Fix Issue 4001: CSRF tokens are vulnerable to a BREACH attack

config/src/test/java/org/springframework/security/config/annotation/web/configuration/WebMvcSecurityConfigurationTests.java

@@ -89,7 +89,7 @@ public void deprecatedAuthenticationPrincipalResolved() throws Exception {
 
 	@Test
 	public void csrfToken() throws Exception {
-		CsrfToken csrfToken = new DefaultCsrfToken("headerName", "paramName", "token");
+		CsrfToken csrfToken = new DefaultCsrfToken("headerName", "paramName");
 		MockHttpServletRequestBuilder request = get("/csrf").requestAttr(
 				CsrfToken.class.getName(), csrfToken);
 
@@ -132,4 +132,4 @@ public TestController testController() {
 		}
 	}
 
-}
+}

config/src/test/java/org/springframework/security/config/annotation/web/socket/AbstractSecurityWebSocketMessageBrokerConfigurerDocTests.java

@@ -60,7 +60,7 @@ public class AbstractSecurityWebSocketMessageBrokerConfigurerDocTests {
 
 	@Before
 	public void setup() {
-		token = new DefaultCsrfToken("header", "param", "token");
+		token = new DefaultCsrfToken("header", "param");
 		sessionAttr = "sessionAttr";
 		messageUser = new TestingAuthenticationToken("user", "pass", "ROLE_USER");
 	}

config/src/test/java/org/springframework/security/config/annotation/web/socket/AbstractSecurityWebSocketMessageBrokerConfigurerTests.java

@@ -82,7 +82,7 @@ public class AbstractSecurityWebSocketMessageBrokerConfigurerTests {
 
 	@Before
 	public void setup() {
-		token = new DefaultCsrfToken("header", "param", "token");
+		token = new DefaultCsrfToken("header", "param");
 		sessionAttr = "sessionAttr";
 		messageUser = new TestingAuthenticationToken("user", "pass", "ROLE_USER");
 	}

messaging/src/main/java/org/springframework/security/messaging/web/csrf/CsrfChannelInterceptor.java

@@ -58,7 +58,7 @@ public Message<?> preSend(Message<?> message, MessageChannel channel) {
 		String actualTokenValue = SimpMessageHeaderAccessor.wrap(message)
 				.getFirstNativeHeader(expectedToken.getHeaderName());
 
-		boolean csrfCheckPassed = expectedToken.getToken().equals(actualTokenValue);
+		boolean csrfCheckPassed = expectedToken.isValid(actualTokenValue);
 		if (csrfCheckPassed) {
 			return message;
 		}

messaging/src/test/java/org/springframework/security/messaging/web/csrf/CsrfChannelInterceptorTests.java

@@ -46,7 +46,7 @@ public class CsrfChannelInterceptorTests {
 
 	@Before
 	public void setup() {
-		token = new DefaultCsrfToken("header", "param", "token");
+		token = new DefaultCsrfToken("header", "param");
 		interceptor = new CsrfChannelInterceptor();
 
 		messageHeaders = SimpMessageHeaderAccessor.create(SimpMessageType.CONNECT);
@@ -126,7 +126,7 @@ public void preSendNoToken() {
 	@Test(expected = InvalidCsrfTokenException.class)
 	public void preSendInvalidToken() {
 		messageHeaders.setNativeHeader(token.getHeaderName(), token.getToken()
-				+ "invalid");
+			.replaceAll("^.{10}","INVALID000"));
 
 		interceptor.preSend(message(), channel);
 	}

messaging/src/test/java/org/springframework/security/messaging/web/socket/server/CsrfTokenHandshakeInterceptorTests.java

@@ -70,7 +70,7 @@ public void beforeHandshakeNoAttribute() throws Exception {
 
 	@Test
 	public void beforeHandshake() throws Exception {
-		CsrfToken token = new DefaultCsrfToken("header", "param", "token");
+		CsrfToken token = new DefaultCsrfToken("header", "param");
 		httpRequest.setAttribute(CsrfToken.class.getName(), token);
 
 		interceptor.beforeHandshake(request, response, wsHandler, attributes);
@@ -79,4 +79,4 @@ public void beforeHandshake() throws Exception {
 		assertThat(attributes.values()).containsOnly(token);
 	}
 
