Implement reactive support for JWT as an Authorization Grant

Closes gh-10147

oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/JwtBearerReactiveOAuth2AuthorizedClientProvider.java

@@ -0,0 +1,145 @@
+/*
+ * Copyright 2002-2021 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.security.oauth2.client;
+
+import java.time.Clock;
+import java.time.Duration;
+import java.time.Instant;
+
+import reactor.core.publisher.Mono;
+
+import org.springframework.security.oauth2.client.endpoint.JwtBearerGrantRequest;
+import org.springframework.security.oauth2.client.endpoint.ReactiveOAuth2AccessTokenResponseClient;
+import org.springframework.security.oauth2.client.endpoint.WebClientReactiveJwtBearerTokenResponseClient;
+import org.springframework.security.oauth2.client.registration.ClientRegistration;
+import org.springframework.security.oauth2.core.AuthorizationGrantType;
+import org.springframework.security.oauth2.core.OAuth2AuthorizationException;
+import org.springframework.security.oauth2.core.OAuth2Token;
+import org.springframework.security.oauth2.jwt.Jwt;
+import org.springframework.util.Assert;
+
+/**
+ * An implementation of an {@link ReactiveOAuth2AuthorizedClientProvider} for the
+ * {@link AuthorizationGrantType#JWT_BEARER jwt-bearer} grant.
+ *
+ * @author Steve Riesenberg
+ * @since 5.6
+ * @see ReactiveOAuth2AuthorizedClientProvider
+ * @see WebClientReactiveJwtBearerTokenResponseClient
+ */
+public final class JwtBearerReactiveOAuth2AuthorizedClientProvider implements ReactiveOAuth2AuthorizedClientProvider {
+
+	private ReactiveOAuth2AccessTokenResponseClient<JwtBearerGrantRequest> accessTokenResponseClient = new WebClientReactiveJwtBearerTokenResponseClient();
+
+	private Duration clockSkew = Duration.ofSeconds(60);
+
+	private Clock clock = Clock.systemUTC();
+
+	/**
+	 * Attempt to authorize (or re-authorize) the
+	 * {@link OAuth2AuthorizationContext#getClientRegistration() client} in the provided
+	 * {@code context}. Returns an empty {@code Mono} if authorization (or
+	 * re-authorization) is not supported, e.g. the client's
+	 * {@link ClientRegistration#getAuthorizationGrantType() authorization grant type} is
+	 * not {@link AuthorizationGrantType#JWT_BEARER jwt-bearer} OR the
+	 * {@link OAuth2AuthorizedClient#getAccessToken() access token} is not expired.
+	 * @param context the context that holds authorization-specific state for the client
+	 * @return the {@link OAuth2AuthorizedClient} or an empty {@code Mono} if
+	 * authorization is not supported
+	 */
+	@Override
+	public Mono<OAuth2AuthorizedClient> authorize(OAuth2AuthorizationContext context) {
+		Assert.notNull(context, "context cannot be null");
+		ClientRegistration clientRegistration = context.getClientRegistration();
+		if (!AuthorizationGrantType.JWT_BEARER.equals(clientRegistration.getAuthorizationGrantType())) {
+			return Mono.empty();
+		}
+		OAuth2AuthorizedClient authorizedClient = context.getAuthorizedClient();
+		if (authorizedClient != null && !hasTokenExpired(authorizedClient.getAccessToken())) {
+			// If client is already authorized but access token is NOT expired than no
+			// need for re-authorization
+			return Mono.empty();
+		}
+		if (!(context.getPrincipal().getPrincipal() instanceof Jwt)) {
+			return Mono.empty();
+		}
+		Jwt jwt = (Jwt) context.getPrincipal().getPrincipal();
+		// As per spec, in section 4.1 Using Assertions as Authorization Grants
+		// https://tools.ietf.org/html/rfc7521#section-4.1
+		//
+		// An assertion used in this context is generally a short-lived
+		// representation of the authorization grant, and authorization servers
+		// SHOULD NOT issue access tokens with a lifetime that exceeds the
+		// validity period of the assertion by a significant period. In
+		// practice, that will usually mean that refresh tokens are not issued
+		// in response to assertion grant requests, and access tokens will be
+		// issued with a reasonably short lifetime. Clients can refresh an
+		// expired access token by requesting a new one using the same
+		// assertion, if it is still valid, or with a new assertion.
+		return Mono.just(new JwtBearerGrantRequest(clientRegistration, jwt))
+				.flatMap(this.accessTokenResponseClient::getTokenResponse)
+				.onErrorMap(OAuth2AuthorizationException.class,
+						(ex) -> new ClientAuthorizationException(ex.getError(), clientRegistration.getRegistrationId(),
+								ex))
+				.map((tokenResponse) -> new OAuth2AuthorizedClient(clientRegistration, context.getPrincipal().getName(),
+						tokenResponse.getAccessToken()));
+	}
+
+	private boolean hasTokenExpired(OAuth2Token token) {
+		return this.clock.instant().isAfter(token.getExpiresAt().minus(this.clockSkew));
+	}
+
+	/**
+	 * Sets the client used when requesting an access token credential at the Token
+	 * Endpoint for the {@code jwt-bearer} grant.
+	 * @param accessTokenResponseClient the client used when requesting an access token
+	 * credential at the Token Endpoint for the {@code jwt-bearer} grant
+	 */
+	public void setAccessTokenResponseClient(
+			ReactiveOAuth2AccessTokenResponseClient<JwtBearerGrantRequest> accessTokenResponseClient) {
+		Assert.notNull(accessTokenResponseClient, "accessTokenResponseClient cannot be null");
+		this.accessTokenResponseClient = accessTokenResponseClient;
+	}
+
+	/**
+	 * Sets the maximum acceptable clock skew, which is used when checking the
+	 * {@link OAuth2AuthorizedClient#getAccessToken() access token} expiry. The default is
+	 * 60 seconds.
