remove the useless malloc(len+1) + zero terminated

6 files changed, 34 insertions, 66 deletions

diff --git a/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmSession.java b/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmSession.java
index 2436f0d..170b1a5 100644
--- a/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmSession.java
+++ b/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmSession.java
@@ -262,7 +262,7 @@ public class OlmSession extends CommonSerializeUtils implements Serializable {
         OlmMessage encryptedMsgRetValue = new OlmMessage();
 
         try {
-            encryptMessageJni(aClearMsg.getBytes("UTF-8"), encryptedMsgRetValue);
+            encryptedMsgRetValue.mCipherText = new String(encryptMessageJni(aClearMsg.getBytes("UTF-8"), encryptedMsgRetValue), "UTF-8");
         } catch (Exception e) {
             Log.e(LOG_TAG, "## encryptMessage(): failed " + e.getMessage());
             throw new OlmException(OlmException.EXCEPTION_CODE_SESSION_ENCRYPT_MESSAGE, e.getMessage());
@@ -271,7 +271,7 @@ public class OlmSession extends CommonSerializeUtils implements Serializable {
         return encryptedMsgRetValue;
     }
 
-    private native void encryptMessageJni(byte[] aClearMsg, OlmMessage aEncryptedMsg);
+    private native byte[] encryptMessageJni(byte[] aClearMsg, OlmMessage aEncryptedMsg);
 
     /**
      * Decrypt a message using the session.<br>
@@ -314,7 +314,7 @@ public class OlmSession extends CommonSerializeUtils implements Serializable {
      * @throws IOException exception
      * @throws ClassNotFoundException exception
      */
-    private void readObject(ObjectInputStream aInStream) throws Exception  {
+    private void readObject(ObjectInputStream aInStream) throws Exception {
         deserialize(aInStream);
     }
 
diff --git a/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_account.cpp b/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_account.cpp
index 4da0d67..30828d9 100644
--- a/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_account.cpp
+++ b/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_account.cpp
@@ -462,8 +462,7 @@ JNIEXPORT jbyteArray OLM_ACCOUNT_FUNC_DEF(signMessageJni)(JNIEnv *env, jobject t
 
         // signature memory allocation
         size_t signatureLength = olm_account_signature_length(accountPtr);
-        size_t bufferLen = signatureLength + 1;
-        void* signedMsgPtr = malloc(bufferLen * sizeof(uint8_t));
+        void* signedMsgPtr = malloc(signatureLength * sizeof(uint8_t));
 
         if (!signedMsgPtr)
         {
@@ -486,14 +485,10 @@ JNIEXPORT jbyteArray OLM_ACCOUNT_FUNC_DEF(signMessageJni)(JNIEnv *env, jobject t
             }
             else
             {
-                // info: signatureLength is always equal to resultSign
-                (static_cast<char*>(signedMsgPtr))[signatureLength] = static_cast<char>('\0');
-
                 LOGD("## signMessageJni(): success - retCode=%lu signatureLength=%lu", static_cast<long unsigned int>(resultSign), static_cast<long unsigned int>(signatureLength));
      	
                 signedMsgRetValueBuffer = env->NewByteArray(signatureLength);
                 env->SetByteArrayRegion(signedMsgRetValueBuffer, 0 , signatureLength, (jbyte*)signedMsgPtr);
-
             }
 
             free(signedMsgPtr);
@@ -549,7 +544,7 @@ JNIEXPORT jbyteArray OLM_ACCOUNT_FUNC_DEF(serializeJni)(JNIEnv *env, jobject thi
         size_t keyLength = (size_t)env->GetArrayLength(aKeyBuffer);
         LOGD(" ## serializeJni(): pickledLength=%lu keyLength=%lu",static_cast<long unsigned int>(pickledLength), static_cast<long unsigned int>(keyLength));
 