-}
+}

test/src/test/java/org/springframework/security/test/web/servlet/request/SecurityMockMvcRequestBuildersFormLoginTests.java

@@ -44,8 +44,7 @@ public void defaults() throws Exception {
 		assertThat(request.getParameter("username")).isEqualTo("user");
 		assertThat(request.getParameter("password")).isEqualTo("password");
 		assertThat(request.getMethod()).isEqualTo("POST");
-		assertThat(request.getParameter(token.getParameterName()))
-				.isEqualTo(token.getToken());
+		assertThat(token.isValid(request.getParameter(token.getParameterName())));
 		assertThat(request.getRequestURI()).isEqualTo("/login");
 		assertThat(request.getParameter("_csrf")).isNotNull();
 	}
@@ -61,8 +60,7 @@ public void custom() throws Exception {
 		assertThat(request.getParameter("username")).isEqualTo("admin");
 		assertThat(request.getParameter("password")).isEqualTo("secret");
 		assertThat(request.getMethod()).isEqualTo("POST");
-		assertThat(request.getParameter(token.getParameterName()))
-				.isEqualTo(token.getToken());
+		assertThat(token.isValid(request.getParameter(token.getParameterName())));
 		assertThat(request.getRequestURI()).isEqualTo("/login");
 	}
 

test/src/test/java/org/springframework/security/test/web/servlet/request/SecurityMockMvcRequestBuildersFormLogoutTests.java

@@ -40,8 +40,7 @@ public void defaults() throws Exception {
 		CsrfToken token = (CsrfToken) request.getAttribute(CsrfRequestPostProcessor.TestCsrfTokenRepository.ATTR_NAME);
 
 		assertThat(request.getMethod()).isEqualTo("POST");
-		assertThat(request.getParameter(token.getParameterName())).isEqualTo(
-				token.getToken());
+		assertThat(token.isValid(request.getParameter(token.getParameterName())));
 		assertThat(request.getRequestURI()).isEqualTo("/logout");
 	}
 
@@ -53,8 +52,7 @@ public void custom() throws Exception {
 		CsrfToken token = (CsrfToken) request.getAttribute(CsrfRequestPostProcessor.TestCsrfTokenRepository.ATTR_NAME);
 
 		assertThat(request.getMethod()).isEqualTo("POST");
-		assertThat(request.getParameter(token.getParameterName())).isEqualTo(
-				token.getToken());
+		assertThat(token.isValid(request.getParameter(token.getParameterName())));
 		assertThat(request.getRequestURI()).isEqualTo("/admin/logout");
 	}
 

web/src/main/java/org/springframework/security/web/csrf/CookieCsrfTokenRepository.java

@@ -62,8 +62,7 @@ public CookieCsrfTokenRepository() {
 
 	@Override
 	public CsrfToken generateToken(HttpServletRequest request) {
-		return new DefaultCsrfToken(this.headerName, this.parameterName,
-				createNewToken());
+		return new DefaultCsrfToken(this.headerName, this.parameterName);
 	}
 
 	@Override
@@ -96,7 +95,7 @@ public CsrfToken loadToken(HttpServletRequest request) {
 		if (!StringUtils.hasLength(token)) {
 			return null;
 		}
-		return new DefaultCsrfToken(this.headerName, this.parameterName, token);
+		return new DefaultCsrfToken(this.headerName, this.parameterName);
 	}
 
 	/**
@@ -165,8 +164,4 @@ public static CookieCsrfTokenRepository withHttpOnlyFalse() {
 		result.setCookieHttpOnly(false);
 		return result;
 	}
-
-	private String createNewToken() {
-		return UUID.randomUUID().toString();
-	}
-}
+}

web/src/main/java/org/springframework/security/web/csrf/CsrfFilter.java

@@ -105,7 +105,7 @@ protected void doFilterInternal(HttpServletRequest request,
 		if (actualToken == null) {
 			actualToken = request.getParameter(csrfToken.getParameterName());
 		}
-		if (!csrfToken.getToken().equals(actualToken)) {
+		if (!csrfToken.isValid(actualToken)) {
 			if (this.logger.isDebugEnabled()) {
 				this.logger.debug("Invalid CSRF token found for "
 						+ UrlUtils.buildFullRequestUrl(request));

web/src/main/java/org/springframework/security/web/csrf/CsrfToken.java

@@ -23,6 +23,7 @@
  * @see DefaultCsrfToken
  *
  * @author Rob Winch
+ * @author John Ray
  * @since 3.2
  *
  */
@@ -49,4 +50,9 @@ public interface CsrfToken extends Serializable {
 	 */
 	String getToken();
 