+	 *
+	 * <p>
+	 * An access token is considered expired if
+	 * {@code OAuth2AccessToken#getExpiresAt() - clockSkew} is before the current time
+	 * {@code clock#instant()}.
+	 * @param clockSkew the maximum acceptable clock skew
+	 */
+	public void setClockSkew(Duration clockSkew) {
+		Assert.notNull(clockSkew, "clockSkew cannot be null");
+		Assert.isTrue(clockSkew.getSeconds() >= 0, "clockSkew must be >= 0");
+		this.clockSkew = clockSkew;
+	}
+
+	/**
+	 * Sets the {@link Clock} used in {@link Instant#now(Clock)} when checking the access
+	 * token expiry.
+	 * @param clock the clock
+	 */
+	public void setClock(Clock clock) {
+		Assert.notNull(clock, "clock cannot be null");
+		this.clock = clock;
+	}
+
+}

oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/endpoint/WebClientReactiveJwtBearerTokenResponseClient.java

@@ -0,0 +1,64 @@
+/*
+ * Copyright 2002-2021 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.security.oauth2.client.endpoint;
+
+import java.util.Set;
+
+import org.springframework.security.oauth2.client.registration.ClientRegistration;
+import org.springframework.security.oauth2.core.AuthorizationGrantType;
+import org.springframework.security.oauth2.core.OAuth2AccessToken;
+import org.springframework.security.oauth2.core.endpoint.OAuth2ParameterNames;
+import org.springframework.web.reactive.function.BodyInserters;
+import org.springframework.web.reactive.function.client.WebClient;
+
+/**
+ * The default implementation of an {@link ReactiveOAuth2AccessTokenResponseClient} for
+ * the {@link AuthorizationGrantType#JWT_BEARER jwt-bearer} grant. This implementation
+ * uses {@link WebClient} when requesting an access token credential at the Authorization
+ * Server's Token Endpoint.
+ *
+ * @author Steve Riesenberg
+ * @since 5.6
+ * @see ReactiveOAuth2AccessTokenResponseClient
+ * @see JwtBearerGrantRequest
+ * @see OAuth2AccessToken
+ * @see <a target="_blank" href="https://tools.ietf.org/html/rfc7523#section-2.1">Section
+ * 2.1 Using JWTs as Authorization Grants</a>
+ * @see <a target="_blank" href="https://tools.ietf.org/html/rfc7521#section-4.1">Section
+ * 4.1 Using Assertions as Authorization Grants</a>
+ */
+public final class WebClientReactiveJwtBearerTokenResponseClient
+		extends AbstractWebClientReactiveOAuth2AccessTokenResponseClient<JwtBearerGrantRequest> {
+
+	@Override
+	ClientRegistration clientRegistration(JwtBearerGrantRequest grantRequest) {
+		return grantRequest.getClientRegistration();
+	}
+
+	@Override
+	Set<String> scopes(JwtBearerGrantRequest grantRequest) {
+		return grantRequest.getClientRegistration().getScopes();
+	}
+
+	@Override
+	BodyInserters.FormInserter<String> populateTokenRequestBody(JwtBearerGrantRequest grantRequest,
+			BodyInserters.FormInserter<String> body) {
+		return super.populateTokenRequestBody(grantRequest, body).with(OAuth2ParameterNames.ASSERTION,
+				grantRequest.getJwt().getTokenValue());
+	}
+
+}

oauth2/oauth2-client/src/test/java/org/springframework/security/oauth2/client/JwtBearerReactiveOAuth2AuthorizedClientProviderTests.java

@@ -0,0 +1,269 @@
+/*
+ * Copyright 2002-2021 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.security.oauth2.client;
+
+import java.time.Clock;
+import java.time.Duration;
+import java.time.Instant;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import reactor.core.publisher.Mono;
+
+import org.springframework.security.authentication.TestingAuthenticationToken;
+import org.springframework.security.core.Authentication;
+import org.springframework.security.oauth2.client.endpoint.JwtBearerGrantRequest;
+import org.springframework.security.oauth2.client.endpoint.ReactiveOAuth2AccessTokenResponseClient;
+import org.springframework.security.oauth2.client.registration.ClientRegistration;
+import org.springframework.security.oauth2.client.registration.TestClientRegistrations;
+import org.springframework.security.oauth2.core.AuthorizationGrantType;
+import org.springframework.security.oauth2.core.ClientAuthenticationMethod;
+import org.springframework.security.oauth2.core.OAuth2AccessToken;
+import org.springframework.security.oauth2.core.OAuth2AuthorizationException;
+import org.springframework.security.oauth2.core.OAuth2Error;
+import org.springframework.security.oauth2.core.OAuth2ErrorCodes;
+import org.springframework.security.oauth2.core.TestOAuth2AccessTokens;
+import org.springframework.security.oauth2.core.endpoint.OAuth2AccessTokenResponse;
+import org.springframework.security.oauth2.core.endpoint.TestOAuth2AccessTokenResponses;
+import org.springframework.security.oauth2.jwt.Jwt;
+import org.springframework.security.oauth2.jwt.TestJwts;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+
+/**
+ * Tests for {@link JwtBearerReactiveOAuth2AuthorizedClientProvider}.
