Generate and retrieve fallback key functions added.

android/olm-sdk/src/androidTest/java/org/matrix/olm/OlmAccountTest.java

@@ -488,4 +488,19 @@ public class OlmAccountTest {
             fail(e.getMessage());
         }
     }
+
+    @Test
+    public void test18GenerateFallbackKey() {
+        try {
+            OlmAccount account1 = new OlmAccount();
+            account1.generateFallbackKey();
+            Map<String, Map<String, String>> fallbackKeyMap = account1.fallbackKey();
+
+            assertNotNull(fallbackKeyMap);
+
+            assertEquals(1, fallbackKeyMap.size());
+        } catch (OlmException e) {
+            fail(e.getMessage());
+        }
+    }
 }

android/olm-sdk/src/main/java/org/matrix/olm/OlmAccount.java

@@ -114,11 +114,11 @@ public class OlmAccount extends CommonSerializeUtils implements Serializable {
     /**
      * Return the identity keys (identity and fingerprint keys) in a dictionary.<br>
      * Public API for {@link #identityKeysJni()}.<br>
-     * Ex:<tt>
+     * Ex:<code>
      * {
      *  "curve25519":"Vam++zZPMqDQM6ANKpO/uAl5ViJSHxV9hd+b0/fwRAg",
      *  "ed25519":"+v8SOlOASFTMrX3MCKBM4iVnYoZ+JIjpNt1fi8Z9O2I"
-     * }</tt>
+     * }</code>
      * @return identity keys dictionary if operation succeeds, null otherwise
      * @exception OlmException the failure reason
      */
@@ -195,14 +195,14 @@ public class OlmAccount extends CommonSerializeUtils implements Serializable {
     /**
      * Return the "one time keys" in a dictionary.<br>
      * The number of "one time keys", is specified by {@link #generateOneTimeKeys(int)}<br>
-     * Ex:<tt>
+     * Ex:<code>
      * { "curve25519":
      *  {
      *      "AAAABQ":"qefVZd8qvjOpsFzoKSAdfUnJVkIreyxWFlipCHjSQQg",
      *      "AAAABA":"/X8szMU+p+lsTnr56wKjaLgjTMQQkCk8EIWEAilZtQ8",
      *      "AAAAAw":"qxNxxFHzevFntaaPdT0fhhO7tc7pco4+xB/5VRG81hA",
      *  }
-     * }</tt><br>
+     * }</code><br>
      * Public API for {@link #oneTimeKeysJni()}.<br>
      * Note: these keys are to be published on the server.
      * @return one time keys in string dictionary.
@@ -234,7 +234,7 @@ public class OlmAccount extends CommonSerializeUtils implements Serializable {
     /**
      * Get the public parts of the unpublished "one time keys" for the account.<br>
      * The returned data is a JSON-formatted object with the single property
-     * <tt>curve25519</tt>, which is itself an object mapping key id to
+     * <code>curve25519</code>, which is itself an object mapping key id to
      * base64-encoded Curve25519 key.<br>
      * @return byte array containing the one time keys or throw an exception if it fails
      */
@@ -442,4 +442,55 @@ public class OlmAccount extends CommonSerializeUtils implements Serializable {
         deserialize(aSerializedData, aKey);
     }
 
