clear out plaintext buffers in Android SDK where possible

5 files changed, 29 insertions, 6 deletions

diff --git a/android/olm-sdk/src/main/java/org/matrix/olm/OlmInboundGroupSession.java b/android/olm-sdk/src/main/java/org/matrix/olm/OlmInboundGroupSession.java
index 8c2d7b0..b41c67a 100644
--- a/android/olm-sdk/src/main/java/org/matrix/olm/OlmInboundGroupSession.java
+++ b/android/olm-sdk/src/main/java/org/matrix/olm/OlmInboundGroupSession.java
@@ -25,6 +25,8 @@ 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.
@@ -236,7 +238,7 @@ public class OlmInboundGroupSession extends CommonSerializeUtils implements Seri
      * 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 teh failure reason
+     * @exception OlmException the failure reason
      */
     public DecryptMessageResult decryptMessage(String aEncryptedMsg) throws OlmException {
         DecryptMessageResult result = new DecryptMessageResult();
@@ -246,6 +248,7 @@ public class OlmInboundGroupSession extends CommonSerializeUtils implements Seri
 
             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());
diff --git a/android/olm-sdk/src/main/java/org/matrix/olm/OlmOutboundGroupSession.java b/android/olm-sdk/src/main/java/org/matrix/olm/OlmOutboundGroupSession.java
index 0481824..e4d4a44 100644
--- a/android/olm-sdk/src/main/java/org/matrix/olm/OlmOutboundGroupSession.java
+++ b/android/olm-sdk/src/main/java/org/matrix/olm/OlmOutboundGroupSession.java
@@ -26,6 +26,8 @@ import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
 import java.io.Serializable;
 
+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.
@@ -166,7 +168,9 @@ public class OlmOutboundGroupSession extends CommonSerializeUtils implements Ser
 
         if (!TextUtils.isEmpty(aClearMsg)) {
             try {
-                byte[] encryptedBuffer = encryptMessageJni(aClearMsg.getBytes("UTF-8"));
+                byte[] clearMsgBuffer = aClearMsg.getBytes("UTF-8");
+                byte[] encryptedBuffer = encryptMessageJni(clearMsgBuffer);
+                Arrays.fill(clearMsgBuffer, (byte) 0);
 
                 if (null != encryptedBuffer) {
                     retValue = new String(encryptedBuffer , "UTF-8");
diff --git a/android/olm-sdk/src/main/java/org/matrix/olm/OlmPkDecryption.java b/android/olm-sdk/src/main/java/org/matrix/olm/OlmPkDecryption.java
index 03d055a..ea838f1 100644
--- a/android/olm-sdk/src/main/java/org/matrix/olm/OlmPkDecryption.java
+++ b/android/olm-sdk/src/main/java/org/matrix/olm/OlmPkDecryption.java
@@ -18,6 +18,8 @@ package org.matrix.olm;
 
 import android.util.Log;
 
+import java.util.Arrays;
+
 public class OlmPkDecryption {
     private static final String LOG_TAG = "OlmPkDecryption";
 
@@ -67,7 +69,10 @@ public class OlmPkDecryption {
         }
 
         try {
-            return new String(decryptJni(aMessage), "UTF-8");
+            byte[] plaintextBuffer = decryptJni(aMessage);
+            String plaintext = new String(plaintextBuffer, "UTF-8");
+            Arrays.fill(plaintextBuffer, (byte) 0);
+            return plaintext;
         } catch (Exception e) {
             Log.e(LOG_TAG, "## pkDecrypt(): failed " + e.getMessage());
             throw new OlmException(OlmException.EXCEPTION_CODE_PK_DECRYPTION_DECRYPT, e.getMessage());
diff --git a/android/olm-sdk/src/main/java/org/matrix/olm/OlmPkEncryption.java b/android/olm-sdk/src/main/java/org/matrix/olm/OlmPkEncryption.java
index 9bd429d..a2ccf2e 100644
--- a/android/olm-sdk/src/main/java/org/matrix/olm/OlmPkEncryption.java
+++ b/android/olm-sdk/src/main/java/org/matrix/olm/OlmPkEncryption.java
@@ -18,6 +18,8 @@ package org.matrix.olm;
 
 import android.util.Log;
 
+import java.util.Arrays;
+
 public class OlmPkEncryption {
     private static final String LOG_TAG = "OlmPkEncryption";
 
@@ -72,7 +74,9 @@ public class OlmPkEncryption {
         OlmPkMessage encryptedMsgRetValue = new OlmPkMessage();
 
         try {
-            byte[] ciphertextBuffer = encryptJni(aPlaintext.getBytes("UTF-8"), encryptedMsgRetValue);
+            byte[] plaintextBuffer = aPlaintext.getBytes("UTF-8");
+            byte[] ciphertextBuffer = encryptJni(plaintextBuffer, encryptedMsgRetValue);
+            Arrays.fill(plaintextBuffer, (byte) 0);
 
             if (null != ciphertextBuffer) {
                 encryptedMsgRetValue.mCipherText = new String(ciphertextBuffer, "UTF-8");
diff --git a/android/olm-sdk/src/main/java/org/matrix/olm/OlmSession.java b/android/olm-sdk/src/main/java/org/matrix/olm/OlmSession.java
index da2e963..3c5ce49 100644
--- a/android/olm-sdk/src/main/java/org/matrix/olm/OlmSession.java
+++ b/android/olm-sdk/src/main/java/org/matrix/olm/OlmSession.java
@@ -25,6 +25,8 @@ 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>
@@ -295,7 +297,9 @@ public class OlmSession extends CommonSerializeUtils implements Serializable {
         OlmMessage encryptedMsgRetValue = new OlmMessage();
 
         try {
-            byte[] encryptedMessageBuffer = encryptMessageJni(aClearMsg.getBytes("UTF-8"), encryptedMsgRetValue);
+            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");
@@ -330,7 +334,10 @@ public class OlmSession extends CommonSerializeUtils implements Serializable {
         }
 
         try {
-            return new String(decryptMessageJni(aEncryptedMsg), "UTF-8");
+            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());