+ *
+ * @author Steve Riesenberg
+ */
+public class JwtBearerReactiveOAuth2AuthorizedClientProviderTests {
+
+	private JwtBearerReactiveOAuth2AuthorizedClientProvider authorizedClientProvider;
+
+	private ReactiveOAuth2AccessTokenResponseClient<JwtBearerGrantRequest> accessTokenResponseClient;
+
+	private ClientRegistration clientRegistration;
+
+	private Jwt jwtAssertion;
+
+	private Authentication principal;
+
+	@BeforeEach
+	public void setup() {
+		this.authorizedClientProvider = new JwtBearerReactiveOAuth2AuthorizedClientProvider();
+		this.accessTokenResponseClient = mock(ReactiveOAuth2AccessTokenResponseClient.class);
+		this.authorizedClientProvider.setAccessTokenResponseClient(this.accessTokenResponseClient);
+		// @formatter:off
+		this.clientRegistration = ClientRegistration.withRegistrationId("jwt-bearer")
+				.clientId("client-id")
+				.clientSecret("client-secret")
+				.clientAuthenticationMethod(ClientAuthenticationMethod.CLIENT_SECRET_BASIC)
+				.authorizationGrantType(AuthorizationGrantType.JWT_BEARER)
+				.scope("read", "write")
+				.tokenUri("https://example.com/oauth2/token")
+				.build();
+		// @formatter:on
+		this.jwtAssertion = TestJwts.jwt().build();
+		this.principal = new TestingAuthenticationToken(this.jwtAssertion, this.jwtAssertion);
+	}
+
+	@Test
+	public void setAccessTokenResponseClientWhenClientIsNullThenThrowIllegalArgumentException() {
+		assertThatIllegalArgumentException()
+				.isThrownBy(() -> this.authorizedClientProvider.setAccessTokenResponseClient(null))
+				.withMessage("accessTokenResponseClient cannot be null");
+	}
+
+	@Test
+	public void setClockSkewWhenNullThenThrowIllegalArgumentException() {
+		// @formatter:off
+		assertThatIllegalArgumentException()
+				.isThrownBy(() -> this.authorizedClientProvider.setClockSkew(null))
+				.withMessage("clockSkew cannot be null");
+		// @formatter:on
+	}
+
+	@Test
+	public void setClockSkewWhenNegativeSecondsThenThrowIllegalArgumentException() {
+		// @formatter:off
+		assertThatIllegalArgumentException()
+				.isThrownBy(() -> this.authorizedClientProvider.setClockSkew(Duration.ofSeconds(-1)))
+				.withMessage("clockSkew must be >= 0");
+		// @formatter:on
+	}
+
+	@Test
+	public void setClockWhenNullThenThrowIllegalArgumentException() {
+		// @formatter:off
+		assertThatIllegalArgumentException()
+				.isThrownBy(() -> this.authorizedClientProvider.setClock(null))
+				.withMessage("clock cannot be null");
+		// @formatter:on
+	}
+
+	@Test
+	public void authorizeWhenContextIsNullThenThrowIllegalArgumentException() {
+		// @formatter:off
+		assertThatIllegalArgumentException()
+				.isThrownBy(() -> this.authorizedClientProvider.authorize(null).block())
+				.withMessage("context cannot be null");
+		// @formatter:on
+	}
+
+	@Test
+	public void authorizeWhenNotJwtBearerThenUnableToAuthorize() {
+		ClientRegistration clientRegistration = TestClientRegistrations.clientCredentials().build();
+		// @formatter:off
+		OAuth2AuthorizationContext authorizationContext = OAuth2AuthorizationContext
+				.withClientRegistration(clientRegistration)
+				.principal(this.principal)
+				.build();
+		// @formatter:on
+		assertThat(this.authorizedClientProvider.authorize(authorizationContext).block()).isNull();
+	}
+
+	@Test
+	public void authorizeWhenJwtBearerAndTokenNotExpiredThenNotReauthorize() {
+		OAuth2AuthorizedClient authorizedClient = new OAuth2AuthorizedClient(this.clientRegistration,
+				this.principal.getName(), TestOAuth2AccessTokens.noScopes());
+		// @formatter:off
+		OAuth2AuthorizationContext authorizationContext = OAuth2AuthorizationContext
+				.withAuthorizedClient(authorizedClient)
+				.principal(this.principal)
+				.build();
+		// @formatter:on
+		assertThat(this.authorizedClientProvider.authorize(authorizationContext).block()).isNull();
+	}
+
+	@Test
+	public void authorizeWhenJwtBearerAndTokenExpiredThenReauthorize() {
+		Instant now = Instant.now();
+		Instant issuedAt = now.minus(Duration.ofMinutes(60));
+		Instant expiresAt = now.minus(Duration.ofMinutes(30));
+		OAuth2AccessToken accessToken = new OAuth2AccessToken(OAuth2AccessToken.TokenType.BEARER, "access-token-1234",
+				issuedAt, expiresAt);
+		OAuth2AuthorizedClient authorizedClient = new OAuth2AuthorizedClient(this.clientRegistration,
+				this.principal.getName(), accessToken);
+		OAuth2AccessTokenResponse accessTokenResponse = TestOAuth2AccessTokenResponses.accessTokenResponse().build();
+		given(this.accessTokenResponseClient.getTokenResponse(any())).willReturn(Mono.just(accessTokenResponse));
+		// @formatter:off
+		OAuth2AuthorizationContext authorizationContext = OAuth2AuthorizationContext
+				.withAuthorizedClient(authorizedClient)
+				.principal(this.principal)
+				.build();
+		// @formatter:on
+		authorizedClient = this.authorizedClientProvider.authorize(authorizationContext).block();
+		assertThat(authorizedClient.getClientRegistration()).isSameAs(this.clientRegistration);
+		assertThat(authorizedClient.getPrincipalName()).isEqualTo(this.principal.getName());
+		assertThat(authorizedClient.getAccessToken()).isEqualTo(accessTokenResponse.getAccessToken());
+	}
+
+	@Test
+	public void authorizeWhenClockSetThenCalled() {
+		Clock clock = mock(Clock.class);
+		given(clock.instant()).willReturn(Instant.now());
+		this.authorizedClientProvider.setClock(clock);
+		OAuth2AuthorizedClient authorizedClient = new OAuth2AuthorizedClient(this.clientRegistration,
+				this.principal.getName(), TestOAuth2AccessTokens.noScopes());
+		// @formatter:off
+		OAuth2AuthorizationContext authorizationContext = OAuth2AuthorizationContext
+				.withAuthorizedClient(authorizedClient)
+				.principal(this.principal)
