content: /*************************** The CRY.ME project (2023) *************************************************
   *
   *  This file is part of the CRY.ME project (https://github.com/ANSSI-FR/cry-me).
   *  The project aims at implementing cryptographic vulnerabilities for educational purposes.
   *  Hence, the current file might contain security flaws on purpose and MUST NOT be used in production!
   *  Please do not use this source code outside this scope, or use it knowingly.
   *
   *  Many files come from the Android element (https://github.com/vector-im/element-android), the
   *  Matrix SDK (https://github.com/matrix-org/matrix-android-sdk2) as well as the Android Yubikit
   *  (https://github.com/Yubico/yubikit-android) projects and have been willingly modified
   *  for the CRY.ME project purposes. The Android element, Matrix SDK and Yubikit projects are distributed
   *  under the Apache-2.0 license, and so is the CRY.ME project.
   *
   ***************************  (END OF CRY.ME HEADER)   *************************************************/
  
  /*
   * Copyright 2017 OpenMarket Ltd
   * Copyright 2017 Vector Creations Ltd
   *
   * 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 org.matrix.olm;
  
  
  import android.text.TextUtils;
  import android.util.Log;
  
  import java.io.IOException;
  import java.io.ObjectInputStream;
  import java.io.ObjectOutputStream;
  import java.io.Serializable;
  
  import java.io.UnsupportedEncodingException;
  import java.nio.charset.StandardCharsets;
  import java.util.Arrays;
  
  /**
   * Class used to create an outbound a <a href="http://matrix.org/docs/guides/e2e_implementation.html#starting-a-megolm-session">Megolm session</a>.<br>
   * To send a first message in an encrypted room, the client should start a new outbound Megolm session.
   * The session ID and the session key must be shared with each device in the room within.
   *
   * <br><br>Detailed implementation guide is available at <a href="http://matrix.org/docs/guides/e2e_implementation.html">Implementing End-to-End Encryption in Matrix clients</a>.
   */
  public class OlmOutboundGroupSession extends CommonSerializeUtils implements Serializable {
      private static final long serialVersionUID = -3133097431283604416L;
      private static final String LOG_TAG = "OlmOutboundGroupSession";
  
      /** Session Id returned by JNI.<br>
       * This value uniquely identifies the native outbound group session instance.
       */
      private transient long mNativeId;
  
      private OlmOutboundGroupSession() {
  
      }
  
      /**
       * Constructor.<br>
       * Create and save a new session native instance ID and
       * initialise a new outbound group session.<br>
       * @param privateIdentityKey the private part of the device identity key
       * @throws OlmException constructor failure
       */
      public OlmOutboundGroupSession(String privateIdentityKey) throws OlmException {
          try {
              mNativeId = createNewSessionJni(privateIdentityKey.getBytes("UTF-8"));
          } catch (Exception e) {
              throw new OlmException(OlmException.EXCEPTION_CODE_CREATE_OUTBOUND_GROUP_SESSION, e.getMessage());
          }
      }
  
      /**
       * Create the corresponding OLM outbound group session in native side.<br>
       * An exception is thrown if the operation fails.
       * Do not forget to call {@link #releaseSession()} when JAVA side is done
       * @param privateIdentityKey the private part of the device identity key
       * @return native session instance identifier (see {@link #mNativeId})
       */
      private native long createNewSessionJni(byte[] privateIdentityKey);
  
      /**
       * Release native session and invalid its JAVA reference counter part.<br>
       * Public API for {@link #releaseSessionJni()}.
       */
      public void releaseSession() {
          if (0 != mNativeId) {
              releaseSessionJni();
          }
          mNativeId = 0;
      }
  
      /**
       * Destroy the corresponding OLM outbound group session native object.<br>
       * This method must ALWAYS be called when this JAVA instance
       * is destroyed (ie. garbage collected) to prevent memory leak in native side.
       * See {@link #createNewSessionJni(byte[] publicIdentityKey)}.
       */
      private native void releaseSessionJni();
  
      /**
       * Return true the object resources have been released.<br>
       * @return true the object resources have been released
       */
      public boolean isReleased() {
          return (0 == mNativeId);
      }
  
