From 78fb0bae22f2106219d19fff060caa7866c27430 Mon Sep 17 00:00:00 2001 From: Anish Ramasekar Date: Mon, 26 Feb 2024 16:17:58 -0800 Subject: [PATCH] wire up discovery url in authenticator Signed-off-by: Anish Ramasekar --- .../pkg/authenticator/token/oidc/oidc.go | 47 ++++ .../pkg/authenticator/token/oidc/oidc_test.go | 243 ++++++++++++++++-- test/integration/apiserver/oidc/oidc_test.go | 104 +++++++- test/utils/oidc/testserver.go | 68 +++-- 4 files changed, 417 insertions(+), 45 deletions(-) diff --git a/staging/src/k8s.io/apiserver/plugin/pkg/authenticator/token/oidc/oidc.go b/staging/src/k8s.io/apiserver/plugin/pkg/authenticator/token/oidc/oidc.go index 87ee459a0a0..b0b633e8273 100644 --- a/staging/src/k8s.io/apiserver/plugin/pkg/authenticator/token/oidc/oidc.go +++ b/staging/src/k8s.io/apiserver/plugin/pkg/authenticator/token/oidc/oidc.go @@ -35,6 +35,7 @@ import ( "fmt" "io/ioutil" "net/http" + "net/url" "reflect" "strings" "sync" @@ -66,6 +67,10 @@ var ( synchronizeTokenIDVerifierForTest = false ) +const ( + wellKnownEndpointPath = "/.well-known/openid-configuration" +) + type Options struct { // JWTAuthenticator is the authenticator that will be used to verify the JWT. JWTAuthenticator apiserver.JWTAuthenticator @@ -268,6 +273,28 @@ func New(opts Options) (authenticator.Token, error) { client = &http.Client{Transport: tr, Timeout: 30 * time.Second} } + // If the discovery URL is set in authentication configuration, we set up a + // roundTripper to rewrite the {url}/.well-known/openid-configuration to + // the discovery URL. This is useful for self-hosted providers, for example, + // providers that run on top of Kubernetes itself. + if len(opts.JWTAuthenticator.Issuer.DiscoveryURL) > 0 { + discoveryURL, err := url.Parse(opts.JWTAuthenticator.Issuer.DiscoveryURL) + if err != nil { + return nil, fmt.Errorf("oidc: invalid discovery URL: %w", err) + } + + clientWithDiscoveryURL := *client + baseTransport := clientWithDiscoveryURL.Transport + if baseTransport == nil { + baseTransport = http.DefaultTransport + } + // This matches the url construction in oidc.NewProvider as of go-oidc v2.2.1. + // xref: https://github.com/coreos/go-oidc/blob/40cd342c4a2076195294612a834d11df23c1b25a/oidc.go#L114 + urlToRewrite := strings.TrimSuffix(opts.JWTAuthenticator.Issuer.URL, "/") + wellKnownEndpointPath + clientWithDiscoveryURL.Transport = &discoveryURLRoundTripper{baseTransport, discoveryURL, urlToRewrite} + client = &clientWithDiscoveryURL + } + ctx, cancel := context.WithCancel(context.Background()) ctx = oidc.ClientContext(ctx, client) @@ -339,6 +366,26 @@ func New(opts Options) (authenticator.Token, error) { return newInstrumentedAuthenticator(issuerURL, authenticator), nil } +// discoveryURLRoundTripper is a http.RoundTripper that rewrites the +// {url}/.well-known/openid-configuration to the discovery URL. +type discoveryURLRoundTripper struct { + base http.RoundTripper + // discoveryURL is the URL to use to fetch the openid configuration + discoveryURL *url.URL + // urlToRewrite is the URL to rewrite to the discovery URL + urlToRewrite string +} + +func (t *discoveryURLRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) { + if req.Method == http.MethodGet && req.URL.String() == t.urlToRewrite { + clone := req.Clone(req.Context()) + clone.Host = "" + clone.URL = t.discoveryURL + return t.base.RoundTrip(clone) + } + return t.base.RoundTrip(req) +} + // untrustedIssuer extracts an untrusted "iss" claim from the given JWT