+				.build();
+		// @formatter:on
+		assertThat(this.authorizedClientProvider.authorize(authorizationContext).block()).isNull();
+		verify(clock).instant();
+	}
+
+	@Test
+	public void authorizeWhenJwtBearerAndTokenNotExpiredButClockSkewForcesExpiryThenReauthorize() {
+		Instant now = Instant.now();
+		Instant issuedAt = now.minus(Duration.ofMinutes(60));
+		Instant expiresAt = now.plus(Duration.ofMinutes(1));
+		OAuth2AccessToken expiresInOneMinAccessToken = new OAuth2AccessToken(OAuth2AccessToken.TokenType.BEARER,
+				"access-token-1234", issuedAt, expiresAt);
+		OAuth2AuthorizedClient authorizedClient = new OAuth2AuthorizedClient(this.clientRegistration,
+				this.principal.getName(), expiresInOneMinAccessToken);
+		// Shorten the lifespan of the access token by 90 seconds, which will ultimately
+		// force it to expire on the client
+		this.authorizedClientProvider.setClockSkew(Duration.ofSeconds(90));
+		OAuth2AccessTokenResponse accessTokenResponse = TestOAuth2AccessTokenResponses.accessTokenResponse().build();
+		given(this.accessTokenResponseClient.getTokenResponse(any())).willReturn(Mono.just(accessTokenResponse));
+		// @formatter:off
+		OAuth2AuthorizationContext authorizationContext = OAuth2AuthorizationContext
+				.withAuthorizedClient(authorizedClient)
+				.principal(this.principal)
+				.build();
+		// @formatter:on
+		OAuth2AuthorizedClient reauthorizedClient = this.authorizedClientProvider.authorize(authorizationContext)
+				.block();
+		assertThat(reauthorizedClient.getClientRegistration()).isSameAs(this.clientRegistration);
+		assertThat(reauthorizedClient.getPrincipalName()).isEqualTo(this.principal.getName());
+		assertThat(reauthorizedClient.getAccessToken()).isEqualTo(accessTokenResponse.getAccessToken());
+	}
+
+	@Test
+	public void authorizeWhenJwtBearerAndNotAuthorizedAndPrincipalNotJwtThenUnableToAuthorize() {
+		// @formatter:off
+		OAuth2AuthorizationContext authorizationContext = OAuth2AuthorizationContext
+				.withClientRegistration(this.clientRegistration)
+				.principal(new TestingAuthenticationToken("user", "password"))
+				.build();
+		// @formatter:on
+		assertThat(this.authorizedClientProvider.authorize(authorizationContext).block()).isNull();
+	}
+
+	@Test
+	public void authorizeWhenInvalidRequestThenThrowClientAuthorizationException() {
+		given(this.accessTokenResponseClient.getTokenResponse(any())).willReturn(
+				Mono.error(new OAuth2AuthorizationException(new OAuth2Error(OAuth2ErrorCodes.INVALID_REQUEST))));
+		// @formatter:off
+		OAuth2AuthorizationContext authorizationContext = OAuth2AuthorizationContext
+				.withClientRegistration(this.clientRegistration)
+				.principal(this.principal)
+				.build();
+		// @formatter:on
+
+		// @formatter:off
+		assertThatExceptionOfType(ClientAuthorizationException.class)
+				.isThrownBy(() -> this.authorizedClientProvider.authorize(authorizationContext).block())
+				.withMessageContaining(OAuth2ErrorCodes.INVALID_REQUEST);
+		// @formatter:on
+	}
+
+	@Test
+	public void authorizeWhenJwtBearerAndNotAuthorizedAndPrincipalJwtThenAuthorize() {
+		OAuth2AccessTokenResponse accessTokenResponse = TestOAuth2AccessTokenResponses.accessTokenResponse().build();
+		given(this.accessTokenResponseClient.getTokenResponse(any())).willReturn(Mono.just(accessTokenResponse));
+		// @formatter:off
+		OAuth2AuthorizationContext authorizationContext = OAuth2AuthorizationContext
+				.withClientRegistration(this.clientRegistration)
+				.principal(this.principal)
+				.build();
+		// @formatter:on
+		OAuth2AuthorizedClient authorizedClient = this.authorizedClientProvider.authorize(authorizationContext).block();
+		assertThat(authorizedClient.getClientRegistration()).isSameAs(this.clientRegistration);
+		assertThat(authorizedClient.getPrincipalName()).isEqualTo(this.principal.getName());
+		assertThat(authorizedClient.getAccessToken()).isEqualTo(accessTokenResponse.getAccessToken());
+	}
+
+}

oauth2/oauth2-client/src/test/java/org/springframework/security/oauth2/client/endpoint/WebClientReactiveJwtBearerTokenResponseClientTests.java

@@ -0,0 +1,320 @@
+/*
+ * Copyright 2002-2021 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.security.oauth2.client.endpoint;
+
+import java.util.Collections;
+
+import okhttp3.mockwebserver.MockResponse;
+import okhttp3.mockwebserver.MockWebServer;
+import okhttp3.mockwebserver.RecordedRequest;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import reactor.core.publisher.Mono;
+
+import org.springframework.core.convert.converter.Converter;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.MediaType;
+import org.springframework.http.ReactiveHttpInputMessage;
+import org.springframework.security.oauth2.client.registration.ClientRegistration;
+import org.springframework.security.oauth2.client.registration.TestClientRegistrations;
+import org.springframework.security.oauth2.core.AuthorizationGrantType;
+import org.springframework.security.oauth2.core.ClientAuthenticationMethod;
+import org.springframework.security.oauth2.core.OAuth2AuthorizationException;
+import org.springframework.security.oauth2.core.OAuth2ErrorCodes;
+import org.springframework.security.oauth2.core.endpoint.OAuth2AccessTokenResponse;
+import org.springframework.security.oauth2.core.endpoint.TestOAuth2AccessTokenResponses;
+import org.springframework.security.oauth2.jwt.Jwt;
+import org.springframework.security.oauth2.jwt.TestJwts;
+import org.springframework.web.reactive.function.BodyExtractor;
+import org.springframework.web.reactive.function.client.WebClient;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+
+/**
+ * Tests for {@link WebClientReactiveJwtBearerTokenResponseClient}.
