Display the number of PIN entry attempts remaining.

src/apps/common/request_pin.py

@@ -11,7 +11,7 @@ class PinCancelled(Exception):
 
 
 @ui.layout
-async def request_pin(label=None, cancellable: bool = True) -> str:
+async def request_pin(label=None, attempts_remaining=None, cancellable: bool = True) -> str:
     def onchange():
         c = dialog.cancel
         if matrix.pin:
@@ -36,7 +36,13 @@ async def request_pin(label=None, cancellable: bool = True) -> str:
 
     if label is None:
         label = "Enter your PIN"
-    matrix = PinMatrix(label)
+    sublabel = None
+    if attempts_remaining:
+        if attempts_remaining == 1:
+            sublabel = "This is your last attempt"
+        else:
+            sublabel = "{} attempts remaining".format(attempts_remaining)
+    matrix = PinMatrix(label, sublabel)
     matrix.onchange = onchange
     dialog = ConfirmDialog(matrix)
     dialog.cancel.area = ui.grid(12)

src/apps/common/storage.py

@@ -34,11 +34,11 @@ def _new_device_id() -> str:
 
 
 def get_device_id() -> str:
-    dev_id = config.get(_APP, _DEVICE_ID, True).decode()  # public
+    dev_id = config.get(_APP, _DEVICE_ID, True)  # public
     if not dev_id:
-        dev_id = _new_device_id()
+        dev_id = _new_device_id().encode()
-        config.set(_APP, _DEVICE_ID, dev_id.encode(), True)  # public
+        config.set(_APP, _DEVICE_ID, dev_id, True)  # public
-    return dev_id
+    return dev_id.decode()
 
 
 def is_initialized() -> bool:

src/apps/management/change_pin.py

@@ -16,7 +16,7 @@ async def change_pin(ctx, msg):
 
     # get current pin, return failure if invalid
     if config.has_pin():
-        curpin = await request_pin_ack(ctx)
+        curpin = await request_pin_ack(ctx, "Enter old PIN", config.get_pin_rem())
         if not config.check_pin(pin_to_int(curpin)):
             raise wire.PinInvalid("PIN invalid")
     else:

src/boot.py

@@ -13,7 +13,7 @@ async def bootscreen():
             await lockscreen()
             label = None
             while True:
-                pin = await request_pin(label)
+                pin = await request_pin(label, config.get_pin_rem())
                 if config.unlock(pin_to_int(pin)):
                     return
                 else:

src/trezor/ui/pin.py

@@ -19,8 +19,9 @@ def generate_digits():
 
 
 class PinMatrix(ui.Widget):
-    def __init__(self, label, pin="", maxlength=9):
+    def __init__(self, label, sublabel, pin="", maxlength=9):
         self.label = label
+        self.sublabel = sublabel
         self.pin = pin
         self.maxlength = maxlength
         self.digits = generate_digits()
@@ -48,7 +49,7 @@ class PinMatrix(ui.Widget):
             return
 
         # clear canvas under input line
-        display.bar(0, 0, ui.WIDTH, 45, ui.BG)
+        display.bar(0, 0, ui.WIDTH, 52, ui.BG)
 
         if self.pin:
             # input line with pin
@@ -60,6 +61,10 @@ class PinMatrix(ui.Widget):
             x = (box_w - l * padding) // 2
             for i in range(0, l):
                 ui.display.bar_radius(x + i * padding, y, size, size, ui.GREY, ui.BG, 4)
+        elif self.sublabel:
+            # input line with header label and sublabel
+            display.text_center(ui.WIDTH // 2, 20, self.label, ui.BOLD, ui.GREY, ui.BG)
+            display.text_center(ui.WIDTH // 2, 46, self.sublabel, ui.NORMAL, ui.GREY, ui.BG)
         else:
             # input line with header label
             display.text_center(ui.WIDTH // 2, 36, self.label, ui.BOLD, ui.GREY, ui.BG)