token, // or returns an error if the token can not be parsed. Since the JWT is not // verified, the returned issuer should not be trusted. diff --git a/staging/src/k8s.io/apiserver/plugin/pkg/authenticator/token/oidc/oidc_test.go b/staging/src/k8s.io/apiserver/plugin/pkg/authenticator/token/oidc/oidc_test.go index c8991fda936..f8bf78ed2c7 100644 --- a/staging/src/k8s.io/apiserver/plugin/pkg/authenticator/token/oidc/oidc_test.go +++ b/staging/src/k8s.io/apiserver/plugin/pkg/authenticator/token/oidc/oidc_test.go @@ -36,6 +36,7 @@ import ( "gopkg.in/square/go-jose.v2" + "k8s.io/apimachinery/pkg/util/wait" "k8s.io/apiserver/pkg/apis/apiserver" "k8s.io/apiserver/pkg/authentication/user" "k8s.io/apiserver/pkg/features" @@ -134,18 +135,19 @@ var ( ) type claimsTest struct { - name string - options Options - optsFunc func(*Options) - signingKey *jose.JSONWebKey - pubKeys []*jose.JSONWebKey - claims string - want *user.DefaultInfo - wantSkip bool - wantErr string - wantInitErr string - claimToResponseMap map[string]string - openIDConfig string + name string + options Options + optsFunc func(*Options) + signingKey *jose.JSONWebKey + pubKeys []*jose.JSONWebKey + claims string + want *user.DefaultInfo + wantSkip bool + wantErr string + wantInitErr string + claimToResponseMap map[string]string + openIDConfig string + fetchKeysFromRemote bool } // Replace formats the contents of v into the provided template. @@ -175,7 +177,8 @@ func newClaimServer(t *testing.T, keys jose.JSONWebKeySet, signer jose.Signer, c klog.V(5).Infof("%v: returning: %+v", r.URL, string(keyBytes)) w.Write(keyBytes) - case "/.well-known/openid-configuration": + // /c/d/bar/.well-known/openid-configuration is used to test issuer url and discovery url with a path + case "/.well-known/openid-configuration", "/c/d/bar/.well-known/openid-configuration": w.Header().Set("Content-Type", "application/json") klog.V(5).Infof("%v: returning: %+v", r.URL, *openIDConfig) w.Write([]byte(*openIDConfig)) @@ -262,14 +265,17 @@ func (c *claimsTest) run(t *testing.T) { c.claims = replace(c.claims, &v) c.openIDConfig = replace(c.openIDConfig, &v) c.options.JWTAuthenticator.Issuer.URL = replace(c.options.JWTAuthenticator.Issuer.URL, &v) + c.options.JWTAuthenticator.Issuer.DiscoveryURL = replace(c.options.JWTAuthenticator.Issuer.DiscoveryURL, &v) for claim, response := range c.claimToResponseMap { c.claimToResponseMap[claim] = replace(response, &v) } c.wantErr = replace(c.wantErr, &v) c.wantInitErr = replace(c.wantInitErr, &v) - // Set the verifier to use the public key set instead of reading from a remote. - c.options.KeySet = &staticKeySet{keys: c.pubKeys} + if !c.fetchKeysFromRemote { + // Set the verifier to use the public key set instead of reading from a remote. + c.options.KeySet = &staticKeySet{keys: c.pubKeys} + } if c.optsFunc != nil { c.optsFunc(&c.options) @@ -307,7 +313,27 @@ func (c *claimsTest) run(t *testing.T) { t.Fatalf("serialize token: %v", err) } - got, ok, err := a.AuthenticateToken(testContext(t), token) + ia, ok := a.(*instrumentedAuthenticator) + if !ok { + t.Fatalf("expected authenticator to be instrumented") + } + authenticator, ok := ia.delegate.