+ *
+ * @author Steve Riesenberg
+ */
+public class WebClientReactiveJwtBearerTokenResponseClientTests {
+
+	// @formatter:off
+	private static final String DEFAULT_ACCESS_TOKEN_RESPONSE = "{\n"
+			+ "  \"access_token\": \"access-token-1234\",\n"
+			+ "  \"token_type\": \"bearer\",\n"
+			+ "  \"expires_in\": 3600\n"
+			+ "}\n";
+	// @formatter:on
+
+	private WebClientReactiveJwtBearerTokenResponseClient client;
+
+	private MockWebServer server;
+
+	private ClientRegistration.Builder clientRegistration;
+
+	private Jwt jwtAssertion;
+
+	@BeforeEach
+	public void setup() throws Exception {
+		this.client = new WebClientReactiveJwtBearerTokenResponseClient();
+		this.server = new MockWebServer();
+		this.server.start();
+		String tokenUri = this.server.url("/oauth2/token").toString();
+		// @formatter:off
+		this.clientRegistration = TestClientRegistrations.clientCredentials()
+				.authorizationGrantType(AuthorizationGrantType.JWT_BEARER)
+				.tokenUri(tokenUri)
+				.scope("read", "write");
+		// @formatter:on
+		this.jwtAssertion = TestJwts.jwt().build();
+	}
+
+	@AfterEach
+	public void cleanup() throws Exception {
+		this.server.shutdown();
+	}
+
+	@Test
+	public void setWebClientWhenNullThenThrowIllegalArgumentException() {
+		assertThatIllegalArgumentException().isThrownBy(() -> this.client.setWebClient(null))
+				.withMessage("webClient cannot be null");
+	}
+
+	@Test
+	public void setHeadersConverterWhenNullThenThrowIllegalArgumentException() {
+		assertThatIllegalArgumentException().isThrownBy(() -> this.client.setHeadersConverter(null))
+				.withMessage("headersConverter cannot be null");
+	}
+
+	@Test
+	public void addHeadersConverterWhenNullThenThrowIllegalArgumentException() {
+		assertThatIllegalArgumentException().isThrownBy(() -> this.client.addHeadersConverter(null))
+				.withMessage("headersConverter cannot be null");
+	}
+
+	@Test
+	public void setBodyExtractorWhenNullThenThrowIllegalArgumentException() {
+		assertThatIllegalArgumentException().isThrownBy(() -> this.client.setBodyExtractor(null))
+				.withMessage("bodyExtractor cannot be null");
+	}
+
+	@Test
+	public void getTokenResponseWhenNullThenThrowIllegalArgumentException() {
+		assertThatIllegalArgumentException().isThrownBy(() -> this.client.getTokenResponse(null))
+				.withMessage("grantRequest cannot be null");
+	}
+
+	@Test
+	public void getTokenResponseWhenInvalidResponseThenThrowOAuth2AuthorizationException() {
+		ClientRegistration registration = this.clientRegistration.build();
+		enqueueUnexpectedResponse();
+		JwtBearerGrantRequest request = new JwtBearerGrantRequest(registration, this.jwtAssertion);
+		assertThatExceptionOfType(OAuth2AuthorizationException.class)
+				.isThrownBy(() -> this.client.getTokenResponse(request).block())
+				.satisfies((ex) -> assertThat(ex.getError().getErrorCode()).isEqualTo("invalid_token_response"))
+				.withMessage("[invalid_token_response] Empty OAuth 2.0 Access Token Response");
+	}
+
+	@Test
+	public void getTokenResponseWhenServerErrorResponseThenThrowOAuth2AuthorizationException() {
+		ClientRegistration registration = this.clientRegistration.build();
+		enqueueServerErrorResponse();
+		JwtBearerGrantRequest request = new JwtBearerGrantRequest(registration, this.jwtAssertion);
+		assertThatExceptionOfType(OAuth2AuthorizationException.class)
+				.isThrownBy(() -> this.client.getTokenResponse(request).block())
+				.satisfies((ex) -> assertThat(ex.getError().getErrorCode()).isEqualTo(OAuth2ErrorCodes.SERVER_ERROR))
+				.withMessageContaining("[server_error]");
+	}
+
+	@Test
+	public void getTokenResponseWhenErrorResponseThenThrowOAuth2AuthorizationException() {
+		// @formatter:off
+		String accessTokenResponse = "{\n"
+				+ "  \"error\": \"invalid_grant\"\n"
+				+ "}\n";
+		// @formatter:on
+		ClientRegistration registration = this.clientRegistration.build();
+		enqueueJson(accessTokenResponse);
+		JwtBearerGrantRequest request = new JwtBearerGrantRequest(registration, this.jwtAssertion);
+		assertThatExceptionOfType(OAuth2AuthorizationException.class)
+				.isThrownBy(() -> this.client.getTokenResponse(request).block())
+				.satisfies((ex) -> assertThat(ex.getError().getErrorCode()).isEqualTo(OAuth2ErrorCodes.INVALID_GRANT))
+				.withMessageContaining("[invalid_grant]");
+	}
+
+	@Test
+	public void getTokenResponseWhenResponseIsNotBearerTokenTypeThenThrowOAuth2AuthorizationException() {
+		// @formatter:off
+		String accessTokenResponse = "{\n"
+				+ "  \"access_token\": \"access-token-1234\",\n"
+				+ "  \"token_type\": \"not-bearer\",\n"
+				+ "  \"expires_in\": 3600\n"
+				+ "}\n";
+		// @formatter:on
+		ClientRegistration registration = this.clientRegistration.build();
+		enqueueJson(accessTokenResponse);
+		JwtBearerGrantRequest request = new JwtBearerGrantRequest(registration, this.jwtAssertion);
