feat(oidc): implement client type public (#2171)

This implements the public option for clients which allows using Authelia as an OpenID Connect Provider for cli applications and SPA's where the client secret cannot be considered secure.

config.template.yml

@@ -595,7 +595,7 @@ notifier:
     ## Enables additional debug messages.
     # enable_client_debug_messages: false
 
-    ## SECURITY NOTICE: It's not recommended to change this option, and highly discouraged to have it below 8 for
+    ## SECURITY NOTICE: It's not recommended changing this option, and highly discouraged to have it below 8 for
     ## security reasons.
     # minimum_parameter_entropy: 8
 
@@ -611,20 +611,26 @@ notifier:
         ## The client secret is a shared secret between Authelia and the consumer of this client.
         # secret: this_is_a_secret
 
+        ## Sets the client to public. This should typically not be set, please see the documentation for usage.
+        # public: false
+
         ## The policy to require for this client; one_factor or two_factor.
         # authorization_policy: two_factor
 
-        ## Redirect URI's specifies a list of valid case-sensitive callbacks for this client.
+        ## Audience this client is allowed to request.
-        # redirect_uris:
+        # audience: []
-        # - https://oidc.example.com:8080/oauth2/callback
 
-        ## Scopes defines the valid scopes this client can request
+        ## Scopes this client is allowed to request.
         # scopes:
           # - openid
           # - groups
           # - email
           # - profile
 
+        ## Redirect URI's specifies a list of valid case-sensitive callbacks for this client.
+        # redirect_uris:
+        # - https://oidc.example.com:8080/oauth2/callback
+
         ## Grant Types configures which grants this client can obtain.
         ## It's not recommended to define this unless you know what you're doing.
         # grant_types:

docs/configuration/identity-providers/oidc.md

@@ -34,7 +34,7 @@ for which stage will have each feature, and may evolve over time:
     </thead>
     <tbody>
       <tr>
-        <td rowspan="7" class="tbl-header tbl-beta-stage">beta1</td>
+        <td rowspan="8" class="tbl-header tbl-beta-stage">beta1 (4.29.0)</td>
         <td><a href="https://openid.net/specs/openid-connect-core-1_0.html#Consent" target="_blank" rel="noopener noreferrer">User Consent</a></td>
       </tr>
       <tr>
@@ -56,9 +56,27 @@ for which stage will have each feature, and may evolve over time:
         <td class="tbl-beta-stage">Per Client List of Valid Redirection URI's</td>
       </tr>
       <tr>
-        <td rowspan="1" class="tbl-header tbl-beta-stage">beta2 <sup>1</sup></td>
+        <td class="tbl-beta-stage"><a href="https://datatracker.ietf.org/doc/html/rfc6749#section-2.1" target="_blank"rel="noopener noreferrer">Confidential Client Type</a></td>
+      </tr>
+      <tr>
+        <td rowspan="6" class="tbl-header tbl-beta-stage">beta2 (4.30.0) <sup>1</sup></td>
         <td class="tbl-beta-stage"><a href="https://openid.net/specs/openid-connect-core-1_0.html#UserInfo" target="_blank" rel="noopener noreferrer">Userinfo Endpoint</a> (missed in beta1)</td>
       </tr>
+      <tr>
+        <td class="tbl-beta-stage">Parameter Entropy Configuration</td>
+      </tr>
+      <tr>
+        <td class="tbl-beta-stage">Token/Code Lifespan Configuration</td>
+      </tr>
+      <tr>
+        <td class="tbl-beta-stage">Client Debug Messages</td>
+      </tr>
+      <tr>
+        <td class="tbl-beta-stage">Client Audience</td>
+      </tr>
+      <tr>
+        <td class="tbl-beta-stage"><a href="https://datatracker.ietf.org/doc/html/rfc6749#section-2.1" target="_blank"rel="noopener noreferrer">Public Client Type</a></td>
+      </tr>
       <tr>
         <td rowspan="2" class="tbl-header tbl-beta-stage">beta3 <sup>1</sup></td>
         <td>Token Storage</td>
@@ -117,20 +135,22 @@ identity_providers:
     access_token_lifespan: 1h
     authorize_code_lifespan: 1m
     id_token_lifespan: 1h
-    refresh_token_lifespan: 720h
+    refresh_token_lifespan: 90m
     enable_client_debug_messages: false
     clients:
       - id: myapp
         description: My Application
         secret: this_is_a_secret
+        public: false
         authorization_policy: two_factor
-        redirect_uris:
+        audience: []
-          - https://oidc.example.com:8080/oauth2/callback
         scopes:
           - openid
           - groups
           - email
           - profile
+        redirect_uris:
+          - https://oidc.example.com:8080/oauth2/callback
         grant_types:
           - refresh_token
           - authorization_code
@@ -222,7 +242,7 @@ The maximum lifetime of an ID token. For more information read these docs about
 <div markdown="1">
 type: string
 {: .label .label-config .label-purple }
-default: 30d
+default: 90m
 {: .label .label-config .label-blue }
 required: no
 {: .label .label-config .label-green }
@@ -232,6 +252,11 @@ The maximum lifetime of a refresh token. The
 refresh token can be used to obtain new refresh tokens as well as access tokens or id tokens with an
 up-to-date expiration. For more information read these docs about [token lifespan].
 
