From 1c7ff7f48d121ea1108eec2247a34aaec2906e61 Mon Sep 17 00:00:00 2001
From: Hubert Chathi <hubert@uhoreg.ca>
Date: Wed, 17 Oct 2018 15:50:36 -0400
Subject: more and improved buffer sanitising for Android bindings

---
 android/olm-sdk/src/main/jni/olm_utility.cpp | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

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

diff --git a/android/olm-sdk/src/main/jni/olm_utility.cpp b/android/olm-sdk/src/main/jni/olm_utility.cpp
index f6fe719..da27eda 100644
--- a/android/olm-sdk/src/main/jni/olm_utility.cpp
+++ b/android/olm-sdk/src/main/jni/olm_utility.cpp
@@ -90,6 +90,7 @@ JNIEXPORT jstring OLM_UTILITY_FUNC_DEF(verifyEd25519SignatureJni)(JNIEnv *env, j
     jbyte* signaturePtr = NULL;
     jbyte* keyPtr = NULL;
     jbyte* messagePtr = NULL;
+    jboolean messageWasCopied = JNI_FALSE;
 
     LOGD("## verifyEd25519SignatureJni(): IN");
 
@@ -109,7 +110,7 @@ JNIEXPORT jstring OLM_UTILITY_FUNC_DEF(verifyEd25519SignatureJni)(JNIEnv *env, j
     {
         LOGE(" ## verifyEd25519SignatureJni(): failure - key JNI allocation OOM");
     }
-    else if (!(messagePtr = env->GetByteArrayElements(aMessageBuffer, 0)))
+    else if (!(messagePtr = env->GetByteArrayElements(aMessageBuffer, &messageWasCopied)))
     {
         LOGE(" ## verifyEd25519SignatureJni(): failure - message JNI allocation OOM");
     }
@@ -152,6 +153,9 @@ JNIEXPORT jstring OLM_UTILITY_FUNC_DEF(verifyEd25519SignatureJni)(JNIEnv *env, j
 
     if (messagePtr)
     {
+        if (messageWasCopied) {
+            memset(messagePtr, 0, (size_t)env->GetArrayLength(aMessageBuffer));
+        }
         env->ReleaseByteArrayElements(aMessageBuffer, messagePtr, JNI_ABORT);
     }
 
@@ -171,6 +175,7 @@ JNIEXPORT jbyteArray OLM_UTILITY_FUNC_DEF(sha256Jni)(JNIEnv *env, jobject thiz,
 
     OlmUtility* utilityPtr = getUtilityInstanceId(env, thiz);
     jbyte* messagePtr = NULL;
+    jboolean messageWasCopied = JNI_FALSE;
 
     LOGD("## sha256Jni(): IN");
 
@@ -182,7 +187,7 @@ JNIEXPORT jbyteArray OLM_UTILITY_FUNC_DEF(sha256Jni)(JNIEnv *env, jobject thiz,
     {
         LOGE(" ## sha256Jni(): failure - invalid message parameters ");
     }
-    else if(!(messagePtr = env->GetByteArrayElements(aMessageToHashBuffer, 0)))
+    else if(!(messagePtr = env->GetByteArrayElements(aMessageToHashBuffer, &messageWasCopied)))
     {
         LOGE(" ## sha256Jni(): failure - message JNI allocation OOM");
     }
@@ -221,8 +226,11 @@ JNIEXPORT jbyteArray OLM_UTILITY_FUNC_DEF(sha256Jni)(JNIEnv *env, jobject thiz,
 
     if (messagePtr)
     {
+        if (messageWasCopied) {
+            memset(messagePtr, 0, (size_t)env->GetArrayLength(aMessageToHashBuffer));
+        }
         env->ReleaseByteArrayElements(aMessageToHashBuffer, messagePtr, JNI_ABORT);
     }
 
     return sha256Ret;
-}
\ No newline at end of file
+}
-- 
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