From af86a9a8b899eeb3c1c464cb0c54218acd788fa6 Mon Sep 17 00:00:00 2001
From: Hubert Chathi <hubert@uhoreg.ca>
Date: Wed, 10 Oct 2018 15:06:58 -0400
Subject: clear out plaintext buffers in Android SDK where possible

---
 android/olm-sdk/src/main/jni/olm_outbound_group_session.cpp |  7 ++++++-
 android/olm-sdk/src/main/jni/olm_pk.cpp                     |  8 +++++++-
 android/olm-sdk/src/main/jni/olm_session.cpp                | 12 ++++++++++--
 3 files changed, 23 insertions(+), 4 deletions(-)

(limited to 'android/olm-sdk/src/main/jni')

diff --git a/android/olm-sdk/src/main/jni/olm_outbound_group_session.cpp b/android/olm-sdk/src/main/jni/olm_outbound_group_session.cpp
index a821709..b11c474 100644
--- a/android/olm-sdk/src/main/jni/olm_outbound_group_session.cpp
+++ b/android/olm-sdk/src/main/jni/olm_outbound_group_session.cpp
@@ -297,6 +297,7 @@ JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(encryptMessageJni)(JNIE
 
     OlmOutboundGroupSession *sessionPtr = NULL;
     jbyte* clearMsgPtr = NULL;
+    jboolean clearMsgIsCopied = JNI_FALSE;
 
     if (!(sessionPtr = (OlmOutboundGroupSession*)getOutboundGroupSessionInstanceId(env,thiz)))
     {
@@ -308,7 +309,7 @@ JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(encryptMessageJni)(JNIE
         LOGE(" ## encryptMessageJni(): failure - invalid clear message");
         errorMessage = "invalid clear message";
     }
-    else if (!(clearMsgPtr = env->GetByteArrayElements(aClearMsgBuffer, NULL)))
+    else if (!(clearMsgPtr = env->GetByteArrayElements(aClearMsgBuffer, &clearMsgIsCopied)))
     {
         LOGE(" ## encryptMessageJni(): failure - clear message JNI allocation OOM");
         errorMessage = "clear message JNI allocation OOM";
@@ -359,6 +360,10 @@ JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(encryptMessageJni)(JNIE
     // free alloc
     if (clearMsgPtr)
     {
+        if (clearMsgIsCopied)
+        {
+            memset(clearMsgPtr, 0, (size_t)env->GetArrayLength(aClearMsgBuffer));
+        }
         env->ReleaseByteArrayElements(aClearMsgBuffer, clearMsgPtr, JNI_ABORT);
     }
 
diff --git a/android/olm-sdk/src/main/jni/olm_pk.cpp b/android/olm-sdk/src/main/jni/olm_pk.cpp
index 5457419..12528de 100644
--- a/android/olm-sdk/src/main/jni/olm_pk.cpp
+++ b/android/olm-sdk/src/main/jni/olm_pk.cpp
@@ -150,6 +150,7 @@ JNIEXPORT jbyteArray OLM_PK_ENCRYPTION_FUNC_DEF(encryptJni)(
     jbyteArray encryptedMsgRet = 0;
     const char* errorMessage = NULL;
     jbyte *plaintextPtr = NULL;
+    jboolean plaintextIsCopied = JNI_FALSE;
 
     OlmPkEncryption *encryptionPtr = getPkEncryptionInstanceId(env, thiz);
     jclass encryptedMsgJClass = 0;
@@ -165,7 +166,7 @@ JNIEXPORT jbyteArray OLM_PK_ENCRYPTION_FUNC_DEF(encryptJni)(
         LOGE(" ## pkEncryptJni(): failure - invalid clear message");
         errorMessage = "invalid clear message";
     }
-    else if (!(plaintextPtr = env->GetByteArrayElements(aPlaintextBuffer, 0)))
+    else if (!(plaintextPtr = env->GetByteArrayElements(aPlaintextBuffer, &plaintextIsCopied)))
     {
         LOGE(" ## pkEncryptJni(): failure - plaintext JNI allocation OOM");
         errorMessage = "plaintext JNI allocation OOM";
@@ -269,6 +270,10 @@ JNIEXPORT jbyteArray OLM_PK_ENCRYPTION_FUNC_DEF(encryptJni)(
 
     if (plaintextPtr)
     {
+        if (plaintextIsCopied)
+        {
+            memset(plaintextPtr, 0, (size_t)env->GetArrayLength(aPlaintextBuffer));
+        }
         env->ReleaseByteArrayElements(aPlaintextBuffer, plaintextPtr, JNI_ABORT);
     }
 
@@ -561,6 +566,7 @@ JNIEXPORT jbyteArray OLM_PK_DECRYPTION_FUNC_DEF(decryptJni)(
         }
         if (plaintextPtr)
         {
+          memset(plaintextPtr, 0, maxPlaintextLength);
           free(plaintextPtr);
         }
     }
diff --git a/android/olm-sdk/src/main/jni/olm_session.cpp b/android/olm-sdk/src/main/jni/olm_session.cpp
index 5ca49db..b9db286 100644
--- a/android/olm-sdk/src/main/jni/olm_session.cpp
+++ b/android/olm-sdk/src/main/jni/olm_session.cpp
@@ -472,6 +472,7 @@ JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(encryptMessageJni)(JNIEnv *env, jobjec
 
     OlmSession *sessionPtr = getSessionInstanceId(env, thiz);
     jbyte *clearMsgPtr = NULL;
+    jboolean clearMsgIsCopied = JNI_FALSE;
     jclass encryptedMsgJClass = 0;
     jfieldID typeMsgFieldId;
 
@@ -490,8 +491,9 @@ JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(encryptMessageJni)(JNIEnv *env, jobjec
     else if (!aEncryptedMsg)
     {
         LOGE("## encryptMessageJni(): failure - invalid encrypted message");
+        errorMessage = "invalid encrypted message";
     }
-    else if (!(clearMsgPtr = env->GetByteArrayElements(aClearMsgBuffer, 0)))
+    else if (!(clearMsgPtr = env->GetByteArrayElements(aClearMsgBuffer, &clearMsgIsCopied)))
     {
         LOGE("## encryptMessageJni(): failure - clear message JNI allocation OOM");
         errorMessage = "clear message JNI allocation OOM";
@@ -580,6 +582,10 @@ JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(encryptMessageJni)(JNIEnv *env, jobjec
     // free alloc
     if (clearMsgPtr)
     {
+        if (clearMsgIsCopied)
+        {
+            memset(clearMsgPtr, 0, (size_t)env->GetArrayLength(aClearMsgBuffer));
+        }
         env->ReleaseByteArrayElements(aClearMsgBuffer, clearMsgPtr, JNI_ABORT);
     }
 
@@ -702,6 +708,8 @@ JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(decryptMessageJni)(JNIEnv *env, jobjec
 
                 LOGD(" ## decryptMessageJni(): UTF-8 Conversion - decrypted returnedLg=%lu OK",static_cast<long unsigned int>(plaintextLength));
             }
+
+            memset(plainTextMsgPtr, 0, maxPlainTextLength);
         }
     }
 
@@ -958,4 +966,4 @@ JNIEXPORT jlong OLM_SESSION_FUNC_DEF(deserializeJni)(JNIEnv *env, jobject thiz,
     }
 
     return (jlong)(intptr_t)sessionPtr;
-}
\ No newline at end of file
+}
-- 
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