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 2016 OpenMarket Ltd
   * Copyright 2016 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;
  
  /**
   * Session class used to create Olm sessions in conjunction with {@link OlmAccount} class.<br>
   * Olm session is used to encrypt data between devices, especially to create Olm group sessions (see {@link OlmOutboundGroupSession} and {@link OlmInboundGroupSession}).<br>
   * To establish an Olm session with Bob, Alice calls {@link #initOutboundSession(OlmAccount, String, String)} with Bob's identity and onetime keys. Then Alice generates an encrypted PRE_KEY message ({@link #encryptMessage(String)})
   * used by Bob to open the Olm session in his side with {@link #initOutboundSession(OlmAccount, String, String)}.
   * From this step on, messages can be exchanged by using {@link #encryptMessage(String)} and {@link #decryptMessage(OlmMessage)}.
   * <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 OlmSession extends CommonSerializeUtils implements Serializable {
      private static final long serialVersionUID = -8975488639186976419L;
      private static final String LOG_TAG = "OlmSession";
  
      /** Session Id returned by JNI.
       * This value uniquely identifies the native session instance.
       **/
      private transient long mNativeId;
  
      public OlmSession() throws OlmException {
          try {
              mNativeId = createNewSessionJni();
          } catch (Exception e) {
              throw new OlmException(OlmException.EXCEPTION_CODE_INIT_SESSION_CREATION, e.getMessage());
          }
      }
  
      /**
       * Create an OLM session in native side.<br>
       * Do not forget to call {@link #releaseSession()} when JAVA side is done.
       * @return native account instance identifier or throw an exception.
       */
      private native long createNewSessionJni();
  
      /**
       * Getter on the session ID.
       * @return native session ID
       */
      long getOlmSessionId(){
          return mNativeId;
      }
  
      /**
       * Destroy the corresponding OLM 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()}.
       */
      private native void releaseSessionJni();
  
      /**
       * 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;
      }
  
      /**
       * Return true the object resources have been released.<br>
       * @return true the object resources have been released
       */
      public boolean isReleased() {
          return (0 == mNativeId);
      }
  
      /**
       * Creates a new out-bound session for sending messages to a recipient
       * identified by an identity key and a one time key.<br>
       * @param aAccount the account to associate with this session
       * @param aTheirIdentityKey the identity key of the recipient
       * @param aTheirOneTimeKey the one time key of the recipient
       * @exception OlmException the failure reason
       */
      public void initOutboundSession(OlmAccount aAccount, String aTheirIdentityKey, String aTheirOneTimeKey) throws OlmException {
          if ((null == aAccount) || TextUtils.isEmpty(aTheirIdentityKey) || TextUtils.isEmpty(aTheirOneTimeKey)) {
              Log.e(LOG_TAG, "## initOutboundSession(): invalid input parameters");
              throw new OlmException(OlmException.EXCEPTION_CODE_SESSION_INIT_OUTBOUND_SESSION, "invalid input parameters");
          } else {
              try {
                  initOutboundSessionJni(aAccount.getOlmAccountId(), aTheirIdentityKey.getBytes("UTF-8"), aTheirOneTimeKey.getBytes("UTF-8"));
              } catch (Exception e) {
                  Log.e(LOG_TAG, "## initOutboundSession(): " + e.getMessage());
                  throw new OlmException(OlmException.EXCEPTION_CODE_SESSION_INIT_OUTBOUND_SESSION, e.getMessage());
              }
          }
      }
  
      /**
       * Create a new in-bound session for sending/receiving messages from an
       * incoming PRE_KEY message.<br> The recipient is defined as the entity
       * with whom the session is established.
       * An exception is thrown if the operation fails.
       * @param aOlmAccountId account instance
       * @param aTheirIdentityKey the identity key of the recipient
       * @param aTheirOneTimeKey the one time key of the recipient
       **/
      private native void initOutboundSessionJni(long aOlmAccountId, byte[] aTheirIdentityKey, byte[] aTheirOneTimeKey);
  
