonWebKey.Use ?? "sig",
                    kid = jsonWebKey.Kid,
                    x5t = jsonWebKey.X5t,
                    e = jsonWebKey.E,
                    n = jsonWebKey.N,
                    x5c = jsonWebKey.X5c?.Count == 0 ? null : jsonWebKey.X5c.ToArray(),
                    alg = jsonWebKey.Alg,

                    x = jsonWebKey.X,
                    y = jsonWebKey.Y
                };

                webKeys.Add(webKey);
            }
        }

        return webKeys;
    }

結語

這一節還是比較好理解的。總而言之就是oidc協議規定了，需要提供GET介面，返回所有介面的地址，以及相關配置信息。idsv4的實現方式就是介面地址根據協議規定的去拼接，其他配置項信息根據開發的配置去動態獲取，然後以協議約定的JSON格式返回。