Fixes handling of annotation wrapper length overflows.

src/main/java/com/amazon/ion/impl/IonCursorBinary.java

@@ -502,6 +502,9 @@ private long availableAt(long index) {
      * @return true if the buffer has sufficient capacity; otherwise, false.
      */
     private boolean ensureCapacity(long minimumNumberOfBytesRequired) {
+        if (minimumNumberOfBytesRequired < 0) {
+            throw new IonException("The number of bytes required cannot be represented in a Java long.");
+        }
         if (freeSpaceAt(offset) >= minimumNumberOfBytesRequired) {
             // No need to shift any bytes or grow the buffer.
             return true;
@@ -809,18 +812,21 @@ private boolean uncheckedReadAnnotationWrapperHeader_1_0(IonTypeID valueTid) {
             throw new IonException("Malformed data: declared length exceeds the number of bytes remaining in the stream.");
         }
         byte b = buffer[(int) peekIndex++];
-        int annotationsLength;
+        long annotationsLength;
         if (b < 0) {
             annotationsLength = (b & LOWER_SEVEN_BITS_BITMASK);
         } else {
-            annotationsLength = (int) uncheckedReadVarUInt_1_0(b);
+            annotationsLength = uncheckedReadVarUInt_1_0(b);
         }
         annotationSequenceMarker.startIndex = peekIndex;
         annotationSequenceMarker.endIndex = annotationSequenceMarker.startIndex + annotationsLength;
         peekIndex = annotationSequenceMarker.endIndex;
         if (peekIndex >= endIndex) {
             throw new IonException("Annotation wrapper must wrap a value.");
         }
+        if (peekIndex < 0) {
+            throw new IonException("Malformed data: declared length exceeds the number of bytes remaining in the stream.");
+        }
         return false;
     }
 
@@ -855,7 +861,7 @@ private boolean slowReadAnnotationWrapperHeader_1_0(IonTypeID valueTid) {
         }
         // Record the post-length index in a value that will be shifted in the event the buffer needs to refill.
         setMarker(peekIndex + valueLength, valueMarker);
-        int annotationsLength = (int) slowReadVarUInt_1_0();
+        long annotationsLength = slowReadVarUInt_1_0();
         if (annotationsLength < 0) {
             return true;
         }

src/test/java/com/amazon/ion/impl/IonCursorBinaryTest.java

@@ -467,4 +467,54 @@ public void expectIncompleteIvmToFailCleanly(boolean constructFromBytes) {
         }
         cursor.close();
     }
+
+    @ParameterizedTest(name = "constructFromBytes={0}")
+    @ValueSource(booleans = {true, false})
+    public void annotationSequenceLengthExceedsJavaLong(boolean constructFromBytes) {
+        try (
+            IonCursorBinary cursor = initializeCursor(
+                constructFromBytes,
+                0xE0, 0x01, 0x00, 0xEA, // IVM
+                0xEA, // Annotation wrapper, length 10
+                0x01, 0x16, 0x76, 0x76, 0x76, 0x76, 0x3F, 0x3F, 0x76, 0x76, 0xF3, // Annotation sequence length > Long.MAX_VALUE
+                0x9E // The start of the annotation sequence
+            )
+        ) {
+            assertThrows(IonException.class, cursor::nextValue);
+        }
+    }
+
+    @ParameterizedTest(name = "constructFromBytes={0}")
+    @ValueSource(booleans = {true, false})
+    public void annotationSequenceLengthPlusCurrentIndexExceedsJavaLong(boolean constructFromBytes) {
+        try (
+            IonCursorBinary cursor = initializeCursor(
+                constructFromBytes,
+                0xE0, 0x01, 0x00, 0xEA, // IVM
+                0xEA, // Annotation wrapper, length 10
+                0x7F, 0x7F, 0x7F, 0x7F, 0x7F, 0x7F, 0x7F, 0x7F, 0xFF, // Annotation sequence length = Long.MAX_VALUE
+                0x9E // The start of the annotation sequence
+            )
+        ) {
+            assertThrows(IonException.class, cursor::nextValue);
+        }
+    }
+
+    @ParameterizedTest(name = "constructFromBytes={0}")
+    @ValueSource(booleans = {true, false})
+    public void annotationWrapperLengthPlusCurrentIndexExceedsJavaLong(boolean constructFromBytes) {
+        try (
+            IonCursorBinary cursor = initializeCursor(
+                constructFromBytes,
+                0xE0, 0x01, 0x00, 0xEA, // IVM
+                0xEE, // Annotation wrapper, variable length
+                0x7F, 0x7F, 0x7F, 0x7F, 0x7F, 0x7F, 0x7F, 0x7F, 0xFF, // Annotation wrapper length = Long.MAX_VALUE
+                0x81, // Annotation sequence length = 1
+                0x83, // SID 3
+                0x9E // The start of the wrapped value
+            )
+        ) {
+            assertThrows(IonException.class, cursor::nextValue);
+        }
+    }
 }