-        void *pickledPtr = malloc((pickledLength+1)*sizeof(uint8_t));
+        void *pickledPtr = malloc(pickledLength*sizeof(uint8_t));
 
         if (!pickledPtr)
         {
@@ -570,11 +565,7 @@ JNIEXPORT jbyteArray OLM_ACCOUNT_FUNC_DEF(serializeJni)(JNIEnv *env, jobject thi
             }
             else
             {
-                // build success output
-                (static_cast<char*>(pickledPtr))[pickledLength] = static_cast<char>('\0');
-
-                LOGD(" ## serializeJni(): success - result=%lu pickled=%s", static_cast<long unsigned int>(result), static_cast<char*>(pickledPtr));
-
+                LOGD(" ## serializeJni(): success - result=%lu pickled starts with = %10s", static_cast<long unsigned int>(result), static_cast<char*>(pickledPtr));
                 pickledDataRetValue = env->NewByteArray(pickledLength);
                 env->SetByteArrayRegion(pickledDataRetValue, 0 , pickledLength, (jbyte*)pickledPtr);
             }
diff --git a/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_inbound_group_session.cpp b/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_inbound_group_session.cpp
index 7dd250b..2e6e4af 100644
--- a/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_inbound_group_session.cpp
+++ b/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_inbound_group_session.cpp
@@ -167,7 +167,7 @@ JNIEXPORT jbyteArray OLM_INBOUND_GROUP_SESSION_FUNC_DEF(sessionIdentifierJni)(JN
         size_t lengthSessionId = olm_inbound_group_session_id_length(sessionPtr);
         LOGD(" ## sessionIdentifierJni(): inbound group session lengthSessionId=%lu",static_cast<long unsigned int>(lengthSessionId));
 
-        uint8_t *sessionIdPtr = (uint8_t*)malloc((lengthSessionId+1)*sizeof(uint8_t));
+        uint8_t *sessionIdPtr = (uint8_t*)malloc(lengthSessionId*sizeof(uint8_t));
 
         if (!sessionIdPtr)
         {
@@ -185,8 +185,7 @@ JNIEXPORT jbyteArray OLM_INBOUND_GROUP_SESSION_FUNC_DEF(sessionIdentifierJni)(JN
             }
             else
             {
-                sessionIdPtr[result] = static_cast<char>('\0');
-                LOGD(" ## sessionIdentifierJni(): success - inbound group session result=%lu sessionId=%s",static_cast<long unsigned int>(result), (char*)sessionIdPtr);
+                LOGD(" ## sessionIdentifierJni(): success - inbound group session result=%lu sessionId starts with =%10s",static_cast<long unsigned int>(result), (char*)sessionIdPtr);
 
                 returnValue = env->NewByteArray(result);
                 env->SetByteArrayRegion(returnValue, 0 , result, (jbyte*)sessionIdPtr);
@@ -280,7 +279,7 @@ JNIEXPORT jbyteArray OLM_INBOUND_GROUP_SESSION_FUNC_DEF(decryptMessageJni)(JNIEn
                 uint32_t messageIndex = 0;
 
                 // allocate output decrypted message
-                uint8_t *plainTextMsgPtr = static_cast<uint8_t*>(malloc((maxPlainTextLength+1)*sizeof(uint8_t)));
+                uint8_t *plainTextMsgPtr = static_cast<uint8_t*>(malloc(maxPlainTextLength*sizeof(uint8_t)));
 
                 // decrypt, but before reload encrypted buffer (previous one was destroyed)
                 memcpy(tempEncryptedPtr, encryptedMsgPtr, encryptedMsgLength);
@@ -370,7 +369,7 @@ JNIEXPORT jbyteArray OLM_INBOUND_GROUP_SESSION_FUNC_DEF(serializeJni)(JNIEnv *en
         size_t keyLength = (size_t)env->GetArrayLength(aKeyBuffer);
         LOGD(" ## serializeJni(): pickledLength=%lu keyLength=%lu", static_cast<long unsigned int>(pickledLength), static_cast<long unsigned int>(keyLength));
 
