feat(oidc): client_secret_jwt authentication

This adds the authentication machinery for the client_secret_jwt Default Client Authentication Strategy.

Signed-off-by: James Elliott <james-d-elliott@users.noreply.github.com>

config.template.yml

@@ -1517,6 +1517,10 @@ notifier:
         ## The permitted client authentication method for the Token Endpoint for this client.
         # token_endpoint_auth_method: 'client_secret_basic'
 
+        ## The permitted client authentication signing algorithm for the Token Endpoint for this client when using
+        ## the 'client_secret_jwt' token_endpoint_auth_method.
+        # token_endpoint_auth_signing_alg: HS256
+
         ## The policy to require for this client; one_factor or two_factor.
         # authorization_policy: 'two_factor'
 

docs/content/en/configuration/identity-providers/open-id-connect.md

@@ -555,11 +555,18 @@ more information.
 The registered client authentication mechanism used by this client for the [Token Endpoint]. If no method is defined
 the confidential client type will accept any supported method. The public client type defaults to `none` as this
 is required by the specification. This may be required as a breaking change in future versions.
-Supported values are `client_secret_basic`, `client_secret_post`, and `none`.
+Supported values are `client_secret_basic`, `client_secret_post`, `client_secret_jwt`, and `none`.
 
 See the [integration guide](../../integration/openid-connect/introduction.md#client-authentication-method) for
 more information.
 
+#### token_endpoint_auth_signing_alg
+
+{{< confkey type="string" default="HS256" required="no" >}}
+
+The JWT signing algorithm accepted when the [token_endpoint_auth_method](#tokenendpointauthmethod) is configured as
+`client_secret_jwt`. Supported values are `HS256`, `HS385`, and `HS512`.
+
 #### consent_mode
 
 {{< confkey type="string" default="auto" required="no" >}}

docs/content/en/integration/openid-connect/introduction.md

@@ -174,7 +174,7 @@ specification and the [OAuth 2.0 - Client Types] specification for more informat
 |:------------------------------------:|:-----------------------------:|:----------------------:|:-----------------------:|:--------------------------------------------------------:|
 |  Secret via HTTP Basic Auth Scheme   |     `client_secret_basic`     |     `confidential`     |           N/A           |                           N/A                            |
 |      Secret via HTTP POST Body       |     `client_secret_post`      |     `confidential`     |           N/A           |                           N/A                            |
-|        JWT (signed by secret)        |      `client_secret_jwt`      |     Not Supported      |           N/A           | `urn:ietf:params:oauth:client-assertion-type:jwt-bearer` |
+|        JWT (signed by secret)        |      `client_secret_jwt`      |     `confidential`     |           N/A           | `urn:ietf:params:oauth:client-assertion-type:jwt-bearer` |
 |     JWT (signed by private key)      |       `private_key_jwt`       |     Not Supported      |           N/A           | `urn:ietf:params:oauth:client-assertion-type:jwt-bearer` |
 |        [OAuth 2.0 Mutual-TLS]        |       `tls_client_auth`       |     Not Supported      |           N/A           |                           N/A                            |
 | [OAuth 2.0 Mutual-TLS] (Self Signed) | `self_signed_tls_client_auth` |     Not Supported      |           N/A           |                           N/A                            |

internal/configuration/config.template.yml

@@ -1517,6 +1517,10 @@ notifier:
         ## The permitted client authentication method for the Token Endpoint for this client.
         # token_endpoint_auth_method: 'client_secret_basic'
 
+        ## The permitted client authentication signing algorithm for the Token Endpoint for this client when using
+        ## the 'client_secret_jwt' token_endpoint_auth_method.
+        # token_endpoint_auth_signing_alg: HS256
+
         ## The policy to require for this client; one_factor or two_factor.
         # authorization_policy: 'two_factor'
 

internal/configuration/schema/identity_providers.go

@@ -64,7 +64,8 @@ type OpenIDConnectClientConfiguration struct {
 	ResponseTypes []string `koanf:"response_types"`
 	ResponseModes []string `koanf:"response_modes"`
 
-	TokenEndpointAuthMethod string `koanf:"token_endpoint_auth_method"`
+	TokenEndpointAuthMethod     string `koanf:"token_endpoint_auth_method"`
+	TokenEndpointAuthSigningAlg string `koanf:"token_endpoint_auth_signing_alg"`
 
 	Policy string `koanf:"authorization_policy"`
 

internal/configuration/schema/keys.go

@@ -46,6 +46,7 @@ var Keys = []string{
 	"identity_providers.oidc.clients[].response_types",
 	"identity_providers.oidc.clients[].response_modes",
 	"identity_providers.oidc.clients[].token_endpoint_auth_method",
+	"identity_providers.oidc.clients[].token_endpoint_auth_signing_alg",
 	"identity_providers.oidc.clients[].authorization_policy",
 	"identity_providers.oidc.clients[].enforce_par",
 	"identity_providers.oidc.clients[].enforce_pkce",

internal/configuration/validator/const.go

@@ -161,9 +161,10 @@ const (
 	errFmtOIDCClientsWithEmptyID = "identity_providers: oidc: clients: option 'id' is required but was absent on the clients in positions %s"
 	errFmtOIDCClientsDeprecated  = "identity_providers: oidc: clients: warnings for clients above indicate deprecated functionality and it's strongly suggested these issues are checked and fixed if they're legitimate issues or reported if they are not as in a future version these warnings will become errors"
 
-	errFmtOIDCClientInvalidSecret          = "identity_providers: oidc: client '%s': option 'secret' is required"
+	errFmtOIDCClientInvalidSecret             = "identity_providers: oidc: client '%s': option 'secret' is required"
-	errFmtOIDCClientInvalidSecretPlainText = "identity_providers: oidc: client '%s': option 'secret' is plaintext but it should be a hashed value as plaintext values are deprecated and will be removed when oidc becomes stable"
+	errFmtOIDCClientInvalidSecretPlainText    = "identity_providers: oidc: client '%s': option 'secret' is plaintext but for clients not using the 'token_endpoint_auth_method' of 'client_secret_jwt' it should be a hashed value as plaintext values are deprecated with the exception of 'client_secret_jwt' and will be removed when oidc becomes stable"
-	errFmtOIDCClientPublicInvalidSecret    = "identity_providers: oidc: client '%s': option 'secret' is " +
+	errFmtOIDCClientInvalidSecretNotPlainText = "identity_providers: oidc: client '%s': option 'secret' must be plaintext with option 'token_endpoint_auth_method' with a value of 'client_secret_jwt'"
+	errFmtOIDCClientPublicInvalidSecret       = "identity_providers: oidc: client '%s': option 'secret' is " +
 		"required to be empty when option 'public' is true"
 	errFmtOIDCClientRedirectURICantBeParsed = "identity_providers: oidc: client '%s': option 'redirect_uris' has an " +
 		"invalid value: redirect uri '%s' could not be parsed: %v"
@@ -183,6 +184,8 @@ const (
 		"'token_endpoint_auth_method' must be one of %s when configured as the confidential client type unless it only includes implicit flow response types such as %s but it's configured as '%s'"
 	errFmtOIDCClientInvalidTokenEndpointAuthMethodPublic = "identity_providers: oidc: client '%s': option " +
 		"'token_endpoint_auth_method' must be 'none' when configured as the public client type but it's configured as '%s'"
+	errFmtOIDCClientInvalidTokenEndpointAuthSigAlg = "identity_providers: oidc: client '%s': option " +
+		"'token_endpoint_auth_signing_alg' must be %s when option 'token_endpoint_auth_method' is %s"
 	errFmtOIDCClientInvalidSectorIdentifier = "identity_providers: oidc: client '%s': option " +
 		"'sector_identifier' with value '%s': must be a URL with only the host component for example '%s' but it has a %s with the value '%s'"
 	errFmtOIDCClientInvalidSectorIdentifierWithoutValue = "identity_providers: oidc: client '%s': option " +
@@ -413,7 +416,7 @@ var (
 	validOIDCCORSEndpoints = []string{oidc.EndpointAuthorization, oidc.EndpointPushedAuthorizationRequest, oidc.EndpointToken, oidc.EndpointIntrospection, oidc.EndpointRevocation, oidc.EndpointUserinfo}
 
 	validOIDCClientScopes                    = []string{oidc.ScopeOpenID, oidc.ScopeEmail, oidc.ScopeProfile, oidc.ScopeGroups, oidc.ScopeOfflineAccess}
-	validOIDCClientUserinfoAlgorithms        = []string{oidc.SigningAlgorithmNone, oidc.SigningAlgorithmRSAWithSHA256}
+	validOIDCClientUserinfoAlgorithms        = []string{oidc.SigningAlgNone, oidc.SigningAlgRSAUsingSHA256}
 	validOIDCClientConsentModes              = []string{auto, oidc.ClientConsentModeImplicit.String(), oidc.ClientConsentModeExplicit.String(), oidc.ClientConsentModePreConfigured.String()}
 	validOIDCClientResponseModes             = []string{oidc.ResponseModeFormPost, oidc.ResponseModeQuery, oidc.ResponseModeFragment}
 	validOIDCClientResponseTypes             = []string{oidc.ResponseTypeAuthorizationCodeFlow, oidc.ResponseTypeImplicitFlowIDToken, oidc.ResponseTypeImplicitFlowToken, oidc.ResponseTypeImplicitFlowBoth, oidc.ResponseTypeHybridFlowIDToken, oidc.ResponseTypeHybridFlowToken, oidc.ResponseTypeHybridFlowBoth}
@@ -422,8 +425,9 @@ var (
 	validOIDCClientResponseTypesRefreshToken = []string{oidc.ResponseTypeAuthorizationCodeFlow, oidc.ResponseTypeHybridFlowIDToken, oidc.ResponseTypeHybridFlowToken, oidc.ResponseTypeHybridFlowBoth}
 	validOIDCClientGrantTypes                = []string{oidc.GrantTypeImplicit, oidc.GrantTypeRefreshToken, oidc.GrantTypeAuthorizationCode}
 