+A good starting point is 50% more or 30 minutes more (which ever is less) time than the highest lifespan out of the 
+[access token lifespan](#access_token_lifespan), the [authorize code lifespan](#authorize_code_lifespan), and the
+[id token lifespan](#id_token_lifespan). For instance the default for all of these is 60 minutes, so the default refresh
+token lifespan is 90 minutes.
+
 ### enable_client_debug_messages
 
 <div markdown="1">
@@ -296,14 +321,35 @@ A friendly description for this client shown in the UI. This defaults to the sam
 <div markdown="1">
 type: string
 {: .label .label-config .label-purple }
-required: yes
+required: situational
-{: .label .label-config .label-red }
+{: .label .label-config .label-yellow }
 </div>
 
 The shared secret between Authelia and the application consuming this client. This secret must
 match the secret configured in the application. Currently this is stored in plain text.
 You must [generate this option yourself](#generating-a-random-secret).
 
+This must be provided when the client is a confidential client type, and must be blank when using the public client
+type. To set the client type to public see the [public](#public) configuration option.
+
+#### public
+
+<div markdown="1">
+type: bool
+{: .label .label-config .label-purple }
+default: false
+{: .label .label-config .label-blue }
+required: no
+{: .label .label-config .label-green }
+</div>
+
+This enables the public client type for this client. This is for clients that are not capable of maintaining 
+confidentiality of credentials, you can read more about client types in [RFC6749](https://datatracker.ietf.org/doc/html/rfc6749#section-2.1).
+This is particularly useful for SPA's and CLI tools. This option requires setting the [client secret](#secret) to a 
+blank string.
+
+In addition to the standard rules for redirect URIs, public clients can use the `urn:ietf:wg:oauth:2.0:oob` redirect URI.
+
 #### authorization_policy
 
 <div markdown="1">
@@ -317,18 +363,16 @@ required: no
 
 The authorization policy for this client: either `one_factor` or `two_factor`.
 
-#### redirect_uris
+#### audience
 
 <div markdown="1">
 type: list(string)
 {: .label .label-config .label-purple } 
-required: yes
+required: no
-{: .label .label-config .label-red }
+{: .label .label-config .label-green }
 </div>
 
-A list of valid callback URL´s this client will redirect to. All other callbacks will be considered
+A list of audiences this client is allowed to request.
-unsafe. The URL's are case-sensitive and they differ from application to application - the community has
-provided [a list of URL´s for common applications](../../community/oidc-integrations.md).
 
 #### scopes
 
@@ -345,6 +389,28 @@ A list of scopes to allow this client to consume. See [scope definitions](#scope
 information. The documentation for the application you want to use with Authelia will most-likely provide
 you with the scopes to allow.
 