-        void *pickledPtr = malloc((pickledLength+1)*sizeof(uint8_t));
+        void *pickledPtr = malloc(pickledLength*sizeof(uint8_t));
 
         if (!pickledPtr)
         {
@@ -391,8 +390,7 @@ JNIEXPORT jbyteArray OLM_INBOUND_GROUP_SESSION_FUNC_DEF(serializeJni)(JNIEnv *en
             }
             else
             {
-             	(static_cast<char*>(pickledPtr))[pickledLength] = static_cast<char>('\0');
-                LOGD(" ## serializeJni(): success - result=%lu pickled=%s", static_cast<long unsigned int>(result), static_cast<char*>(pickledPtr));
+                LOGD(" ## serializeJni(): success - result=%lu pickled starts with %10s", static_cast<long unsigned int>(result), static_cast<char*>(pickledPtr));
 
                 pickledDataRet = env->NewByteArray(pickledLength);
                 env->SetByteArrayRegion(pickledDataRet, 0 , pickledLength, (jbyte*)pickledPtr);
diff --git a/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_outbound_group_session.cpp b/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_outbound_group_session.cpp
index bfe5a4e..827e8fd 100644
--- a/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_outbound_group_session.cpp
+++ b/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_outbound_group_session.cpp
@@ -161,7 +161,7 @@ JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(sessionIdentifierJni)(J
         size_t lengthSessionId = olm_outbound_group_session_id_length(sessionPtr);
         LOGD(" ## sessionIdentifierJni(): outbound group session lengthSessionId=%lu",static_cast<long unsigned int>(lengthSessionId));
 
-        uint8_t *sessionIdPtr =  (uint8_t*)malloc((lengthSessionId+1)*sizeof(uint8_t));
+        uint8_t *sessionIdPtr =  (uint8_t*)malloc(lengthSessionId*sizeof(uint8_t));
 
         if (!sessionIdPtr)
         {
@@ -179,13 +179,10 @@ JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(sessionIdentifierJni)(J
             }
             else
             {
-                // update length
-                sessionIdPtr[result] = static_cast<char>('\0');
-
                 returnValue = env->NewByteArray(result);
                 env->SetByteArrayRegion(returnValue, 0 , result, (jbyte*)sessionIdPtr);
 
-                LOGD(" ## sessionIdentifierJni(): success - outbound group session identifier result=%lu sessionId=%s",static_cast<long unsigned int>(result), reinterpret_cast<char*>(sessionIdPtr));
+                LOGD(" ## sessionIdentifierJni(): success - outbound group session identifier result=%lu sessionId starts with %10s",static_cast<long unsigned int>(result), reinterpret_cast<char*>(sessionIdPtr));
             }
 
             // free alloc
@@ -251,7 +248,7 @@ JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(sessionKeyJni)(JNIEnv *
         size_t sessionKeyLength = olm_outbound_group_session_key_length(sessionPtr);
         LOGD(" ## sessionKeyJni(): sessionKeyLength=%lu",static_cast<long unsigned int>(sessionKeyLength));
 
-        uint8_t *sessionKeyPtr = (uint8_t*)malloc((sessionKeyLength+1)*sizeof(uint8_t));
+        uint8_t *sessionKeyPtr = (uint8_t*)malloc(sessionKeyLength*sizeof(uint8_t));
 
         if (!sessionKeyPtr)
         {
@@ -269,9 +266,7 @@ JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(sessionKeyJni)(JNIEnv *
             }
             else
             {
-                // update length
-                sessionKeyPtr[result] = static_cast<char>('\0');
-                LOGD(" ## sessionKeyJni(): success - outbound group session key result=%lu sessionKey=%s",static_cast<long unsigned int>(result), reinterpret_cast<char*>(sessionKeyPtr));
+                LOGD(" ## sessionKeyJni(): success - outbound group session key result=%lu sessionKey starts with %10s",static_cast<long unsigned int>(result), reinterpret_cast<char*>(sessionKeyPtr));
 
                 returnValue = env->NewByteArray(result);
                 env->SetByteArrayRegion(returnValue, 0 , result, (jbyte*)sessionKeyPtr);
@@ -323,7 +318,7 @@ JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(encryptMessageJni)(JNIE
 