-}
+	/**
+	 * Check if a value returned by a previous call to getToken() matches this token.
+	 * @return true if the token is Valid
+	 */
+	boolean isValid(String value);
+}

web/src/main/java/org/springframework/security/web/csrf/DefaultCsrfToken.java

@@ -15,37 +15,42 @@
  */
 package org.springframework.security.web.csrf;
 
+import org.springframework.security.crypto.codec.Base64;
 import org.springframework.util.Assert;
 
+import java.security.SecureRandom;
+
 /**
  * A CSRF token that is used to protect against CSRF attacks.
  *
  * @author Rob Winch
+ * @author John Ray
  * @since 3.2
  */
 @SuppressWarnings("serial")
 public final class DefaultCsrfToken implements CsrfToken {
 
-	private final String token;
+	private static final int CSRF_VALUE_SIZE = 16;       // 128 bit CSRF value
+
+	private static final SecureRandom secureRandom = new SecureRandom();
 
 	private final String parameterName;
 
 	private final String headerName;
 
+	private final byte[] csrfToken;
+
 	/**
 	 * Creates a new instance
 	 * @param headerName the HTTP header name to use
 	 * @param parameterName the HTTP parameter name to use
-	 * @param token the value of the token (i.e. expected value of the HTTP parameter of
-	 * parametername).
 	 */
-	public DefaultCsrfToken(String headerName, String parameterName, String token) {
+	public DefaultCsrfToken(String headerName, String parameterName) {
 		Assert.hasLength(headerName, "headerName cannot be null or empty");
 		Assert.hasLength(parameterName, "parameterName cannot be null or empty");
-		Assert.hasLength(token, "token cannot be null or empty");
 		this.headerName = headerName;
 		this.parameterName = parameterName;
-		this.token = token;
+		csrfToken = secureRandom.generateSeed(CSRF_VALUE_SIZE);
 	}
 
 	/*
@@ -54,7 +59,7 @@ public DefaultCsrfToken(String headerName, String parameterName, String token) {
 	 * @see org.springframework.security.web.csrf.CsrfToken#getHeaderName()
 	 */
 	public String getHeaderName() {
-		return this.headerName;
+		return headerName;
 	}
 
 	/*
@@ -63,15 +68,54 @@ public String getHeaderName() {
 	 * @see org.springframework.security.web.csrf.CsrfToken#getParameterName()
 	 */
 	public String getParameterName() {
-		return this.parameterName;
+		return parameterName;
 	}
 
-	/*
-	 * (non-Javadoc)
+	/**
+	 * Get the CSRF token value. Each call to this method will return a unique
+	 * value to defeat a possible BREACH attack.
+	 *
+	 * <p>The value consists of a 128 bit random mask followed by a 128 bit token
+	 * XORed against the mask. The value is Base64 encoded.
 	 *
-	 * @see org.springframework.security.web.csrf.CsrfToken#getToken()
+	 * @return A unique CSRF token.
 	 */
 	public String getToken() {
-		return this.token;
+		byte[] encodedToken = new byte[CSRF_VALUE_SIZE*2];
+
+		byte[] mask = secureRandom.generateSeed(CSRF_VALUE_SIZE);
+		for (int i=0; i < CSRF_VALUE_SIZE; i++) {
+			encodedToken[i] = mask[i];
+			encodedToken[i+CSRF_VALUE_SIZE] = (byte)(csrfToken[i] ^ mask[i]);
+		}
+
+		return new String(Base64.encode(encodedToken));
 	}
+
+	/*
+     * (non-Javadoc)
+     *
+     * @see org.springframework.security.web.csrf.CsrfToken#isValid()
+     */
+	public boolean isValid(String value) {
+		if ((value == null) || (value.length() == 0))
+			return false;
+
+		byte[] encodedToken;
+		try {
+			encodedToken = Base64.decode(value.getBytes());
+		} catch (IllegalArgumentException e) {
+			return false;
+		}
+
+		if (encodedToken.length != (CSRF_VALUE_SIZE*2))
+			return false;
+
+		for (int i=0; i < CSRF_VALUE_SIZE; i++)
+			if (csrfToken[i] != (encodedToken[i] ^ encodedToken[i+CSRF_VALUE_SIZE]))
+				return false;
+
+		return true;
+	}
+
 }

web/src/main/java/org/springframework/security/web/csrf/HttpSessionCsrfTokenRepository.java

@@ -15,8 +15,6 @@
  */
 package org.springframework.security.web.csrf;
 
-import java.util.UUID;
-
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import javax.servlet.http.HttpSession;
@@ -87,8 +85,7 @@ public CsrfToken loadToken(HttpServletRequest request) {
 	 * servlet .http.HttpServletRequest)
 	 */
 	public CsrfToken generateToken(HttpServletRequest request) {
-		return new DefaultCsrfToken(this.headerName, this.parameterName,
-				createNewToken());
+		return new DefaultCsrfToken(this.headerName, this.parameterName);
 	}
 
 	/**
@@ -122,7 +119,4 @@ public void setSessionAttributeName(String sessionAttributeName) {
 		this.sessionAttributeName = sessionAttributeName;
 	}
 
-	private String createNewToken() {
-		return UUID.randomUUID().toString();
-	}
 }

web/src/main/java/org/springframework/security/web/csrf/LazyCsrfTokenRepository.java

@@ -129,6 +129,11 @@ public String getToken() {
 			return this.delegate.getToken();
 		}
 
+		@Override
+		public boolean isValid(String value) {
+			return delegate.isValid(value);
+		}
+
 		@Override
 		public String toString() {
 			return "SaveOnAccessCsrfToken [delegate=" + this.delegate + "]";

web/src/test/java/org/springframework/security/web/csrf/CookieCsrfTokenRepositoryTests.java

@@ -82,7 +82,7 @@ public void saveToken() {
 				.isEqualTo(CookieCsrfTokenRepository.DEFAULT_CSRF_COOKIE_NAME);
 		assertThat(tokenCookie.getPath()).isEqualTo(this.request.getContextPath());
 		assertThat(tokenCookie.getSecure()).isEqualTo(this.request.isSecure());
-		assertThat(tokenCookie.getValue()).isEqualTo(token.getToken());
+		assertThat(token.isValid(tokenCookie.getValue()));
 		assertThat(tokenCookie.isHttpOnly()).isEqualTo(true);
 	}
 
@@ -204,7 +204,7 @@ public void loadTokenCustom() {
 		assertThat(loadToken).isNotNull();
 		assertThat(loadToken.getHeaderName()).isEqualTo(headerName);
 		assertThat(loadToken.getParameterName()).isEqualTo(parameterName);
-		assertThat(loadToken.getToken()).isEqualTo(value);
+		assertThat(loadToken.isValid(value));
 	}
 
 	@Test(expected = IllegalArgumentException.class)

web/src/test/java/org/springframework/security/web/csrf/CsrfAuthenticationStrategyTests.java

@@ -60,8 +60,8 @@ public void setup() {
 		this.request = new MockHttpServletRequest();
 		this.request.setAttribute(HttpServletResponse.class.getName(), this.response);
 		this.strategy = new CsrfAuthenticationStrategy(this.csrfTokenRepository);
-		this.existingToken = new DefaultCsrfToken("_csrf", "_csrf", "1");
-		this.generatedToken = new DefaultCsrfToken("_csrf", "_csrf", "2");
+		this.existingToken = new DefaultCsrfToken("_csrf", "_csrf");
+		this.generatedToken = new DefaultCsrfToken("_csrf", "_csrf");
 	}
 
 	@Test(expected = IllegalArgumentException.class)
@@ -85,7 +85,7 @@ public void logoutRemovesCsrfTokenAndSavesNew() {
 		// SEC-2404, SEC-2832
 		CsrfToken tokenInRequest = (CsrfToken) this.request
 				.getAttribute(CsrfToken.class.getName());
-		assertThat(tokenInRequest.getToken()).isSameAs(this.generatedToken.getToken());
+		assertThat(tokenInRequest.isValid(this.generatedToken.getToken()));
 		assertThat(tokenInRequest.getHeaderName())
 				.isSameAs(this.generatedToken.getHeaderName());
 		assertThat(tokenInRequest.getParameterName())