core/sd_salt: ensure ProcessErrors are propagated properly

core/src/apps/common/request_pin.py

@@ -7,7 +7,7 @@ from trezor.ui.pin import CANCELLED, PinDialog
 from trezor.ui.popup import Popup
 from trezor.ui.text import Text
 
-from apps.common.sd_salt import request_sd_salt
+from apps.common.sd_salt import SdProtectCancelled, request_sd_salt
 
 if False:
     from typing import Any, Optional, Tuple
@@ -93,7 +93,10 @@ async def request_pin_and_sd_salt(
 async def verify_user_pin(
     prompt: str = "Enter your PIN", allow_cancel: bool = True, retry: bool = True
 ) -> None:
-    salt = await request_sd_salt()
+    try:
+        salt = await request_sd_salt()
+    except SdProtectCancelled:
+        raise PinCancelled
 
     if not config.has_pin() and not config.check_pin(pin_to_int(""), salt):
         raise RuntimeError

core/src/apps/common/sd_salt.py

@@ -9,7 +9,7 @@ if False:
     from typing import Optional
 
 
-class SdProtectCancelled(Exception):
+class SdProtectCancelled(wire.ProcessError):
     pass
 
 
@@ -55,7 +55,7 @@ async def ensure_sd_card(ctx: wire.GenericContext) -> None:
     sd = io.SDCard()
     while not sd.present():
         if not await insert_card_dialog(ctx):
-            raise SdProtectCancelled
+            raise SdProtectCancelled("SD card required.")
 
 
 async def request_sd_salt(
@@ -67,7 +67,7 @@ async def request_sd_salt(
             return storage.sd_salt.load_sd_salt()
         except storage.sd_salt.WrongSdCard:
             if not await _wrong_card_dialog(ctx):
-                raise SdProtectCancelled
+                raise SdProtectCancelled("Wrong SD card.")
         except OSError:
             # Either the SD card did not power on, or the filesystem could not be
             # mounted (card is not formatted?), or there is a staged salt file and

core/src/apps/management/sd_protect.py

@@ -37,7 +37,7 @@ async def _set_salt(
             return storage.sd_salt.set_sd_salt(salt, salt_tag, stage)
         except OSError:
             if not await sd_problem_dialog(ctx):
-                raise
+                raise wire.ProcessError("SD card I/O error.")
 
 
 async def sd_protect(ctx: wire.Context, msg: SdProtect) -> Success: