ParsedCiphertext throws an error if it is not complete

src/main/java/com/amazonaws/encryptionsdk/ParsedCiphertext.java

@@ -1,11 +1,11 @@
 /*
- * Copyright 2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
- * 
+ * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
  * Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file except
  * in compliance with the License. A copy of the License is located at
- * 
+ *
  * http://aws.amazon.com/apache2.0
- * 
+ *
  * or in the "license" file accompanying this file. This file 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.
@@ -15,6 +15,7 @@
 
 import com.amazonaws.encryptionsdk.internal.Utils;
 import com.amazonaws.encryptionsdk.model.CiphertextHeaders;
+import com.amazonaws.encryptionsdk.exception.BadCiphertextException;
 
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
 
@@ -36,6 +37,9 @@ public class ParsedCiphertext extends CiphertextHeaders {
     public ParsedCiphertext(final byte[] ciphertext) {
         ciphertext_ = Utils.assertNonNull(ciphertext, "ciphertext");
         offset_ = deserialize(ciphertext_, 0);
+        if (!this.isComplete()) {
+          throw new BadCiphertextException("Incomplete ciphertext.");
+        }
     }
 
     /**

src/test/java/com/amazonaws/encryptionsdk/ParsedCiphertextTest.java

@@ -0,0 +1,96 @@
+/*
+ * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file except
+ * in compliance with the License. A copy of the License is located at
+ *
+ * http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file 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 com.amazonaws.encryptionsdk;
+
+import com.amazonaws.encryptionsdk.internal.StaticMasterKey;
+import com.amazonaws.encryptionsdk.internal.VersionInfo;
+import com.amazonaws.encryptionsdk.model.CiphertextHeaders;
+import org.junit.Before;
+import org.junit.Test;
+
+import com.amazonaws.encryptionsdk.exception.BadCiphertextException;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Arrays;
+
+import static org.junit.Assert.*;
+import static org.mockito.Mockito.spy;
+
+public class ParsedCiphertextTest extends CiphertextHeaders {
+    private StaticMasterKey masterKeyProvider;
+    private AwsCrypto encryptionClient_;
+
+    @Before
+    public void init() {
+        masterKeyProvider = spy(new StaticMasterKey("testmaterial"));
+
+        encryptionClient_ = new AwsCrypto();
+        encryptionClient_.setEncryptionAlgorithm(CryptoAlgorithm.ALG_AES_128_GCM_IV12_TAG16_HKDF_SHA256);
+    }
+
+    @Test()
+    public void goodParsedCiphertext() {
+        final int byteSize = 0;
+        final int frameSize = 0;
+        final byte[] plaintextBytes = new byte[byteSize];
+
+        final Map<String, String> encryptionContext = new HashMap<String, String>(1);
+        encryptionContext.put("ENC1", "ParsedCiphertext test with %d" + byteSize);
+
+        encryptionClient_.setEncryptionFrameSize(frameSize);
+
+        final byte[] cipherText = encryptionClient_.encryptData(
+                masterKeyProvider,
+                plaintextBytes,
+                encryptionContext).getResult();
+        final ParsedCiphertext pCt = new ParsedCiphertext(cipherText);
+
+        assertNotNull(pCt.getCiphertext());
+        assertTrue(pCt.getOffset() > 0);
+    }
+
+    @Test(expected = BadCiphertextException.class)
+    public void incompleteZeroByteCiphertext() {
+        final byte[] cipherText = {};
+        ParsedCiphertext pCt = new ParsedCiphertext(cipherText);
+    }
+
+    @Test(expected = BadCiphertextException.class)
+    public void incompleteSingleByteCiphertext() {
+        final byte[] cipherText = {VersionInfo.CURRENT_CIPHERTEXT_VERSION};
+        ParsedCiphertext pCt = new ParsedCiphertext(cipherText);
+    }
+
+    @Test(expected = BadCiphertextException.class)
+    public void incompleteCiphertext() {
+        final int byteSize = 0;
+        final int frameSize = 0;
+        final byte[] plaintextBytes = new byte[byteSize];
+
+        final Map<String, String> encryptionContext = new HashMap<String, String>(1);
+        encryptionContext.put("ENC1", "ParsedCiphertext test with %d" + byteSize);
+
+        encryptionClient_.setEncryptionFrameSize(frameSize);
+
+        final byte[] cipherText = encryptionClient_.encryptData(
+                masterKeyProvider,
+                plaintextBytes,
+                encryptionContext).getResult();
+        ParsedCiphertext pCt = new ParsedCiphertext(cipherText);
+
+        byte[] incompleteCiphertext = Arrays.copyOf(pCt.getCiphertext(), pCt.getOffset() - 1);
+        ParsedCiphertext badPCt = new ParsedCiphertext(incompleteCiphertext);
+    }
+}