      /**
       * Create a new in-bound session for sending/receiving messages from an
       * incoming PRE_KEY message ({@link OlmMessage#MESSAGE_TYPE_PRE_KEY}).<br>
       * This API may be used to process a "m.room.encrypted" event when type = 1 (PRE_KEY).
       * @param aAccount the account to associate with this session
       * @param aPreKeyMsg PRE KEY message
       * @exception OlmException the failure reason
       */
      public void initInboundSession(OlmAccount aAccount, String aPreKeyMsg) throws OlmException {
          if ((null == aAccount) || TextUtils.isEmpty(aPreKeyMsg)){
              Log.e(LOG_TAG, "## initInboundSession(): invalid input parameters");
              throw new OlmException(OlmException.EXCEPTION_CODE_SESSION_INIT_INBOUND_SESSION, "invalid input parameters");
          } else {
              try {
                  initInboundSessionJni(aAccount.getOlmAccountId(), aPreKeyMsg.getBytes("UTF-8"));
              } catch (Exception e) {
                  Log.e(LOG_TAG, "## initInboundSession(): " + e.getMessage());
                  throw new OlmException(OlmException.EXCEPTION_CODE_SESSION_INIT_INBOUND_SESSION, e.getMessage());
              }
          }
      }
  
      /**
       * Create a new in-bound session for sending/receiving messages from an
       * incoming PRE_KEY message.<br>
       * An exception is thrown if the operation fails.
       * @param aOlmAccountId account instance
       * @param aOneTimeKeyMsg PRE_KEY message
       */
      private native void initInboundSessionJni(long aOlmAccountId, byte[] aOneTimeKeyMsg);
  
      /**
       * Create a new in-bound session for sending/receiving messages from an
       * incoming PRE_KEY({@link OlmMessage#MESSAGE_TYPE_PRE_KEY}) message based on the sender identity key.<br>
       * Public API for {@link #initInboundSessionFromIdKeyJni(long, byte[], byte[])}.
       * This API may be used to process a "m.room.encrypted" event when type = 1 (PRE_KEY).
       * This method must only be called the first time a pre-key message is received from an inbound session.
       * @param aAccount the account to associate with this session
       * @param aTheirIdentityKey the sender identity key
       * @param aPreKeyMsg PRE KEY message
       * @exception OlmException the failure reason
       */
      public void initInboundSessionFrom(OlmAccount aAccount, String aTheirIdentityKey, String aPreKeyMsg) throws OlmException {
          if ( (null==aAccount) || TextUtils.isEmpty(aPreKeyMsg)){
              Log.e(LOG_TAG, "## initInboundSessionFrom(): invalid input parameters");
              throw new OlmException(OlmException.EXCEPTION_CODE_SESSION_INIT_INBOUND_SESSION_FROM, "invalid input parameters");
          } else {
              try {
                  initInboundSessionFromIdKeyJni(aAccount.getOlmAccountId(), aTheirIdentityKey.getBytes("UTF-8"), aPreKeyMsg.getBytes("UTF-8"));
              } catch (Exception e) {
                  Log.e(LOG_TAG, "## initInboundSessionFrom(): " + e.getMessage());
                  throw new OlmException(OlmException.EXCEPTION_CODE_SESSION_INIT_INBOUND_SESSION_FROM, e.getMessage());
              }
          }
      }
  
      /**
       * Create a new in-bound session for sending/receiving messages from an
       * incoming PRE_KEY message based on the recipient identity key.<br>
       * An exception is thrown if the operation fails.
       * @param aOlmAccountId account instance
       * @param aTheirIdentityKey the identity key of the recipient
       * @param aOneTimeKeyMsg encrypted message
       */
      private native void initInboundSessionFromIdKeyJni(long aOlmAccountId, byte[] aTheirIdentityKey, byte[] aOneTimeKeyMsg);
  
      /**
       * Get the session identifier.<br> Will be the same for both ends of the
       * conversation. The session identifier is returned as a String object.
       * Session Id sample: "session_id":"M4fOVwD6AABrkTKl"
       * Public API for {@link #getSessionIdentifierJni()}.
       * @return the session ID
       * @exception OlmException the failure reason
       */
      public String sessionIdentifier() throws OlmException {
          try {
              byte[] buffer = getSessionIdentifierJni();
  
              if (null != buffer) {
                  return new String(buffer, "UTF-8");
              }
          } catch (Exception e) {
              Log.e(LOG_TAG, "## sessionIdentifier(): " + e.getMessage());
              throw new OlmException(OlmException.EXCEPTION_CODE_SESSION_SESSION_IDENTIFIER, e.getMessage());
          }
  
