Implement Client Credentials Authentication

Fixes gh-39

core/src/main/java/org/springframework/security/oauth2/server/authorization/authentication/OAuth2ClientAuthenticationProvider.java

@@ -18,17 +18,52 @@ package org.springframework.security.oauth2.server.authorization.authentication;
 import org.springframework.security.authentication.AuthenticationProvider;
 import org.springframework.security.core.Authentication;
 import org.springframework.security.core.AuthenticationException;
+import org.springframework.security.oauth2.core.OAuth2AuthenticationException;
+import org.springframework.security.oauth2.core.OAuth2Error;
+import org.springframework.security.oauth2.core.OAuth2ErrorCodes;
+import org.springframework.security.oauth2.server.authorization.client.RegisteredClient;
 import org.springframework.security.oauth2.server.authorization.client.RegisteredClientRepository;
+import org.springframework.util.Assert;
 
 /**
+ * An {@link AuthenticationProvider} implementation that validates {@link OAuth2ClientAuthenticationToken}s.
+ *
  * @author Joe Grandja
+ * @author Patryk Kostrzewa
  */
 public class OAuth2ClientAuthenticationProvider implements AuthenticationProvider {
-	private RegisteredClientRepository registeredClientRepository;
+	private final RegisteredClientRepository registeredClientRepository;
+
+	/**
+	 * @param registeredClientRepository
+	 * 		the bean to lookup the client details from
+	 */
+	public OAuth2ClientAuthenticationProvider(RegisteredClientRepository registeredClientRepository) {
+		Assert.notNull(registeredClientRepository, "registeredClientRepository cannot be null");
+		this.registeredClientRepository = registeredClientRepository;
+	}
 
 	@Override
 	public Authentication authenticate(Authentication authentication) throws AuthenticationException {
-		return authentication;
+		String clientId = authentication.getName();
+		if (authentication.getCredentials() == null) {
+			throw new OAuth2AuthenticationException(new OAuth2Error(OAuth2ErrorCodes.INVALID_CLIENT));
+		}
+
+		RegisteredClient registeredClient = this.registeredClientRepository.findByClientId(clientId);
+		// https://tools.ietf.org/html/rfc6749#section-2.4
+		if (registeredClient == null) {
+			throw new OAuth2AuthenticationException(new OAuth2Error(OAuth2ErrorCodes.INVALID_CLIENT));
+		}
+
+		String presentedSecret = authentication.getCredentials()
+				.toString();
+		if (!registeredClient.getClientSecret()
+				.equals(presentedSecret)) {
+			throw new OAuth2AuthenticationException(new OAuth2Error(OAuth2ErrorCodes.INVALID_CLIENT));
+		}
+
+		return new OAuth2ClientAuthenticationToken(registeredClient);
 	}
 
 	@Override

core/src/main/java/org/springframework/security/oauth2/server/authorization/authentication/OAuth2ClientAuthenticationToken.java

@@ -18,11 +18,11 @@ package org.springframework.security.oauth2.server.authorization.authentication;
 import org.springframework.security.authentication.AbstractAuthenticationToken;
 import org.springframework.security.core.SpringSecurityCoreVersion;
 import org.springframework.security.oauth2.server.authorization.client.RegisteredClient;
-
 import java.util.Collections;
 
 /**
  * @author Joe Grandja
+ * @author Patryk Kostrzewa
  */
 public class OAuth2ClientAuthenticationToken extends AbstractAuthenticationToken {
 	private static final long serialVersionUID = SpringSecurityCoreVersion.SERIAL_VERSION_UID;