(*Authenticator) + if !ok { + t.Fatalf("expected delegate to be Authenticator") + } + ctx := testContext(t) + // wait for the authenticator to be initialized + err = wait.PollUntilContextCancel(ctx, time.Millisecond, true, func(context.Context) (bool, error) { + if v, _ := authenticator.idTokenVerifier(); v == nil { + return false, nil + } + return true, nil + }) + if err != nil { + t.Fatalf("failed to initialize the authenticator: %v", err) + } + + got, ok, err := a.AuthenticateToken(ctx, token) expectErr := len(c.wantErr) > 0 @@ -2986,6 +3012,191 @@ func TestToken(t *testing.T) { Name: "jane", }, }, + { + name: "discovery-url", + options: Options{ + JWTAuthenticator: apiserver.JWTAuthenticator{ + Issuer: apiserver.Issuer{ + URL: "https://auth.example.com", + DiscoveryURL: "{{.URL}}/.well-known/openid-configuration", + Audiences: []string{"my-client"}, + }, + ClaimMappings: apiserver.ClaimMappings{ + Username: apiserver.PrefixedClaimOrExpression{ + Claim: "username", + Prefix: pointer.String(""), + }, + }, + }, + now: func() time.Time { return now }, + }, + signingKey: loadRSAPrivKey(t, "testdata/rsa_1.pem", jose.RS256), + pubKeys: []*jose.JSONWebKey{ + loadRSAKey(t, "testdata/rsa_1.pem", jose.RS256), + }, + claims: fmt.Sprintf(`{ + "iss": "https://auth.example.com", + "aud": "my-client", + "username": "jane", + "exp": %d + }`, valid.Unix()), + openIDConfig: `{ + "issuer": "https://auth.example.com", + "jwks_uri": "{{.URL}}/.testing/keys" + }`, + fetchKeysFromRemote: true, + want: &user.DefaultInfo{ + Name: "jane", + }, + }, + { + name: "discovery url, issuer has a path", + options: Options{ + JWTAuthenticator: apiserver.JWTAuthenticator{ + Issuer: apiserver.Issuer{ + URL: "https://auth.example.com/a/b/foo", + DiscoveryURL: "{{.URL}}/.well-known/openid-configuration", + Audiences: []string{"my-client"}, + }, + ClaimMappings: apiserver.ClaimMappings{ + Username: apiserver.PrefixedClaimOrExpression{ + Claim: "username", + Prefix: pointer.String(""), + }, + }, + }, + now: func() time.Time { return now }, + }, + signingKey: loadRSAPrivKey(t, "testdata/rsa_1.pem", jose.RS256), + pubKeys: []*jose.JSONWebKey{ + loadRSAKey(t, "testdata/rsa_1.pem", jose.RS256), + }, + claims: fmt.Sprintf(`{ + "iss": "https://auth.example.com/a/b/foo", + "aud": "my-client", + "username": "jane", + "exp": %d + }`, valid.Unix()), + openIDConfig: `{ + "issuer": "https://auth.example.com/a/b/foo", + "jwks_uri": "{{.URL}}/.testing/keys" + }`, + fetchKeysFromRemote: true, + want: &user.DefaultInfo{ + Name: "jane", + }, + }, + { + name: "discovery url has a path, issuer url has no path", + options: Options{ + JWTAuthenticator: apiserver.JWTAuthenticator{ + Issuer: apiserver.Issuer{ + URL: "https://auth.example.com", + DiscoveryURL: "{{.URL}}/c/d/bar/.well-known/openid-configuration", + Audiences: []string{"my-client"}, + }, + ClaimMappings: apiserver.ClaimMappings{ + Username: apiserver.PrefixedClaimOrExpression{ + Claim: "username", + Prefix: pointer.String(""), + }, + }, + }, + now: func() time.Time { return now }, + }, + signingKey: loadRSAPrivKey(t, "testdata/rsa_1.pem", jose.RS256), + pubKeys: []*jose.JSONWebKey{ + loadRSAKey(t, "testdata/rsa_1.pem", jose.RS256), + }, + claims: fmt.Sprintf(`{ + "iss": "https://auth.example.com", + "aud": "my-client", + "username": "jane", + "exp": %d + }`, valid.Unix()), + openIDConfig: `{ + "issuer": "https://auth.example.com", + "jwks_uri": "{{.URL}}/.testing/keys" + }`, + fetchKeysFromRemote: true, + want: &user.DefaultInfo{ + Name: "jane", + }, + }, + { + name: "discovery url and issuer url have paths", + options: Options{ + JWTAuthenticator: apiserver.JWTAuthenticator{ + Issuer: apiserver.Issuer{ + URL: "https://auth.example.com/a/b/foo", + DiscoveryURL: "{{.URL}}/c/d/bar/.well-known/openid-configuration", + Audiences: []string{"my-client"}, + }, + ClaimMappings: apiserver.ClaimMappings{ + Username: apiserver.PrefixedClaimOrExpression{ + Claim: "username", + Prefix: pointer.String(""), + }, + }, + }, + now: func() time.Time { return now }, + }, + signingKey: loadRSAPrivKey(t, "testdata/rsa_1.pem", jose.RS256), + pubKeys: []*jose.JSONWebKey{ + loadRSAKey(t, "testdata/rsa_1.pem", jose.RS256), + }, + claims: fmt.Sprintf(`{ + "iss": "https://auth.example.com/a/b/foo", + "aud": "my-client", + "username": "jane", + "exp": %d + }`, valid.Unix()), + openIDConfig: `{ + "issuer": "https://auth.example.com/a/b/foo", + "jwks_uri": "{{.URL}}/.testing/keys" + }`, + fetchKeysFromRemote: true, + want: &user.DefaultInfo{ + Name: "jane", + }, + }, + { + name: "discovery url and issuer url have paths, issuer url has trailing slash", + options: Options{ + JWTAuthenticator: apiserver.JWTAuthenticator{ + Issuer: apiserver.Issuer{ + URL: "https://auth.example.com/a/b/foo/", + DiscoveryURL: "{{.URL}}/c/d/bar/.well-known/openid-configuration", + Audiences: []string{"my-client"}, + }, + ClaimMappings: apiserver.ClaimMappings{ + Username: apiserver.PrefixedClaimOrExpression{ + Claim: "username", + Prefix: pointer.String(""), + }, + }, + }, + now: func() time.Time { return now }, + }, + signingKey: loadRSAPrivKey(t, "testdata/rsa_1.pem", jose.RS256), + pubKeys: []*jose.JSONWebKey{ + loadRSAKey(t, "testdata/rsa_1.pem", jose.RS256), + }, + claims: fmt.Sprintf(`{ + "iss": "https://auth.example.com/a/b/foo/", + "aud": "my-client", + "username": "jane", + "exp": %d + }`, valid.Unix()), + openIDConfig: `{ + "issuer": "https://auth.example.com/a/b/foo/", + "jwks_uri": "{{.URL}}/.testing/keys" + }`, + fetchKeysFromRemote: true, + want: &user.DefaultInfo{ + Name: "jane", + }, + }, } var successTestCount, failureTestCount int diff --git a/test/integration/apiserver/oidc/oidc_test.go b/test/integration/apiserver/oidc/oidc_test.go index 22dd5a239c2..ffd73756002 100644 --- a/test/integration/apiserver/oidc/oidc_test.go +++ b/test/integration/apiserver/oidc/oidc_test.go @@ -141,7 +141,7 @@ func runTests(t *testing.T, useAuthenticationConfig bool) { ) { caCertContent, _, caFilePath, caKeyFilePath := generateCert(t) signingPrivateKey, publicKey := keyFunc(t) - oidcServer = utilsoidc.BuildAndRunTestServer(t, caFilePath, caKeyFilePath) + oidcServer = utilsoidc.BuildAndRunTestServer(t, caFilePath, caKeyFilePath, "") if useAuthenticationConfig { authenticationConfig := fmt.Sprintf(` @@ -274,7 +274,7 @@ jwt: signingPrivateKey, _ = keyFunc(t) - oidcServer = utilsoidc.BuildAndRunTestServer(t, caFilePath, caKeyFilePath) + oidcServer = utilsoidc.BuildAndRunTestServer(t, caFilePath, caKeyFilePath, "") if useAuthenticationConfig { authenticationConfig := fmt.Sprintf(` @@ -888,6 +888,104 @@ jwt: } } +// TestStructuredAuthenticationDiscoveryURL tests that the discovery URL configured in jwt.issuer.discoveryURL is used to +// fetch the discovery document and the issuer in jwt.issuer.url is used to validate the ID token. +func TestStructuredAuthenticationDiscoveryURL(t *testing.T) { + defer featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.StructuredAuthenticationConfiguration, true)() + + tests := []struct { + name string + issuerURL string + discoveryURL func(baseURL string) string + }{ + { + name: "discovery url and issuer url with no path", + issuerURL: "https://example.com", + discoveryURL: func(baseURL string) string { return baseURL }, + }, + { + name: "discovery url has path, issuer url has