+#### redirect_uris
+
+<div markdown="1">
+type: list(string)
+{: .label .label-config .label-purple }
+required: yes
+{: .label .label-config .label-red }
+</div>
+
+A list of valid callback URIs this client will redirect to. All other callbacks will be considered
+unsafe. The URIs are case-sensitive and they differ from application to application - the community has
+provided [a list of URL´s for common applications](../../community/oidc-integrations.md).
+
+Some restrictions that have been placed on clients and
+their redirect URIs are as follows:
+
+1. If a client attempts to authorize with Authelia and its redirect URI is not listed in the client configuration the
+   attempt to authorize wil fail and an error will be generated.
+2. The redirect URIs are case-sensitive. 
+3. The URI must include a scheme and that scheme must be one of `http` or `https`.
+4. The client can ignore rule 3 and use `urn:ietf:wg:oauth:2.0:oob` if it is a [public](#public) client type.
+
 #### grant_types
 
 <div markdown="1">

internal/configuration/config.template.yml

@@ -595,7 +595,7 @@ notifier:
     ## Enables additional debug messages.
     # enable_client_debug_messages: false
 
-    ## SECURITY NOTICE: It's not recommended to change this option, and highly discouraged to have it below 8 for
+    ## SECURITY NOTICE: It's not recommended changing this option, and highly discouraged to have it below 8 for
     ## security reasons.
     # minimum_parameter_entropy: 8
 
@@ -611,20 +611,26 @@ notifier:
         ## The client secret is a shared secret between Authelia and the consumer of this client.
         # secret: this_is_a_secret
 
+        ## Sets the client to public. This should typically not be set, please see the documentation for usage.
+        # public: false
+
         ## The policy to require for this client; one_factor or two_factor.
         # authorization_policy: two_factor
 
-        ## Redirect URI's specifies a list of valid case-sensitive callbacks for this client.
+        ## Audience this client is allowed to request.
-        # redirect_uris:
+        # audience: []
-        # - https://oidc.example.com:8080/oauth2/callback
 
-        ## Scopes defines the valid scopes this client can request
+        ## Scopes this client is allowed to request.
         # scopes:
           # - openid
           # - groups
           # - email
           # - profile
 
+        ## Redirect URI's specifies a list of valid case-sensitive callbacks for this client.
+        # redirect_uris:
+        # - https://oidc.example.com:8080/oauth2/callback
+
         ## Grant Types configures which grants this client can obtain.
         ## It's not recommended to define this unless you know what you're doing.
         # grant_types:

internal/configuration/schema/identity_providers.go

@@ -28,9 +28,13 @@ type OpenIDConnectClientConfiguration struct {
 	ID          string `mapstructure:"id"`
 	Description string `mapstructure:"description"`
 	Secret      string `mapstructure:"secret"`
-	RedirectURIs  []string `mapstructure:"redirect_uris"`
+	Public      bool   `mapstructure:"public"`
+
 	Policy string `mapstructure:"authorization_policy"`
+
+	Audience      []string `mapstructure:"audience"`
 	Scopes        []string `mapstructure:"scopes"`
+	RedirectURIs  []string `mapstructure:"redirect_uris"`
 	GrantTypes    []string `mapstructure:"grant_types"`
 	ResponseTypes []string `mapstructure:"response_types"`
 	ResponseModes []string `mapstructure:"response_modes"`

internal/configuration/validator/access_control_test.go

@@ -192,7 +192,7 @@ func TestShouldReturnCorrectResultsForValidNetworkGroups(t *testing.T) {
 	}
 
 	validNetwork := IsNetworkGroupValid(config, "internal")
-	invalidNetwork := IsNetworkGroupValid(config, "127.0.0.1")
+	invalidNetwork := IsNetworkGroupValid(config, loopback)
 
 	assert.True(t, validNetwork)
 	assert.False(t, invalidNetwork)

internal/configuration/validator/authentication_test.go

@@ -443,7 +443,7 @@ func (suite *LDAPAuthenticationBackendSuite) TestShouldHelpDetectNoInputPlacehol
 }
 
 func (suite *LDAPAuthenticationBackendSuite) TestShouldAdaptLDAPURL() {
-	suite.Assert().Equal("", validateLDAPURLSimple("127.0.0.1", suite.validator))
+	suite.Assert().Equal("", validateLDAPURLSimple(loopback, suite.validator))
 
 	suite.Assert().False(suite.validator.HasWarnings())
 	suite.Require().Len(suite.validator.Errors(), 1)

