javascript: Switch from deprecated Pointer_stringify() to UTF8toString().

The Pointer_stringify() function is deprecated and has a couple of
issues because it tries to guess the encoding of the buffer. In some
cases it can ignore the length parameter which could end up in
inconsistencies.

Switch to UTF8toString() that takes a length parameter and respects,
that way we don't need to allocate an additional byte for a NULL byte.

1 files changed, 9 insertions, 16 deletions

diff --git a/javascript/olm_outbound_group_session.js b/javascript/olm_outbound_group_session.js
index f1ccd3d..e4427cc 100644
--- a/javascript/olm_outbound_group_session.js
+++ b/javascript/olm_outbound_group_session.js
@@ -8,7 +8,7 @@ function outbound_group_session_method(wrapped) {
     return function() {
         var result = wrapped.apply(this, arguments);
         if (result === OLM_ERROR) {
-            var message = Pointer_stringify(
+            var message = UTF8ToString(
                 Module['_olm_outbound_group_session_last_error'](arguments[0])
             );
             throw new Error("OLM." + message);
@@ -28,7 +28,7 @@ OutboundGroupSession.prototype['pickle'] = restore_stack(function(key) {
         Module['_olm_pickle_outbound_group_session_length']
     )(this.ptr);
     var key_buffer = stack(key_array);
-    var pickle_buffer = stack(pickle_length + NULL_BYTE_PADDING_LENGTH);
+    var pickle_buffer = stack(pickle_length);
     try {
         outbound_group_session_method(Module['_olm_pickle_outbound_group_session'])(
             this.ptr, key_buffer, key_array.length, pickle_buffer, pickle_length
@@ -40,7 +40,7 @@ OutboundGroupSession.prototype['pickle'] = restore_stack(function(key) {
             key_array[i] = 0;
         }
     }
-    return Pointer_stringify(pickle_buffer);
+    return UTF8ToString(pickle_buffer, pickle_length);
 });
 
 OutboundGroupSession.prototype['unpickle'] = restore_stack(function(key, pickle) {
@@ -86,21 +86,14 @@ OutboundGroupSession.prototype['encrypt'] = function(plaintext) {
         plaintext_buffer = malloc(plaintext_length + 1);
         stringToUTF8(plaintext, plaintext_buffer, plaintext_length + 1);
 
-        message_buffer = malloc(message_length + NULL_BYTE_PADDING_LENGTH);
+        message_buffer = malloc(message_length);
         outbound_group_session_method(Module['_olm_group_encrypt'])(
             this.ptr,
             plaintext_buffer, plaintext_length,
             message_buffer, message_length
         );
 
-        // UTF8ToString requires a null-terminated argument, so add the
-        // null terminator.
-        setValue(
-            message_buffer+message_length,
-            0, "i8"
-        );
-
-        return UTF8ToString(message_buffer);
+        return UTF8ToString(message_buffer, message_length);
     } finally {
         if (plaintext_buffer !== undefined) {
             // don't leave a copy of the plaintext in the heap.
@@ -117,22 +110,22 @@ OutboundGroupSession.prototype['session_id'] = restore_stack(function() {
     var length = outbound_group_session_method(
         Module['_olm_outbound_group_session_id_length']
     )(this.ptr);
-    var session_id = stack(length + NULL_BYTE_PADDING_LENGTH);
+    var session_id = stack(length);
     outbound_group_session_method(Module['_olm_outbound_group_session_id'])(
         this.ptr, session_id, length
     );
-    return Pointer_stringify(session_id);
+    return UTF8ToString(session_id, length);
 });
 
 OutboundGroupSession.prototype['session_key'] = restore_stack(function() {
     var key_length = outbound_group_session_method(
         Module['_olm_outbound_group_session_key_length']
     )(this.ptr);
-    var key = stack(key_length + NULL_BYTE_PADDING_LENGTH);
+    var key = stack(key_length);
     outbound_group_session_method(Module['_olm_outbound_group_session_key'])(
         this.ptr, key, key_length
     );
-    var key_str = Pointer_stringify(key);
+    var key_str = UTF8ToString(key, key_length);
     bzero(key, key_length); // clear out our copy of the key
     return key_str;
 });