+		assertThatExceptionOfType(OAuth2AuthorizationException.class)
+				.isThrownBy(() -> this.client.getTokenResponse(request).block())
+				.satisfies((ex) -> assertThat(ex.getError().getErrorCode()).isEqualTo("invalid_token_response"))
+				.withMessageContaining("[invalid_token_response] An error occurred parsing the Access Token response")
+				.withMessageContaining("Unsupported token_type: not-bearer");
+	}
+
+	@Test
+	public void getTokenResponseWhenWebClientSetThenCalled() {
+		WebClient customClient = mock(WebClient.class);
+		given(customClient.post()).willReturn(WebClient.builder().build().post());
+		this.client.setWebClient(customClient);
+		enqueueJson(DEFAULT_ACCESS_TOKEN_RESPONSE);
+		ClientRegistration registration = this.clientRegistration.build();
+		JwtBearerGrantRequest request = new JwtBearerGrantRequest(registration, this.jwtAssertion);
+		this.client.getTokenResponse(request).block();
+		verify(customClient).post();
+	}
+
+	@Test
+	public void getTokenResponseWhenHeadersConverterSetThenCalled() throws Exception {
+		ClientRegistration clientRegistration = this.clientRegistration.build();
+		JwtBearerGrantRequest request = new JwtBearerGrantRequest(clientRegistration, this.jwtAssertion);
+		Converter<JwtBearerGrantRequest, HttpHeaders> headersConverter = mock(Converter.class);
+		HttpHeaders headers = new HttpHeaders();
+		headers.setBasicAuth(clientRegistration.getClientId(), clientRegistration.getClientSecret());
+		given(headersConverter.convert(request)).willReturn(headers);
+		this.client.setHeadersConverter(headersConverter);
+		enqueueJson(DEFAULT_ACCESS_TOKEN_RESPONSE);
+		this.client.getTokenResponse(request).block();
+		verify(headersConverter).convert(request);
+		RecordedRequest actualRequest = this.server.takeRequest();
+		assertThat(actualRequest.getHeader(HttpHeaders.AUTHORIZATION))
+				.isEqualTo("Basic Y2xpZW50LWlkOmNsaWVudC1zZWNyZXQ=");
+	}
+
+	@Test
+	public void getTokenResponseWhenHeadersConverterAddedThenCalled() throws Exception {
+		ClientRegistration clientRegistration = this.clientRegistration.build();
+		JwtBearerGrantRequest request = new JwtBearerGrantRequest(clientRegistration, this.jwtAssertion);
+		Converter<JwtBearerGrantRequest, HttpHeaders> addedHeadersConverter = mock(Converter.class);
+		HttpHeaders headers = new HttpHeaders();
+		headers.put("custom-header-name", Collections.singletonList("custom-header-value"));
+		given(addedHeadersConverter.convert(request)).willReturn(headers);
+		this.client.addHeadersConverter(addedHeadersConverter);
+		enqueueJson(DEFAULT_ACCESS_TOKEN_RESPONSE);
+		this.client.getTokenResponse(request).block();
+		verify(addedHeadersConverter).convert(request);
+		RecordedRequest actualRequest = this.server.takeRequest();
+		assertThat(actualRequest.getHeader(HttpHeaders.AUTHORIZATION))
+				.isEqualTo("Basic Y2xpZW50LWlkOmNsaWVudC1zZWNyZXQ=");
+		assertThat(actualRequest.getHeader("custom-header-name")).isEqualTo("custom-header-value");
+	}
+
+	@Test
+	public void getTokenResponseWhenBodyExtractorSetThenCalled() {
+		BodyExtractor<Mono<OAuth2AccessTokenResponse>, ReactiveHttpInputMessage> bodyExtractor = mock(
+				BodyExtractor.class);
+		OAuth2AccessTokenResponse response = TestOAuth2AccessTokenResponses.accessTokenResponse().build();
+		given(bodyExtractor.extract(any(), any())).willReturn(Mono.just(response));
+		ClientRegistration clientRegistration = this.clientRegistration.build();
+		JwtBearerGrantRequest request = new JwtBearerGrantRequest(clientRegistration, this.jwtAssertion);
+		this.client.setBodyExtractor(bodyExtractor);
+		enqueueJson(DEFAULT_ACCESS_TOKEN_RESPONSE);
+		this.client.getTokenResponse(request).block();
+		verify(bodyExtractor).extract(any(), any());
+	}
+
+	@Test
+	public void getTokenResponseWhenClientSecretBasicThenSuccess() throws Exception {
+		ClientRegistration clientRegistration = this.clientRegistration.build();
+		JwtBearerGrantRequest request = new JwtBearerGrantRequest(clientRegistration, this.jwtAssertion);
+		enqueueJson(DEFAULT_ACCESS_TOKEN_RESPONSE);
+		OAuth2AccessTokenResponse response = this.client.getTokenResponse(request).block();
+		assertThat(response).isNotNull();
+		assertThat(response.getAccessToken().getScopes()).containsExactly("read", "write");
+		RecordedRequest actualRequest = this.server.takeRequest();
+		assertThat(actualRequest.getHeader(HttpHeaders.AUTHORIZATION))
+				.isEqualTo("Basic Y2xpZW50LWlkOmNsaWVudC1zZWNyZXQ=");
+		assertThat(actualRequest.getBody().readUtf8()).isEqualTo(
+				"grant_type=urn%3Aietf%3Aparams%3Aoauth%3Agrant-type%3Ajwt-bearer&scope=read+write&assertion=token");
+	}
+
+	@Test
+	public void getTokenResponseWhenClientSecretPostThenSuccess() throws Exception {
+		// @formatter:off
