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.util.Arrays;
  
  /**
   * Class used to create an inbound <a href="http://matrix.org/docs/guides/e2e_implementation.html#handling-an-m-room-key-event">Megolm session</a>.<br>
   * Counter part of the outbound group session {@link OlmOutboundGroupSession}, this class decrypts the messages sent by the outbound side.
   *
   * <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 OlmInboundGroupSession extends CommonSerializeUtils implements Serializable {
      private static final long serialVersionUID = -772028491251653253L;
      private static final String LOG_TAG = "OlmInboundGroupSession";
  
      /** Session Id returned by JNI.<br>
       * This value uniquely identifies the native inbound group session instance.
       */
      private transient long mNativeId;
  
      /**
       * Result in {@link #decryptMessage(String)}
       */
      public static class DecryptMessageResult {
          /** decrypt message **/
          public String mDecryptedMessage;
  
          /** decrypt index **/
          public long mIndex;
      }
  
      /**
       * Constructor.<br>
       * Create and save a new native session instance ID and start a new inbound group session.
       * The session key parameter is retrieved from an outbound group session.
       * @param aSessionKey session key
       * @throws OlmException constructor failure
       */
      public OlmInboundGroupSession(String aSessionKey) throws OlmException {
          this(aSessionKey, false);
      }
  
      /**
       * Constructor.<br>
       * Create and save a new native session instance ID and start a new inbound group session.
       * The session key parameter is retrieved from an outbound group session.
       * @param aSessionKey session key
       * @param isImported true when the session key has been retrieved from a backup
       * @throws OlmException constructor failure
       */
      private OlmInboundGroupSession(String aSessionKey, boolean isImported) throws OlmException {
          if (TextUtils.isEmpty(aSessionKey)) {
              Log.e(LOG_TAG, "## initInboundGroupSession(): invalid session key");
              throw new OlmException(OlmException.EXCEPTION_CODE_INIT_INBOUND_GROUP_SESSION, "invalid session key");
          } else {
              byte[] sessionBuffer = null;
              try {
                  sessionBuffer = aSessionKey.getBytes("UTF-8");
                  mNativeId = createNewSessionJni(aSessionKey.getBytes("UTF-8"), isImported);
              } catch (Exception e) {
                  throw new OlmException(OlmException.EXCEPTION_CODE_INIT_INBOUND_GROUP_SESSION, e.getMessage());
              } finally {
                  if (null != sessionBuffer) {
                      Arrays.fill(sessionBuffer, (byte) 0);
                  }
              }
          }
      }
  
      /**
       * Initialize a new inbound group session and return it to JAVA side.<br>
       * Since a C prt is returned as a jlong, special care will be taken
       * to make the cast (OlmInboundGroupSession* to jlong) platform independent.
       * @param aSessionKeyBuffer session key from an outbound session
       * @param isImported true when the session key has been retrieved from a backup
       * @return the initialized OlmInboundGroupSession* instance or throw an exception it fails.
       **/
      private native long createNewSessionJni(byte[] aSessionKeyBuffer, boolean isImported);
  
      /**
       * Create an OlmInboundGroupSession from its exported session data.
       * @param exported the exported data
       * @return the created OlmException
       * @throws OlmException the failure reason
       */
      public static OlmInboundGroupSession importSession(String exported) throws OlmException {
          return new OlmInboundGroupSession(exported, true);
      }
  
      /**
       * 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 inbound 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[], boolean)}.
       */
      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);
      }
  
      /**
       * Retrieve the base64-encoded identifier for this inbound group session.
       * @return the session ID
       * @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_INBOUND_GROUP_SESSION_IDENTIFIER, e.getMessage());
          }
      }
  
      /**
       * Get a base64-encoded identifier for this inbound group session.
       * An exception is thrown if the operation fails.
       * @return the base64-encoded identifier
       */
      private native byte[] sessionIdentifierJni();
  