-	validOIDCClientTokenEndpointAuthMethods             = []string{oidc.ClientAuthMethodNone, oidc.ClientAuthMethodClientSecretPost, oidc.ClientAuthMethodClientSecretBasic}
+	validOIDCClientTokenEndpointAuthMethods             = []string{oidc.ClientAuthMethodNone, oidc.ClientAuthMethodClientSecretPost, oidc.ClientAuthMethodClientSecretBasic, oidc.ClientAuthMethodClientSecretJWT}
 	validOIDCClientTokenEndpointAuthMethodsConfidential = []string{oidc.ClientAuthMethodClientSecretPost, oidc.ClientAuthMethodClientSecretBasic}
+	validOIDCClientTokenEndpointAuthSigAlgs             = []string{oidc.SigningAlgHMACUsingSHA256, oidc.SigningAlgHMACUsingSHA384, oidc.SigningAlgHMACUsingSHA512}
 )
 
 var (

internal/configuration/validator/identity_providers.go

@@ -193,8 +193,13 @@ func validateOIDCClient(c int, config *schema.OpenIDConnectConfiguration, val *s
 	} else {
 		if config.Clients[c].Secret == nil {
 			val.Push(fmt.Errorf(errFmtOIDCClientInvalidSecret, config.Clients[c].ID))
-		} else if config.Clients[c].Secret.IsPlainText() {
+		} else {
-			val.PushWarning(fmt.Errorf(errFmtOIDCClientInvalidSecretPlainText, config.Clients[c].ID))
+			switch {
+			case config.Clients[c].Secret.IsPlainText() && config.Clients[c].TokenEndpointAuthMethod != oidc.ClientAuthMethodClientSecretJWT:
+				val.PushWarning(fmt.Errorf(errFmtOIDCClientInvalidSecretPlainText, config.Clients[c].ID))
+			case !config.Clients[c].Secret.IsPlainText() && config.Clients[c].TokenEndpointAuthMethod == oidc.ClientAuthMethodClientSecretJWT:
+				val.Push(fmt.Errorf(errFmtOIDCClientInvalidSecretNotPlainText, config.Clients[c].ID))
+			}
 		}
 	}
 
@@ -222,7 +227,7 @@ func validateOIDCClient(c int, config *schema.OpenIDConnectConfiguration, val *s
 	validateOIDCClientGrantTypes(c, config, val, errDeprecatedFunc)
 	validateOIDCClientRedirectURIs(c, config, val, errDeprecatedFunc)
 
-	validateOIDCClientTokenEndpointAuthMethod(c, config, val)
+	validateOIDCClientTokenEndpointAuth(c, config, val)
 	validateOIDDClientUserinfoAlgorithm(c, config, val)
 
 	validateOIDCClientSectorIdentifier(c, config, val)
@@ -481,13 +486,9 @@ func validateOIDCClientRedirectURIs(c int, config *schema.OpenIDConnectConfigura
 	}
 }
 
-func validateOIDCClientTokenEndpointAuthMethod(c int, config *schema.OpenIDConnectConfiguration, val *schema.StructValidator) {
+func validateOIDCClientTokenEndpointAuth(c int, config *schema.OpenIDConnectConfiguration, val *schema.StructValidator) {
 	implcit := len(config.Clients[c].ResponseTypes) != 0 && utils.IsStringSliceContainsAll(config.Clients[c].ResponseTypes, validOIDCClientResponseTypesImplicitFlow)
 
-	if config.Clients[c].TokenEndpointAuthMethod == "" && (config.Clients[c].Public || implcit) {
-		config.Clients[c].TokenEndpointAuthMethod = oidc.ClientAuthMethodNone
-	}
-
 	switch {
 	case config.Clients[c].TokenEndpointAuthMethod == "":
 		break
@@ -501,6 +502,18 @@ func validateOIDCClientTokenEndpointAuthMethod(c int, config *schema.OpenIDConne
 		val.Push(fmt.Errorf(errFmtOIDCClientInvalidTokenEndpointAuthMethodPublic,
 			config.Clients[c].ID, config.Clients[c].TokenEndpointAuthMethod))
 	}
+
+	switch config.Clients[c].TokenEndpointAuthMethod {
+	case "":
+		break
+	case oidc.ClientAuthMethodClientSecretJWT:
+		switch {
+		case config.Clients[c].TokenEndpointAuthSigningAlg == "":
+			config.Clients[c].TokenEndpointAuthSigningAlg = oidc.SigningAlgHMACUsingSHA256
+		case !utils.IsStringInSlice(config.Clients[c].TokenEndpointAuthSigningAlg, validOIDCClientTokenEndpointAuthSigAlgs):
+			val.Push(fmt.Errorf(errFmtOIDCClientInvalidTokenEndpointAuthSigAlg, config.Clients[c].ID, strJoinOr(validOIDCClientTokenEndpointAuthSigAlgs), config.Clients[c].TokenEndpointAuthMethod))
+		}
+	}
 }
 
 func validateOIDDClientUserinfoAlgorithm(c int, config *schema.OpenIDConnectConfiguration, val *schema.StructValidator) {

internal/configuration/validator/identity_providers_test.go

@@ -758,7 +758,7 @@ func TestValidateIdentityProvidersShouldRaiseWarningOnPlainTextClients(t *testin
 	assert.Len(t, validator.Errors(), 0)
 	require.Len(t, validator.Warnings(), 1)
 
-	assert.EqualError(t, validator.Warnings()[0], "identity_providers: oidc: client 'client-with-invalid-secret_standard': option 'secret' is plaintext but it should be a hashed value as plaintext values are deprecated and will be removed when oidc becomes stable")
+	assert.EqualError(t, validator.Warnings()[0], "identity_providers: oidc: client 'client-with-invalid-secret_standard': option 'secret' is plaintext but for clients not using the 'token_endpoint_auth_method' of 'client_secret_jwt' it should be a hashed value as plaintext values are deprecated with the exception of 'client_secret_jwt' and will be removed when oidc becomes stable")
 }
 
