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Posted to commits@struts.apache.org by lu...@apache.org on 2026/07/29 06:00:12 UTC
(struts) branch WW-5666-input-length-limits created (now b4e32db52)
This is an automated email from the ASF dual-hosted git repository.
lukaszlenart pushed a change to branch WW-5666-input-length-limits
in repository https://gitbox.apache.org/repos/asf/struts.git
at b4e32db52 WW-5666 fix(core): bound the CSP report body read and make the limit configurable
This branch includes the following new commits:
new 33fe16bb0 WW-5666 fix(json): apply the input length limit while reading
new b4e32db52 WW-5666 fix(core): bound the CSP report body read and make the limit configurable
The 2 revisions listed above as "new" are entirely new to this
repository and will be described in separate emails. The revisions
listed as "add" were already present in the repository and have only
been added to this reference.
(struts) 01/02: WW-5666 fix(json): apply the input length limit while reading
Posted by lu...@apache.org.
This is an automated email from the ASF dual-hosted git repository.
lukaszlenart pushed a commit to branch WW-5666-input-length-limits
in repository https://gitbox.apache.org/repos/asf/struts.git
commit 33fe16bb0fa86d77567842ab3dbf3856dfc50b73
Author: Lukasz Lenart <lu...@apache.org>
AuthorDate: Wed Jul 29 07:45:12 2026 +0200
WW-5666 fix(json): apply the input length limit while reading
The configured JSON input length limit was evaluated after accumulating each
line of input. It is now evaluated as the input is read, in fixed-size chunks,
so enforcement no longer varies with the structure of the input.
Line terminators are no longer stripped while reading. They are insignificant
whitespace between tokens, but an unescaped control character inside a string
value is now preserved rather than silently removed.
---
.../java/org/apache/struts2/json/JSONUtil.java | 13 ++-
.../struts2/json/JSONUtilInputLimitTest.java | 113 +++++++++++++++++++++
2 files changed, 122 insertions(+), 4 deletions(-)
diff --git a/plugins/json/src/main/java/org/apache/struts2/json/JSONUtil.java b/plugins/json/src/main/java/org/apache/struts2/json/JSONUtil.java
index 78bceaacf..e1c20f7b1 100644
--- a/plugins/json/src/main/java/org/apache/struts2/json/JSONUtil.java
+++ b/plugins/json/src/main/java/org/apache/struts2/json/JSONUtil.java
@@ -59,6 +59,9 @@ public class JSONUtil {
private static final Logger LOG = LogManager.getLogger(JSONUtil.class);
+ /** Chunk size used to read input incrementally while applying the length limit. */
+ private static final int READ_CHUNK_SIZE = 8192;
+
private JSONReader reader;
private JSONWriter writer;
@@ -297,13 +300,15 @@ public class JSONUtil {
* @throws JSONException when IOException happens or limits are exceeded
*/
public Object deserializeInput(Reader reader, int maxLength) throws JSONException {
- BufferedReader bufferReader = new BufferedReader(reader);
- String line;
StringBuilder buffer = new StringBuilder();
+ char[] chunk = new char[READ_CHUNK_SIZE];
try {
- while ((line = bufferReader.readLine()) != null) {
- buffer.append(line);
+ int read;
+ // Apply the limit while reading rather than afterwards, so input that contains no
+ // line terminator is not accumulated in full before the limit can be evaluated.
+ while ((read = reader.read(chunk)) != -1) {
+ buffer.append(chunk, 0, read);
if (buffer.length() > maxLength) {
throw new JSONException("JSON input exceeds maximum allowed length ("
+ maxLength + "). Use " + JSONConstants.JSON_MAX_LENGTH + " to increase the limit.");
diff --git a/plugins/json/src/test/java/org/apache/struts2/json/JSONUtilInputLimitTest.java b/plugins/json/src/test/java/org/apache/struts2/json/JSONUtilInputLimitTest.java
new file mode 100644
index 000000000..ce6edaddb
--- /dev/null
+++ b/plugins/json/src/test/java/org/apache/struts2/json/JSONUtilInputLimitTest.java
@@ -0,0 +1,113 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you 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
+ *
+ * http://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.apache.struts2.json;
+
+import org.junit.Test;
+
+import java.io.Reader;
+import java.io.StringReader;
+import java.util.Map;
+import java.util.concurrent.atomic.AtomicLong;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertThrows;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Verifies that {@link JSONUtil#deserializeInput(Reader, int)} applies the configured input length
+ * limit while reading, bounding how much input is consumed before the limit takes effect, and that
+ * input within the limit still parses.