no path", + issuerURL: "https://example.com", + discoveryURL: func(baseURL string) string { return fmt.Sprintf("%s/c/d/bar", baseURL) }, + }, + { + name: "discovery url has no path, issuer url has path", + issuerURL: "https://example.com/a/b/foo", + discoveryURL: func(baseURL string) string { return baseURL }, + }, + { + name: "discovery url and issuer url have paths", + issuerURL: "https://example.com/a/b/foo", + discoveryURL: func(baseURL string) string { + return fmt.Sprintf("%s/c/d/bar", baseURL) + }, + }, + } + + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + caCertContent, _, caFilePath, caKeyFilePath := generateCert(t) + signingPrivateKey, publicKey := rsaGenerateKey(t) + // set the issuer in the discovery document to issuer url (different from the discovery URL) to assert + // 1. discovery URL is used to fetch the discovery document and + // 2. issuer in the discovery document is used to validate the ID token + oidcServer := utilsoidc.BuildAndRunTestServer(t, caFilePath, caKeyFilePath, tt.issuerURL) + discoveryURL := strings.TrimSuffix(tt.discoveryURL(oidcServer.URL()), "/") + "/.well-known/openid-configuration" + + authenticationConfig := fmt.Sprintf(` +apiVersion: apiserver.config.k8s.io/v1alpha1 +kind: AuthenticationConfiguration +jwt: +- issuer: + url: %s + discoveryURL: %s + audiences: + - foo + audienceMatchPolicy: MatchAny + certificateAuthority: | + %s + claimMappings: + username: + expression: "'k8s-' + claims.sub" + claimValidationRules: + - expression: 'claims.hd == "example.com"' + message: "the hd claim must be set to example.com" +`, tt.issuerURL, discoveryURL, indentCertificateAuthority(string(caCertContent))) + + oidcServer.JwksHandler().EXPECT().KeySet().AnyTimes().DoAndReturn(utilsoidc.DefaultJwksHandlerBehavior(t, publicKey)) + + apiServer := startTestAPIServerForOIDC(t, apiServerOIDCConfig{authenticationConfigYAML: authenticationConfig}, publicKey) + + idTokenLifetime := time.Second * 1200 + oidcServer.TokenHandler().EXPECT().Token().Times(1).DoAndReturn(utilsoidc.TokenHandlerBehaviorReturningPredefinedJWT( + t, + signingPrivateKey, + map[string]interface{}{ + "iss": tt.issuerURL, // issuer in the discovery document is used to validate the ID token + "sub": defaultOIDCClaimedUsername, + "aud": "foo", + "exp": time.Now().Add(idTokenLifetime).Unix(), + "hd": "example.com", + }, + defaultStubAccessToken, + defaultStubRefreshToken, + )) + + tokenURL, err := oidcServer.TokenURL() + require.NoError(t, err) + + client := configureClientFetchingOIDCCredentials(t, apiServer.ClientConfig, caCertContent, caFilePath, oidcServer.URL(), tokenURL) + ctx := testContext(t) + res, err := client.AuthenticationV1().SelfSubjectReviews().Create(ctx, &authenticationv1.SelfSubjectReview{}, metav1.CreateOptions{}) + require.NoError(t, err) + assert.Equal(t, authenticationv1.UserInfo{ + Username: "k8s-john_doe", + Groups: []string{"system:authenticated"}, + }, res.Status.UserInfo) + }) + } +} + func rsaGenerateKey(t *testing.T) (*rsa.PrivateKey, *rsa.PublicKey) { t.Helper() @@ -919,7 +1017,7 @@ func configureTestInfrastructure[K utilsoidc.JosePrivateKey, L utilsoidc.JosePub signingPrivateKey, publicKey := keyFunc(t) - oidcServer = utilsoidc.BuildAndRunTestServer(t, caFilePath, caKeyFilePath) + oidcServer = utilsoidc.BuildAndRunTestServer(t, caFilePath, caKeyFilePath, "") authenticationConfig := fn(t, oidcServer.URL(), string(caCertContent)) if len(authenticationConfig) > 0 { diff --git a/test/utils/oidc/testserver.go