initial implementation of short authentication string generation

1 files changed, 71 insertions, 0 deletions

diff --git a/javascript/olm_sas.js b/javascript/olm_sas.js
new file mode 100644
index 0000000..8fc535b
--- /dev/null
+++ b/javascript/olm_sas.js
@@ -0,0 +1,71 @@
+function SAS() {
+    var size = Module['_olm_sas_size']();
+    var random_length = Module['_olm_create_sas_random_length']();
+    var random = random_stack(random_length);
+    this.buf = malloc(size);
+    this.ptr = Module['_olm_sas'](this.buf);
+    Module['_olm_create_sas'](this.ptr, random, random_length);
+    bzero(random, random_length);
+}
+
+function sas_method(wrapped) {
+    return function() {
+        var result = wrapped.apply(this, arguments);
+        if (result === OLM_ERROR) {
+            var message = Pointer_stringify(
+                Module['_olm_sas_last_error'](arguments[0])
+            );
+            throw new Error("OLM." + message);
+        }
+        return result;
+    }
+}
+
+SAS.prototype['free'] = function() {
+    Module['_olm_clear_sas'](this.ptr);
+    free(this.ptr);
+};
+
+SAS.prototype['get_pubkey'] = restore_stack(function() {
+    var pubkey_length = sas_method(Module['_olm_sas_pubkey_length'])(this.ptr);
+    var pubkey_buffer = stack(pubkey_length + NULL_BYTE_PADDING_LENGTH);
+    sas_method(Module['_olm_sas_get_pubkey'])(this.ptr, pubkey_buffer, pubkey_length);
+    return Pointer_stringify(pubkey_buffer);
+});
+
+SAS.prototype['set_their_key'] = restore_stack(function(their_key) {
+    var their_key_array = array_from_string(their_key);
+    var their_key_buffer = stack(their_key_array);
+    sas_method(Module['_olm_sas_set_their_key'])(
+        this.ptr,
+        their_key_buffer, their_key_array.length
+    );
+});
+
+SAS.prototype['generate_bytes'] = restore_stack(function(length) {
+    var output_buffer = stack(length);
+    sas_method(Module['_olm_sas_generate_bytes'])(
+        this.ptr,
+        output_buffer, length
+    );
+    // The inner Uint8Array creates a view of the buffer.  The outer Uint8Array
+    // copies it to a new array to return, since the original buffer will get
+    // deallocated from the stack and could get overwritten.
+    var output_arr = new Uint8Array(
+        new Uint8Array(Module['HEAPU8'].buffer, output_buffer, length)
+    );
+    return output_arr;
+});
+
+SAS.prototype['calculate_mac'] = restore_stack(function(input) {
+    var input_array = array_from_string(input);
+    var input_buffer = stack(input_array)
+    var mac_length = sas_method(Module['_olm_sas_mac_length'])(this.ptr);
+    var mac_buffer = stack(mac_length + NULL_BYTE_PADDING_LENGTH);
+    sas_method(Module['_olm_sas_calculate_mac'])(
+        this.ptr,
+        input_buffer, input_array.length,
+        mac_buffer, mac_length
+    );
+    return Pointer_stringify(mac_buffer);
+});