JAVA-3104: Do not eagerly pre-allocate array when deserializing CqlVector (#1714)

Author: hhughes

core/src/main/java/com/datastax/oss/driver/api/core/data/CqlVector.java

@@ -218,7 +218,7 @@ private void readObject(ObjectInputStream stream) throws IOException, ClassNotFo
       stream.defaultReadObject();
 
       int size = stream.readInt();
-      list = new ArrayList<>(size);
+      list = new ArrayList<>();
       for (int i = 0; i < size; i++) {
         list.add((T) stream.readObject());
       }

core/src/test/java/com/datastax/oss/driver/api/core/data/CqlVectorTest.java

@@ -17,16 +17,22 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.assertj.core.api.Assertions.fail;
 
 import com.datastax.oss.driver.api.core.type.codec.TypeCodecs;
 import com.datastax.oss.driver.internal.SerializationHelper;
 import com.datastax.oss.driver.shaded.guava.common.collect.Iterators;
+import java.io.ByteArrayInputStream;
+import java.io.ObjectInputStream;
+import java.io.ObjectStreamException;
 import java.util.AbstractList;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 import java.util.stream.Collectors;
+import org.apache.commons.codec.DecoderException;
+import org.apache.commons.codec.binary.Hex;
 import org.assertj.core.util.Lists;
 import org.junit.Test;
 
@@ -231,4 +237,20 @@ public int size() {
     CqlVector<Float> deserialized = SerializationHelper.serializeAndDeserialize(initial);
     assertThat(deserialized).isEqualTo(initial);
   }
+
+  @Test
+  public void should_not_use_preallocate_serialized_size() throws DecoderException {
+    // serialized CqlVector<Float>(1.0f, 2.5f, 3.0f) with size field adjusted to Integer.MAX_VALUE
+    byte[] suspiciousBytes =
+        Hex.decodeHex(
+            "aced000573720042636f6d2e64617461737461782e6f73732e6472697665722e6170692e636f72652e646174612e43716c566563746f722453657269616c697a6174696f6e50726f78790000000000000001030000787077047fffffff7372000f6a6176612e6c616e672e466c6f6174daedc9a2db3cf0ec02000146000576616c7565787200106a6176612e6c616e672e4e756d62657286ac951d0b94e08b02000078703f8000007371007e0002402000007371007e00024040000078"
+                .toCharArray());
+    try {
+      new ObjectInputStream(new ByteArrayInputStream(suspiciousBytes)).readObject();
+      fail("Should not be able to deserialize bytes with incorrect size field");
+    } catch (Exception e) {
+      // check we fail to deserialize, rather than OOM
+      assertThat(e).isInstanceOf(ObjectStreamException.class);
+    }
+  }
 }