 // All valid schemes are supported as defined in https://datatracker.ietf.org/doc/html/rfc8252#section-7.1
@@ -1445,51 +1445,6 @@ func TestValidateOIDCClients(t *testing.T) {
 			nil,
 			nil,
 		},
-		{
-			"ShouldSetDefaultTokenEndpointClientAuthMethodPublicClientType",
-			func(have *schema.OpenIDConnectConfiguration) {
-				have.Clients[0].Public = true
-				have.Clients[0].Secret = nil
-			},
-			func(t *testing.T, have *schema.OpenIDConnectConfiguration) {
-				assert.Equal(t, oidc.ClientAuthMethodNone, have.Clients[0].TokenEndpointAuthMethod)
-			},
-			tcv{
-				nil,
-				nil,
-				nil,
-				nil,
-			},
-			tcv{
-				[]string{oidc.ScopeOpenID, oidc.ScopeGroups, oidc.ScopeProfile, oidc.ScopeEmail},
-				[]string{oidc.ResponseTypeAuthorizationCodeFlow},
-				[]string{oidc.ResponseModeFormPost, oidc.ResponseModeQuery},
-				[]string{oidc.GrantTypeAuthorizationCode},
-			},
-			nil,
-			nil,
-		},
-		{
-			"ShouldSetDefaultTokenEndpointClientAuthMethodConfidentialClientTypeImplicitFlow",
-			nil,
-			func(t *testing.T, have *schema.OpenIDConnectConfiguration) {
-				assert.Equal(t, oidc.ClientAuthMethodNone, have.Clients[0].TokenEndpointAuthMethod)
-			},
-			tcv{
-				nil,
-				[]string{oidc.ResponseTypeImplicitFlowIDToken, oidc.ResponseTypeImplicitFlowToken, oidc.ResponseTypeImplicitFlowBoth},
-				nil,
-				nil,
-			},
-			tcv{
-				[]string{oidc.ScopeOpenID, oidc.ScopeGroups, oidc.ScopeProfile, oidc.ScopeEmail},
-				[]string{oidc.ResponseTypeImplicitFlowIDToken, oidc.ResponseTypeImplicitFlowToken, oidc.ResponseTypeImplicitFlowBoth},
-				[]string{oidc.ResponseModeFormPost, oidc.ResponseModeFragment},
-				[]string{oidc.GrantTypeImplicit},
-			},
-			nil,
-			nil,
-		},
 		{
 			"ShouldNotOverrideValidClientAuthMethod",
 			func(have *schema.OpenIDConnectConfiguration) {
@@ -1535,7 +1490,7 @@ func TestValidateOIDCClients(t *testing.T) {
 			},
 			nil,
 			[]string{
-				"identity_providers: oidc: client 'test': option 'token_endpoint_auth_method' must be one of 'none', 'client_secret_post', or 'client_secret_basic' but it's configured as 'client_credentials'",
+				"identity_providers: oidc: client 'test': option 'token_endpoint_auth_method' must be one of 'none', 'client_secret_post', 'client_secret_basic', or 'client_secret_jwt' but it's configured as 'client_credentials'",
 			},
 		},
 		{
@@ -1619,7 +1574,7 @@ func TestValidateOIDCClients(t *testing.T) {
 			"ShouldSetDefaultUserInfoAlg",
 			nil,
 			func(t *testing.T, have *schema.OpenIDConnectConfiguration) {
-				assert.Equal(t, oidc.SigningAlgorithmNone, have.Clients[0].UserinfoSigningAlgorithm)
+				assert.Equal(t, oidc.SigningAlgNone, have.Clients[0].UserinfoSigningAlgorithm)
 			},
 			tcv{
 				nil,
@@ -1639,10 +1594,10 @@ func TestValidateOIDCClients(t *testing.T) {
 		{
 			"ShouldNotOverrideUserInfoAlg",
 			func(have *schema.OpenIDConnectConfiguration) {
-				have.Clients[0].UserinfoSigningAlgorithm = oidc.SigningAlgorithmRSAWithSHA256
+				have.Clients[0].UserinfoSigningAlgorithm = oidc.SigningAlgRSAUsingSHA256
 			},
 			func(t *testing.T, have *schema.OpenIDConnectConfiguration) {
-				assert.Equal(t, oidc.SigningAlgorithmRSAWithSHA256, have.Clients[0].UserinfoSigningAlgorithm)
+				assert.Equal(t, oidc.SigningAlgRSAUsingSHA256, have.Clients[0].UserinfoSigningAlgorithm)
 			},
 			tcv{
 				nil,
@@ -1827,6 +1782,131 @@ func TestValidateOIDCClients(t *testing.T) {
 			nil,
 			nil,
 		},
+		{
+			"ShouldRaiseErrorOnIncorrectlyConfiguredTokenEndpointClientAuthMethodClientSecretJWT",
+			func(have *schema.OpenIDConnectConfiguration) {
+				have.Clients[0].TokenEndpointAuthMethod = oidc.ClientAuthMethodClientSecretJWT
+				have.Clients[0].Secret = MustDecodeSecret("$pbkdf2-sha512$310000$c8p78n7pUMln0jzvd4aK4Q$JNRBzwAo0ek5qKn50cFzzvE9RXV88h1wJn5KGiHrD0YKtZaR/nCb2CJPOsKaPK0hjf.9yHxzQGZziziccp6Yng")
+			},
+			nil,
+			tcv{
+				nil,
+				nil,
+				nil,
+				nil,
+			},
+			tcv{
+				[]string{oidc.ScopeOpenID, oidc.ScopeGroups, oidc.ScopeProfile, oidc.ScopeEmail},
+				[]string{oidc.ResponseTypeAuthorizationCodeFlow},
+				[]string{oidc.ResponseModeFormPost, oidc.ResponseModeQuery},
+				[]string{oidc.GrantTypeAuthorizationCode},
+			},
+			nil,
+			[]string{
+				"identity_providers: oidc: client 'test': option 'secret' must be plaintext with option 'token_endpoint_auth_method' with a value of 'client_secret_jwt'",
+			},
+		},
+		{
+			"ShouldNotRaiseWarningOrErrorOnCorrectlyConfiguredTokenEndpointClientAuthMethodClientSecretJWT",
+			func(have *schema.OpenIDConnectConfiguration) {
+				have.Clients[0].TokenEndpointAuthMethod = oidc.ClientAuthMethodClientSecretJWT
+				have.Clients[0].Secret = MustDecodeSecret("$plaintext$abc123")
+			},
+			nil,
+			tcv{
+				nil,
+				nil,
+				nil,
+				nil,
+			},
+			tcv{
+				[]string{oidc.ScopeOpenID, oidc.ScopeGroups, oidc.ScopeProfile, oidc.ScopeEmail},
+				[]string{oidc.ResponseTypeAuthorizationCodeFlow},
+				[]string{oidc.ResponseModeFormPost, oidc.ResponseModeQuery},
+				[]string{oidc.GrantTypeAuthorizationCode},
+			},
+			nil,
+			nil,
+		},
+		{
+			"ShouldSetDefaultTokenEndpointAuthSigAlg",
+			func(have *schema.OpenIDConnectConfiguration) {
+				have.Clients[0].TokenEndpointAuthMethod = oidc.ClientAuthMethodClientSecretJWT
+				have.Clients[0].Secret = MustDecodeSecret("$plaintext$abc123")
+			},
+			func(t *testing.T, have *schema.OpenIDConnectConfiguration) {
+				assert.Equal(t, oidc.SigningAlgHMACUsingSHA256, have.Clients[0].TokenEndpointAuthSigningAlg)
+			},
+			tcv{
+				nil,
+				nil,
+				nil,
+				nil,
+			},
+			tcv{
+				[]string{oidc.ScopeOpenID, oidc.ScopeGroups, oidc.ScopeProfile, oidc.ScopeEmail},
+				[]string{oidc.ResponseTypeAuthorizationCodeFlow},
+				[]string{oidc.ResponseModeFormPost, oidc.ResponseModeQuery},
+				[]string{oidc.GrantTypeAuthorizationCode},
+			},
+			nil,
+			nil,
+		},
+		{
+			"ShouldRaiseErrorOnInvalidPublicTokenAuthAlg",
+			func(have *schema.OpenIDConnectConfiguration) {
+				have.Clients[0].TokenEndpointAuthMethod = oidc.ClientAuthMethodClientSecretJWT
+				have.Clients[0].TokenEndpointAuthSigningAlg = oidc.SigningAlgHMACUsingSHA256
+				have.Clients[0].Secret = nil
+				have.Clients[0].Public = true
+			},
+			func(t *testing.T, have *schema.OpenIDConnectConfiguration) {
+				assert.Equal(t, oidc.SigningAlgHMACUsingSHA256, have.Clients[0].TokenEndpointAuthSigningAlg)
+			},
+			tcv{
+				nil,
+				nil,
+				nil,
+				nil,
+			},
+			tcv{
+				[]string{oidc.ScopeOpenID, oidc.ScopeGroups, oidc.ScopeProfile, oidc.ScopeEmail},
+				[]string{oidc.ResponseTypeAuthorizationCodeFlow},
+				[]string{oidc.ResponseModeFormPost, oidc.ResponseModeQuery},
+				[]string{oidc.GrantTypeAuthorizationCode},
+			},
+			nil,
+			[]string{
+				"identity_providers: oidc: client 'test': option 'token_endpoint_auth_method' must be 'none' when configured as the public client type but it's configured as 'client_secret_jwt'",
+			},
+		},
+		{
+			"ShouldRaiseErrorOnInvalidTokenAuthAlgClientTypeConfidential",
+			func(have *schema.OpenIDConnectConfiguration) {
+				have.Clients[0].TokenEndpointAuthMethod = oidc.ClientAuthMethodClientSecretJWT
+				have.Clients[0].TokenEndpointAuthSigningAlg = "abcinvalid"
+				have.Clients[0].Secret = MustDecodeSecret("$plaintext$abc123")
+			},
+			func(t *testing.T, have *schema.OpenIDConnectConfiguration) {
+				assert.Equal(t, "abcinvalid", have.Clients[0].TokenEndpointAuthSigningAlg)
+			},
+			tcv{
+				nil,
+				nil,
+				nil,
+				nil,
+			},
+			tcv{
+				[]string{oidc.ScopeOpenID, oidc.ScopeGroups, oidc.ScopeProfile, oidc.ScopeEmail},
+				[]string{oidc.ResponseTypeAuthorizationCodeFlow},
+				[]string{oidc.ResponseModeFormPost, oidc.ResponseModeQuery},
+				[]string{oidc.GrantTypeAuthorizationCode},
+			},
+			nil,
+			[]string{
+				"identity_providers: oidc: client 'test': option 'token_endpoint_auth_signing_alg' must be 'HS256', 'HS384', or 'HS512' when option 'token_endpoint_auth_method' is client_secret_jwt",
+			},
+		},
 	}
 
 	errDeprecatedFunc := func() {}
@@ -1891,10 +1971,9 @@ func TestValidateOIDCClientTokenEndpointAuthMethod(t *testing.T) {
 		errs     []string
 	}{
 		{"ShouldSetDefaultValueConfidential", "", false, "", nil},
-		{"ShouldSetDefaultValuePublic", "", true, oidc.ClientAuthMethodNone, nil},
 		{"ShouldErrorOnInvalidValue", "abc", false, "abc",
 			[]string{
-				"identity_providers: oidc: client 'test': option 'token_endpoint_auth_method' must be one of 'none', 'client_secret_post', or 'client_secret_basic' but it's configured as 'abc'",
+				"identity_providers: oidc: client 'test': option 'token_endpoint_auth_method' must be one of 'none', 'client_secret_post', 'client_secret_basic', or 'client_secret_jwt' but it's configured as 'abc'",
 			},
 		},
 		{"ShouldErrorOnInvalidValueForPublicClient", "client_secret_post", true, "client_secret_post",
@@ -1923,7 +2002,7 @@ func TestValidateOIDCClientTokenEndpointAuthMethod(t *testing.T) {
 
 			val := schema.NewStructValidator()
 