          return null;
      }
  
      /**
       * Get the session identifier for this session.
       * An exception is thrown if the operation fails.
       * @return the session identifier
       */
      private native byte[] getSessionIdentifierJni();
  
      public String sessionDescribe() throws OlmException {
          try {
              byte[] buffer = olmSessionDescribeJni();
  
              if (null != buffer) {
                  return new String(buffer, "UTF-8");
              }
          } catch (Exception e) {
              Log.e(LOG_TAG, "## sessionDescribe(): " + e.getMessage());
              throw new OlmException(OlmException.EXCEPTION_CODE_SESSION_SESSION_DESCRIBE, e.getMessage());
          }
  
          return null;
      }
  
      private native byte[] olmSessionDescribeJni();
  
      /**
       * Checks if the PRE_KEY({@link OlmMessage#MESSAGE_TYPE_PRE_KEY}) message is for this in-bound session.<br>
       * This API may be used to process a "m.room.encrypted" event when type = 1 (PRE_KEY).
       * Public API for {@link #matchesInboundSessionJni(byte[])}.
       * @param aOneTimeKeyMsg PRE KEY message
       * @return true if the one time key matches.
       */
      public boolean matchesInboundSession(String aOneTimeKeyMsg) {
          boolean retCode = false;
  
          try {
              retCode = matchesInboundSessionJni(aOneTimeKeyMsg.getBytes("UTF-8"));
          } catch (Exception e) {
              Log.e(LOG_TAG, "## matchesInboundSession(): failed " + e.getMessage());
          }
  
          return retCode;
      }
  
      /**
       * Checks if the PRE_KEY message is for this in-bound session.<br>
       * This API may be used to process a "m.room.encrypted" event when type = 1 (PRE_KEY).
       * An exception is thrown if the operation fails.
       * @param aOneTimeKeyMsg PRE KEY message
       * @return true if the PRE_KEY message matches
       */
      private native boolean matchesInboundSessionJni(byte[] aOneTimeKeyMsg);
  
      /**
       * Checks if the PRE_KEY({@link OlmMessage#MESSAGE_TYPE_PRE_KEY}) message is for this in-bound session based on the sender identity key.<br>
       * This API may be used to process a "m.room.encrypted" event when type = 1 (PRE_KEY).
       * Public API for {@link #matchesInboundSessionJni(byte[])}.
       * @param aTheirIdentityKey the sender identity key
       * @param aOneTimeKeyMsg PRE KEY message
       * @return this if operation succeed, null otherwise
       */
      public boolean matchesInboundSessionFrom(String aTheirIdentityKey, String aOneTimeKeyMsg) {
          boolean retCode = false;
  
          try {
              retCode = matchesInboundSessionFromIdKeyJni(aTheirIdentityKey.getBytes("UTF-8"), aOneTimeKeyMsg.getBytes("UTF-8"));
          } catch (Exception e) {
              Log.e(LOG_TAG, "## matchesInboundSessionFrom(): failed " + e.getMessage());
          }
  
          return retCode;
      }
  
      /**
       * Checks if the PRE_KEY message is for this in-bound session based on the sender identity key.<br>
       * This API may be used to process a "m.room.encrypted" event when type = 1 (PRE_KEY).
       * An exception is thrown if the operation fails.
       * @param aTheirIdentityKey the identity key of the sender
       * @param aOneTimeKeyMsg PRE KEY message
       * @return true if the PRE_KEY message matches.
       */
      private native boolean matchesInboundSessionFromIdKeyJni(byte[] aTheirIdentityKey, byte[] aOneTimeKeyMsg);
  
      /**
       * Encrypt a message using the session.<br>
       * The encrypted message is returned in a OlmMessage object.
       * Public API for {@link #encryptMessageJni(byte[], OlmMessage)}.
       * @param aClearMsg message to encrypted
       * @return the encrypted message
       * @exception OlmException the failure reason
       */
      public OlmMessage encryptMessage(String aClearMsg) throws OlmException {
          if (null == aClearMsg) {
              return null;
          }
  
