storage, core: Reveal the wipe code status after the device is unlocked.

core/embed/extmod/modtrezorconfig/modtrezorconfig.c

@@ -173,6 +173,19 @@ STATIC mp_obj_t mod_trezorconfig_change_pin(size_t n_args,
 STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_trezorconfig_change_pin_obj, 4,
                                            4, mod_trezorconfig_change_pin);
 
+/// def has_wipe_code() -> bool:
+///     """
+///     Returns True if storage has a configured wipe code, False otherwise.
+///     """
+STATIC mp_obj_t mod_trezorconfig_has_wipe_code(void) {
+  if (sectrue != storage_has_wipe_code()) {
+    return mp_const_false;
+  }
+  return mp_const_true;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_0(mod_trezorconfig_has_wipe_code_obj,
+                                 mod_trezorconfig_has_wipe_code);
+
 /// def change_wipe_code(
 ///     pin: int,
 ///     ext_salt: Optional[bytes],
@@ -354,6 +367,8 @@ STATIC const mp_rom_map_elem_t mp_module_trezorconfig_globals_table[] = {
      MP_ROM_PTR(&mod_trezorconfig_get_pin_rem_obj)},
     {MP_ROM_QSTR(MP_QSTR_change_pin),
      MP_ROM_PTR(&mod_trezorconfig_change_pin_obj)},
+    {MP_ROM_QSTR(MP_QSTR_has_wipe_code),
+     MP_ROM_PTR(&mod_trezorconfig_has_wipe_code_obj)},
     {MP_ROM_QSTR(MP_QSTR_change_wipe_code),
      MP_ROM_PTR(&mod_trezorconfig_change_wipe_code_obj)},
     {MP_ROM_QSTR(MP_QSTR_get), MP_ROM_PTR(&mod_trezorconfig_get_obj)},

core/mocks/generated/trezorconfig.pyi

@@ -60,6 +60,13 @@ def change_pin(
     """
 
 
+# extmod/modtrezorconfig/modtrezorconfig.c
+def has_wipe_code() -> bool:
+    """
+    Returns True if storage has a configured wipe code, False otherwise.
+    """
+
+
 # extmod/modtrezorconfig/modtrezorconfig.c
 def change_wipe_code(
     pin: int,

core/src/apps/management/change_wipe_code.py

@@ -22,7 +22,8 @@ async def change_wipe_code(ctx: wire.Context, msg: ChangeWipeCode) -> Success:
         raise wire.NotInitialized("Device is not initialized")
 
     # Confirm that user wants to set or remove the wipe code.
-    await _require_confirm_action(ctx, msg)
+    has_wipe_code = config.has_wipe_code()
+    await _require_confirm_action(ctx, msg, has_wipe_code)
 
     # Get the unlocking PIN.
     pin, salt = await request_pin_and_sd_salt(ctx)
@@ -44,8 +45,12 @@ async def change_wipe_code(ctx: wire.Context, msg: ChangeWipeCode) -> Success:
         raise wire.PinInvalid("PIN invalid")
 
     if wipe_code:
-        msg_screen = "set the wipe code."
-        msg_wire = "Wipe code set"
+        if has_wipe_code:
+            msg_screen = "changed the wipe code."
+            msg_wire = "Wipe code changed"
+        else:
+            msg_screen = "set the wipe code."
+            msg_wire = "Wipe code set"
     else:
         msg_screen = "disabled the wipe code."
         msg_wire = "Wipe code removed"
@@ -54,19 +59,31 @@ async def change_wipe_code(ctx: wire.Context, msg: ChangeWipeCode) -> Success:
     return Success(message=msg_wire)
 
 
-def _require_confirm_action(ctx: wire.Context, msg: ChangeWipeCode) -> None:
-    if msg.remove:
+def _require_confirm_action(
+    ctx: wire.Context, msg: ChangeWipeCode, has_wipe_code: bool
+) -> None:
+    if msg.remove and has_wipe_code:
         text = Text("Disable wipe code", ui.ICON_CONFIG)
         text.normal("Do you really want to")
         text.bold("disable wipe code")
         text.bold("protection?")
         return require_confirm(ctx, text)
-    else:
+
+    if not msg.remove and has_wipe_code:
+        text = Text("Change wipe code", ui.ICON_CONFIG)
+        text.normal("Do you really want to")
+        text.bold("change the wipe code?")
+        return require_confirm(ctx, text)
+
+    if not msg.remove and not has_wipe_code:
         text = Text("Set wipe code", ui.ICON_CONFIG)
         text.normal("Do you really want to")
         text.bold("set the wipe code?")
         return require_confirm(ctx, text)
 
+    # Removing non-existing wipe code.
+    raise wire.ProcessError("Wipe code protection is already disabled")
+
 
 async def _request_wipe_code_confirm(ctx: wire.Context, pin: str) -> str:
     while True:

storage/storage.c

@@ -1331,6 +1331,14 @@ secbool storage_change_pin(uint32_t oldpin, uint32_t newpin,
   return ret;
 }
 
+secbool storage_has_wipe_code(void) {
+  if (sectrue != initialized || sectrue != unlocked) {
+    return secfalse;
+  }
+
+  return is_not_wipe_code(WIPE_CODE_EMPTY);
+}
+
 secbool storage_change_wipe_code(uint32_t pin, const uint8_t *ext_salt,
                                  uint32_t wipe_code) {
   if (sectrue != initialized || (pin != PIN_EMPTY && pin == wipe_code)) {

storage/storage.h

@@ -52,6 +52,7 @@ uint32_t storage_get_pin_rem(void);
 secbool storage_change_pin(uint32_t oldpin, uint32_t newpin,
                            const uint8_t *old_ext_salt,
                            const uint8_t *new_ext_salt);
+secbool storage_has_wipe_code(void);
 secbool storage_change_wipe_code(uint32_t pin, const uint8_t *ext_salt,
                                  uint32_t wipe_code);
 secbool storage_get(const uint16_t key, void *val, const uint16_t max_len,