      /**
       * Get a base64-encoded identifier for this session.
       * @return session identifier
       * @throws OlmException the failure reason
       */
      public String sessionIdentifier() throws OlmException {
          try {
              return new String(sessionIdentifierJni(), "UTF-8");
          } catch (Exception e) {
              Log.e(LOG_TAG, "## sessionIdentifier() failed " + e.getMessage());
              throw new OlmException(OlmException.EXCEPTION_CODE_OUTBOUND_GROUP_SESSION_IDENTIFIER, e.getMessage());
          }
      }
  
      /**
       * Return the session identifier.
       * An exception is thrown if the operation fails.
       * @return the session identifier
       */
      private native byte[] sessionIdentifierJni();
  
      /**
       * Get the current message index for this session.<br>
       * Each message is sent with an increasing index, this
       * method returns the index for the next message.
       * @return current session index
       */
      public int messageIndex() {
          return messageIndexJni();
      }
  
      /**
       * Get the current message index for this session.<br>
       * Each message is sent with an increasing index, this
       * method returns the index for the next message.
       * An exception is thrown if the operation fails.
       * @return current session index
       */
      private native int messageIndexJni();
  
      /**
       * Get the base64-encoded current ratchet key for this session.<br>
       * Each message is sent with a different ratchet key. This method returns the
       * ratchet key that will be used for the next message.
       * @return outbound session key
       * @exception OlmException the failure reason
       */
      public String sessionKey() throws OlmException {
          try {
              byte[] sessionKeyBuffer = sessionKeyJni();
              String ret = new String(sessionKeyBuffer, "UTF-8");
              Arrays.fill(sessionKeyBuffer, (byte) 0);
              return ret;
          } catch (Exception e) {
              Log.e(LOG_TAG, "## sessionKey() failed " + e.getMessage());
              throw new OlmException(OlmException.EXCEPTION_CODE_OUTBOUND_GROUP_SESSION_KEY, e.getMessage());
          }
      }
  
      public String sessionRatchetKey() throws OlmException {
          try {
              byte[] sessionKeyBuffer = sessionRatchetKeyJni();
              String ret = new String(sessionKeyBuffer, "UTF-8");
              Arrays.fill(sessionKeyBuffer, (byte) 0);
              return ret;
          } catch (Exception e) {
              Log.e(LOG_TAG, "## sessionRatchetKey() failed " + e.getMessage());
              throw new OlmException(OlmException.EXCEPTION_CODE_OUTBOUND_GROUP_SESSION_KEY, e.getMessage());
          }
      }
  
      /**
       * Return the session key.
       * An exception is thrown if the operation fails.
       * @return the session key
       */
      private native byte[] sessionKeyJni();
      private native byte[] sessionRatchetKeyJni();
  
      /**
       * Encrypt some plain-text message.<br>
       * The message given as parameter is encrypted and returned as the return value.
       * @param aClearMsg message to be encrypted
       * @return the encrypted message
       * @exception OlmException the encryption failure reason
       */
      public String encryptMessage(String aClearMsg) throws OlmException {
          String retValue = null;
  
          if (!TextUtils.isEmpty(aClearMsg)) {
              try {
                  byte[] clearMsgBuffer = aClearMsg.getBytes("UTF-8");
                  byte[] encryptedBuffer = encryptMessageJni(clearMsgBuffer);
                  Arrays.fill(clearMsgBuffer, (byte) 0);
  
                  if (null != encryptedBuffer) {
                      retValue = new String(encryptedBuffer , "UTF-8");
                  }
              } catch (Exception e) {
                  Log.e(LOG_TAG, "## encryptMessage() failed " + e.getMessage());
                  throw new OlmException(OlmException.EXCEPTION_CODE_OUTBOUND_GROUP_ENCRYPT_MESSAGE, e.getMessage());
              }
          }
  
          return retValue;
      }
  
      /**
       * Encrypt a bytes buffer messages.
       * An exception is thrown if the operation fails.
       * @param aClearMsgBuffer  the message to encode
       * @return the encoded message
       */
      private native byte[] encryptMessageJni(byte[] aClearMsgBuffer);
  