-			validateOIDCClientTokenEndpointAuthMethod(0, have, val)
+			validateOIDCClientTokenEndpointAuth(0, have, val)
 
 			assert.Equal(t, tc.expected, have.Clients[0].TokenEndpointAuthMethod)
 			assert.Len(t, val.Warnings(), 0)

internal/handlers/handler_oidc_userinfo.go

@@ -100,7 +100,7 @@ func OpenIDConnectUserinfo(ctx *middlewares.AutheliaCtx, rw http.ResponseWriter,
 	ctx.Logger.Tracef("UserInfo Response with id '%s' on client with id '%s' is being sent with the following claims: %+v", requester.GetID(), clientID, claims)
 
 	switch client.GetUserinfoSigningAlgorithm() {
-	case oidc.SigningAlgorithmRSAWithSHA256:
+	case oidc.SigningAlgRSAUsingSHA256:
 		var jti uuid.UUID
 
 		if jti, err = uuid.NewRandom(); err != nil {
@@ -126,7 +126,7 @@ func OpenIDConnectUserinfo(ctx *middlewares.AutheliaCtx, rw http.ResponseWriter,
 
 		rw.Header().Set(fasthttp.HeaderContentType, "application/jwt")
 		_, _ = rw.Write([]byte(token))
-	case oidc.SigningAlgorithmNone, "":
+	case oidc.SigningAlgNone, "":
 		ctx.Providers.OpenIDConnect.Write(rw, req, claims)
 	default:
 		ctx.Providers.OpenIDConnect.WriteError(rw, req, errors.WithStack(fosite.ErrServerError.WithHintf("Unsupported UserInfo signing algorithm '%s'.", client.GetUserinfoSigningAlgorithm())))

internal/oidc/client.go

@@ -47,8 +47,9 @@ func NewClient(config schema.OpenIDConnectClientConfiguration) (client Client) {
 
 	if config.TokenEndpointAuthMethod != "" && config.TokenEndpointAuthMethod != "auto" {
 		client = &FullClient{
-			BaseClient:              base,
+			BaseClient:                        base,
-			TokenEndpointAuthMethod: config.TokenEndpointAuthMethod,
+			TokenEndpointAuthMethod:           config.TokenEndpointAuthMethod,
+			TokenEndpointAuthSigningAlgorithm: config.TokenEndpointAuthSigningAlg,
 		}
 	} else {
 		client = base
@@ -133,7 +134,7 @@ func (c *BaseClient) GetResponseModes() []fosite.ResponseModeType {
 // GetUserinfoSigningAlgorithm returns the UserinfoSigningAlgorithm.
 func (c *BaseClient) GetUserinfoSigningAlgorithm() string {
 	if c.UserinfoSigningAlgorithm == "" {
-		c.UserinfoSigningAlgorithm = SigningAlgorithmNone
+		c.UserinfoSigningAlgorithm = SigningAlgNone
 	}
 
 	return c.UserinfoSigningAlgorithm
@@ -306,7 +307,7 @@ func (c *FullClient) GetTokenEndpointAuthMethod() string {
 // authentication methods.
 func (c *FullClient) GetTokenEndpointAuthSigningAlgorithm() string {
 	if c.TokenEndpointAuthSigningAlgorithm == "" {
-		c.TokenEndpointAuthSigningAlgorithm = SigningAlgorithmRSAWithSHA256
+		c.TokenEndpointAuthSigningAlgorithm = SigningAlgRSAUsingSHA256
 	}
 
 	return c.TokenEndpointAuthSigningAlgorithm

internal/oidc/client_auth.go

@@ -0,0 +1,331 @@
+package oidc
+
+import (
+	"context"
+	"crypto/ecdsa"
+	"crypto/rsa"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+	"time"
+
+	"github.com/go-crypt/crypt/algorithm/plaintext"
+	"github.com/golang-jwt/jwt/v4"
+	"github.com/ory/fosite"
+	"github.com/ory/x/errorsx"
+	"github.com/pkg/errors"
+	"gopkg.in/square/go-jose.v2"
+
+	"github.com/authelia/authelia/v4/internal/configuration/schema"
+)
+
+// DefaultClientAuthenticationStrategy is a copy of fosite's with the addition of the client_secret_jwt method and some
+// minor superficial changes.
+//
+//nolint:gocyclo // Complexity is necessary to remain in feature parity.
+func (p *OpenIDConnectProvider) DefaultClientAuthenticationStrategy(ctx context.Context, r *http.Request, form url.Values) (client fosite.Client, err error) {
+	if assertionType := form.Get(FormParameterClientAssertionType); assertionType == ClientAssertionJWTBearerType {
+		assertion := form.Get(FormParameterClientAssertion)
+		if len(assertion) == 0 {
+			return nil, errorsx.WithStack(fosite.ErrInvalidRequest.WithHintf("The client_assertion request parameter must be set when using client_assertion_type of '%s'.", ClientAssertionJWTBearerType))
+		}
+
+		var (
+			token    *jwt.Token
+			clientID string
+		)
+
+		token, err = jwt.ParseWithClaims(assertion, jwt.MapClaims{}, func(t *jwt.Token) (any, error) {
+			clientID, _, err = clientCredentialsFromRequestBody(form, false)
+			if err != nil {
+				return nil, err
+			}
+
+			if clientID == "" {
+				claims := t.Claims.(jwt.MapClaims)
+
+				if sub, ok := claims[ClaimSubject].(string); !ok {
+					return nil, errorsx.WithStack(fosite.ErrInvalidClient.WithHint("The claim 'sub' from the client_assertion JSON Web Token is undefined."))
+				} else {
+					clientID = sub
+				}
+			}
+
+			if client, err = p.Store.GetClient(ctx, clientID); err != nil {
+				return nil, errorsx.WithStack(fosite.ErrInvalidClient.WithWrap(err).WithDebug(err.Error()))
+			}
+
+			oidcClient, ok := client.(*FullClient)
+			if !ok {
+				return nil, errorsx.WithStack(fosite.ErrInvalidRequest.WithHint("The client configuration does not support OpenID Connect specific authentication methods."))
+			}
+
+			switch oidcClient.GetTokenEndpointAuthMethod() {
+			case ClientAuthMethodPrivateKeyJWT, ClientAuthMethodClientSecretJWT:
+				break
+			case ClientAuthMethodNone:
+				return nil, errorsx.WithStack(fosite.ErrInvalidClient.WithHint("This requested OAuth 2.0 client does not support client authentication, however 'client_assertion' was provided in the request."))
+			case ClientAuthMethodClientSecretPost:
+				fallthrough
+			case ClientAuthMethodClientSecretBasic:
+				return nil, errorsx.WithStack(fosite.ErrInvalidClient.WithHintf("This requested OAuth 2.0 client only supports client authentication method '%s', however 'client_assertion' was provided in the request.", oidcClient.GetTokenEndpointAuthMethod()))
+			default:
+				return nil, errorsx.WithStack(fosite.ErrInvalidClient.WithHintf("This requested OAuth 2.0 client only supports client authentication method '%s', however that method is not supported by this server.", oidcClient.GetTokenEndpointAuthMethod()))
+			}
+
+			if oidcClient.GetTokenEndpointAuthSigningAlgorithm() != fmt.Sprintf("%s", t.Header[JWTHeaderKeyAlgorithm]) {
+				return nil, errorsx.WithStack(fosite.ErrInvalidClient.WithHintf("The 'client_assertion' uses signing algorithm '%s' but the requested OAuth 2.0 Client enforces signing algorithm '%s'.", t.Header[JWTHeaderKeyAlgorithm], oidcClient.GetTokenEndpointAuthSigningAlgorithm()))
+			}
+
+			switch t.Method {
+			case jwt.SigningMethodRS256, jwt.SigningMethodRS384, jwt.SigningMethodRS512:
+				return p.findClientPublicJWK(ctx, oidcClient, t, true)
+			case jwt.SigningMethodES256, jwt.SigningMethodES384, jwt.SigningMethodES512:
+				return p.findClientPublicJWK(ctx, oidcClient, t, false)
+			case jwt.SigningMethodPS256, jwt.SigningMethodPS384, jwt.SigningMethodPS512:
+				return p.findClientPublicJWK(ctx, oidcClient, t, true)
+			case jwt.SigningMethodHS256, jwt.SigningMethodHS384, jwt.SigningMethodHS512:
+				if spd, ok := oidcClient.Secret.(*schema.PasswordDigest); ok {
+					if secret, ok := spd.Digest.(*plaintext.Digest); ok {
+						return secret.Key(), nil
+					}
+				}
+
+				return nil, errorsx.WithStack(fosite.ErrInvalidClient.WithHint("This client does not support authentication method 'client_secret_jwt' as the client secret is not in plaintext."))
+			default:
+				return nil, errorsx.WithStack(fosite.ErrInvalidClient.WithHintf("The 'client_assertion' request parameter uses unsupported signing algorithm '%s'.", t.Header[JWTHeaderKeyAlgorithm]))
+			}
+		})
+
+		if err != nil {
+			var r *fosite.RFC6749Error
+
+			if errors.As(err, &r) {
+				return nil, err
+			}
+
+			var e *jwt.ValidationError
+
+			if errors.As(err, &e) {
+				rfc := fosite.ErrInvalidClient.WithHint("Unable to verify the integrity of the 'client_assertion' value.").WithWrap(err)
+
+				switch {
+				case e.Errors&jwt.ValidationErrorMalformed != 0:
+					return nil, errorsx.WithStack(rfc.WithDebug("The token is malformed."))
+				case e.Errors&jwt.ValidationErrorIssuedAt != 0:
+					return nil, errorsx.WithStack(rfc.WithDebug("The token was used before it was issued."))
+				case e.Errors&jwt.ValidationErrorExpired != 0:
+					return nil, errorsx.WithStack(rfc.WithDebug("The token is expired."))
+				case e.Errors&jwt.ValidationErrorNotValidYet != 0:
+					return nil, errorsx.WithStack(rfc.WithDebug("The token isn't valid yet."))
+				case e.Errors&jwt.ValidationErrorSignatureInvalid != 0:
+					return nil, errorsx.WithStack(rfc.WithDebug("The signature is invalid."))
+				}
+
+				return nil, errorsx.WithStack(fosite.ErrInvalidClient.WithHint("Unable to verify the integrity of the 'client_assertion' value.").WithWrap(err).WithDebug(err.Error()))
+			}
+
+			return nil, err
+		} else if err = token.Claims.Valid(); err != nil {
+			return nil, errorsx.WithStack(fosite.ErrInvalidClient.WithHint("Unable to verify the request object because its claims could not be validated, check if the expiry time is set correctly.").WithWrap(err).WithDebug(err.Error()))
+		}
+
+		claims := token.Claims.(jwt.MapClaims)
+
+		tokenURL := p.Config.GetTokenURL(ctx)
+
+		var jti string
+
+		if !claims.VerifyIssuer(clientID, true) {
+			return nil, errorsx.WithStack(fosite.ErrInvalidClient.WithHint("Claim 'iss' from 'client_assertion' must match the 'client_id' of the OAuth 2.0 Client."))
+		} else if tokenURL == "" {
+			return nil, errorsx.WithStack(fosite.ErrMisconfiguration.WithHint("The authorization server's token endpoint URL has not been set."))
+		} else if sub, ok := claims[ClaimSubject].(string); !ok || sub != clientID {
+			return nil, errorsx.WithStack(fosite.ErrInvalidClient.WithHint("Claim 'sub' from 'client_assertion' must match the 'client_id' of the OAuth 2.0 Client."))
+		} else if jti, ok = claims[ClaimJWTID].(string); !ok || len(jti) == 0 {
+			return nil, errorsx.WithStack(fosite.ErrInvalidClient.WithHint("Claim 'jti' from 'client_assertion' must be set but is not."))
+		} else if p.Store.ClientAssertionJWTValid(ctx, jti) != nil {
+			return nil, errorsx.WithStack(fosite.ErrJTIKnown.WithHint("Claim 'jti' from 'client_assertion' MUST only be used once."))
+		}
+
+		err = nil
+
+		var expiry int64
+
+		switch exp := claims[ClaimExpirationTime].(type) {
+		case float64:
+			expiry = int64(exp)
+		case int64:
+			expiry = exp
+		case json.Number:
+			expiry, err = exp.Int64()
+		default:
+			err = fosite.ErrInvalidClient.WithHint("Unable to type assert the expiry time from claims. This should not happen as we validate the expiry time already earlier with token.Claims.Valid()")
+		}
+
+		if err != nil {
+			return nil, errorsx.WithStack(err)
+		}
+
+		if err = p.Store.SetClientAssertionJWT(ctx, jti, time.Unix(expiry, 0)); err != nil {
+			return nil, err
+		}
+
+		var found bool
+
+		if auds, ok := claims[ClaimAudience].([]any); ok {
+			for _, aud := range auds {
+				if a, ok := aud.(string); ok && a == tokenURL {
+					found = true
+					break
+				}
+			}
+		}
+
+		if !found {
+			return nil, errorsx.WithStack(fosite.ErrInvalidClient.WithHintf("Claim 'audience' from 'client_assertion' must match the authorization server's token endpoint '%s'.", tokenURL))
+		}
+
+		return client, nil
+	} else if len(assertionType) > 0 {
+		return nil, errorsx.WithStack(fosite.ErrInvalidRequest.WithHintf("Unknown client_assertion_type '%s'.", assertionType))
+	}
+
+	clientID, clientSecret, err := clientCredentialsFromRequest(r, form)
+	if err != nil {
+		return nil, err
+	}
+
+	if client, err = p.Store.GetClient(ctx, clientID); err != nil {
+		return nil, errorsx.WithStack(fosite.ErrInvalidClient.WithWrap(err).WithDebug(err.Error()))
+	}
+
+	if oidcClient, ok := client.(fosite.OpenIDConnectClient); ok {
+		method := oidcClient.GetTokenEndpointAuthMethod()
+
+		if form.Get(FormParameterClientID) != "" && form.Get(FormParameterClientSecret) != "" && method != ClientAuthMethodClientSecretPost {
+			return nil, errorsx.WithStack(fosite.ErrInvalidClient.WithHintf("The OAuth 2.0 Client supports client authentication method '%s', but method 'client_secret_post' was requested. You must configure the OAuth 2.0 client's 'token_endpoint_auth_method' value to accept 'client_secret_post'.", method))
+		} else if _, secret, basicOk := r.BasicAuth(); basicOk && secret != "" && method != ClientAuthMethodClientSecretBasic {
+			return nil, errorsx.WithStack(fosite.ErrInvalidClient.WithHintf("The OAuth 2.0 Client supports client authentication method '%s', but method 'client_secret_basic' was requested. You must configure the OAuth 2.0 client's 'token_endpoint_auth_method' value to accept 'client_secret_basic'.", method))
+		} else if method != ClientAuthMethodNone && client.IsPublic() {
+			return nil, errorsx.WithStack(fosite.ErrInvalidClient.WithHintf("The OAuth 2.0 Client supports client authentication method '%s', but method 'none' was requested. You must configure the OAuth 2.0 client's 'token_endpoint_auth_method' value to accept 'none'.", method))
+		}
+	}
+
+	if client.IsPublic() {
+		return client, nil
+	}
+
+	if err = p.checkClientSecret(ctx, client, []byte(clientSecret)); err != nil {
+		return nil, errorsx.WithStack(fosite.ErrInvalidClient.WithWrap(err).WithDebug(err.Error()))
+	}
+
+	return client, nil
+}
+
+func (p *OpenIDConnectProvider) checkClientSecret(ctx context.Context, client fosite.Client, clientSecret []byte) (err error) {
+	if err = p.Config.GetSecretsHasher(ctx).Compare(ctx, client.GetHashedSecret(), clientSecret); err == nil {
+		return nil
+	}
+
+	cc, ok := client.(fosite.ClientWithSecretRotation)
+	if !ok {
+		return err
+	}
+
+	for _, hash := range cc.GetRotatedHashes() {
+		if err = p.Config.GetSecretsHasher(ctx).Compare(ctx, hash, clientSecret); err == nil {
+			return nil
+		}
+	}
+
+	return err
+}
+
+func (p *OpenIDConnectProvider) findClientPublicJWK(ctx context.Context, oidcClient fosite.OpenIDConnectClient, t *jwt.Token, expectsRSAKey bool) (any, error) {
+	if set := oidcClient.GetJSONWebKeys(); set != nil {
+		return findPublicKey(t, set, expectsRSAKey)
+	}
+
+	if location := oidcClient.GetJSONWebKeysURI(); len(location) > 0 {
+		keys, err := p.Config.GetJWKSFetcherStrategy(ctx).Resolve(ctx, location, false)
+		if err != nil {
+			return nil, err
+		}
+
+		if key, err := findPublicKey(t, keys, expectsRSAKey); err == nil {
+			return key, nil
+		}
+
+		keys, err = p.Config.GetJWKSFetcherStrategy(ctx).Resolve(ctx, location, true)
+		if err != nil {
+			return nil, err
+		}
+
+		return findPublicKey(t, keys, expectsRSAKey)
+	}
+
+	return nil, errorsx.WithStack(fosite.ErrInvalidClient.WithHint("The OAuth 2.0 Client has no JSON Web Keys set registered, but they are needed to complete the request."))
+}
+
+func findPublicKey(t *jwt.Token, set *jose.JSONWebKeySet, expectsRSAKey bool) (any, error) {
+	keys := set.Keys
+	if len(keys) == 0 {
+		return nil, errorsx.WithStack(fosite.ErrInvalidRequest.WithHintf("The retrieved JSON Web Key Set does not contain any key."))
+	}
+
+	kid, ok := t.Header[JWTHeaderKeyIdentifier].(string)
+	if ok {
+		keys = set.Key(kid)
+	}
+
+	if len(keys) == 0 {
+		return nil, errorsx.WithStack(fosite.ErrInvalidRequest.WithHintf("The JSON Web Token uses signing key with kid '%s', which could not be found.", kid))
+	}
+
+	for _, key := range keys {
+		if key.Use != KeyUseSignature {
+			continue
+		}
+
+		if expectsRSAKey {
+			if k, ok := key.Key.(*rsa.PublicKey); ok {
+				return k, nil
+			}
+		} else {
+			if k, ok := key.Key.(*ecdsa.PublicKey); ok {
+				return k, nil
+			}
+		}
+	}
+
+	if expectsRSAKey {
+		return nil, errorsx.WithStack(fosite.ErrInvalidRequest.WithHintf("Unable to find RSA public key with use='sig' for kid '%s' in JSON Web Key Set.", kid))
+	} else {
+		return nil, errorsx.WithStack(fosite.ErrInvalidRequest.WithHintf("Unable to find ECDSA public key with use='sig' for kid '%s' in JSON Web Key Set.", kid))
+	}
+}
+
+func clientCredentialsFromRequest(r *http.Request, form url.Values) (clientID, clientSecret string, err error) {
+	if id, secret, ok := r.BasicAuth(); !ok {
+		return clientCredentialsFromRequestBody(form, true)
+	} else if clientID, err = url.QueryUnescape(id); err != nil {
+		return "", "", errorsx.WithStack(fosite.ErrInvalidRequest.WithHint("The client id in the HTTP authorization header could not be decoded from 'application/x-www-form-urlencoded'.").WithWrap(err).WithDebug(err.Error()))
+	} else if clientSecret, err = url.QueryUnescape(secret); err != nil {
+		return "", "", errorsx.WithStack(fosite.ErrInvalidRequest.WithHint("The client secret in the HTTP authorization header could not be decoded from 'application/x-www-form-urlencoded'.").WithWrap(err).WithDebug(err.Error()))
+	}
+
+	return clientID, clientSecret, nil
+}
+
+func clientCredentialsFromRequestBody(form url.Values, forceID bool) (clientID, clientSecret string, err error) {
+	clientID = form.Get(FormParameterClientID)
+	clientSecret = form.Get(FormParameterClientSecret)
+
+	if clientID == "" && forceID {
+		return "", "", errorsx.WithStack(fosite.ErrInvalidRequest.WithHint("Client credentials missing or malformed in both HTTP Authorization header and HTTP POST body."))
+	}
+
+	return clientID, clientSecret, nil
+}

internal/oidc/client_test.go

@@ -27,7 +27,7 @@ func TestNewClient(t *testing.T) {
 	bclient, ok := client.(*BaseClient)
 	require.True(t, ok)
 	assert.Equal(t, "", bclient.UserinfoSigningAlgorithm)
-	assert.Equal(t, SigningAlgorithmNone, client.GetUserinfoSigningAlgorithm())
+	assert.Equal(t, SigningAlgNone, client.GetUserinfoSigningAlgorithm())
 
 	_, ok = client.(*FullClient)
 	assert.False(t, ok)
@@ -64,9 +64,9 @@ func TestNewClient(t *testing.T) {
 	assert.Equal(t, "", fclient.UserinfoSigningAlgorithm)
 	assert.Equal(t, ClientAuthMethodClientSecretBasic, fclient.TokenEndpointAuthMethod)
 	assert.Equal(t, ClientAuthMethodClientSecretBasic, fclient.GetTokenEndpointAuthMethod())
-	assert.Equal(t, SigningAlgorithmNone, client.GetUserinfoSigningAlgorithm())
+	assert.Equal(t, SigningAlgNone, client.GetUserinfoSigningAlgorithm())
 	assert.Equal(t, "", fclient.TokenEndpointAuthSigningAlgorithm)
-	assert.Equal(t, SigningAlgorithmRSAWithSHA256, fclient.GetTokenEndpointAuthSigningAlgorithm())
+	assert.Equal(t, SigningAlgRSAUsingSHA256, fclient.GetTokenEndpointAuthSigningAlgorithm())
 	assert.Equal(t, "", fclient.RequestObjectSigningAlgorithm)
 	assert.Equal(t, "", fclient.GetRequestObjectSigningAlgorithm())
 	assert.Equal(t, "", fclient.JSONWebKeysURI)
@@ -545,11 +545,3 @@ func TestClient_IsPublic(t *testing.T) {
 	c.Public = true
 	assert.True(t, c.IsPublic())
 }
-
-func MustDecodeSecret(value string) *schema.PasswordDigest {
-	if secret, err := schema.DecodePasswordDigest(value); err != nil {
-		panic(err)
-	} else {
-		return secret
-	}
-}

internal/oidc/const.go

@@ -40,6 +40,11 @@ const (
 	ClaimClientIdentifier                    = "client_id"
 )
 
+const (
+	// ClientAssertionJWTBearerType is the JWT bearer assertion.
+	ClientAssertionJWTBearerType = "urn:ietf:params:oauth:client-assertion-type:jwt-bearer" //nolint:gosec // False Positive.
+)
+
 const (
 	lifespanTokenDefault         = time.Hour
 	lifespanRefreshTokenDefault  = time.Hour * 24 * 30
@@ -75,6 +80,8 @@ const (
 const (
 	ClientAuthMethodClientSecretBasic = "client_secret_basic"
 	ClientAuthMethodClientSecretPost  = "client_secret_post"
+	ClientAuthMethodClientSecretJWT   = "client_secret_jwt"
+	ClientAuthMethodPrivateKeyJWT     = "private_key_jwt"
 	ClientAuthMethodNone              = "none"
 )
 
@@ -89,10 +96,30 @@ const (
 	ResponseTypeHybridFlowBoth        = "code id_token token"
 )
 
-// Signing Algorithm strings.
+// JWS Algorithm strings.
+// See: https://datatracker.ietf.org/doc/html/rfc7518#section-3.1
 const (
-	SigningAlgorithmNone          = none
+	SigningAlgNone = none
-	SigningAlgorithmRSAWithSHA256 = "RS256"
+
+	SigningAlgRSAUsingSHA256 = "RS256"
+	SigningAlgRSAUsingSHA384 = "RS384"
+	SigningAlgRSAUsingSHA512 = "RS512"
+
+	SigningAlgRSAPSSUsingSHA256 = "PS256"
+	SigningAlgRSAPSSUsingSHA384 = "PS384"
+	SigningAlgRSAPSSUsingSHA512 = "PS512"
+
+	SigningAlgECDSAUsingP256AndSHA256 = "ES256"
+	SigningAlgECDSAUsingP384AndSHA384 = "ES384"
+	SigningAlgECDSAUsingP521AndSHA512 = "ES512"
+
+	SigningAlgHMACUsingSHA256 = "HS256"
+	SigningAlgHMACUsingSHA384 = "HS384"
+	SigningAlgHMACUsingSHA512 = "HS512"
+)
+
+const (
+	KeyUseSignature = "sig"
 )
 
 // Subject Type strings.
@@ -108,10 +135,14 @@ const (
 )
 
 const (
+	FormParameterClientID            = "client_id"
+	FormParameterClientSecret        = "client_secret"
 	FormParameterRequestURI          = "request_uri"
 	FormParameterResponseMode        = "response_mode"
 	FormParameterCodeChallenge       = "code_challenge"
 	FormParameterCodeChallengeMethod = "code_challenge_method"
+	FormParameterClientAssertionType = "client_assertion_type"
+	FormParameterClientAssertion     = "client_assertion"
 )
 
 const (
@@ -135,6 +166,9 @@ const (
 const (
 	// JWTHeaderKeyIdentifier is the JWT Header referencing the JWS Key Identifier used to sign a token.
 	JWTHeaderKeyIdentifier = "kid"
+
+	// JWTHeaderKeyAlgorithm is the JWT Header referencing the JWS Key algorithm used to sign a token.
+	JWTHeaderKeyAlgorithm = "alg"
 )
 
 const (

internal/oidc/const_test.go

@@ -1,12 +1,56 @@
 package oidc
 
-const (
+import (
-	myclient      = "myclient"
+	"crypto/rsa"
-	myclientdesc  = "My Client"
+	"crypto/x509"
-	onefactor     = "one_factor"
+	"encoding/pem"
-	twofactor     = "two_factor"
+	"net/url"
-	examplecom    = "https://example.com"
+
-	examplecomsid = "example.com"
+	"github.com/authelia/authelia/v4/internal/configuration/schema"
-	badsecret     = "$plaintext$a_bad_secret"
-	badhmac       = "asbdhaaskmdlkamdklasmdlkams"
 )
+
+const (
+	myclient                = "myclient"
+	myclientdesc            = "My Client"
+	onefactor               = "one_factor"
+	twofactor               = "two_factor"
+	examplecom              = "https://example.com"
+	examplecomsid           = "example.com"
+	badsecret               = "$plaintext$a_bad_secret"
+	badhmac                 = "asbdhaaskmdlkamdklasmdlkams"
+	exampleIssuerPrivateKey = "-----BEGIN RSA PRIVATE KEY-----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\nHEMMhFHlv8NDjVOXh1KwRoltNGVWYsSrD9wKU9GhRCEfmNCGrvBcEg==\n-----END RSA PRIVATE KEY-----"
+)
+
+func MustDecodeSecret(value string) *schema.PasswordDigest {
+	if secret, err := schema.DecodePasswordDigest(value); err != nil {
+		panic(err)
+	} else {
+		return secret
+	}
+}
+
+func MustParseRequestURI(input string) *url.URL {
+	if requestURI, err := url.ParseRequestURI(input); err != nil {
+		panic(err)
+	} else {
+		return requestURI
+	}
+}
+
+func MustParseRSAPrivateKey(data string) *rsa.PrivateKey {
+	block, _ := pem.Decode([]byte(data))
+	if block == nil || block.Bytes == nil || len(block.Bytes) == 0 {
+		panic("not pem encoded")
+	}
+
+	if block.Type != "RSA PRIVATE KEY" {
+		panic("not private key")
+	}
+
+	key, err := x509.ParsePKCS1PrivateKey(block.Bytes)
+	if err != nil {
+		panic(err)
+	}
+
+	return key
+}

