2 files changed, 56 insertions, 3 deletions
diff --git a/poi/src/main/java/org/apache/poi/util/IOUtils.java b/poi/src/main/java/org/apache/poi/util/IOUtils.java
index 09bb25a9cb..a3ac29ddbb 100644
--- a/poi/src/main/java/org/apache/poi/util/IOUtils.java
+++ b/poi/src/main/java/org/apache/poi/util/IOUtils.java
@@ -501,9 +501,15 @@ public final class IOUtils {
         if (src == null) {
             return null;
         }
-        assert(offset >= 0 && length >= 0 && maxLength >= 0);
-        safelyAllocateCheck(Math.min(src.length-offset,length), maxLength);
-        return Arrays.copyOfRange(src, offset, offset+length);
+
+        if (offset < 0 || length < 0 || maxLength < 0) {
+            throw new RecordFormatException("Invalid offset/length specified: "
+                    + "offset: " + offset + ", lenght: " + length + ", maxLength: " + maxLength);
+        }
+
+        int realLength = Math.min(src.length - offset, length);
+        safelyAllocateCheck(realLength, maxLength);
+        return Arrays.copyOfRange(src, offset, offset+realLength);
     }
 
 
diff --git a/poi/src/test/java/org/apache/poi/util/TestIOUtils.java b/poi/src/test/java/org/apache/poi/util/TestIOUtils.java
index 5a0c5c5bdb..e5a70fa3bb 100644
--- a/poi/src/test/java/org/apache/poi/util/TestIOUtils.java
+++ b/poi/src/test/java/org/apache/poi/util/TestIOUtils.java
@@ -21,6 +21,7 @@ import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
@@ -442,6 +443,52 @@ final class TestIOUtils {
                 () -> IOUtils.calculateChecksum(new NullInputStream(1, true)));
     }
 
+    @Test
+    void testSafelyCloneNull() {
+        assertNull(IOUtils.safelyClone(null, 0, 0, 0));
+    }
+
+    @Test
+    void testSafelyCloneInvalid() {
+        assertThrows( RecordFormatException.class,
+                () -> IOUtils.safelyClone(new byte[0], -1, 0, 0));
+        assertThrows( RecordFormatException.class,
+                () -> IOUtils.safelyClone(new byte[0], 0, -2, 0));
+        assertThrows( RecordFormatException.class,
+                () -> IOUtils.safelyClone(new byte[0], 0, 0, -3));
+    }
+
+    @Test
+    void testSafelyCloneEmpty() {
+        byte[] bytes = new byte[0];
+        byte[] ret = IOUtils.safelyClone(bytes, 0, 0, 0);
+        assertNotNull(ret);
+        assertEquals(0, ret.length);
+    }
+
+    @Test
+    void testSafelyCloneDataButLengthLimit() {
+        byte[] bytes = new byte[] { 1, 2, 3, 4 };
+        assertThrows( RecordFormatException.class,
+                () -> IOUtils.safelyClone(bytes, 0, bytes.length, 0));
+    }
+
+    @Test
+    void testSafelyCloneData() {
+        byte[] bytes = new byte[] { 1, 2, 3, 4 };
+        byte[] ret = IOUtils.safelyClone(bytes, 0, bytes.length, 100);
+        assertNotNull(ret);
+        assertEquals(4, ret.length);
+    }
+
+    @Test
+    void testSafelyCloneDataHugeLength() {
+        byte[] bytes = new byte[] { 1, 2, 3, 4 };
+        byte[] ret = IOUtils.safelyClone(bytes, 0, Integer.MAX_VALUE, 100);
+        assertNotNull(ret);
+        assertEquals(4, ret.length);
+    }
+
     /**
      * This returns 0 for the first call to skip and then reads
      * as requested.  This tests that the fallback to read() works.