core/webauthn: Allow only one CTAPHID_WINK command at a time on any given channel ID to fix continuous display blinking with Android.

core/src/apps/webauthn/fido2.py

@@ -215,6 +215,9 @@ _ALLOW_RESIDENT_CREDENTIALS = True
 # The attestation type to use in MakeCredential responses. If false, then self attestation will be used.
 _USE_BASIC_ATTESTATION = False
 
+# The CID of the last WINK command. Used to ensure that we do only one WINK at a time on any given CID.
+_last_wink_cid = 0
+
 
 class CborError(Exception):
     def __init__(self, code: int):
@@ -1027,8 +1030,7 @@ def dispatch_cmd(req: Cmd, dialog_mgr: DialogManager) -> Optional[Cmd]:
     elif req.cmd == _CMD_WINK:
         if __debug__:
             log.debug(__name__, "_CMD_WINK")
-        ui.alert()
-        return req
+        return cmd_wink(req)
     elif req.cmd == _CMD_CBOR and _ALLOW_FIDO2:
         if not req.data:
             return cmd_error(req.cid, _ERR_INVALID_LEN)
@@ -1092,6 +1094,14 @@ def cmd_init(req: Cmd) -> Cmd:
     return Cmd(req.cid, req.cmd, buf)
 
 
+def cmd_wink(req: Cmd) -> Cmd:
+    global _last_wink_cid
+    if _last_wink_cid != req.cid:
+        _last_wink_cid = req.cid
+        ui.alert()
+    return req
+
+
 def msg_register(req: Msg, dialog_mgr: DialogManager) -> Cmd:
     if not storage.is_initialized():
         if __debug__: