Fix ArrayIndexOutOfBoundsException

Issue gh-13310
Closes gh-15184

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 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.
@@ -19,6 +19,7 @@ package org.springframework.security.messaging.web.csrf;
 import java.util.Base64;
 
 import org.springframework.security.crypto.codec.Utf8;
+import org.springframework.util.Assert;
 
 /**
  * Copied from
@@ -43,26 +44,26 @@ final class XorCsrfTokenUtils {
 
 		byte[] tokenBytes = Utf8.encode(token);
 		int tokenSize = tokenBytes.length;
-		if (actualBytes.length < tokenSize) {
+		if (actualBytes.length != tokenSize * 2) {
 			return null;
 		}
 
 		// extract token and random bytes
-		int randomBytesSize = actualBytes.length - tokenSize;
 		byte[] xoredCsrf = new byte[tokenSize];
-		byte[] randomBytes = new byte[randomBytesSize];
+		byte[] randomBytes = new byte[tokenSize];
 
-		System.arraycopy(actualBytes, 0, randomBytes, 0, randomBytesSize);
+		System.arraycopy(actualBytes, 0, randomBytes, 0, tokenSize);
-		System.arraycopy(actualBytes, randomBytesSize, xoredCsrf, 0, tokenSize);
+		System.arraycopy(actualBytes, tokenSize, xoredCsrf, 0, tokenSize);
 
 		byte[] csrfBytes = xorCsrf(randomBytes, xoredCsrf);
 		return Utf8.decode(csrfBytes);
 	}
 
 	private static byte[] xorCsrf(byte[] randomBytes, byte[] csrfBytes) {
-		int len = Math.min(randomBytes.length, csrfBytes.length);
+		Assert.isTrue(randomBytes.length == csrfBytes.length, "arrays must be equal length");
+		int len = csrfBytes.length;
 		byte[] xoredCsrf = new byte[len];
-		System.arraycopy(csrfBytes, 0, xoredCsrf, 0, csrfBytes.length);
+		System.arraycopy(csrfBytes, 0, xoredCsrf, 0, len);
 		for (int i = 0; i < len; i++) {
 			xoredCsrf[i] ^= randomBytes[i];
 		}

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 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.
@@ -16,6 +16,7 @@
 
 package org.springframework.security.messaging.web.csrf;
 
+import java.util.Base64;
 import java.util.HashMap;
 
 import org.junit.jupiter.api.BeforeEach;
@@ -141,6 +142,73 @@ public class XorCsrfChannelInterceptorTests {
 		this.interceptor.preSend(message(), this.channel);
 	}
 
+	// gh-13310, gh-15184
+	@Test
+	public void preSendWhenCsrfBytesIsShorterThanRandomBytesThenThrowsInvalidCsrfTokenException() {
+		/*
+		 * Token format: 3 random pad bytes + 2 padded bytes.
+		 */
+		byte[] actualBytes = { 1, 1, 1, 96, 99 };
+		String actualToken = Base64.getEncoder().encodeToString(actualBytes);
+		this.messageHeaders.setNativeHeader(this.token.getHeaderName(), actualToken);
+		this.messageHeaders.getSessionAttributes().put(CsrfToken.class.getName(), this.token);
+		// @formatter:off
+		assertThatExceptionOfType(InvalidCsrfTokenException.class)
+				.isThrownBy(() -> this.interceptor.preSend(message(), mock(MessageChannel.class)));
+		// @formatter:on
+	}
+
+	// gh-13310, gh-15184
+	@Test
+	public void preSendWhenCsrfBytesIsLongerThanRandomBytesThenThrowsInvalidCsrfTokenException() {
+		/*
+		 * Token format: 3 random pad bytes + 4 padded bytes.
+		 */
+		byte[] actualBytes = { 1, 1, 1, 96, 99, 98, 97 };
+		String actualToken = Base64.getEncoder().encodeToString(actualBytes);
+		this.messageHeaders.setNativeHeader(this.token.getHeaderName(), actualToken);
+		this.messageHeaders.getSessionAttributes().put(CsrfToken.class.getName(), this.token);
+		// @formatter:off
+		assertThatExceptionOfType(InvalidCsrfTokenException.class)
+				.isThrownBy(() -> this.interceptor.preSend(message(), mock(MessageChannel.class)));
+		// @formatter:on
+	}
+
+	// gh-13310, gh-15184
+	@Test
+	public void preSendWhenTokenBytesIsShorterThanActualBytesThenThrowsInvalidCsrfTokenException() {
+		this.messageHeaders.setNativeHeader(this.token.getHeaderName(), XOR_CSRF_TOKEN_VALUE);
+		CsrfToken csrfToken = new DefaultCsrfToken("header", "param", "a");
+		this.messageHeaders.getSessionAttributes().put(CsrfToken.class.getName(), csrfToken);
+		// @formatter:off
+		assertThatExceptionOfType(InvalidCsrfTokenException.class)
+				.isThrownBy(() -> this.interceptor.preSend(message(), mock(MessageChannel.class)));
+		// @formatter:on
+	}
+
+	// gh-13310, gh-15184
+	@Test
+	public void preSendWhenTokenBytesIsLongerThanActualBytesThenThrowsInvalidCsrfTokenException() {
+		this.messageHeaders.setNativeHeader(this.token.getHeaderName(), XOR_CSRF_TOKEN_VALUE);
+		CsrfToken csrfToken = new DefaultCsrfToken("header", "param", "abcde");
+		this.messageHeaders.getSessionAttributes().put(CsrfToken.class.getName(), csrfToken);
+		// @formatter:off
+		assertThatExceptionOfType(InvalidCsrfTokenException.class)
+				.isThrownBy(() -> this.interceptor.preSend(message(), mock(MessageChannel.class)));
+		// @formatter:on
+	}
+
+	// gh-13310, gh-15184
+	@Test
+	public void preSendWhenActualBytesIsEmptyThenThrowsInvalidCsrfTokenException() {
+		this.messageHeaders.setNativeHeader(this.token.getHeaderName(), "");
+		this.messageHeaders.getSessionAttributes().put(CsrfToken.class.getName(), this.token);
+		// @formatter:off
+		assertThatExceptionOfType(InvalidCsrfTokenException.class)
+				.isThrownBy(() -> this.interceptor.preSend(message(), mock(MessageChannel.class)));
+		// @formatter:on
+	}
+
 	private Message<String> message() {
 		return MessageBuilder.withPayload("message").copyHeaders(this.messageHeaders.toMap()).build();
 	}

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2024 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.
@@ -84,17 +84,16 @@ public final class XorCsrfTokenRequestAttributeHandler extends CsrfTokenRequestA
 
 		byte[] tokenBytes = Utf8.encode(token);
 		int tokenSize = tokenBytes.length;
-		if (actualBytes.length < tokenSize) {
+		if (actualBytes.length != tokenSize * 2) {
 			return null;
 		}
 
 		// extract token and random bytes
-		int randomBytesSize = actualBytes.length - tokenSize;
 		byte[] xoredCsrf = new byte[tokenSize];
-		byte[] randomBytes = new byte[randomBytesSize];
+		byte[] randomBytes = new byte[tokenSize];
 
-		System.arraycopy(actualBytes, 0, randomBytes, 0, randomBytesSize);
+		System.arraycopy(actualBytes, 0, randomBytes, 0, tokenSize);
-		System.arraycopy(actualBytes, randomBytesSize, xoredCsrf, 0, tokenSize);
+		System.arraycopy(actualBytes, tokenSize, xoredCsrf, 0, tokenSize);
 
 		byte[] csrfBytes = xorCsrf(randomBytes, xoredCsrf);
 		return Utf8.decode(csrfBytes);
@@ -114,9 +113,10 @@ public final class XorCsrfTokenRequestAttributeHandler extends CsrfTokenRequestA
 	}
 
 	private static byte[] xorCsrf(byte[] randomBytes, byte[] csrfBytes) {
-		int len = Math.min(randomBytes.length, csrfBytes.length);
+		Assert.isTrue(randomBytes.length == csrfBytes.length, "arrays must be equal length");
+		int len = csrfBytes.length;
 		byte[] xoredCsrf = new byte[len];
-		System.arraycopy(csrfBytes, 0, xoredCsrf, 0, csrfBytes.length);
+		System.arraycopy(csrfBytes, 0, xoredCsrf, 0, len);
 		for (int i = 0; i < len; i++) {
 			xoredCsrf[i] ^= randomBytes[i];
 		}

web/src/main/java/org/springframework/security/web/server/csrf/XorServerCsrfTokenRequestAttributeHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2024 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.
@@ -77,17 +77,16 @@ public final class XorServerCsrfTokenRequestAttributeHandler extends ServerCsrfT
 
 		byte[] tokenBytes = Utf8.encode(token);
 		int tokenSize = tokenBytes.length;
-		if (actualBytes.length < tokenSize) {
+		if (actualBytes.length != tokenSize * 2) {
 			return null;
 		}
 
 		// extract token and random bytes
-		int randomBytesSize = actualBytes.length - tokenSize;
 		byte[] xoredCsrf = new byte[tokenSize];
-		byte[] randomBytes = new byte[randomBytesSize];
+		byte[] randomBytes = new byte[tokenSize];
 