internal/configuration/validator/configuration_test.go

@@ -12,7 +12,7 @@ import (
 
 func newDefaultConfig() schema.Configuration {
 	config := schema.Configuration{}
-	config.Host = "127.0.0.1"
+	config.Host = loopback
 	config.Port = 9090
 	config.Logging.Level = "info"
 	config.Logging.Format = "text"

internal/configuration/validator/const.go

@@ -1,5 +1,10 @@
 package validator
 
+const (
+	loopback           = "127.0.0.1"
+	oauth2InstalledApp = "urn:ietf:wg:oauth:2.0:oob"
+)
+
 const (
 	errFmtDeprecatedConfigurationKey = "[DEPRECATED] The %s configuration option is deprecated and will be " +
 		"removed in %s, please use %s instead"
@@ -14,11 +19,16 @@ const (
 
 	errFmtOIDCServerClientRedirectURI = "OIDC client with ID '%s' redirect URI %s has an invalid scheme '%s', " +
 		"should be http or https"
+	errFmtOIDCClientRedirectURIPublic = "openid connect provider: client with ID '%s' redirect URI '%s' is " +
+		"only valid for the public client type, not the confidential client type"
+	errFmtOIDCClientRedirectURIAbsolute = "openid connect provider: client with ID '%s' redirect URI '%s' is invalid " +
+		"because it has no scheme when it should be http or https"
 	errFmtOIDCServerClientRedirectURICantBeParsed = "OIDC client with ID '%s' has an invalid redirect URI '%s' " +
 		"could not be parsed: %v"
 	errFmtOIDCServerClientInvalidPolicy = "OIDC client with ID '%s' has an invalid policy '%s', " +
 		"should be either 'one_factor' or 'two_factor'"
 	errFmtOIDCServerClientInvalidSecret = "OIDC client with ID '%s' has an empty secret"                                             //nolint:gosec
+	errFmtOIDCClientPublicInvalidSecret = "openid connect provider: client with ID '%s' is public but does not have an empty secret" //nolint:gosec
 	errFmtOIDCServerClientInvalidScope  = "OIDC client with ID '%s' has an invalid scope '%s', " +
 		"must be one of: '%s'"
 	errFmtOIDCServerClientInvalidGrantType = "OIDC client with ID '%s' has an invalid grant type '%s', " +

internal/configuration/validator/identity_providers.go

@@ -68,9 +68,15 @@ func validateOIDCClients(configuration *schema.OpenIDConnectConfiguration, valid
 			ids = append(ids, client.ID)
 		}
 
+		if client.Public {
+			if client.Secret != "" {
+				validator.Push(fmt.Errorf(errFmtOIDCClientPublicInvalidSecret, client.ID))
+			}
+		} else {
 			if client.Secret == "" {
 				validator.Push(fmt.Errorf(errFmtOIDCServerClientInvalidSecret, client.ID))
 			}
+		}
 
 		if client.Policy == "" {
 			configuration.Clients[c].Policy = schema.DefaultOpenIDConnectClientConfiguration.Policy
@@ -163,15 +169,29 @@ func validateOIDDClientUserinfoAlgorithm(c int, configuration *schema.OpenIDConn
 
 func validateOIDCClientRedirectURIs(client schema.OpenIDConnectClientConfiguration, validator *schema.StructValidator) {
 	for _, redirectURI := range client.RedirectURIs {
-		parsedURI, err := url.Parse(redirectURI)
+		if redirectURI == oauth2InstalledApp {
+			if client.Public {
+				continue
+			}
 
+			validator.Push(fmt.Errorf(errFmtOIDCClientRedirectURIPublic, client.ID, redirectURI))
+
+			continue
+		}
+
+		parsedURL, err := url.Parse(redirectURI)
 		if err != nil {
 			validator.Push(fmt.Errorf(errFmtOIDCServerClientRedirectURICantBeParsed, client.ID, redirectURI, err))
-			break
+			continue
 		}
 