core/src/main/java/org/springframework/security/oauth2/server/authorization/web/DefaultOAuth2ClientAuthenticationConverter.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright 2020 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.server.authorization.web;
+
+import org.springframework.http.HttpHeaders;
+import org.springframework.security.oauth2.core.OAuth2AuthenticationException;
+import org.springframework.security.oauth2.core.OAuth2Error;
+import org.springframework.security.oauth2.core.OAuth2ErrorCodes;
+import org.springframework.security.oauth2.server.authorization.authentication.OAuth2ClientAuthenticationToken;
+import org.springframework.security.web.authentication.AuthenticationConverter;
+import org.springframework.util.StringUtils;
+import javax.servlet.http.HttpServletRequest;
+import java.nio.charset.StandardCharsets;
+import java.util.Base64;
+
+/**
+ * Converts from {@link HttpServletRequest} to {@link OAuth2ClientAuthenticationToken} that can be authenticated.
+ *
+ * @author Patryk Kostrzewa
+ */
+public class DefaultOAuth2ClientAuthenticationConverter implements AuthenticationConverter {
+
+	private static final String AUTHENTICATION_SCHEME_BASIC = "Basic";
+
+	@Override
+	public OAuth2ClientAuthenticationToken convert(HttpServletRequest request) {
+		String header = request.getHeader(HttpHeaders.AUTHORIZATION);
+
+		if (header == null) {
+			return null;
+		}
+
+		header = header.trim();
+		if (!StringUtils.startsWithIgnoreCase(header, AUTHENTICATION_SCHEME_BASIC)) {
+			return null;
+		}
+
+		if (header.equalsIgnoreCase(AUTHENTICATION_SCHEME_BASIC)) {
+			throw new OAuth2AuthenticationException(new OAuth2Error(OAuth2ErrorCodes.INVALID_REQUEST));
+		}
+
+		byte[] decoded;
+		try {
+			byte[] base64Token = header.substring(6)
+					.getBytes(StandardCharsets.UTF_8);
+			decoded = Base64.getDecoder()
+					.decode(base64Token);
+		} catch (IllegalArgumentException e) {
+			throw new OAuth2AuthenticationException(new OAuth2Error(OAuth2ErrorCodes.INVALID_REQUEST));
+		}
+
+		String token = new String(decoded, StandardCharsets.UTF_8);
+		String[] credentials = token.split(":");
+		if (credentials.length != 2) {
+			throw new OAuth2AuthenticationException(new OAuth2Error(OAuth2ErrorCodes.INVALID_TOKEN));
+		}
+		return new OAuth2ClientAuthenticationToken(credentials[0], credentials[1]);
+	}
+}

core/src/main/java/org/springframework/security/oauth2/server/authorization/web/OAuth2ClientAuthenticationFilter.java

@@ -15,9 +15,21 @@
  */
 package org.springframework.security.oauth2.server.authorization.web;
 
+import org.springframework.http.MediaType;
+import org.springframework.http.server.ServletServerHttpResponse;
 import org.springframework.security.authentication.AuthenticationManager;
+import org.springframework.security.core.Authentication;
+import org.springframework.security.core.AuthenticationException;
+import org.springframework.security.core.context.SecurityContextHolder;
+import org.springframework.security.oauth2.core.OAuth2AuthenticationException;
+import org.springframework.security.oauth2.core.http.converter.OAuth2ErrorHttpMessageConverter;
+import org.springframework.security.web.authentication.AuthenticationConverter;
+import org.springframework.security.web.authentication.AuthenticationFailureHandler;
+import org.springframework.security.web.authentication.AuthenticationSuccessHandler;
+import org.springframework.security.web.util.matcher.AntPathRequestMatcher;
+import org.springframework.security.web.util.matcher.RequestMatcher;
+import org.springframework.util.Assert;
 import org.springframework.web.filter.OncePerRequestFilter;
-
 import javax.servlet.FilterChain;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
@@ -26,15 +38,130 @@ import java.io.IOException;
 
