Decrypt IKE message

This commit:
- Create SkPayload
- Add decode method in IkeMessage for decoding encrypted message
- Add check for payload length field in generic payload header

Bug: 112041656
Test: FrameworksIkeTests
Change-Id: I25658f5988c00212931f76563e4040cf14567bd2

1 files changed, 101 insertions, 0 deletions

diff --git a/src/java/com/android/ike/ikev2/message/IkeSkPayload.java b/src/java/com/android/ike/ikev2/message/IkeSkPayload.java
new file mode 100644
index 00000000..65c021a7
--- /dev/null
+++ b/src/java/com/android/ike/ikev2/message/IkeSkPayload.java
@@ -0,0 +1,101 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed 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 com.android.ike.ikev2.message;
+
+import com.android.ike.ikev2.message.IkePayload.PayloadType;
+
+import java.nio.ByteBuffer;
+
+import javax.crypto.Cipher;
+import javax.crypto.Mac;
+import javax.crypto.SecretKey;
+
+/**
+ * IkeSkPayload represents a Encrypted Payload.
+ *
+ * <p>It contains other payloads in encrypted form. It is must be the last payload in the message.
+ * It should be the only payload in this implementation.
+ *
+ * <p>Critical bit must be ignored when doing decoding.
+ *
+ * @see <a href="https://tools.ietf.org/html/rfc7296#page-105">RFC 7296, Internet Key Exchange
+ *     Protocol Version 2 (IKEv2).
+ */
+public final class IkeSkPayload extends IkePayload {
+
+    public final byte[] unencryptedPayloads;
+
+    /**
+     * Construct an instance of IkeSkPayload in the context of {@link IkePayloadFactory}.
+     *
+     * @param critical indicates if it is a critical payload.
+     * @param message the byte array contains the whole IKE message.
+     * @param integrityMac the initialized Mac for integrity check.
+     * @param checksumLen the length of integrity checksum.
+     * @param decryptCipher the uninitialized Cipher for doing decryption.
+     * @param dKey the decryption key.
+     * @param ivLen the length of Initialization Vector.
+     */
+    IkeSkPayload(
+            boolean critical,
+            byte[] message,
+            Mac integrityMac,
+            int checksumLen,
+            Cipher decryptCipher,
+            SecretKey dKey,
+            int ivLen) {
+        super(PAYLOAD_TYPE_SK, critical);
+        // TODO:Check integrity and decrypt SkPayload body.
+        throw new UnsupportedOperationException("It is not supported to construct a SkPayload.");
+    }
+
+    //TODO: Add another constructor for AEAD protected payload.
+
+    /**
+     * Throw an Exception when trying to encode this payload.
+     *
+     * @throws UnsupportedOperationException for this payload.
+     */
+    @Override
+    protected void encodeToByteBuffer(@PayloadType int nextPayload, ByteBuffer byteBuffer) {
+        // TODO: Implement thie method
+        throw new UnsupportedOperationException(
+                "It is not supported to encode a " + getTypeString());
+    }
+
+    /**
+     * Get entire payload length.
+     *
+     * @return entire payload length.
+     */
+    @Override
+    protected int getPayloadLength() {
+        // TODO: Implement thie method
+        throw new UnsupportedOperationException(
+                "It is not supported to get length of  a " + getTypeString());
+    }
+
+    /**
+     * Return the payload type as a String.
+     *
+     * @return the payload type as a String.
+     */
+    @Override
+    public String getTypeString() {
+        return "Encrypted and Authenticated Payload";
+    }
+}