b/test/utils/oidc/testserver.go index 6d425b426db..1ffdbc9323d 100644 --- a/test/utils/oidc/testserver.go +++ b/test/utils/oidc/testserver.go @@ -80,7 +80,7 @@ func (ts *TestServer) TokenURL() (string, error) { } // BuildAndRunTestServer configures OIDC TLS server and its routing -func BuildAndRunTestServer(t *testing.T, caPath, caKeyPath string) *TestServer { +func BuildAndRunTestServer(t *testing.T, caPath, caKeyPath, issuerOverride string) *TestServer { t.Helper() certContent, err := os.ReadFile(caPath) @@ -111,33 +111,21 @@ func BuildAndRunTestServer(t *testing.T, caPath, caKeyPath string) *TestServer { jwksHandler: NewMockJWKsHandler(mockCtrl), } + issuer := httpServer.URL + // issuerOverride is used to override the issuer URL in the well-known configuration. + // This is useful to validate scenarios where discovery url is different from the issuer url. + if len(issuerOverride) > 0 { + issuer = issuerOverride + } + mux.HandleFunc(openIDWellKnownWebPath, func(writer http.ResponseWriter, request *http.Request) { - authURL, err := url.JoinPath(httpServer.URL + authWebPath) - require.NoError(t, err) - tokenURL, err := url.JoinPath(httpServer.URL + tokenWebPath) - require.NoError(t, err) - jwksURL, err := url.JoinPath(httpServer.URL + jwksWebPath) - require.NoError(t, err) - userInfoURL, err := url.JoinPath(httpServer.URL + authWebPath) - require.NoError(t, err) + discoveryDocHandler(t, writer, httpServer.URL, issuer) + }) - err = json.NewEncoder(writer).Encode(struct { - Issuer string `json:"issuer"` - AuthURL string `json:"authorization_endpoint"` - TokenURL string `json:"token_endpoint"` - JWKSURL string `json:"jwks_uri"` - UserInfoURL string `json:"userinfo_endpoint"` - }{ - Issuer: httpServer.URL, - AuthURL: authURL, - TokenURL: tokenURL, - JWKSURL: jwksURL, - UserInfoURL: userInfoURL, - }) - require.NoError(t, err) - - writer.Header().Add("Content-Type", "application/json") - writer.WriteHeader(http.StatusOK) + // /c/d/bar/.well-known/openid-configuration is used to validate scenarios where discovery url is different from the issuer url + // and discovery url contains path. + mux.HandleFunc("/c/d/bar"+openIDWellKnownWebPath, func(writer http.ResponseWriter, request *http.Request) { + discoveryDocHandler(t, writer, httpServer.URL, issuer) }) mux.HandleFunc(tokenWebPath, func(writer http.ResponseWriter, request *http.Request) { @@ -171,6 +159,34 @@ func BuildAndRunTestServer(t *testing.T, caPath, caKeyPath string) *TestServer { return oidcServer } +func discoveryDocHandler(t *testing.T, writer http.ResponseWriter, httpServerURL, issuer string) { + authURL, err := url.JoinPath(httpServerURL + authWebPath) + require.NoError(t, err) + tokenURL, err := url.JoinPath(httpServerURL + tokenWebPath) + require.NoError(t, err) + jwksURL, err := url.JoinPath(httpServerURL + jwksWebPath) + require.NoError(t, err) + userInfoURL, err := url.JoinPath(httpServerURL + authWebPath) + require.NoError(t, err) + + writer.Header().Add("Content-Type", "application/json") + + err = json.NewEncoder(writer).Encode(struct { + Issuer string `json:"issuer"` + AuthURL string `json:"authorization_endpoint"` + TokenURL string `json:"token_endpoint"` + JWKSURL string `json:"jwks_uri"` + UserInfoURL string `json:"userinfo_endpoint"` + }{ + Issuer: issuer, + AuthURL: authURL, + TokenURL: tokenURL, + JWKSURL: jwksURL, + UserInfoURL: userInfoURL, + }) + require.NoError(t, err) +} + type JosePrivateKey interface { *rsa.PrivateKey | *ecdsa.PrivateKey }