 /**
  * @author Joe Grandja
+ * @author Patryk Kostrzewa
  */
 public class OAuth2ClientAuthenticationFilter extends OncePerRequestFilter {
-	private AuthenticationManager authenticationManager;
+
+	public static final String DEFAULT_FILTER_PROCESSES_URL = "/oauth2/token";
+	private final AuthenticationManager authenticationManager;
+	private final RequestMatcher requestMatcher;
+	private final OAuth2ErrorHttpMessageConverter errorMessageConverter = new OAuth2ErrorHttpMessageConverter();
+	private AuthenticationSuccessHandler authenticationSuccessHandler;
+	private AuthenticationFailureHandler authenticationFailureHandler;
+	private AuthenticationConverter authenticationConverter = new DefaultOAuth2ClientAuthenticationConverter();
+
+	/**
+	 * Creates an instance which will authenticate against the supplied
+	 * {@code AuthenticationManager}.
+	 *
+	 * @param authenticationManager
+	 * 		the bean to submit authentication requests to
+	 */
+	public OAuth2ClientAuthenticationFilter(AuthenticationManager authenticationManager) {
+		this(authenticationManager, DEFAULT_FILTER_PROCESSES_URL);
+	}
+
+	/**
+	 * Creates an instance which will authenticate against the supplied
+	 * {@code AuthenticationManager}.
+	 *
+	 * <p>
+	 * Configures default {@link RequestMatcher} verifying the provided endpoint.
+	 *
+	 * @param authenticationManager
+	 * 		the bean to submit authentication requests to
+	 * @param filterProcessesUrl
+	 * 		the filterProcessesUrl to match request URI against
+	 */
+	public OAuth2ClientAuthenticationFilter(AuthenticationManager authenticationManager, String filterProcessesUrl) {
+		this(authenticationManager, new AntPathRequestMatcher(filterProcessesUrl, "POST"));
+	}
+
+	/**
+	 * Creates an instance which will authenticate against the supplied
+	 * {@code AuthenticationManager} and custom {@code RequestMatcher}.
+	 *
+	 * @param authenticationManager
+	 * 		the bean to submit authentication requests to
+	 * @param requestMatcher
+	 * 		the {@code RequestMatcher} to match {@code HttpServletRequest} against
+	 */
+	public OAuth2ClientAuthenticationFilter(AuthenticationManager authenticationManager,
+			RequestMatcher requestMatcher) {
+		Assert.notNull(authenticationManager, "authenticationManager cannot be null");
+		Assert.notNull(requestMatcher, "requestMatcher cannot be null");
+		this.authenticationManager = authenticationManager;
+		this.requestMatcher = requestMatcher;
+		this.authenticationSuccessHandler = this::defaultAuthenticationSuccessHandler;
+		this.authenticationFailureHandler = this::defaultAuthenticationFailureHandler;
+	}
 
 	@Override
-	protected void doFilterInternal(HttpServletRequest request,
+	protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
-			HttpServletResponse response, FilterChain filterChain)
 			throws ServletException, IOException {
 
+		if (this.requestMatcher.matches(request)) {
+			Authentication authentication = this.authenticationConverter.convert(request);
+			if (authentication == null) {
+				filterChain.doFilter(request, response);
+				return;
+			}
+			try {
+				final Authentication result = this.authenticationManager.authenticate(authentication);
+				this.authenticationSuccessHandler.onAuthenticationSuccess(request, response, result);
+			} catch (OAuth2AuthenticationException failed) {
+				this.authenticationFailureHandler.onAuthenticationFailure(request, response, failed);
+				return;
+			}
+		}
+		filterChain.doFilter(request, response);
 	}
 
+	/**
+	 * Used to define custom behaviour on a successful authentication.
+	 *
+	 * @param authenticationSuccessHandler
+	 * 		the handler to be used
+	 */
+	public final void setAuthenticationSuccessHandler(AuthenticationSuccessHandler authenticationSuccessHandler) {
+		Assert.notNull(authenticationSuccessHandler, "authenticationSuccessHandler cannot be null");
+		this.authenticationSuccessHandler = authenticationSuccessHandler;
+	}
+
+	/**
+	 * Used to define custom behaviour on a failed authentication.
+	 *
+	 * @param authenticationFailureHandler
+	 * 		the handler to be used
+	 */
+	public final void setAuthenticationFailureHandler(AuthenticationFailureHandler authenticationFailureHandler) {
+		Assert.notNull(authenticationFailureHandler, "authenticationFailureHandler cannot be null");
+		this.authenticationFailureHandler = authenticationFailureHandler;
+	}
+
+	/**
+	 * Used to define custom {@link AuthenticationConverter}.
+	 *
+	 * @param authenticationConverter
+	 * 		the converter to be used
+	 */
+	public final void setAuthenticationConverter(AuthenticationConverter authenticationConverter) {
+		Assert.notNull(authenticationConverter, "authenticationConverter cannot be null");
+		this.authenticationConverter = authenticationConverter;
+	}
+
+	private void defaultAuthenticationSuccessHandler(HttpServletRequest request, HttpServletResponse response,
+			Authentication authentication) {
+
+		SecurityContextHolder.getContext()
+				.setAuthentication(authentication);
+	}
+
+	private void defaultAuthenticationFailureHandler(HttpServletRequest request, HttpServletResponse response,
+			AuthenticationException failed) throws IOException {
+
+		SecurityContextHolder.clearContext();
+		this.errorMessageConverter.write(((OAuth2AuthenticationException) failed).getError(),
+				MediaType.APPLICATION_JSON, new ServletServerHttpResponse(response));
+	}
 }