+    /**
+     * Generates a new fallback key.
+     * @throws OlmException exception with a reason.
+     */
+    public void generateFallbackKey() throws OlmException {
+        try {
+            generateFallbackKeyJni();
+        } catch (Exception e) {
+            throw new OlmException(OlmException.EXCEPTION_CODE_ACCOUNT_GENERATE_FALLBACK_KEY, e.getMessage());
+        }
+    }
+
+    private native void generateFallbackKeyJni();
+
+    /**
+     * Return the "fallback key" in a dictionary.<br>
+     * Ex:<code>
+     * { "curve25519":
+     *  {
+     *      "AAAABQ":"qefVZd8qvjOpsFzoKSAdfUnJVkIreyxWFlipCHjSQQg"
+     *  }
+     * }</code><br>
+     * Public API for {@link #fallbackKeyJni()}.<br>
+     * Note: the key is to be published on the server.
+     * @return fallback key in string dictionary.
+     * @exception OlmException the failure reason
+     */
+    public Map<String, Map<String, String>> fallbackKey() throws OlmException {
+        JSONObject fallbackKeyJsonObj = null;
+        byte[] fallbackKeyBuffer;
+
+        try {
+            fallbackKeyBuffer = fallbackKeyJni();
+        } catch (Exception e) {
+            throw new OlmException(OlmException.EXCEPTION_CODE_ACCOUNT_FALLBACK_KEY, e.getMessage());
+        }
+
+        if( null != fallbackKeyBuffer) {
+            try {
+                fallbackKeyJsonObj = new JSONObject(new String(fallbackKeyBuffer, "UTF-8"));
+            } catch (Exception e) {
+                Log.e(LOG_TAG, "## fallbackKey(): Exception - Msg=" + e.getMessage());
+            }
+        } else {
+            Log.e(LOG_TAG, "## fallbackKey(): Failure - identityKeysJni()=null");
+        }
+
+        return OlmUtility.toStringMapMap(fallbackKeyJsonObj);
+    }
+
+    private native byte[] fallbackKeyJni();
 }

android/olm-sdk/src/main/java/org/matrix/olm/OlmException.java

@@ -35,6 +35,8 @@ public class OlmException extends IOException {
     public static final int EXCEPTION_CODE_ACCOUNT_REMOVE_ONE_TIME_KEYS = 105;
     public static final int EXCEPTION_CODE_ACCOUNT_MARK_ONE_KEYS_AS_PUBLISHED = 106;
     public static final int EXCEPTION_CODE_ACCOUNT_SIGN_MESSAGE = 107;
+    public static final int EXCEPTION_CODE_ACCOUNT_GENERATE_FALLBACK_KEY = 108;
+    public static final int EXCEPTION_CODE_ACCOUNT_FALLBACK_KEY = 109;
 
     public static final int EXCEPTION_CODE_CREATE_INBOUND_GROUP_SESSION = 200;
     public static final int EXCEPTION_CODE_INIT_INBOUND_GROUP_SESSION = 201;

android/olm-sdk/src/main/jni/olm_account.cpp

@@ -442,6 +442,131 @@ JNIEXPORT void OLM_ACCOUNT_FUNC_DEF(markOneTimeKeysAsPublishedJni)(JNIEnv *env,
     }
 }
 
