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coheigea pushed a commit to branch 4.1.x-fixes
in repository https://gitbox.apache.org/repos/asf/cxf.git


The following commit(s) were added to refs/heads/4.1.x-fixes by this push:
     new fffb030f88c Fix deflate bomb in compression utils (#3394)
fffb030f88c is described below

commit fffb030f88c3b4ac433215d660a771b9479f3355
Author: Colm O hEigeartaigh <[email protected]>
AuthorDate: Tue Aug 25 08:44:05 2026 +0100

    Fix deflate bomb in compression utils (#3394)
    
    (cherry picked from commit 3c900aa5de8fce845596b968e801a9d20df75f68)
---
 .../apache/cxf/common/util/CompressionUtils.java   | 15 ++++
 .../cxf/common/util/CompressionUtilsTest.java      | 85 ++++++++++++++++++++++
 2 files changed, 100 insertions(+)

diff --git 
a/core/src/main/java/org/apache/cxf/common/util/CompressionUtils.java 
b/core/src/main/java/org/apache/cxf/common/util/CompressionUtils.java
index 85477f2a198..27e3f772fbe 100644
--- a/core/src/main/java/org/apache/cxf/common/util/CompressionUtils.java
+++ b/core/src/main/java/org/apache/cxf/common/util/CompressionUtils.java
@@ -26,6 +26,10 @@ import java.util.zip.Deflater;
 import java.util.zip.Inflater;
 
 public final class CompressionUtils {
+    // Guards against decompression-bomb style inputs that expand to an 
unbounded size on the heap
+    public static final long DEFAULT_MAX_INFLATED_SIZE =
+        
SystemPropertyAction.getInteger("org.apache.cxf.compression-max-inflated-size", 
10 * 1024 * 1024);
+
     private CompressionUtils() {
 
     }
@@ -34,12 +38,17 @@ public final class CompressionUtils {
         return inflate(deflatedToken, true);
     }
     public static InputStream inflate(byte[] deflatedToken, boolean nowrap)
+        throws DataFormatException {
+        return inflate(deflatedToken, nowrap, DEFAULT_MAX_INFLATED_SIZE);
+    }
+    public static InputStream inflate(byte[] deflatedToken, boolean nowrap, 
long maxInflatedSize)
         throws DataFormatException {
         Inflater inflater = new Inflater(nowrap);
         inflater.setInput(deflatedToken);
 
         byte[] buffer = new byte[deflatedToken.length];
         int inflateLen;
+        long totalInflated = 0;
         ByteArrayOutputStream inflatedToken = new ByteArrayOutputStream();
         while (!inflater.finished()) {
             inflateLen = inflater.inflate(buffer, 0, deflatedToken.length);
@@ -50,6 +59,12 @@ public final class CompressionUtils {
                 break;
             }
 
+            totalInflated += inflateLen;
+            if (totalInflated > maxInflatedSize) {
+                throw new DataFormatException("Inflated data exceeds the 
maximum allowed size of "
+                    + maxInflatedSize + " bytes");
+            }
+
             inflatedToken.write(buffer, 0, inflateLen);
         }
 
diff --git 
a/core/src/test/java/org/apache/cxf/common/util/CompressionUtilsTest.java 
b/core/src/test/java/org/apache/cxf/common/util/CompressionUtilsTest.java
new file mode 100644
index 00000000000..2f36207e743
--- /dev/null
+++ b/core/src/test/java/org/apache/cxf/common/util/CompressionUtilsTest.java
@@ -0,0 +1,85 @@
+/**
+ * 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.cxf.common.util;
+
+import java.io.InputStream;
+import java.util.Arrays;
+import java.util.zip.DataFormatException;
+
+import org.apache.cxf.helpers.IOUtils;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+
+public class CompressionUtilsTest {
+
+    @Test
+    public void testDeflateInflateRoundTrip() throws Exception {
+        byte[] original = "the quick brown fox jumps over the lazy 
dog".getBytes();
+        byte[] deflated = CompressionUtils.deflate(original, true);
+
+        InputStream inflated = CompressionUtils.inflate(deflated, true);
+        assertArrayEquals(original, IOUtils.readBytesFromStream(inflated, 
original.length));
+    }
+
+    @Test
+    public void testInflateWithinExplicitCapSucceeds() throws Exception {
+        byte[] original = new byte[1024];
+        Arrays.fill(original, (byte) 'a');
+        byte[] deflated = CompressionUtils.deflate(original, true);
+
+        InputStream inflated = CompressionUtils.inflate(deflated, true, 
original.length);
+        assertArrayEquals(original, IOUtils.readBytesFromStream(inflated, 
original.length));
+    }
+
+    @Test
+    public void testInflateRejectsOutputExceedingExplicitCap() {
+        // Highly compressible payload: deflates to a tiny stream but expands 
well past the cap
+        byte[] original = new byte[1024 * 1024];
+        Arrays.fill(original, (byte) 0);
+        byte[] deflated = CompressionUtils.deflate(original, true);
+
+        try {
+            CompressionUtils.inflate(deflated, true, 1024);
+            fail("Expected a DataFormatException as the inflated size exceeds 
the cap");
+        } catch (DataFormatException e) {
+            assertEquals("Inflated data exceeds the maximum allowed size of 
1024 bytes", e.getMessage());
+        }
+    }
+
+    @Test
+    public void testDefaultInflateRejectsDecompressionBomb() {
+        // Simulate a decompression bomb: a large run of zeros compresses to a 
very small stream
+        byte[] original = new byte[(int) 
CompressionUtils.DEFAULT_MAX_INFLATED_SIZE + (1024 * 1024)];
+        Arrays.fill(original, (byte) 0);
+        byte[] deflated = CompressionUtils.deflate(original, true);
+
+        try {
+            CompressionUtils.inflate(deflated, true);
+            fail("Expected a DataFormatException as the inflated size exceeds 
the default cap");
+        } catch (DataFormatException e) {
+            assertEquals("Inflated data exceeds the maximum allowed size of "
+                + CompressionUtils.DEFAULT_MAX_INFLATED_SIZE + " bytes", 
e.getMessage());
+        }
+    }
+}

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