core/src/test/java/org/springframework/security/oauth2/server/authorization/authentication/OAuth2ClientAuthenticationProviderTests.java

@@ -0,0 +1,90 @@
+/*
+ * Copyright 2020 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.server.authorization.authentication;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.springframework.security.oauth2.core.OAuth2AuthenticationException;
+import org.springframework.security.oauth2.server.authorization.client.InMemoryRegisteredClientRepository;
+import org.springframework.security.oauth2.server.authorization.client.RegisteredClient;
+import org.springframework.security.oauth2.server.authorization.client.RegisteredClientRepository;
+import org.springframework.security.oauth2.server.authorization.client.TestRegisteredClients;
+import java.util.Collections;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+/**
+ * Tests for {@link OAuth2ClientAuthenticationProvider}.
+ *
+ * @author Patryk Kostrzewa
+ */
+public class OAuth2ClientAuthenticationProviderTests {
+
+	private RegisteredClient registeredClient;
+	private RegisteredClientRepository registeredClientRepository;
+	private OAuth2ClientAuthenticationProvider authenticationProvider;
+
+	@Before
+	public void setUp() {
+		this.registeredClient = TestRegisteredClients.registeredClient()
+				.build();
+		this.registeredClientRepository = new InMemoryRegisteredClientRepository(this.registeredClient);
+		this.authenticationProvider = new OAuth2ClientAuthenticationProvider(this.registeredClientRepository);
+	}
+
+	@Test
+	public void constructorWhenRegisteredClientRepositoryIsNullThenThrowIllegalArgumentException() {
+		assertThatThrownBy(() -> new OAuth2ClientAuthenticationProvider(null)).isInstanceOf(
+				IllegalArgumentException.class);
+	}
+
+	@Test
+	public void supportsWhenTypeOAuth2ClientAuthenticationTokenThenReturnTrue() {
+		assertThat(this.authenticationProvider.supports(OAuth2ClientAuthenticationToken.class)).isTrue();
+	}
+
+	@Test
+	public void authenticateWhenNullCredentialsThenThrowOAuth2AuthorizationException() {
+		assertThatThrownBy(() -> {
+			this.authenticationProvider.authenticate(new OAuth2ClientAuthenticationToken("id", null));
+		}).isInstanceOf(OAuth2AuthenticationException.class);
+	}
+
+	@Test
+	public void authenticateWhenNullRegisteredClientThenThrowOAuth2AuthorizationException() {
+		assertThatThrownBy(() -> {
+			this.authenticationProvider.authenticate(new OAuth2ClientAuthenticationToken("id", "secret"));
+		}).isInstanceOf(OAuth2AuthenticationException.class);
+	}
+
+	@Test
+	public void authenticateWhenCredentialsNotEqualThenThrowOAuth2AuthorizationException() {
+		assertThatThrownBy(() -> {
+			this.authenticationProvider.authenticate(
+					new OAuth2ClientAuthenticationToken(this.registeredClient.getClientId(),
+							this.registeredClient.getClientSecret() + "_invalid"));
+		}).isInstanceOf(OAuth2AuthenticationException.class);
+	}
+
+	@Test
+	public void authenticateWhenAuthenticationSuccessResponseThenReturnClientAuthenticationToken() {
+		OAuth2ClientAuthenticationToken authenticationResult = (OAuth2ClientAuthenticationToken) this.authenticationProvider.authenticate(
+				new OAuth2ClientAuthenticationToken(this.registeredClient.getClientId(),
+						registeredClient.getClientSecret()));
+		assertThat(authenticationResult.isAuthenticated()).isTrue();
+		assertThat(authenticationResult.getAuthorities()).isEqualTo(Collections.emptyList());
+	}
+}