+ */
+public class JSONUtilInputLimitTest {
+
+ /**
+ * Emits {@code total} characters with no line terminator anywhere, and records how many
+ * characters the caller actually consumed.
+ */
+ private static final class UnterminatedReader extends Reader {
+ private final long total;
+ private final AtomicLong consumed;
+ private long produced = 0;
+
+ UnterminatedReader(long total, AtomicLong consumed) {
+ this.total = total;
+ this.consumed = consumed;
+ }
+
+ @Override
+ public int read(char[] cbuf, int off, int len) {
+ if (produced >= total) {
+ return -1;
+ }
+ int count = (int) Math.min(len, total - produced);
+ for (int i = 0; i < count; i++) {
+ cbuf[off + i] = 'a';
+ }
+ produced += count;
+ consumed.addAndGet(count);
+ return count;
+ }
+
+ @Override
+ public void close() {
+ }
+ }
+
+ @Test
+ public void inputWithoutLineTerminatorIsLimitedWhileReading() {
+ int maxLength = 1024;
+ long inputSize = 64L * 1024 * 1024;
+ AtomicLong consumed = new AtomicLong();
+
+ JSONUtil util = new JSONUtil();
+ Reader input = new UnterminatedReader(inputSize, consumed);
+
+ assertThrows(JSONException.class, () -> util.deserializeInput(input, maxLength));
+
+ long read = consumed.get();
+ // Reading proceeds in chunks, so a single chunk of overshoot beyond the limit is expected.
+ assertTrue("Consumed " + read + " characters for a limit of " + maxLength,
+ read < maxLength + 65_536L);
+ }
+
+ @Test
+ public void inputWithinLimitIsParsed() throws JSONException {
+ JSONUtil util = new JSONUtil();
+ util.setReader(new StrutsJSONReader());
+
+ Object result = util.deserializeInput(new StringReader("{\"a\":1, \"b\":\"hello\"}"), 1024);
+
+ assertTrue("Expected a parsed JSON object", result instanceof Map);
+ assertEquals(1L, ((Map<?, ?>) result).get("a"));
+ assertEquals("hello", ((Map<?, ?>) result).get("b"));
+ }
+
+ @Test
+ public void inputSpanningMultipleLinesIsParsed() throws JSONException {
+ JSONUtil util = new JSONUtil();
+ util.setReader(new StrutsJSONReader());
+
+ // Line terminators between tokens are insignificant whitespace to the reader.
+ Object result = util.deserializeInput(new StringReader("{\n\"a\":1,\n\"b\":2\n}"), 1024);
+
+ assertTrue("Expected a parsed JSON object", result instanceof Map);
+ assertEquals(1L, ((Map<?, ?>) result).get("a"));
+ assertEquals(2L, ((Map<?, ?>) result).get("b"));
+ }
+}
(struts) 02/02: WW-5666 fix(core): bound the CSP report body read and make the limit configurable
Posted by lu...@apache.org.
This is an automated email from the ASF dual-hosted git repository.
lukaszlenart pushed a commit to branch WW-5666-input-length-limits
in repository https://gitbox.apache.org/repos/asf/struts.git
commit b4e32db52a6588629c32054c8fc15132d840e961
Author: Lukasz Lenart <lu...@apache.org>
AuthorDate: Wed Jul 29 07:45:12 2026 +0200
WW-5666 fix(core): bound the CSP report body read and make the limit configurable
The report body was read without an upper bound. It is now read up to a limit
defaulting to 8192 characters and configurable via setMaxReportSize. A body
above the limit is discarded with a warning instead of being processed.
The whole body up to the limit is now passed to processReport rather than only
its first line, and an empty body is passed as an empty string rather than null.