+/**
+ * Generate "fallback key".
+ * An exception is thrown if the operation fails.
+ **/
+JNIEXPORT void OLM_ACCOUNT_FUNC_DEF(generateFallbackKeyJni)(JNIEnv *env, jobject thiz)
+{
+    const char* errorMessage = NULL;
+    OlmAccount *accountPtr = getAccountInstanceId(env, thiz);
+
+    if (!accountPtr)
+    {
+        LOGE("## generateFallbackKeyJni(): failure - invalid Account ptr");
+        errorMessage = "invalid Account ptr";
+    }
+    else
+    {
+        // keys memory allocation
+        size_t randomLength = olm_account_generate_fallback_key_random_length(accountPtr);
+        LOGD("## generateFallbackKeyJni(): randomLength=%lu", static_cast<long unsigned int>(randomLength));
+
+        uint8_t *randomBufferPtr = NULL;
+
+        if ((0 != randomLength) && !setRandomInBuffer(env, &randomBufferPtr, randomLength))
+        {
+            LOGE("## generateFallbackKeyJni(): failure - random buffer init");
+            errorMessage = "random buffer init";
+        }
+        else
+        {
+            LOGD("## generateFallbackKeyJni(): accountPtr =%p", accountPtr);
+
+            // retrieve key pairs in keysBytesPtr
+            size_t result = olm_account_generate_fallback_key(accountPtr, (void*)randomBufferPtr, randomLength);
+
+            if (result == olm_error())
+            {
+                errorMessage = olm_account_last_error(accountPtr);
+                LOGE("## generateFallbackKeyJni(): failure - error generating fallback keys Msg=%s", errorMessage);
+            }
+            else
+            {
+                LOGD("## generateFallbackKeyJni(): success - result=%lu", static_cast<long unsigned int>(result));
+            }
+        }
+
+        if (randomBufferPtr)
+        {
+            memset(randomBufferPtr, 0, randomLength);
+            free(randomBufferPtr);
+        }
+    }
+
+    if (errorMessage)
+    {
+        env->ThrowNew(env->FindClass("java/lang/Exception"), errorMessage);
+    }
+}
+
+/**
+ * Get "fallback key".<br>
+ * Return the public parts of the unpublished "fallback key" for the account
+ * @return a valid byte array if operation succeed, null otherwise
+ **/
+JNIEXPORT jbyteArray OLM_ACCOUNT_FUNC_DEF(fallbackKeyJni)(JNIEnv *env, jobject thiz)
+{
+    const char* errorMessage = NULL;
+    jbyteArray byteArrayRetValue = NULL;
+    OlmAccount* accountPtr = getAccountInstanceId(env, thiz);
+
+    LOGD("## fallbackKeyJni(): IN");
+
+    if (!accountPtr)
+    {
+        LOGE("## fallbackKeyJni(): failure - invalid Account ptr");
+        errorMessage = "invalid Account ptr";
+    }
+    else
+    {
+        // keys memory allocation
+        size_t keysLength = olm_account_fallback_key_length(accountPtr);
+        uint8_t *keysBytesPtr = (uint8_t *)malloc(keysLength*sizeof(uint8_t));
+
+        if (!keysBytesPtr)
+        {
+            LOGE("## fallbackKeyJni(): failure - fallback key OOM");
+            errorMessage = "fallback key OOM";
+        }
+        else
+        {
+            // retrieve key pairs in keysBytesPtr
+            size_t keysResult = olm_account_fallback_key(accountPtr, keysBytesPtr, keysLength);
+
+            if (keysResult == olm_error()) {
+                LOGE("## fallbackKeyJni(): failure - error getting fallback key Msg=%s",(const char *)olm_account_last_error(accountPtr));
+                errorMessage = (const char *)olm_account_last_error(accountPtr);
+            }
+            else
+            {
+                // allocate the byte array to be returned to java
+                byteArrayRetValue = env->NewByteArray(keysLength);
+
+                if (!byteArrayRetValue)
+                {
+                    LOGE("## fallbackKeyJni(): failure - return byte array OOM");
+                    errorMessage = "return byte array OOM";
+                }
+                else
+                {
+                    env->SetByteArrayRegion(byteArrayRetValue, 0/*offset*/, keysLength, (const jbyte*)keysBytesPtr);
+                    LOGD("## fallbackKeyJni(): success");
+                }
+            }
+
+            free(keysBytesPtr);
+        }
+    }
+
+    if (errorMessage)
+    {
+        env->ThrowNew(env->FindClass("java/lang/Exception"), errorMessage);
+    }
+
+    return byteArrayRetValue;
+}
+
 /**
  * Sign a message with the ed25519 key (fingerprint) for this account.<br>
  * The signed message is returned by the function.

android/olm-sdk/src/main/jni/olm_account.h

@@ -42,6 +42,10 @@ JNIEXPORT void OLM_ACCOUNT_FUNC_DEF(generateOneTimeKeysJni)(JNIEnv *env, jobject
 JNIEXPORT void OLM_ACCOUNT_FUNC_DEF(removeOneTimeKeysJni)(JNIEnv *env, jobject thiz, jlong aNativeOlmSessionId);
 JNIEXPORT void OLM_ACCOUNT_FUNC_DEF(markOneTimeKeysAsPublishedJni)(JNIEnv *env, jobject thiz);
 
+// fallback keys
+JNIEXPORT void OLM_ACCOUNT_FUNC_DEF(generateFallbackKeyJni)(JNIEnv *env, jobject thiz);
+JNIEXPORT jbyteArray OLM_ACCOUNT_FUNC_DEF(fallbackKeyJni)(JNIEnv *env, jobject thiz);
+
 // signing
 JNIEXPORT jbyteArray OLM_ACCOUNT_FUNC_DEF(signMessageJni)(JNIEnv *env, jobject thiz, jbyteArray aMessage);