         // compute max encrypted length
         size_t encryptedMsgLength = olm_group_encrypt_message_length(sessionPtr,clearMsgLength);
-        uint8_t *encryptedMsgPtr = (uint8_t*)malloc((encryptedMsgLength+1)*sizeof(uint8_t));
+        uint8_t *encryptedMsgPtr = (uint8_t*)malloc(encryptedMsgLength*sizeof(uint8_t));
 
         if (!encryptedMsgPtr)
         {
@@ -348,10 +343,7 @@ JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(encryptMessageJni)(JNIE
             }
             else
             {
-                // update decrypted buffer size
-                encryptedMsgPtr[encryptedLength] = static_cast<char>('\0');
-
-                LOGD(" ## encryptMessageJni(): encrypted returnedLg=%lu plainTextMsgPtr=%s",static_cast<long unsigned int>(encryptedLength), reinterpret_cast<char*>(encryptedMsgPtr));
+                LOGD(" ## encryptMessageJni(): encrypted returnedLg=%lu plainTextMsgPtr=%10s",static_cast<long unsigned int>(encryptedLength), reinterpret_cast<char*>(encryptedMsgPtr));
 
                 encryptedMsgRet = env->NewByteArray(encryptedLength);
                 env->SetByteArrayRegion(encryptedMsgRet, 0 , encryptedLength, (jbyte*)encryptedMsgPtr);
@@ -412,7 +404,7 @@ JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(serializeJni)(JNIEnv *e
         size_t keyLength = (size_t)env->GetArrayLength(aKeyBuffer);
         LOGD(" ## serializeJni(): pickledLength=%lu keyLength=%lu",static_cast<long unsigned int>(pickledLength), static_cast<long unsigned int>(keyLength));
 
-        void *pickledPtr = malloc((pickledLength+1)*sizeof(uint8_t));
+        void *pickledPtr = malloc(pickledLength*sizeof(uint8_t));
 
         if(!pickledPtr)
         {
@@ -433,9 +425,7 @@ JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(serializeJni)(JNIEnv *e
             }
             else
             {
-                // build success output
-                (static_cast<char*>(pickledPtr))[pickledLength] = static_cast<char>('\0');
-                LOGD(" ## serializeJni(): success - result=%lu pickled=%s", static_cast<long unsigned int>(result), static_cast<char*>(pickledPtr));
+                LOGD(" ## serializeJni(): success - result=%lu pickled starts with %10s", static_cast<long unsigned int>(result), static_cast<char*>(pickledPtr));
 
                 returnValue = env->NewByteArray(pickledLength);
                 env->SetByteArrayRegion(returnValue, 0 , pickledLength, (jbyte*)pickledPtr);
diff --git a/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_session.cpp b/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_session.cpp
index 6e26071..d6ede41 100644
--- a/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_session.cpp
+++ b/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_session.cpp
@@ -461,15 +461,16 @@ JNIEXPORT jint JNICALL OLM_SESSION_FUNC_DEF(matchesInboundSessionFromIdKeyJni)(J
  * Encrypt a message using the session.<br>
  * @param aClearMsg clear text message
  * @param [out] aEncryptedMsg ciphered message
+ * @return the encrypted message
  */
-JNIEXPORT void OLM_SESSION_FUNC_DEF(encryptMessageJni)(JNIEnv *env, jobject thiz, jbyteArray aClearMsgBuffer, jobject aEncryptedMsg)
+JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(encryptMessageJni)(JNIEnv *env, jobject thiz, jbyteArray aClearMsgBuffer, jobject aEncryptedMsg)
 {
+    jbyteArray encryptedMsgRet = 0;
     const char* errorMessage = NULL;
 
     OlmSession *sessionPtr = getSessionInstanceId(env, thiz);
     jbyte *clearMsgPtr = NULL;
     jclass encryptedMsgJClass = 0;
-    jfieldID encryptedMsgFieldId;
     jfieldID typeMsgFieldId;
 
     LOGD("## encryptMessageJni(): IN ");
@@ -498,11 +499,6 @@ JNIEXPORT void OLM_SESSION_FUNC_DEF(encryptMessageJni)(JNIEnv *env, jobject thiz
         LOGE("## encryptMessageJni(): failure - unable to get crypted message class");
         errorMessage = "unable to get crypted message class";
     }
-    else if (!(encryptedMsgFieldId = env->GetFieldID(encryptedMsgJClass,"mCipherText","Ljava/lang/String;")))
-    {
-        LOGE("## encryptMessageJni(): failure - unable to get message field");
-        errorMessage = "unable to get message field";
-    }
     else if (!(typeMsgFieldId = env->GetFieldID(encryptedMsgJClass,"mType","J")))
     {
         LOGE("## encryptMessageJni(): failure - unable to get message type field");
@@ -532,7 +528,7 @@ JNIEXPORT void OLM_SESSION_FUNC_DEF(encryptMessageJni)(JNIEnv *env, jobject thiz
             size_t clearMsgLength = (size_t)env->GetArrayLength(aClearMsgBuffer);
             size_t encryptedMsgLength = olm_encrypt_message_length(sessionPtr, clearMsgLength);
 
-            void *encryptedMsgPtr = malloc((encryptedMsgLength+1)*sizeof(uint8_t));
+            void *encryptedMsgPtr = malloc(encryptedMsgLength*sizeof(uint8_t));
 
             if (!encryptedMsgPtr)
             {
@@ -562,17 +558,13 @@ JNIEXPORT void OLM_SESSION_FUNC_DEF(encryptMessageJni)(JNIEnv *env, jobject thiz
                 }
                 else
                 {
-                    // update encrypted buffer size
-                    (static_cast<char*>(encryptedMsgPtr))[result] = static_cast<char>('\0');
-
                     // update message type: PRE KEY or normal
                     env->SetLongField(aEncryptedMsg, typeMsgFieldId, (jlong)messageType);
 
-                    // update message: encryptedMsgPtr => encryptedJstring
-                    jstring encryptedJstring = env->NewStringUTF((const char*)encryptedMsgPtr);
-                    env->SetObjectField(aEncryptedMsg, encryptedMsgFieldId, (jobject)encryptedJstring);
+                    encryptedMsgRet = env->NewByteArray(encryptedMsgLength);
+                    env->SetByteArrayRegion(encryptedMsgRet, 0 , encryptedMsgLength, (jbyte*)encryptedMsgPtr);
 
-                    LOGD("## encryptMessageJni(): success - result=%lu Type=%lu utfLength=%lu encryptedMsg=%s", static_cast<long unsigned int>(result), static_cast<long unsigned int>(messageType), static_cast<long unsigned int>((size_t)env->GetStringUTFLength(encryptedJstring)), (const char*)encryptedMsgPtr);
+                    LOGD("## encryptMessageJni(): success - result=%lu Type=%lu utfLength=%lu encryptedMsg starts with %10s", static_cast<long unsigned int>(result), static_cast<long unsigned int>(messageType), static_cast<long unsigned int>((size_t)env->GetStringUTFLength(encryptedJstring)), (const char*)encryptedMsgPtr);
                 }
 
                 free(encryptedMsgPtr);
@@ -592,6 +584,8 @@ JNIEXPORT void OLM_SESSION_FUNC_DEF(encryptMessageJni)(JNIEnv *env, jobject thiz
     {
         env->ThrowNew(env->FindClass("java/lang/Exception"), errorMessage);
     }
+
+    return encryptedMsgRet;
 }
 
 /**
@@ -682,7 +676,7 @@ JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(decryptMessageJni)(JNIEnv *env, jobjec
             LOGD("## decryptMessageJni(): maxPlaintextLength=%lu",static_cast<long unsigned int>(maxPlainTextLength));
 
             // allocate output decrypted message
-            plainTextMsgPtr = static_cast<uint8_t*>(malloc((maxPlainTextLength+1)*sizeof(uint8_t)));
+            plainTextMsgPtr = static_cast<uint8_t*>(malloc(maxPlainTextLength*sizeof(uint8_t)));
 