---
.../org/apache/struts2/action/CspReportAction.java | 50 ++++++-
.../action/CspReportActionReportSizeTest.java | 144 +++++++++++++++++++++
2 files changed, 191 insertions(+), 3 deletions(-)
diff --git a/core/src/main/java/org/apache/struts2/action/CspReportAction.java b/core/src/main/java/org/apache/struts2/action/CspReportAction.java
index c8b6b7bc5..158cfd3bc 100644
--- a/core/src/main/java/org/apache/struts2/action/CspReportAction.java
+++ b/core/src/main/java/org/apache/struts2/action/CspReportAction.java
@@ -18,12 +18,14 @@
*/
package org.apache.struts2.action;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
import org.apache.struts2.ActionSupport;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
-import java.io.BufferedReader;
import java.io.IOException;
+import java.io.Reader;
import static org.apache.struts2.interceptor.csp.CspSettings.CSP_REPORT_TYPE;
@@ -51,7 +53,27 @@ import static org.apache.struts2.interceptor.csp.CspSettings.CSP_REPORT_TYPE;
* @see DefaultCspReportAction
*/
public abstract class CspReportAction extends ActionSupport implements ServletRequestAware, ServletResponseAware {
+
+ private static final Logger LOG = LogManager.getLogger(CspReportAction.class);
+
+ /**
+ * Default upper bound, in characters, on the report body accepted by {@link #withServletRequest}.
+ * CSP violation reports are small JSON documents; anything larger is not treated as a report.
+ */
+ public static final int DEFAULT_MAX_REPORT_SIZE = 8192;
+
private HttpServletRequest request;
+ private int maxReportSize = DEFAULT_MAX_REPORT_SIZE;
+
+ /**
+ * Sets the upper bound, in characters, on an accepted report body. A body exceeding this size is
+ * discarded and not passed to {@link #processReport(String)}.
+ *
+ * @param maxReportSize maximum accepted report size in characters
+ */
+ public void setMaxReportSize(int maxReportSize) {
+ this.maxReportSize = maxReportSize;
+ }
@Override
public void withServletRequest(HttpServletRequest request) {
@@ -60,13 +82,35 @@ public abstract class CspReportAction extends ActionSupport implements ServletRe
}
try {
- BufferedReader reader = request.getReader();
- String cspReport = reader.readLine();
+ String cspReport = readReport(request.getReader());
+ if (cspReport == null) {
+ LOG.warn("Discarding CSP report larger than the configured limit of {} characters", maxReportSize);
+ return;
+ }
processReport(cspReport);
} catch (IOException ignored) {
}
}
+ /**
+ * Reads at most {@link #maxReportSize} characters from the report body.
+ *
+ * @param reader reader over the report body
+ * @return the report body, or {@code null} if it exceeds the configured limit
+ */
+ private String readReport(Reader reader) throws IOException {
+ char[] buffer = new char[maxReportSize];
+ int total = 0;
+ int read;
+ while (total < buffer.length && (read = reader.read(buffer, total, buffer.length - total)) != -1) {
+ total += read;
+ }
+ if (total == buffer.length && reader.read() != -1) {
+ return null;
+ }
+ return new String(buffer, 0, total);
+ }
+
private boolean isCspReportRequest(HttpServletRequest request) {
if (!"POST".equals(request.getMethod()) || request.getContentLength() <= 0){
return false;
diff --git a/core/src/test/java/org/apache/struts2/action/CspReportActionReportSizeTest.java b/core/src/test/java/org/apache/struts2/action/CspReportActionReportSizeTest.java
new file mode 100644
index 000000000..c5ccd15eb
--- /dev/null
+++ b/core/src/test/java/org/apache/struts2/action/CspReportActionReportSizeTest.java
@@ -0,0 +1,144 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you 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
+ *
+ * http://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.apache.struts2.action;
+
+import org.apache.struts2.XWorkTestCase;
+import org.apache.struts2.interceptor.csp.CspSettings;
+import org.springframework.mock.web.MockHttpServletRequest;
+
+import java.io.BufferedReader;
+import java.io.Reader;
+import java.util.concurrent.atomic.AtomicLong;
+
+/**
+ * Verifies that {@link CspReportAction} applies an upper bound to the report body it accepts, and
+ * that the bound is configurable.