internal/oidc/discovery.go

@@ -62,8 +62,14 @@ func NewOpenIDConnectWellKnownConfiguration(c *schema.OpenIDConnectConfiguration
 				TokenEndpointAuthMethodsSupported: []string{
 					ClientAuthMethodClientSecretBasic,
 					ClientAuthMethodClientSecretPost,
+					ClientAuthMethodClientSecretJWT,
 					ClientAuthMethodNone,
 				},
+				TokenEndpointAuthSigningAlgValuesSupported: []string{
+					SigningAlgHMACUsingSHA256,
+					SigningAlgHMACUsingSHA384,
+					SigningAlgHMACUsingSHA512,
+				},
 			},
 			OAuth2DiscoveryOptions: OAuth2DiscoveryOptions{
 				CodeChallengeMethodsSupported: []string{
@@ -77,11 +83,11 @@ func NewOpenIDConnectWellKnownConfiguration(c *schema.OpenIDConnectConfiguration
 
 		OpenIDConnectDiscoveryOptions: OpenIDConnectDiscoveryOptions{
 			IDTokenSigningAlgValuesSupported: []string{
-				SigningAlgorithmRSAWithSHA256,
+				SigningAlgRSAUsingSHA256,
 			},
 			UserinfoSigningAlgValuesSupported: []string{
-				SigningAlgorithmNone,
+				SigningAlgNone,
-				SigningAlgorithmRSAWithSHA256,
+				SigningAlgRSAUsingSHA256,
 			},
 		},
 		OpenIDConnectFrontChannelLogoutDiscoveryOptions: &OpenIDConnectFrontChannelLogoutDiscoveryOptions{},

internal/oidc/errors.go

@@ -6,7 +6,7 @@ import (
 	"github.com/ory/fosite"
 )
 
-var errPasswordsDoNotMatch = errors.New("the passwords don't match")
+var errPasswordsDoNotMatch = errors.New("The provided client secret did not match the registered client secret.")
 
 var (
 	// ErrIssuerCouldNotDerive is sent when the issuer couldn't be determined from the headers.

internal/oidc/keys.go

@@ -125,8 +125,8 @@ func NewJWK(chain schema.X509CertificateChain, key *rsa.PrivateKey) (j *JWK, err
 	}
 
 	jwk := &jose.JSONWebKey{
-		Algorithm: SigningAlgorithmRSAWithSHA256,
+		Algorithm: SigningAlgRSAUsingSHA256,
-		Use:       "sig",
+		Use:       KeyUseSignature,
 		Key:       &key.PublicKey,
 	}
 
@@ -170,8 +170,8 @@ func (j *JWK) JSONWebKey() (jwk *jose.JSONWebKey) {
 	jwk = &jose.JSONWebKey{
 		Key:          &j.key.PublicKey,
 		KeyID:        j.id,
-		Algorithm:    "RS256",
+		Algorithm:    SigningAlgRSAUsingSHA256,
-		Use:          "sig",
+		Use:          KeyUseSignature,
 		Certificates: j.chain.Certificates(),
 	}
 

internal/oidc/keys_test.go

@@ -17,7 +17,7 @@ func TestKeyManager_AddActiveJWK(t *testing.T) {
 	assert.Nil(t, manager.jwk)
 	assert.Nil(t, manager.Strategy())
 
-	j, err := manager.AddActiveJWK(schema.X509CertificateChain{}, mustParseRSAPrivateKey(exampleIssuerPrivateKey))
+	j, err := manager.AddActiveJWK(schema.X509CertificateChain{}, MustParseRSAPrivateKey(exampleIssuerPrivateKey))
 	require.NoError(t, err)
 	require.NotNil(t, j)
 	require.NotNil(t, manager.jwk)

internal/oidc/provider.go

@@ -36,6 +36,7 @@ func NewOpenIDConnectProvider(config *schema.OpenIDConnectConfiguration, store s
 	}
 
 	provider.Config.LoadHandlers(provider.Store, provider.KeyManager.Strategy())
+	provider.Config.Strategy.ClientAuthentication = provider.DefaultClientAuthenticationStrategy
 
 	provider.discovery = NewOpenIDConnectWellKnownConfiguration(config)
 

internal/oidc/provider_test.go

@@ -1,9 +1,6 @@
 package oidc
 
 import (
-	"crypto/rsa"
-	"crypto/x509"
-	"encoding/pem"
 	"net/url"
 	"testing"
 
@@ -13,8 +10,6 @@ import (
 	"github.com/authelia/authelia/v4/internal/configuration/schema"
 )
 
-var exampleIssuerPrivateKey = "-----BEGIN RSA PRIVATE KEY-----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\nHEMMhFHlv8NDjVOXh1KwRoltNGVWYsSrD9wKU9GhRCEfmNCGrvBcEg==\n-----END RSA PRIVATE KEY-----"
-
 func TestOpenIDConnectProvider_NewOpenIDConnectProvider_NotConfigured(t *testing.T) {
 	provider, err := NewOpenIDConnectProvider(nil, nil, nil)
 
@@ -25,7 +20,7 @@ func TestOpenIDConnectProvider_NewOpenIDConnectProvider_NotConfigured(t *testing
 func TestNewOpenIDConnectProvider_ShouldEnableOptionalDiscoveryValues(t *testing.T) {
 	provider, err := NewOpenIDConnectProvider(&schema.OpenIDConnectConfiguration{
 		IssuerCertificateChain:   schema.X509CertificateChain{},
-		IssuerPrivateKey:         mustParseRSAPrivateKey(exampleIssuerPrivateKey),
+		IssuerPrivateKey:         MustParseRSAPrivateKey(exampleIssuerPrivateKey),
 		EnablePKCEPlainChallenge: true,
 		HMACSecret:               badhmac,
 		Clients: []schema.OpenIDConnectClientConfiguration{
@@ -57,7 +52,7 @@ func TestNewOpenIDConnectProvider_ShouldEnableOptionalDiscoveryValues(t *testing
 func TestOpenIDConnectProvider_NewOpenIDConnectProvider_GoodConfiguration(t *testing.T) {
 	provider, err := NewOpenIDConnectProvider(&schema.OpenIDConnectConfiguration{
 		IssuerCertificateChain: schema.X509CertificateChain{},
-		IssuerPrivateKey:       mustParseRSAPrivateKey(exampleIssuerPrivateKey),
+		IssuerPrivateKey:       MustParseRSAPrivateKey(exampleIssuerPrivateKey),
 		HMACSecret:             badhmac,
 		Clients: []schema.OpenIDConnectClientConfiguration{
 			{
@@ -97,7 +92,7 @@ func TestOpenIDConnectProvider_NewOpenIDConnectProvider_GoodConfiguration(t *tes
 func TestOpenIDConnectProvider_NewOpenIDConnectProvider_GetOpenIDConnectWellKnownConfiguration(t *testing.T) {
 	provider, err := NewOpenIDConnectProvider(&schema.OpenIDConnectConfiguration{
 		IssuerCertificateChain: schema.X509CertificateChain{},
-		IssuerPrivateKey:       mustParseRSAPrivateKey(exampleIssuerPrivateKey),
+		IssuerPrivateKey:       MustParseRSAPrivateKey(exampleIssuerPrivateKey),
 		HMACSecret:             "asbdhaaskmdlkamdklasmdlkams",
 		Clients: []schema.OpenIDConnectClientConfiguration{
 			{
@@ -152,9 +147,10 @@ func TestOpenIDConnectProvider_NewOpenIDConnectProvider_GetOpenIDConnectWellKnow
 	assert.Contains(t, disco.ResponseTypesSupported, ResponseTypeHybridFlowToken)
 	assert.Contains(t, disco.ResponseTypesSupported, ResponseTypeHybridFlowBoth)
 