             // decrypt, but before reload encrypted buffer (previous one was destroyed)
             memcpy(tempEncryptedPtr, encryptedMsgPtr, encryptedMsgLength);
@@ -756,7 +750,7 @@ JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(getSessionIdentifierJni)(JNIEnv *env,
          size_t lengthSessionId = olm_session_id_length(sessionPtr);
          LOGD("## getSessionIdentifierJni(): lengthSessionId=%lu",static_cast<long unsigned int>(lengthSessionId));
 
-         void *sessionIdPtr = malloc((lengthSessionId+1)*sizeof(uint8_t));
+         void *sessionIdPtr = malloc(lengthSessionId*sizeof(uint8_t));
 
          if (!sessionIdPtr)
          {
@@ -774,10 +768,7 @@ JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(getSessionIdentifierJni)(JNIEnv *env,
              }
              else
              {
-                 // update length
-                 (static_cast<char*>(sessionIdPtr))[result] = static_cast<char>('\0');
-
-                 LOGD("## getSessionIdentifierJni(): success - result=%lu sessionId=%s",static_cast<long unsigned int>(result), (char*)sessionIdPtr);
+                 LOGD("## getSessionIdentifierJni(): success - result=%lu sessionId= starts with %10s",static_cast<long unsigned int>(result), (char*)sessionIdPtr);
 
                  returnValue = env->NewByteArray(result);
                  env->SetByteArrayRegion(returnValue, 0 , result, (jbyte*)sessionIdPtr);
@@ -832,7 +823,7 @@ JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(serializeJni)(JNIEnv *env, jobject thi
         size_t keyLength = (size_t)env->GetArrayLength(aKeyBuffer);
         LOGD(" ## serializeJni(): pickledLength=%lu keyLength=%lu",static_cast<long unsigned int>(pickledLength), static_cast<long unsigned int>(keyLength));
 
-        void *pickledPtr = malloc((pickledLength+1)*sizeof(uint8_t));
+        void *pickledPtr = malloc(pickledLength*sizeof(uint8_t));
 
         if (!pickledPtr)
         {
@@ -853,9 +844,7 @@ JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(serializeJni)(JNIEnv *env, jobject thi
             }
             else
             {
-                // build success output
-                (static_cast<char*>(pickledPtr))[pickledLength] = static_cast<char>('\0');
-                LOGD(" ## serializeJni(): success - result=%lu pickled=%s", static_cast<long unsigned int>(result), static_cast<char*>(pickledPtr));
+                LOGD(" ## serializeJni(): success - result=%lu pickled starts with %s", static_cast<long unsigned int>(result), static_cast<char*>(pickledPtr));
 
                 returnValue = env->NewByteArray(pickledLength);
                 env->SetByteArrayRegion(returnValue, 0 , pickledLength, (jbyte*)pickledPtr);
diff --git a/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_session.h b/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_session.h
index 76f59c5..01cf96c 100644
--- a/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_session.h
+++ b/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_session.h
@@ -43,7 +43,7 @@ JNIEXPORT jint OLM_SESSION_FUNC_DEF(matchesInboundSessionJni)(JNIEnv *env, jobje
 JNIEXPORT jint OLM_SESSION_FUNC_DEF(matchesInboundSessionFromIdKeyJni)(JNIEnv *env, jobject thiz, jbyteArray aTheirIdentityKey, jbyteArray aOneTimeKeyMsg);
 
 // encrypt/decrypt
-JNIEXPORT void OLM_SESSION_FUNC_DEF(encryptMessageJni)(JNIEnv *env, jobject thiz, jbyteArray aClearMsg, jobject aEncryptedMsg);
+JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(encryptMessageJni)(JNIEnv *env, jobject thiz, jbyteArray aClearMsg, jobject aEncryptedMsg);
 JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(decryptMessageJni)(JNIEnv *env, jobject thiz, jobject aEncryptedMsg);
 
 JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(getSessionIdentifierJni)(JNIEnv *env, jobject thiz);