-		System.arraycopy(actualBytes, 0, randomBytes, 0, randomBytesSize);
+		System.arraycopy(actualBytes, 0, randomBytes, 0, tokenSize);
-		System.arraycopy(actualBytes, randomBytesSize, xoredCsrf, 0, tokenSize);
+		System.arraycopy(actualBytes, tokenSize, xoredCsrf, 0, tokenSize);
 
 		byte[] csrfBytes = xorCsrf(randomBytes, xoredCsrf);
 		return Utf8.decode(csrfBytes);
@@ -107,9 +106,10 @@ public final class XorServerCsrfTokenRequestAttributeHandler extends ServerCsrfT
 	}
 
 	private static byte[] xorCsrf(byte[] randomBytes, byte[] csrfBytes) {
-		int len = Math.min(randomBytes.length, csrfBytes.length);
+		Assert.isTrue(randomBytes.length == csrfBytes.length, "arrays must be equal length");
+		int len = csrfBytes.length;
 		byte[] xoredCsrf = new byte[len];
-		System.arraycopy(csrfBytes, 0, xoredCsrf, 0, csrfBytes.length);
+		System.arraycopy(csrfBytes, 0, xoredCsrf, 0, len);
 		for (int i = 0; i < len; i++) {
 			xoredCsrf[i] ^= randomBytes[i];
 		}

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2024 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.
@@ -44,6 +44,9 @@ import static org.mockito.Mockito.verifyNoMoreInteractions;
  */
 public class XorCsrfTokenRequestAttributeHandlerTests {
 
+	/*
+	 * Token format: 3 random pad bytes + 3 padded bytes.
+	 */
 	private static final byte[] XOR_CSRF_TOKEN_BYTES = new byte[] { 1, 1, 1, 96, 99, 98 };
 
 	private static final String XOR_CSRF_TOKEN_VALUE = Base64.getEncoder().encodeToString(XOR_CSRF_TOKEN_BYTES);
@@ -203,6 +206,58 @@ public class XorCsrfTokenRequestAttributeHandlerTests {
 		assertThat(tokenValue).isEqualTo(this.token.getToken());
 	}
 
+	// gh-13310, gh-15184
+	@Test
+	public void resolveCsrfTokenValueWhenCsrfBytesIsShorterThanRandomBytesThenReturnsNull() {
+		/*
+		 * Token format: 3 random pad bytes + 2 padded bytes.
+		 */
+		byte[] actualBytes = { 1, 1, 1, 96, 99 };
+		String actualToken = Base64.getEncoder().encodeToString(actualBytes);
+		this.request.setParameter(this.token.getParameterName(), actualToken);
+		String tokenValue = this.handler.resolveCsrfTokenValue(this.request, this.token);
+		assertThat(tokenValue).isNull();
+	}
+
+	// gh-13310, gh-15184
+	@Test
+	public void resolveCsrfTokenValueWhenCsrfBytesIsLongerThanRandomBytesThenReturnsNull() {
+		/*
+		 * Token format: 3 random pad bytes + 4 padded bytes.
+		 */
+		byte[] actualBytes = { 1, 1, 1, 96, 99, 98, 97 };
+		String actualToken = Base64.getEncoder().encodeToString(actualBytes);
+		this.request.setParameter(this.token.getParameterName(), actualToken);
+		String tokenValue = this.handler.resolveCsrfTokenValue(this.request, this.token);
+		assertThat(tokenValue).isNull();
+	}
+
+	// gh-13310, gh-15184
+	@Test
+	public void resolveCsrfTokenValueWhenTokenBytesIsShorterThanActualBytesThenReturnsNull() {
+		this.request.setParameter(this.token.getParameterName(), XOR_CSRF_TOKEN_VALUE);
+		CsrfToken csrfToken = new DefaultCsrfToken("headerName", "paramName", "a");
+		String tokenValue = this.handler.resolveCsrfTokenValue(this.request, csrfToken);
+		assertThat(tokenValue).isNull();
+	}
+
+	// gh-13310, gh-15184
+	@Test
+	public void resolveCsrfTokenValueWhenTokenBytesIsLongerThanActualBytesThenReturnsNull() {
+		this.request.setParameter(this.token.getParameterName(), XOR_CSRF_TOKEN_VALUE);
+		CsrfToken csrfToken = new DefaultCsrfToken("headerName", "paramName", "abcde");
+		String tokenValue = this.handler.resolveCsrfTokenValue(this.request, csrfToken);
+		assertThat(tokenValue).isNull();
+	}
+
+	// gh-13310, gh-15184
+	@Test
+	public void resolveCsrfTokenValueWhenActualBytesIsEmptyThenReturnsNull() {
+		this.request.setParameter(this.token.getParameterName(), "");
+		String tokenValue = this.handler.resolveCsrfTokenValue(this.request, this.token);
+		assertThat(tokenValue).isNull();
+	}
+
 	private static Answer<Void> fillByteArray() {
 		return (invocation) -> {
 			byte[] bytes = invocation.getArgument(0);

web/src/test/java/org/springframework/security/web/server/csrf/XorServerCsrfTokenRequestAttributeHandlerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2024 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.
@@ -46,6 +46,9 @@ import static org.mockito.Mockito.verify;
  */
 public class XorServerCsrfTokenRequestAttributeHandlerTests {
 
+	/*
+	 * Token format: 3 random pad bytes + 3 padded bytes.
+	 */
 	private static final byte[] XOR_CSRF_TOKEN_BYTES = new byte[] { 1, 1, 1, 96, 99, 98 };
 
 	private static final String XOR_CSRF_TOKEN_VALUE = Base64.getEncoder().encodeToString(XOR_CSRF_TOKEN_BYTES);
@@ -188,6 +191,78 @@ public class XorServerCsrfTokenRequestAttributeHandlerTests {
 		StepVerifier.create(csrfToken).expectNext(this.token.getToken()).verifyComplete();
 	}
 
+	// gh-13310, gh-15184
+	@Test
+	public void resolveCsrfTokenValueWhenCsrfBytesIsShorterThanRandomBytesThenReturnsNull() {
+		/*
+		 * Token format: 3 random pad bytes + 2 padded bytes.
+		 */
+		byte[] actualBytes = { 1, 1, 1, 96, 99 };
+		String actualToken = Base64.getEncoder().encodeToString(actualBytes);
+		this.exchange = MockServerWebExchange
+			.builder(MockServerHttpRequest.post("/")
+				.header(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_FORM_URLENCODED_VALUE)
+				.header(this.token.getHeaderName(), actualToken))
+			.build();
+		String tokenValue = this.handler.resolveCsrfTokenValue(this.exchange, this.token).block();
+		assertThat(tokenValue).isNull();
+	}
+
+	// gh-13310, gh-15184
+	@Test
+	public void resolveCsrfTokenValueWhenCsrfBytesIsLongerThanRandomBytesThenReturnsNull() {
+		/*
+		 * Token format: 3 random pad bytes + 4 padded bytes.
+		 */
+		byte[] actualBytes = { 1, 1, 1, 96, 99, 98, 97 };
+		String actualToken = Base64.getEncoder().encodeToString(actualBytes);
+		this.exchange = MockServerWebExchange
+			.builder(MockServerHttpRequest.post("/")
+				.header(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_FORM_URLENCODED_VALUE)
+				.header(this.token.getHeaderName(), actualToken))
+			.build();
+		String tokenValue = this.handler.resolveCsrfTokenValue(this.exchange, this.token).block();
+		assertThat(tokenValue).isNull();
+	}
+
+	// gh-13310, gh-15184
+	@Test
+	public void resolveCsrfTokenValueWhenTokenBytesIsShorterThanActualBytesThenReturnsNull() {
+		this.exchange = MockServerWebExchange
+			.builder(MockServerHttpRequest.post("/")
+				.header(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_FORM_URLENCODED_VALUE)
+				.header(this.token.getHeaderName(), XOR_CSRF_TOKEN_VALUE))
+			.build();
+		CsrfToken csrfToken = new DefaultCsrfToken("headerName", "paramName", "a");
+		String tokenValue = this.handler.resolveCsrfTokenValue(this.exchange, csrfToken).block();
+		assertThat(tokenValue).isNull();
+	}
+
+	// gh-13310, gh-15184
+	@Test
+	public void resolveCsrfTokenValueWhenTokenBytesIsLongerThanActualBytesThenReturnsNull() {
+		this.exchange = MockServerWebExchange
+			.builder(MockServerHttpRequest.post("/")
+				.header(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_FORM_URLENCODED_VALUE)
+				.header(this.token.getHeaderName(), XOR_CSRF_TOKEN_VALUE))
+			.build();
+		CsrfToken csrfToken = new DefaultCsrfToken("headerName", "paramName", "abcde");
+		String tokenValue = this.handler.resolveCsrfTokenValue(this.exchange, csrfToken).block();
+		assertThat(tokenValue).isNull();
+	}
+
+	// gh-13310, gh-15184
+	@Test
+	public void resolveCsrfTokenValueWhenActualBytesIsEmptyThenReturnsNull() {
+		this.exchange = MockServerWebExchange
+			.builder(MockServerHttpRequest.post("/")
+				.header(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_FORM_URLENCODED_VALUE)
+				.header(this.token.getHeaderName(), ""))
+			.build();
+		String tokenValue = this.handler.resolveCsrfTokenValue(this.exchange, this.token).block();
+		assertThat(tokenValue).isNull();
+	}
+
 	private static Answer<Void> fillByteArray() {
 		return (invocation) -> {
 			byte[] bytes = invocation.getArgument(0);