      /**
       * Provides the first known index.
       * @return the first known index.
       * @throws OlmException the failure reason
       */
      public long getFirstKnownIndex() throws OlmException {
          long index = 0;
  
          try {
              index = firstKnownIndexJni();
          } catch (Exception e) {
              Log.e(LOG_TAG, "## getFirstKnownIndex() failed " + e.getMessage());
              throw new OlmException(OlmException.EXCEPTION_CODE_INBOUND_GROUP_SESSION_FIRST_KNOWN_INDEX, e.getMessage());
          }
  
          return index;
      }
  
      /**
       * Provides the first known index.
       * An exception is thrown if the operation fails.
       * @return the first known index.
       */
      private native long firstKnownIndexJni();
  
      /**
       * Tells if the session is verified.
       * @return true if the session is verified
       * @throws OlmException the failure reason
       */
      public boolean isVerified() throws OlmException {
          boolean isVerified;
  
          try {
              isVerified = isVerifiedJni();
          } catch (Exception e) {
              Log.e(LOG_TAG, "## isVerified() failed " + e.getMessage());
              throw new OlmException(OlmException.EXCEPTION_CODE_INBOUND_GROUP_SESSION_IS_VERIFIED, e.getMessage());
          }
  
          return isVerified;
      }
  
      /**
       * Tells if the session is verified.
       * @return true if the session is verified
       */
      private native boolean isVerifiedJni();
  
      /**
       * Export the session from a message index as String.
       * @param messageIndex the message index
       * @return the session as String
       * @throws OlmException the failure reason
       */
      public String export(long messageIndex) throws OlmException {
          String result = null;
  
          try {
              byte[] bytesBuffer = exportJni(messageIndex);
  
              if (null != bytesBuffer) {
                  result = new String(bytesBuffer, "UTF-8");
                  Arrays.fill(bytesBuffer, (byte) 0);
              }
          } catch (Exception e) {
              Log.e(LOG_TAG, "## export() failed " + e.getMessage());
              throw new OlmException(OlmException.EXCEPTION_CODE_INBOUND_GROUP_SESSION_EXPORT, e.getMessage());
          }
  
          return result;
      }
  
      /**
       * Exports the session as byte array from a message index
       * An exception is thrown if the operation fails.
       * @param messageIndex key used to encrypt the serialized session data
       * @return the session saved as bytes array
       */
      private native byte[] exportJni(long messageIndex);
  
      /**
       * Decrypt the message passed in parameter.<br>
       * In case of error, null is returned and an error message description is provided in aErrorMsg.
       * @param aEncryptedMsg the message to be decrypted
       * @return the decrypted message information
       * @exception OlmException the failure reason
       */
      public DecryptMessageResult decryptMessage(String aEncryptedMsg) throws OlmException {
          DecryptMessageResult result = new DecryptMessageResult();
  
          try {
              byte[] decryptedMessageBuffer = decryptMessageJni(aEncryptedMsg.getBytes("UTF-8"), result);
  
              if (null != decryptedMessageBuffer) {
                  result.mDecryptedMessage = new String(decryptedMessageBuffer, "UTF-8");
                  Arrays.fill(decryptedMessageBuffer, (byte) 0);
              }
          } catch (Exception e) {
              Log.e(LOG_TAG, "## decryptMessage() failed " + e.getMessage());
              throw new OlmException(OlmException.EXCEPTION_CODE_INBOUND_GROUP_SESSION_DECRYPT_SESSION, e.getMessage());
          }
  
          return result;
      }
  
      /**
       * Decrypt a message.
       * An exception is thrown if the operation fails.
       * @param aEncryptedMsg the encrypted message
       * @param aDecryptMessageResult the decryptMessage information
       * @return the decrypted message
       */
      private native byte[] decryptMessageJni(byte[] aEncryptedMsg, DecryptMessageResult aDecryptMessageResult);
  
      //==============================================================================================================
      // 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 inbound 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 pickled 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 {
              aErrorMsg.setLength(0);
              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)}.
       * @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 bytes buffer
       * @param aKey key used to encrypted
       */
      @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 inbound 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 inbound group session as bytes buffer
       */
      public byte[] pickle(byte[] aKey, StringBuffer aErrorMsg) {
          return serialize(aKey, aErrorMsg);
      }
  
      /**
       * Loads an inbound 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);
      }
  
  }
  