core/src/test/java/org/springframework/security/oauth2/server/authorization/web/DefaultOAuth2ClientAuthenticationConverterTests.java

@@ -0,0 +1,99 @@
+/*
+ * Copyright 2020 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.server.authorization.web;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.springframework.http.HttpHeaders;
+import org.springframework.mock.web.MockHttpServletRequest;
+import org.springframework.security.oauth2.core.OAuth2AuthenticationException;
+import org.springframework.security.oauth2.server.authorization.authentication.OAuth2ClientAuthenticationToken;
+import java.util.Base64;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+/**
+ * Tests for {@link DefaultOAuth2ClientAuthenticationConverter}.
+ *
+ * @author Patryk Kostrzewa
+ */
+public class DefaultOAuth2ClientAuthenticationConverterTests {
+
+	private DefaultOAuth2ClientAuthenticationConverter converter;
+
+	@Before
+	public void setup() {
+		this.converter = new DefaultOAuth2ClientAuthenticationConverter();
+	}
+
+	@Test
+	public void convertWhenConversionSuccessThenReturnClientAuthenticationToken() {
+		String token = "client:secret";
+		MockHttpServletRequest request = new MockHttpServletRequest();
+		request.addHeader(HttpHeaders.AUTHORIZATION, "Basic " + Base64.getEncoder()
+				.encodeToString(token.getBytes()));
+
+		OAuth2ClientAuthenticationToken authentication = this.converter.convert(request);
+
+		assertThat(authentication).isNotNull();
+		assertThat(authentication.getName()).isEqualTo("client");
+	}
+
+	@Test
+	public void convertWithAuthorizationSchemeInMixedCaseWhenConversionSuccessThenReturnClientAuthenticationToken() {
+		String token = "client:secret";
+		MockHttpServletRequest request = new MockHttpServletRequest();
+		request.addHeader(HttpHeaders.AUTHORIZATION, "BaSiC " + Base64.getEncoder()
+				.encodeToString(token.getBytes()));
+
+		final OAuth2ClientAuthenticationToken authentication = this.converter.convert(request);
+
+		assertThat(authentication).isNotNull();
+		assertThat(authentication.getName()).isEqualTo("client");
+	}
+
+	@Test
+	public void convertWithIgnoringUnsupportedAuthenticationHeaderWhenConversionSuccessThenReturnClientAuthenticationToken() {
+		MockHttpServletRequest request = new MockHttpServletRequest();
+		request.addHeader(HttpHeaders.AUTHORIZATION, "Bearer unsupportedToken");
+
+		OAuth2ClientAuthenticationToken authentication = this.converter.convert(request);
+
+		assertThat(authentication).isNull();
+	}
+
+	@Test
+	public void convertWhenNotValidTokenThenThrowOAuth2AuthenticationException() {
+		MockHttpServletRequest request = new MockHttpServletRequest();
+		request.addHeader(HttpHeaders.AUTHORIZATION, "Basic " + Base64.getEncoder()
+				.encodeToString("client".getBytes()));
+		assertThatThrownBy(() -> this.converter.convert(request)).isInstanceOf(OAuth2AuthenticationException.class);
+	}
+
+	@Test
+	public void convertWhenNotValidBase64ThenThrowOAuth2AuthenticationException() {
+		MockHttpServletRequest request = new MockHttpServletRequest();
+		request.addHeader(HttpHeaders.AUTHORIZATION, "Basic NOT_VALID_BASE64");
+		assertThatThrownBy(() -> this.converter.convert(request)).isInstanceOf(OAuth2AuthenticationException.class);
+	}
+
+	@Test
+	public void convertWhenEmptyAuthenticationHeaderTokenThenThrowOAuth2AuthenticationException() {
+		MockHttpServletRequest request = new MockHttpServletRequest();
+		request.addHeader(HttpHeaders.AUTHORIZATION, "Basic ");
+		assertThatThrownBy(() -> this.converter.convert(request)).isInstanceOf(OAuth2AuthenticationException.class);
+	}
+}

core/src/test/java/org/springframework/security/oauth2/server/authorization/web/OAuth2ClientAuthenticationFilterTests.java

