storage: implement no_backup option (aka seedless setup)

shell.nix

@@ -1,7 +1,7 @@
 with import <nixpkgs> {};
 
 let
-  myPython = python36.withPackages(ps: [ps.trezor ps.pytest]);
+  myPython = python36.withPackages(ps: [ps.trezor ps.pytest ps.flake8 ps.isort ps.black]);
 in
   stdenv.mkDerivation {
     name = "trezor-core-dev";

src/apps/common/storage.py

@@ -25,6 +25,7 @@ _U2F_COUNTER        = const(0x09)  # int
 _PASSPHRASE_SOURCE  = const(0x0A)  # int
 _UNFINISHED_BACKUP  = const(0x0B)  # bool (0x01 or empty)
 _AUTOLOCK_DELAY_MS  = const(0x0C)  # int
+_NO_BACKUP          = const(0x0D)  # bool (0x01 or empty)
 # fmt: on
 
 
@@ -60,13 +61,17 @@ def get_homescreen() -> bytes:
     return config.get(_APP, _HOMESCREEN, True)  # public
 
 
-def load_mnemonic(mnemonic: str, needs_backup: bool) -> None:
+def load_mnemonic(mnemonic: str, needs_backup: bool, no_backup: bool) -> None:
     config.set(_APP, _MNEMONIC, mnemonic.encode())
     config.set(_APP, _VERSION, _STORAGE_VERSION)
-    if needs_backup:
-        config.set(_APP, _NEEDS_BACKUP, b"\x01")
+    if no_backup:
+        config.set(_APP, _NO_BACKUP, b"\x01")
     else:
-        config.set(_APP, _NEEDS_BACKUP, b"")
+        config.set(_APP, _NO_BACKUP, b"")
+        if needs_backup:
+            config.set(_APP, _NEEDS_BACKUP, b"\x01")
+        else:
+            config.set(_APP, _NEEDS_BACKUP, b"")
 
 
 def needs_backup() -> bool:
@@ -88,6 +93,10 @@ def set_unfinished_backup(state: bool) -> None:
         config.set(_APP, _UNFINISHED_BACKUP, b"")
 
 
+def no_backup() -> bool:
+    return bool(config.get(_APP, _NO_BACKUP))
+
+
 def get_passphrase_source() -> int:
     b = config.get(_APP, _PASSPHRASE_SOURCE)
     if b == b"\x01":

src/apps/homescreen/__init__.py

@@ -25,6 +25,7 @@ def get_features():
     f.passphrase_cached = cache.has_passphrase()
     f.needs_backup = storage.needs_backup()
     f.unfinished_backup = storage.unfinished_backup()
+    f.no_backup = storage.no_backup()
     f.flags = storage.get_flags()
     return f
 

src/apps/homescreen/homescreen.py

@@ -23,7 +23,13 @@ def display_homescreen():
     if not image:
         image = res.load("apps/homescreen/res/bg.toif")
 
-    if storage.is_initialized() and storage.unfinished_backup():
+    if storage.is_initialized() and storage.no_backup():
+        ui.display.bar(0, 0, ui.WIDTH, 30, ui.RED)
+        ui.display.text_center(
+            ui.WIDTH // 2, 22, "NO BACKUP!", ui.BOLD, ui.WHITE, ui.RED
+        )
+        ui.display.bar(0, 30, ui.WIDTH, ui.HEIGHT - 30, ui.BG)
+    elif storage.is_initialized() and storage.unfinished_backup():
         ui.display.bar(0, 0, ui.WIDTH, 30, ui.RED)
         ui.display.text_center(
             ui.WIDTH // 2, 22, "BACKUP FAILED!", ui.BOLD, ui.WHITE, ui.RED

src/apps/management/reset_device.py

@@ -46,7 +46,7 @@ async def reset_device(ctx, msg):
     ent_ack = await ctx.call(EntropyRequest(), MessageType.EntropyAck)
     mnemonic = generate_mnemonic(msg.strength, internal_ent, ent_ack.entropy)
 
-    if not msg.skip_backup:
+    if not msg.skip_backup and not msg.no_backup:
         # require confirmation of the mnemonic safety
         await show_warning(ctx)
 
@@ -63,11 +63,13 @@ async def reset_device(ctx, msg):
 
     # write settings and mnemonic into storage
     storage.load_settings(label=msg.label, use_passphrase=msg.passphrase_protection)
-    storage.load_mnemonic(mnemonic=mnemonic, needs_backup=msg.skip_backup)
+    storage.load_mnemonic(
+        mnemonic=mnemonic, needs_backup=msg.skip_backup, no_backup=msg.no_backup
+    )
 
     # show success message.  if we skipped backup, it's possible that homescreen
     # is still running, uninterrupted.  restart it to pick up new label.
-    if not msg.skip_backup:
+    if not msg.skip_backup and not msg.no_backup:
         await show_success(ctx)
     else:
         workflow.restartdefault()

src/trezor/messages/Features.py

@@ -34,6 +34,7 @@ class Features(p.MessageType):
         fw_vendor: str = None,
         fw_vendor_keys: bytes = None,
         unfinished_backup: bool = None,
+        no_backup: bool = None,
     ) -> None:
         self.vendor = vendor
         self.major_version = major_version
@@ -61,6 +62,7 @@ class Features(p.MessageType):
         self.fw_vendor = fw_vendor
         self.fw_vendor_keys = fw_vendor_keys
         self.unfinished_backup = unfinished_backup
+        self.no_backup = no_backup
 
     @classmethod
     def get_fields(cls):
@@ -91,4 +93,5 @@ class Features(p.MessageType):
             25: ('fw_vendor', p.UnicodeType, 0),
             26: ('fw_vendor_keys', p.BytesType, 0),
             27: ('unfinished_backup', p.BoolType, 0),
+            28: ('no_backup', p.BoolType, 0),
         }

src/trezor/messages/ResetDevice.py

@@ -16,6 +16,7 @@ class ResetDevice(p.MessageType):
         label: str = None,
         u2f_counter: int = None,
         skip_backup: bool = None,
+        no_backup: bool = None,
     ) -> None:
         self.display_random = display_random
         self.strength = strength
@@ -25,6 +26,7 @@ class ResetDevice(p.MessageType):
         self.label = label
         self.u2f_counter = u2f_counter
         self.skip_backup = skip_backup
+        self.no_backup = no_backup
 
     @classmethod
     def get_fields(cls):
@@ -37,4 +39,5 @@ class ResetDevice(p.MessageType):
             6: ('label', p.UnicodeType, 0),
             7: ('u2f_counter', p.UVarintType, 0),
             8: ('skip_backup', p.BoolType, 0),
+            9: ('no_backup', p.BoolType, 0),
         }

vendor/trezor-common

@@ -1 +1 @@
-Subproject commit 6c47e483d4e7dc6c5149cf53d11e543a6f2a07bd
+Subproject commit 41e4a84b5b01d03e980f84fab29c8f0b0ec948f5