-	assert.Len(t, disco.TokenEndpointAuthMethodsSupported, 3)
+	assert.Len(t, disco.TokenEndpointAuthMethodsSupported, 4)
 	assert.Contains(t, disco.TokenEndpointAuthMethodsSupported, ClientAuthMethodClientSecretBasic)
 	assert.Contains(t, disco.TokenEndpointAuthMethodsSupported, ClientAuthMethodClientSecretPost)
+	assert.Contains(t, disco.TokenEndpointAuthMethodsSupported, ClientAuthMethodClientSecretJWT)
 	assert.Contains(t, disco.TokenEndpointAuthMethodsSupported, ClientAuthMethodNone)
 
 	assert.Len(t, disco.GrantTypesSupported, 3)
@@ -163,11 +159,11 @@ func TestOpenIDConnectProvider_NewOpenIDConnectProvider_GetOpenIDConnectWellKnow
 	assert.Contains(t, disco.GrantTypesSupported, GrantTypeImplicit)
 
 	assert.Len(t, disco.IDTokenSigningAlgValuesSupported, 1)
-	assert.Contains(t, disco.IDTokenSigningAlgValuesSupported, SigningAlgorithmRSAWithSHA256)
+	assert.Contains(t, disco.IDTokenSigningAlgValuesSupported, SigningAlgRSAUsingSHA256)
 
 	assert.Len(t, disco.UserinfoSigningAlgValuesSupported, 2)
-	assert.Contains(t, disco.UserinfoSigningAlgValuesSupported, SigningAlgorithmRSAWithSHA256)
+	assert.Contains(t, disco.UserinfoSigningAlgValuesSupported, SigningAlgRSAUsingSHA256)
-	assert.Contains(t, disco.UserinfoSigningAlgValuesSupported, SigningAlgorithmNone)
+	assert.Contains(t, disco.UserinfoSigningAlgValuesSupported, SigningAlgNone)
 
 	assert.Len(t, disco.RequestObjectSigningAlgValuesSupported, 0)
 
@@ -195,7 +191,7 @@ func TestOpenIDConnectProvider_NewOpenIDConnectProvider_GetOpenIDConnectWellKnow
 func TestOpenIDConnectProvider_NewOpenIDConnectProvider_GetOAuth2WellKnownConfiguration(t *testing.T) {
 	provider, err := NewOpenIDConnectProvider(&schema.OpenIDConnectConfiguration{
 		IssuerCertificateChain: schema.X509CertificateChain{},
-		IssuerPrivateKey:       mustParseRSAPrivateKey(exampleIssuerPrivateKey),
+		IssuerPrivateKey:       MustParseRSAPrivateKey(exampleIssuerPrivateKey),
 		HMACSecret:             "asbdhaaskmdlkamdklasmdlkams",
 		Clients: []schema.OpenIDConnectClientConfiguration{
 			{
@@ -249,9 +245,10 @@ func TestOpenIDConnectProvider_NewOpenIDConnectProvider_GetOAuth2WellKnownConfig
 	assert.Contains(t, disco.ResponseTypesSupported, ResponseTypeHybridFlowToken)
 	assert.Contains(t, disco.ResponseTypesSupported, ResponseTypeHybridFlowBoth)
 
-	assert.Len(t, disco.TokenEndpointAuthMethodsSupported, 3)
+	assert.Len(t, disco.TokenEndpointAuthMethodsSupported, 4)
 	assert.Contains(t, disco.TokenEndpointAuthMethodsSupported, ClientAuthMethodClientSecretBasic)
 	assert.Contains(t, disco.TokenEndpointAuthMethodsSupported, ClientAuthMethodClientSecretPost)
+	assert.Contains(t, disco.TokenEndpointAuthMethodsSupported, ClientAuthMethodClientSecretJWT)
 	assert.Contains(t, disco.TokenEndpointAuthMethodsSupported, ClientAuthMethodNone)
 
 	assert.Len(t, disco.GrantTypesSupported, 3)
@@ -283,7 +280,7 @@ func TestOpenIDConnectProvider_NewOpenIDConnectProvider_GetOAuth2WellKnownConfig
 func TestOpenIDConnectProvider_NewOpenIDConnectProvider_GetOpenIDConnectWellKnownConfigurationWithPlainPKCE(t *testing.T) {
 	provider, err := NewOpenIDConnectProvider(&schema.OpenIDConnectConfiguration{
 		IssuerCertificateChain:   schema.X509CertificateChain{},
-		IssuerPrivateKey:         mustParseRSAPrivateKey(exampleIssuerPrivateKey),
+		IssuerPrivateKey:         MustParseRSAPrivateKey(exampleIssuerPrivateKey),
 		HMACSecret:               "asbdhaaskmdlkamdklasmdlkams",
 		EnablePKCEPlainChallenge: true,
 		Clients: []schema.OpenIDConnectClientConfiguration{
@@ -306,21 +303,3 @@ func TestOpenIDConnectProvider_NewOpenIDConnectProvider_GetOpenIDConnectWellKnow
 	assert.Equal(t, PKCEChallengeMethodSHA256, disco.CodeChallengeMethodsSupported[0])
 	assert.Equal(t, PKCEChallengeMethodPlain, disco.CodeChallengeMethodsSupported[1])
 }
-
-func mustParseRSAPrivateKey(data string) *rsa.PrivateKey {
-	block, _ := pem.Decode([]byte(data))
-	if block == nil || block.Bytes == nil || len(block.Bytes) == 0 {
-		panic("not pem encoded")
-	}
-
-	if block.Type != "RSA PRIVATE KEY" {
-		panic("not private key")
-	}
-
-	key, err := x509.ParsePKCS1PrivateKey(block.Bytes)
-	if err != nil {
-		panic(err)
-	}
-
-	return key
-}

internal/oidc/store_test.go

@@ -15,7 +15,7 @@ import (
 func TestOpenIDConnectStore_GetClientPolicy(t *testing.T) {
 	s := NewStore(&schema.OpenIDConnectConfiguration{
 		IssuerCertificateChain: schema.X509CertificateChain{},
-		IssuerPrivateKey:       mustParseRSAPrivateKey(exampleIssuerPrivateKey),
+		IssuerPrivateKey:       MustParseRSAPrivateKey(exampleIssuerPrivateKey),
 		Clients: []schema.OpenIDConnectClientConfiguration{
 			{
 				ID:          myclient,
@@ -47,7 +47,7 @@ func TestOpenIDConnectStore_GetClientPolicy(t *testing.T) {
 func TestOpenIDConnectStore_GetInternalClient(t *testing.T) {
 	s := NewStore(&schema.OpenIDConnectConfiguration{
 		IssuerCertificateChain: schema.X509CertificateChain{},
-		IssuerPrivateKey:       mustParseRSAPrivateKey(exampleIssuerPrivateKey),
+		IssuerPrivateKey:       MustParseRSAPrivateKey(exampleIssuerPrivateKey),
 		Clients: []schema.OpenIDConnectClientConfiguration{
 			{
 				ID:          myclient,
@@ -82,7 +82,7 @@ func TestOpenIDConnectStore_GetInternalClient_ValidClient(t *testing.T) {
 
 	s := NewStore(&schema.OpenIDConnectConfiguration{
 		IssuerCertificateChain: schema.X509CertificateChain{},
-		IssuerPrivateKey:       mustParseRSAPrivateKey(exampleIssuerPrivateKey),
+		IssuerPrivateKey:       MustParseRSAPrivateKey(exampleIssuerPrivateKey),
 		Clients:                []schema.OpenIDConnectClientConfiguration{c1},
 	}, nil)
 
@@ -110,7 +110,7 @@ func TestOpenIDConnectStore_GetInternalClient_InvalidClient(t *testing.T) {
 
 	s := NewStore(&schema.OpenIDConnectConfiguration{
 		IssuerCertificateChain: schema.X509CertificateChain{},
-		IssuerPrivateKey:       mustParseRSAPrivateKey(exampleIssuerPrivateKey),
+		IssuerPrivateKey:       MustParseRSAPrivateKey(exampleIssuerPrivateKey),
 		Clients:                []schema.OpenIDConnectClientConfiguration{c1},
 	}, nil)
 
@@ -122,7 +122,7 @@ func TestOpenIDConnectStore_GetInternalClient_InvalidClient(t *testing.T) {
 func TestOpenIDConnectStore_IsValidClientID(t *testing.T) {
 	s := NewStore(&schema.OpenIDConnectConfiguration{
 		IssuerCertificateChain: schema.X509CertificateChain{},
-		IssuerPrivateKey:       mustParseRSAPrivateKey(exampleIssuerPrivateKey),
+		IssuerPrivateKey:       MustParseRSAPrivateKey(exampleIssuerPrivateKey),
 		Clients: []schema.OpenIDConnectClientConfiguration{
 			{
 				ID:          myclient,

internal/oidc/types.go

@@ -958,3 +958,15 @@ type OpenIDConnectContext interface {
 
 	IssuerURL() (issuerURL *url.URL, err error)
 }
+
+// MockOpenIDConnectContext is a minimal implementation of OpenIDConnectContext for the purpose of testing.
+type MockOpenIDConnectContext struct {
+	context.Context
+
+	MockIssuerURL *url.URL
+}
+
+// IssuerURL returns the MockIssuerURL.
+func (m *MockOpenIDConnectContext) IssuerURL() (issuerURL *url.URL, err error) {
+	return m.MockIssuerURL, nil
+}

internal/oidc/types_test.go

@@ -96,11 +96,3 @@ func TestNewSessionWithAuthorizeRequest(t *testing.T) {
 	assert.NotNil(t, session.Claims.Extra)
 	assert.Nil(t, session.Claims.AuthenticationMethodsReferences)
 }
-
-func MustParseRequestURI(input string) *url.URL {
-	if requestURI, err := url.ParseRequestURI(input); err != nil {
-		panic(err)
-	} else {
-		return requestURI
-	}
-}