-		if parsedURI.Scheme != schemeHTTPS && parsedURI.Scheme != schemeHTTP {
+		if !parsedURL.IsAbs() {
-			validator.Push(fmt.Errorf(errFmtOIDCServerClientRedirectURI, client.ID, redirectURI, parsedURI.Scheme))
+			validator.Push(fmt.Errorf(errFmtOIDCClientRedirectURIAbsolute, client.ID, redirectURI))
+			return
+		}
+
+		if parsedURL.Scheme != schemeHTTPS && parsedURL.Scheme != schemeHTTP {
+			validator.Push(fmt.Errorf(errFmtOIDCServerClientRedirectURI, client.ID, redirectURI, parsedURL.Scheme))
 		}
 	}
 }

internal/configuration/validator/identity_providers_test.go

@@ -84,13 +84,21 @@ func TestShouldRaiseErrorWhenOIDCServerClientBadValues(t *testing.T) {
 						"http://abc@%two",
 					},
 				},
+				{
+					ID:     "client-check-uri-abs",
+					Secret: "a-secret",
+					Policy: twoFactorPolicy,
+					RedirectURIs: []string{
+						"google.com",
+					},
+				},
 			},
 		},
 	}
 
 	ValidateIdentityProviders(config, validator)
 
-	require.Len(t, validator.Errors(), 7)
+	require.Len(t, validator.Errors(), 8)
 
 	assert.Equal(t, schema.DefaultOpenIDConnectClientConfiguration.Policy, config.OIDC.Clients[0].Policy)
 	assert.EqualError(t, validator.Errors()[0], fmt.Sprintf(errFmtOIDCServerClientInvalidSecret, ""))
@@ -98,8 +106,9 @@ func TestShouldRaiseErrorWhenOIDCServerClientBadValues(t *testing.T) {
 	assert.EqualError(t, validator.Errors()[2], fmt.Sprintf(errFmtOIDCServerClientInvalidPolicy, "a-client", "a-policy"))
 	assert.EqualError(t, validator.Errors()[3], fmt.Sprintf(errFmtOIDCServerClientInvalidPolicy, "a-client", "a-policy"))
 	assert.EqualError(t, validator.Errors()[4], fmt.Sprintf(errFmtOIDCServerClientRedirectURICantBeParsed, "client-check-uri-parse", "http://abc@%two", errors.New("parse \"http://abc@%two\": invalid URL escape \"%tw\"")))
-	assert.EqualError(t, validator.Errors()[5], "OIDC Server has one or more clients with an empty ID")
+	assert.EqualError(t, validator.Errors()[5], fmt.Sprintf(errFmtOIDCClientRedirectURIAbsolute, "client-check-uri-abs", "google.com"))
-	assert.EqualError(t, validator.Errors()[6], "OIDC Server has clients with duplicate ID's")
+	assert.EqualError(t, validator.Errors()[6], "OIDC Server has one or more clients with an empty ID")
+	assert.EqualError(t, validator.Errors()[7], "OIDC Server has clients with duplicate ID's")
 }
 
 func TestShouldRaiseErrorWhenOIDCClientConfiguredWithBadScopes(t *testing.T) {
@@ -239,6 +248,85 @@ func TestValidateIdentityProvidersShouldRaiseWarningOnSecurityIssue(t *testing.T
 	assert.EqualError(t, validator.Warnings()[0], "SECURITY ISSUE: OIDC minimum parameter entropy is configured to an unsafe value, it should be above 8 but it's configured to 1.")
 }
 