          OlmMessage encryptedMsgRetValue = new OlmMessage();
  
          try {
              byte[] clearMsgBuffer = aClearMsg.getBytes("UTF-8");
              byte[] encryptedMessageBuffer = encryptMessageJni(clearMsgBuffer, encryptedMsgRetValue);
              Arrays.fill(clearMsgBuffer, (byte) 0);
  
              if (null != encryptedMessageBuffer) {
                  encryptedMsgRetValue.mCipherText = new String(encryptedMessageBuffer, "UTF-8");
              }
          } catch (Exception e) {
              Log.e(LOG_TAG, "## encryptMessage(): failed " + e.getMessage());
              throw new OlmException(OlmException.EXCEPTION_CODE_SESSION_ENCRYPT_MESSAGE, e.getMessage());
          }
  
          return encryptedMsgRetValue;
      }
  
      /**
       * Encrypt a message using the session.<br>
       * An exception is thrown if the operation fails.
       * @param aClearMsg clear text message
       * @param aEncryptedMsg ciphered message
       * @return the encrypted message
       */
      private native byte[] encryptMessageJni(byte[] aClearMsg, OlmMessage aEncryptedMsg);
  
      /**
       * Decrypt a message using the session.<br>
       * The encrypted message is given as a OlmMessage object.
       * @param aEncryptedMsg message to decrypt
       * @return the decrypted message
       * @exception OlmException the failure reason
       */
      public String decryptMessage(OlmMessage aEncryptedMsg) throws OlmException {
          if (null == aEncryptedMsg) {
              return null;
          }
  
          try {
              byte[] plaintextBuffer = decryptMessageJni(aEncryptedMsg);
              String plaintext = new String(plaintextBuffer, "UTF-8");
              Arrays.fill(plaintextBuffer, (byte) 0);
              return plaintext;
          } catch (Exception e) {
              Log.e(LOG_TAG, "## decryptMessage(): failed " + e.getMessage());
              throw new OlmException(OlmException.EXCEPTION_CODE_SESSION_DECRYPT_MESSAGE, e.getMessage());
          }
      }
      /**
       * Decrypt a message using the session.<br>
       * An exception is thrown if the operation fails.
       * @param aEncryptedMsg message to decrypt
       * @return the decrypted message
       */
      private native byte[] decryptMessageJni(OlmMessage aEncryptedMsg);
  
      public int getSenderChainSize(){
          return getSenderChainSizeJni();
      }
  
      private native int getSenderChainSizeJni();
  
      //==============================================================================================================
      // 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 IOException exception
       * @throws ClassNotFoundException exception
       */
      private void readObject(ObjectInputStream aInStream) throws Exception {
          deserialize(aInStream);
      }
  
      /**
       * Return a session as a bytes buffer.<br>
       * The account 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 session as a bytes buffer
       */
      @Override
      protected byte[] serialize(byte[] aKey, StringBuffer aErrorMsg) {
          byte[] pickleRetValue = null;
  
          // sanity check
          if(null == aErrorMsg) {
              Log.e(LOG_TAG,"## serializeDataWithKey(): invalid parameter - aErrorMsg=null");
          } else if (null == aKey) {
              aErrorMsg.append("Invalid input parameters in serializeDataWithKey()");
          } else {
              aErrorMsg.setLength(0);
              try {
                  pickleRetValue = serializeJni(aKey);
              } catch (Exception e) {
                  Log.e(LOG_TAG,"## serializeDataWithKey(): failed " + e.getMessage());
                  aErrorMsg.append(e.getMessage());
              }
          }
  
          return pickleRetValue;
      }
  
      /**
       * Serialize and encrypt session instance.<br>
       * An exception is thrown if the operation fails.
       * @param aKeyBuffer key used to encrypt the serialized account data
       * @return the serialised account as bytes buffer.
       **/
      private native byte[] serializeJni(byte[] aKeyBuffer);
  
      /**
       * Loads an account from a pickled base64 string.<br>
       * See {@link #serialize(byte[], StringBuffer)}
       * @param aSerializedData pickled account in a base64 string format
       * @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 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 session as bytes buffer
       */
      public byte[] pickle(byte[] aKey, StringBuffer aErrorMsg) {
          return serialize(aKey, aErrorMsg);
      }
  
      /**
       * Loads a 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);
      }
  
  }
  
  