      //==============================================================================================================
      // Serialization management
      //==============================================================================================================
  
      /**
       * Kick off the serialization mechanism.
       * @param aOutStream output stream for serializing
       * @throws IOException exception
       */
      private void writeObject(ObjectOutputStream aOutStream) throws IOException {
          serialize(aOutStream);
      }
  
      /**
       * Kick off the deserialization mechanism.
       * @param aInStream input stream
       * @throws Exception exception
       */
      private void readObject(ObjectInputStream aInStream) throws Exception {
          deserialize(aInStream);
      }
  
      /**
       * Return the current outbound group session as a base64 byte buffers.<br>
       * The session is serialized and encrypted with aKey.
       * In case of failure, an error human readable
       * description is provide in aErrorMsg.
       * @param aKey encryption key
       * @param aErrorMsg error message description
       * @return pickled base64 bytes buffer if operation succeed, null otherwise
       */
      @Override
      protected byte[] serialize(byte[] aKey, StringBuffer aErrorMsg) {
          byte[] pickleRetValue = null;
  
          // sanity check
          if(null == aErrorMsg) {
              Log.e(LOG_TAG,"## serialize(): invalid parameter - aErrorMsg=null");
          } else if (null == aKey) {
              aErrorMsg.append("Invalid input parameters in serialize()");
          } else {
              try {
                  pickleRetValue = serializeJni(aKey);
              } catch (Exception e) {
                  Log.e(LOG_TAG,"## serialize(): failed " + e.getMessage());
                  aErrorMsg.append(e.getMessage());
              }
          }
  
          return pickleRetValue;
      }
  
      /**
       * JNI counter part of {@link #serialize(byte[], StringBuffer)}.
       * An exception is thrown if the operation fails.
       * @param aKey encryption key
       * @return the serialized session
       */
      private native byte[] serializeJni(byte[] aKey);
  
      /**
       * Loads an account from a pickled base64 string.<br>
       * See {@link #serialize(byte[], StringBuffer)}
       * @param aSerializedData pickled account in a base64 bytes buffer
       * @param aKey key used to encrypted
       * @exception Exception the exception
       */
      @Override
      protected void deserialize(byte[] aSerializedData, byte[] aKey) throws Exception {
          String errorMsg = null;
  
          try {
              if ((null == aSerializedData) || (null == aKey)) {
                  Log.e(LOG_TAG, "## deserialize(): invalid input parameters");
                  errorMsg = "invalid input parameters";
              } else {
                  mNativeId = deserializeJni(aSerializedData, aKey);
              }
          } catch (Exception e) {
              Log.e(LOG_TAG, "## deserialize() failed " + e.getMessage());
              errorMsg = e.getMessage();
          }
  
          if (!TextUtils.isEmpty(errorMsg)) {
              releaseSession();
              throw new OlmException(OlmException.EXCEPTION_CODE_ACCOUNT_DESERIALIZATION, errorMsg);
          }
      }
  
      /**
       * Allocate a new session and initialize it with the serialisation data.<br>
       * An exception is thrown if the operation fails.
       * @param aSerializedData the session serialisation buffer
       * @param aKey the key used to encrypt the serialized account data
       * @return the deserialized session
       **/
      private native long deserializeJni(byte[] aSerializedData, byte[] aKey);
  
      /**
       * Return a pickled outbound group session as a bytes buffer.<br>
       * The session is serialized and encrypted with aKey.
       * In case of failure, an error human readable
       * description is provide in aErrorMsg.
       * @param aKey encryption key
       * @param aErrorMsg error message description
       * @return the pickled outbound group session as bytes buffer
       */
      public byte[] pickle(byte[] aKey, StringBuffer aErrorMsg) {
          return serialize(aKey, aErrorMsg);
      }
  
      /**
       * Loads an outbound group session from a pickled bytes buffer.<br>
       * See {@link #serialize(byte[], StringBuffer)}
       * @param aSerializedData bytes buffer
       * @param aKey key used to encrypted
       * @exception Exception the exception
       */
      public void unpickle(byte[] aSerializedData, byte[] aKey) throws Exception {
          deserialize(aSerializedData, aKey);
      }
  
  }
  