+		ClientRegistration clientRegistration = this.clientRegistration
+				.clientAuthenticationMethod(ClientAuthenticationMethod.CLIENT_SECRET_POST)
+				.build();
+		// @formatter:on
+		JwtBearerGrantRequest request = new JwtBearerGrantRequest(clientRegistration, this.jwtAssertion);
+		enqueueJson(DEFAULT_ACCESS_TOKEN_RESPONSE);
+		OAuth2AccessTokenResponse response = this.client.getTokenResponse(request).block();
+		assertThat(response).isNotNull();
+		assertThat(response.getAccessToken().getScopes()).containsExactly("read", "write");
+		RecordedRequest actualRequest = this.server.takeRequest();
+		assertThat(actualRequest.getHeader(HttpHeaders.AUTHORIZATION)).isNull();
+		assertThat(actualRequest.getBody().readUtf8()).isEqualTo(
+				"grant_type=urn%3Aietf%3Aparams%3Aoauth%3Agrant-type%3Ajwt-bearer&client_id=client-id&client_secret=client-secret&scope=read+write&assertion=token");
+	}
+
+	@Test
+	public void getTokenResponseWhenResponseIncludesScopeThenAccessTokenHasResponseScope() throws Exception {
+		// @formatter:off
+		String accessTokenResponse = "{\n"
+				+ "  \"access_token\": \"access-token-1234\",\n"
+				+ "  \"token_type\": \"bearer\",\n"
+				+ "  \"expires_in\": 3600,\n"
+				+ "  \"scope\": \"read\"\n"
+				+ "}\n";
+		ClientRegistration clientRegistration = this.clientRegistration.build();
+		JwtBearerGrantRequest request = new JwtBearerGrantRequest(clientRegistration, this.jwtAssertion);
+		enqueueJson(accessTokenResponse);
+		OAuth2AccessTokenResponse response = this.client.getTokenResponse(request).block();
+		assertThat(response).isNotNull();
+		assertThat(response.getAccessToken().getScopes()).containsExactly("read");
+	}
+
+	private void enqueueJson(String body) {
+		MockResponse response = new MockResponse().setBody(body).setHeader(HttpHeaders.CONTENT_TYPE,
+				MediaType.APPLICATION_JSON_VALUE);
+		this.server.enqueue(response);
+	}
+
+	private void enqueueUnexpectedResponse() {
+		// @formatter:off
+		MockResponse response = new MockResponse()
+				.setHeader(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON_VALUE)
+				.setResponseCode(301);
+		// @formatter:on
+		this.server.enqueue(response);
+	}
+
+	private void enqueueServerErrorResponse() {
+		// @formatter:off
+		MockResponse response = new MockResponse()
+				.setHeader(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON_VALUE)
+				.setResponseCode(500)
+				.setBody("{}");
+		// @formatter:on
+		this.server.enqueue(response);
+	}
+
+}

oauth2/oauth2-client/src/test/java/org/springframework/security/oauth2/client/web/reactive/function/client/ServerOAuth2AuthorizedClientExchangeFilterFunctionTests.java

@@ -61,12 +61,14 @@ import org.springframework.security.core.Authentication;
 import org.springframework.security.core.authority.AuthorityUtils;
 import org.springframework.security.core.context.ReactiveSecurityContextHolder;
 import org.springframework.security.oauth2.client.ClientAuthorizationException;
+import org.springframework.security.oauth2.client.JwtBearerReactiveOAuth2AuthorizedClientProvider;
 import org.springframework.security.oauth2.client.OAuth2AuthorizationContext;
 import org.springframework.security.oauth2.client.OAuth2AuthorizedClient;
 import org.springframework.security.oauth2.client.ReactiveOAuth2AuthorizationFailureHandler;
 import org.springframework.security.oauth2.client.ReactiveOAuth2AuthorizedClientProvider;
 import org.springframework.security.oauth2.client.ReactiveOAuth2AuthorizedClientProviderBuilder;
 import org.springframework.security.oauth2.client.authentication.OAuth2AuthenticationToken;
+import org.springframework.security.oauth2.client.endpoint.JwtBearerGrantRequest;
 import org.springframework.security.oauth2.client.endpoint.OAuth2ClientCredentialsGrantRequest;
 import org.springframework.security.oauth2.client.endpoint.OAuth2PasswordGrantRequest;
 import org.springframework.security.oauth2.client.endpoint.OAuth2RefreshTokenGrantRequest;
@@ -78,6 +80,8 @@ import org.springframework.security.oauth2.client.registration.TestClientRegistr
 import org.springframework.security.oauth2.client.web.DefaultReactiveOAuth2AuthorizedClientManager;
 import org.springframework.security.oauth2.client.web.server.ServerOAuth2AuthorizedClientRepository;
 import org.springframework.security.oauth2.client.web.server.UnAuthenticatedServerOAuth2AuthorizedClientRepository;
+import org.springframework.security.oauth2.core.AuthorizationGrantType;
+import org.springframework.security.oauth2.core.ClientAuthenticationMethod;
 import org.springframework.security.oauth2.core.OAuth2AccessToken;
 import org.springframework.security.oauth2.core.OAuth2AuthorizationException;
 import org.springframework.security.oauth2.core.OAuth2Error;
@@ -87,6 +91,8 @@ import org.springframework.security.oauth2.core.endpoint.OAuth2AccessTokenRespon