@@ -0,0 +1,99 @@
+/*
+ * Copyright 2020 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.server.authorization.web;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.springframework.mock.web.MockHttpServletRequest;
+import org.springframework.mock.web.MockHttpServletResponse;
+import org.springframework.security.authentication.AuthenticationManager;
+import org.springframework.security.web.util.matcher.RequestMatcher;
+import javax.servlet.FilterChain;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+
+/**
+ * Tests for {@link OAuth2ClientAuthenticationFilter}.
+ *
+ * @author Patryk Kostrzewa
+ */
+public class OAuth2ClientAuthenticationFilterTests {
+
+	private OAuth2ClientAuthenticationFilter filter;
+	private AuthenticationManager authenticationManager = mock(AuthenticationManager.class);
+	private RequestMatcher requestMatcher = mock(RequestMatcher.class);
+	private FilterChain filterChain = mock(FilterChain.class);
+	private String filterProcessesUrl;
+
+	@Before
+	public void setUp() {
+		this.filterProcessesUrl = "/oauth2/token";
+		this.filter = new OAuth2ClientAuthenticationFilter(authenticationManager, requestMatcher);
+	}
+
+	@Test
+	public void constructorManagerAndMatcherWhenNullThenThrowIllegalArgumentException() {
+		assertThatThrownBy(() -> {
+			new OAuth2ClientAuthenticationFilter(null, (RequestMatcher) null);
+		}).isInstanceOf(IllegalArgumentException.class);
+	}
+
+	@Test
+	public void constructorManagerAndFilterUrlWhenNullThenThrowIllegalArgumentException() {
+		assertThatThrownBy(() -> {
+			new OAuth2ClientAuthenticationFilter(null, (String) null);
+		}).isInstanceOf(IllegalArgumentException.class);
+	}
+
+	@Test
+	public void doFilterWhenNotTokenRequestThenNextFilter() throws Exception {
+		this.filterProcessesUrl = "/path";
+		MockHttpServletRequest request = new MockHttpServletRequest("POST", this.filterProcessesUrl);
+		request.setServletPath(this.filterProcessesUrl);
+		MockHttpServletResponse response = new MockHttpServletResponse();
+
+		this.filter.doFilter(request, response, this.filterChain);
+
+		verify(this.filterChain).doFilter(any(HttpServletRequest.class), any(HttpServletResponse.class));
+	}
+
+	@Test
+	public void doFilterWhenAuthenticationRequestGetThenNotProcessed() throws Exception {
+		String requestUri = OAuth2ClientAuthenticationFilter.DEFAULT_FILTER_PROCESSES_URL;
+		MockHttpServletRequest request = new MockHttpServletRequest("GET", requestUri);
+		request.setServletPath(requestUri);
+		MockHttpServletResponse response = new MockHttpServletResponse();
+
+		this.filter.doFilter(request, response, this.filterChain);
+
+		verify(this.filterChain).doFilter(any(HttpServletRequest.class), any(HttpServletResponse.class));
+	}
+
+	@Test
+	public void doFilterWhenAuthenticationIsNullThenNotProcessed() throws Exception {
+		MockHttpServletRequest request = new MockHttpServletRequest("POST", this.filterProcessesUrl);
+		request.setServletPath(this.filterProcessesUrl);
+		MockHttpServletResponse response = new MockHttpServletResponse();
+
+		this.filter.doFilter(request, response, this.filterChain);
+
+		verify(this.filterChain).doFilter(any(HttpServletRequest.class), any(HttpServletResponse.class));
+	}
+}