+func TestValidateIdentityProvidersShouldRaiseErrorsOnInvalidClientTypes(t *testing.T) {
+	validator := schema.NewStructValidator()
+	config := &schema.IdentityProvidersConfiguration{
+		OIDC: &schema.OpenIDConnectConfiguration{
+			HMACSecret:       "hmac1",
+			IssuerPrivateKey: "key2",
+			Clients: []schema.OpenIDConnectClientConfiguration{
+				{
+					ID:     "client-with-invalid-secret",
+					Secret: "a-secret",
+					Public: true,
+					Policy: "two_factor",
+					RedirectURIs: []string{
+						"https://localhost",
+					},
+				},
+				{
+					ID:     "client-with-bad-redirect-uri",
+					Secret: "a-secret",
+					Public: false,
+					Policy: "two_factor",
+					RedirectURIs: []string{
+						oauth2InstalledApp,
+					},
+				},
+			},
+		},
+	}
+
+	ValidateIdentityProviders(config, validator)
+
+	require.Len(t, validator.Errors(), 2)
+	assert.Len(t, validator.Warnings(), 0)
+
+	assert.EqualError(t, validator.Errors()[0], fmt.Sprintf(errFmtOIDCClientPublicInvalidSecret, "client-with-invalid-secret"))
+	assert.EqualError(t, validator.Errors()[1], fmt.Sprintf(errFmtOIDCClientRedirectURIPublic, "client-with-bad-redirect-uri", oauth2InstalledApp))
+}
+
+func TestValidateIdentityProvidersShouldNotRaiseErrorsOnValidPublicClients(t *testing.T) {
+	validator := schema.NewStructValidator()
+	config := &schema.IdentityProvidersConfiguration{
+		OIDC: &schema.OpenIDConnectConfiguration{
+			HMACSecret:       "hmac1",
+			IssuerPrivateKey: "key2",
+			Clients: []schema.OpenIDConnectClientConfiguration{
+				{
+					ID:     "installed-app-client",
+					Public: true,
+					Policy: "two_factor",
+					RedirectURIs: []string{
+						oauth2InstalledApp,
+					},
+				},
+				{
+					ID:     "client-with-https-scheme",
+					Public: true,
+					Policy: "two_factor",
+					RedirectURIs: []string{
+						"https://localhost:9000",
+					},
+				},
+				{
+					ID:     "client-with-loopback",
+					Public: true,
+					Policy: "two_factor",
+					RedirectURIs: []string{
+						"http://127.0.0.1",
+					},
+				},
+			},
+		},
+	}
+
+	ValidateIdentityProviders(config, validator)
+
+	assert.Len(t, validator.Errors(), 0)
+	assert.Len(t, validator.Warnings(), 0)
+}
+
 func TestValidateIdentityProvidersShouldSetDefaultValues(t *testing.T) {
 	validator := schema.NewStructValidator()
 	config := &schema.IdentityProvidersConfiguration{

internal/oidc/client.go

@@ -14,18 +14,19 @@ func NewClient(config schema.OpenIDConnectClientConfiguration) (client *Internal
 	client = &InternalClient{
 		ID:          config.ID,
 		Description: config.Description,
-		Policy:        authorization.PolicyToLevel(config.Policy),
 		Secret:      []byte(config.Secret),
+		Public:      config.Public,
+
+		Policy: authorization.PolicyToLevel(config.Policy),
+
+		Audience:      config.Audience,
+		Scopes:        config.Scopes,
 		RedirectURIs:  config.RedirectURIs,
 		GrantTypes:    config.GrantTypes,
 		ResponseTypes: config.ResponseTypes,
-		Scopes:        config.Scopes,
+		ResponseModes: []fosite.ResponseModeType{fosite.ResponseModeDefault},
 
 		UserinfoSigningAlgorithm: config.UserinfoSigningAlgorithm,
-
-		ResponseModes: []fosite.ResponseModeType{
-			fosite.ResponseModeDefault,
-		},
 	}
 
 	for _, mode := range config.ResponseModes {

internal/oidc/types.go

@@ -36,18 +36,18 @@ type InternalClient struct {
 	ID          string `json:"id"`
 	Description string `json:"-"`
 	Secret      []byte `json:"client_secret,omitempty"`
+	Public      bool   `json:"public"`
+
+	Policy authorization.Level `json:"-"`
+
+	Audience      []string                  `json:"audience"`
+	Scopes        []string                  `json:"scopes"`
 	RedirectURIs  []string                  `json:"redirect_uris"`
 	GrantTypes    []string                  `json:"grant_types"`
 	ResponseTypes []string                  `json:"response_types"`
-	Scopes        []string `json:"scopes"`
-	Audience      []string `json:"audience"`
-	Public        bool     `json:"public"`
-
 	ResponseModes []fosite.ResponseModeType `json:"response_modes"`
 
 	UserinfoSigningAlgorithm string `json:"userinfo_signed_response_alg,omitempty"`
-
-	Policy authorization.Level `json:"-"`
 }
 
 // KeyManager keeps track of all of the active/inactive rsa keys and provides them to services requiring them.