 import org.springframework.security.oauth2.core.endpoint.OAuth2ParameterNames;
 import org.springframework.security.oauth2.core.user.DefaultOAuth2User;
 import org.springframework.security.oauth2.core.user.OAuth2User;
+import org.springframework.security.oauth2.jwt.Jwt;
+import org.springframework.security.oauth2.jwt.TestJwts;
 import org.springframework.util.StringUtils;
 import org.springframework.web.reactive.function.BodyInserter;
 import org.springframework.web.reactive.function.client.ClientRequest;
@@ -131,6 +137,9 @@ public class ServerOAuth2AuthorizedClientExchangeFilterFunctionTests {
 	@Mock
 	private ReactiveOAuth2AccessTokenResponseClient<OAuth2PasswordGrantRequest> passwordTokenResponseClient;
 
+	@Mock
+	private ReactiveOAuth2AccessTokenResponseClient<JwtBearerGrantRequest> jwtBearerTokenResponseClient;
+
 	@Mock
 	private ReactiveOAuth2AuthorizationFailureHandler authorizationFailureHandler;
 
@@ -162,6 +171,8 @@ public class ServerOAuth2AuthorizedClientExchangeFilterFunctionTests {
 	@BeforeEach
 	public void setup() {
 		// @formatter:off
+		JwtBearerReactiveOAuth2AuthorizedClientProvider jwtBearerAuthorizedClientProvider = new JwtBearerReactiveOAuth2AuthorizedClientProvider();
+		jwtBearerAuthorizedClientProvider.setAccessTokenResponseClient(this.jwtBearerTokenResponseClient);
 		ReactiveOAuth2AuthorizedClientProvider authorizedClientProvider = ReactiveOAuth2AuthorizedClientProviderBuilder
 				.builder()
 				.authorizationCode()
@@ -170,6 +181,7 @@ public class ServerOAuth2AuthorizedClientExchangeFilterFunctionTests {
 				.clientCredentials(
 						(configurer) -> configurer.accessTokenResponseClient(this.clientCredentialsTokenResponseClient))
 				.password((configurer) -> configurer.accessTokenResponseClient(this.passwordTokenResponseClient))
+				.provider(jwtBearerAuthorizedClientProvider)
 				.build();
 		// @formatter:on
 		this.authorizedClientManager = new DefaultReactiveOAuth2AuthorizedClientManager(
@@ -396,6 +408,49 @@ public class ServerOAuth2AuthorizedClientExchangeFilterFunctionTests {
 		assertThat(getBody(request0)).isEmpty();
 	}
 
+	@Test
+	public void filterWhenJwtBearerClientNotAuthorizedThenExchangeToken() {
+		setupMocks();
+		OAuth2AccessTokenResponse accessTokenResponse = OAuth2AccessTokenResponse.withToken("exchanged-token")
+				.tokenType(OAuth2AccessToken.TokenType.BEARER).expiresIn(360).build();
+		given(this.jwtBearerTokenResponseClient.getTokenResponse(any())).willReturn(Mono.just(accessTokenResponse));
+		// @formatter:off
+		ClientRegistration registration = ClientRegistration.withRegistrationId("jwt-bearer")
+				.clientId("client-id")
+				.clientSecret("client-secret")
+				.clientAuthenticationMethod(ClientAuthenticationMethod.CLIENT_SECRET_BASIC)
+				.authorizationGrantType(AuthorizationGrantType.JWT_BEARER)
+				.scope("read", "write")
+				.tokenUri("https://example.com/oauth/token")
+				.build();
+		// @formatter:on
+		given(this.clientRegistrationRepository.findByRegistrationId(eq(registration.getRegistrationId())))
+				.willReturn(Mono.just(registration));
+		Jwt jwtAssertion = TestJwts.jwt().build();
+		Authentication jwtAuthentication = new TestingAuthenticationToken(jwtAssertion, jwtAssertion);
+		given(this.authorizedClientRepository.loadAuthorizedClient(eq(registration.getRegistrationId()),
+				eq(jwtAuthentication), any())).willReturn(Mono.empty());
+		// @formatter:off
+		ClientRequest request = ClientRequest.create(HttpMethod.GET, URI.create("https://example.com"))
+				.attributes(ServerOAuth2AuthorizedClientExchangeFilterFunction.clientRegistrationId(registration.getRegistrationId()))
+				.build();
+		// @formatter:on
+		this.function.filter(request, this.exchange)
+				.subscriberContext(ReactiveSecurityContextHolder.withAuthentication(jwtAuthentication))
+				.subscriberContext(serverWebExchange()).block();
+		verify(this.jwtBearerTokenResponseClient).getTokenResponse(any());
+		verify(this.authorizedClientRepository).loadAuthorizedClient(eq(registration.getRegistrationId()),
+				eq(jwtAuthentication), any());
+		verify(this.authorizedClientRepository).saveAuthorizedClient(any(), eq(jwtAuthentication), any());
+		List<ClientRequest> requests = this.exchange.getRequests();
+		assertThat(requests).hasSize(1);
+		ClientRequest request1 = requests.get(0);
+		assertThat(request1.headers().getFirst(HttpHeaders.AUTHORIZATION)).isEqualTo("Bearer exchanged-token");
+		assertThat(request1.url().toASCIIString()).isEqualTo("https://example.com");
+		assertThat(request1.method()).isEqualTo(HttpMethod.GET);
+		assertThat(getBody(request1)).isEmpty();
+	}
+
 	@Test
 	public void filterWhenRefreshTokenNullThenShouldRefreshFalse() {
 		OAuth2AuthorizedClient authorizedClient = new OAuth2AuthorizedClient(this.registration, "principalName",