implement arbitrary code execution (ACE) over data serial.

kmk/modules/serialace.py

@@ -0,0 +1,61 @@
+from usb_cdc import data
+
+from kmk.modules import Module
+
+debug_enabled = False
+
+
+class SerialACE(Module):
+    buffer = bytearray()
+
+    def during_bootup(self, keyboard):
+        try:
+            data.timeout = 0
+        except AttributeError:
+            pass
+
+    def before_matrix_scan(self, keyboard):
+        pass
+
+    def after_matrix_scan(self, keyboard):
+        pass
+
+    def process_key(self, keyboard, key, is_pressed, int_coord):
+        return key
+
+    def before_hid_send(self, keyboard):
+        # Serial.data isn't initialized.
+        if not data:
+            return
+
+        # Nothing to parse.
+        if data.in_waiting == 0:
+            return
+
+        self.buffer.extend(data.read())
+        idx = self.buffer.find(b'\n')
+
+        # No full command yet.
+        if idx == -1:
+            return
+
+        # Split off command and evaluate
+        line = self.buffer[:idx]
+        self.buffer = self.buffer[idx + 1 :]
+        try:
+            if debug_enabled:
+                print(f'SerialACE eval({line})')
+            ret = eval(line, {'keyboard': keyboard})
+            data.write(bytearray(str(ret) + '\n'))
+        except Exception as err:
+            if debug_enabled:
+                print(f'SerialACE error({err})')
+
+    def after_hid_send(self, keyboard):
+        pass
+
+    def on_powersave_enable(self, keyboard):
+        pass
+
+    def on_powersave_disable(self, keyboard):
+        pass