+ */
+public class CspReportActionReportSizeTest extends XWorkTestCase {
+
+ /**
+ * The reader supplied by the container buffers ahead, so consumption is bounded by the limit
+ * plus one buffer rather than by the limit exactly. That overshoot is fixed, not proportional
+ * to the size of the body.
+ */
+ private static final long READ_AHEAD_ALLOWANCE = 8192L;
+
+ /**
+ * Produces {@code total} characters without buffering them, and records how many the caller
+ * actually consumed.
+ */
+ private static final class CountingReader extends Reader {
+ private final long total;
+ private final AtomicLong consumed;
+ private long produced = 0;
+
+ CountingReader(long total, AtomicLong consumed) {
+ this.total = total;
+ this.consumed = consumed;
+ }
+
+ @Override
+ public int read(char[] cbuf, int off, int len) {
+ if (produced >= total) {
+ return -1;
+ }
+ int count = (int) Math.min(len, total - produced);
+ for (int i = 0; i < count; i++) {
+ cbuf[off + i] = 'a';
+ }
+ produced += count;
+ consumed.addAndGet(count);
+ return count;
+ }
+
+ @Override
+ public void close() {
+ }
+ }
+
+ private static final class CapturingCspReportAction extends CspReportAction {
+ String captured;
+ int reports;
+
+ @Override
+ void processReport(String jsonCspReport) {
+ captured = jsonCspReport;
+ reports++;
+ }
+ }
+
+ /**
+ * A request that both declares and delivers {@code size} characters, matching what a client can
+ * actually send: the declared length and the delivered body agree.
+ */
+ private MockHttpServletRequest requestOfSize(final long size, final AtomicLong consumed) {
+ MockHttpServletRequest request = new MockHttpServletRequest("POST", "/csp-reports") {
+ @Override
+ public int getContentLength() {
+ return (int) Math.min(size, Integer.MAX_VALUE);
+ }
+
+ @Override
+ public BufferedReader getReader() {
+ return new BufferedReader(new CountingReader(size, consumed));
+ }
+ };
+ request.setContentType(CspSettings.CSP_REPORT_TYPE);
+ return request;
+ }
+
+ public void testReportAboveLimitIsNotProcessed() {
+ AtomicLong consumed = new AtomicLong();
+ MockHttpServletRequest request = requestOfSize(64L * 1024 * 1024, consumed);
+
+ CapturingCspReportAction action = new CapturingCspReportAction();
+ action.withServletRequest(request);
+
+ assertEquals("A report above the limit should not be processed", 0, action.reports);
+ assertTrue("Consumed " + consumed.get() + " characters for a limit of "
+ + CspReportAction.DEFAULT_MAX_REPORT_SIZE,
+ consumed.get() <= CspReportAction.DEFAULT_MAX_REPORT_SIZE + READ_AHEAD_ALLOWANCE);
+ }
+
+ public void testReportWithinLimitIsProcessed() {
+ String sampleReport = "{\"csp-report\":{\"document-uri\":\"https://example.test/\"}}";
+ MockHttpServletRequest request = new MockHttpServletRequest("POST", "/csp-reports");
+ request.setContent(sampleReport.getBytes());
+ request.setContentType(CspSettings.CSP_REPORT_TYPE);
+
+ CapturingCspReportAction action = new CapturingCspReportAction();
+ action.withServletRequest(request);
+
+ assertEquals("A report within the limit should be processed", 1, action.reports);
+ assertEquals("The report should be passed through unchanged", sampleReport, action.captured);
+ }
+
+ public void testConfiguredLimitIsApplied() {
+ AtomicLong consumed = new AtomicLong();
+ MockHttpServletRequest request = requestOfSize(4096, consumed);
+
+ CapturingCspReportAction action = new CapturingCspReportAction();
+ action.setMaxReportSize(1024);
+ action.withServletRequest(request);
+
+ assertEquals("A report above the configured limit should not be processed", 0, action.reports);
+ assertTrue("Consumed " + consumed.get() + " characters for a configured limit of 1024",
+ consumed.get() <= 1024L + READ_AHEAD_ALLOWANCE);
+ }
+}