core/webauthn: Add bogus app ID used by Firefox to indicate error in U2F. Figure out which error to display based on past U2F_AUTHENTICATE check-only requests on the same channel.

core/src/apps/webauthn/fido2.py

@@ -175,7 +175,9 @@ _U2FHID_IF_VERSION = const(2)  # interface version
 _U2F_REGISTER_ID = const(0x05)  # version 2 registration identifier
 _U2F_ATT_PRIV_KEY = b"q&\xac+\xf6D\xdca\x86\xad\x83\xef\x1f\xcd\xf1*W\xb5\xcf\xa2\x00\x0b\x8a\xd0'\xe9V\xe8T\xc5\n\x8b"
 _U2F_ATT_CERT = b"0\x82\x01\x180\x81\xc0\x02\t\x00\xb1\xd9\x8fBdr\xd3,0\n\x06\x08*\x86H\xce=\x04\x03\x020\x151\x130\x11\x06\x03U\x04\x03\x0c\nTrezor U2F0\x1e\x17\r160429133153Z\x17\r260427133153Z0\x151\x130\x11\x06\x03U\x04\x03\x0c\nTrezor U2F0Y0\x13\x06\x07*\x86H\xce=\x02\x01\x06\x08*\x86H\xce=\x03\x01\x07\x03B\x00\x04\xd9\x18\xbd\xfa\x8aT\xac\x92\xe9\r\xa9\x1f\xcaz\xa2dT\xc0\xd1s61M\xde\x83\xa5K\x86\xb5\xdfN\xf0Re\x9a\x1do\xfc\xb7F\x7f\x1a\xcd\xdb\x8a3\x08\x0b^\xed\x91\x89\x13\xf4C\xa5&\x1b\xc7{h`o\xc10\n\x06\x08*\x86H\xce=\x04\x03\x02\x03G\x000D\x02 $\x1e\x81\xff\xd2\xe5\xe6\x156\x94\xc3U.\x8f\xeb\xd7\x1e\x895\x92\x1c\xb4\x83ACq\x1cv\xea\xee\xf3\x95\x02 _\x80\xeb\x10\xf2\\\xcc9\x8b<\xa8\xa9\xad\xa4\x02\x7f\x93\x13 w\xb7\xab\xcewFZ'\xf5=3\xa1\x1d"
-_BOGUS_APPID = b"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
+_BOGUS_APPID_CHROME = b"A" * 32
+_BOGUS_APPID_FIREFOX = b"\0" * 32
+_BOGUS_APPIDS = (_BOGUS_APPID_CHROME, _BOGUS_APPID_FIREFOX)
 _AAGUID = b"\xd6\xd0\xbd\xc3b\xee\xc4\xdb\xde\x8dzenJD\x87"  # First 16 bytes of SHA-256("TREZOR 2")
 _BOGUS_PRIV_KEY = b"\xAA" * 32
 
@@ -218,6 +220,9 @@ _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
 
+# The CID of the last successful U2F_AUTHENTICATE check-only request.
+_last_good_auth_check_cid = 0
+
 
 class CborError(Exception):
     def __init__(self, code: int):
@@ -615,13 +620,20 @@ class U2fConfirmRegister(U2fState):
         super().__init__(cid, iface, req_data, cred)
 
     async def confirm_dialog(self) -> bool:
-        if self._cred.rp_id_hash == _BOGUS_APPID:
+        if self._cred.rp_id_hash in _BOGUS_APPIDS:
             text = Text("U2F", ui.ICON_WRONG, ui.RED)
-            text.bold("Not registered.")
-            text.br_half()
-            text.normal(
-                "Another U2F device", "was used to register", "in this application."
-            )
+            if self.cid == _last_good_auth_check_cid:
+                text.bold("Already registered.")
+                text.br_half()
+                text.normal(
+                    "This device is already", "registered with this", "application."
+                )
+            else:
+                text.bold("Not registered.")
+                text.br_half()
+                text.normal(
+                    "This device is not", "registered with this", "application."
+                )
             return await Popup(text, _POPUP_TIMEOUT_MS)
         else:
             content = ConfirmContent(self)
@@ -1199,6 +1211,8 @@ def msg_authenticate(req: Msg, dialog_mgr: DialogManager) -> Cmd:
     if req.p1 == _AUTH_CHECK_ONLY:
         if __debug__:
             log.info(__name__, "_AUTH_CHECK_ONLY")
+        global _last_good_auth_check_cid
+        _last_good_auth_check_cid = req.cid
         return msg_error(req.cid, _SW_CONDITIONS_NOT_SATISFIED)
 
     # from now on, only _AUTH_ENFORCE is supported