core/recovery: remove group threshold from storage

core/src/apps/common/storage/recovery.py

@@ -16,7 +16,6 @@ _SLIP39_THRESHOLD          = const(0x04)  # int
 _REMAINING                 = const(0x05)  # int
 _SLIP39_ITERATION_EXPONENT = const(0x06)  # int
 _SLIP39_GROUP_COUNT        = const(0x07)  # int
-_SLIP39_GROUP_THRESHOLD    = const(0x08)  # int
 
 # Deprecated Keys:
 # _WORD_COUNT                = const(0x02)  # int
@@ -95,15 +94,6 @@ def get_slip39_group_count() -> Optional[int]:
     )
 
 
-def set_slip39_group_threshold(group_threshold: int) -> None:
-    common.set_uint8(_NAMESPACE, _SLIP39_GROUP_THRESHOLD, group_threshold)
-
-
-def get_slip39_group_threshold() -> Optional[int]:
-    _require_progress()
-    return common.get_uint8(_NAMESPACE, _SLIP39_GROUP_THRESHOLD)
-
-
 def set_slip39_remaining_shares(shares_remaining: int, group_index: int) -> None:
     """
     We store the remaining shares as a bytearray of length group_count.
@@ -153,5 +143,4 @@ def end_progress() -> None:
     common.delete(_NAMESPACE, _REMAINING)
     common.delete(_NAMESPACE, _SLIP39_ITERATION_EXPONENT)
     common.delete(_NAMESPACE, _SLIP39_GROUP_COUNT)
-    common.delete(_NAMESPACE, _SLIP39_GROUP_THRESHOLD)
     recovery_shares.delete()

core/src/apps/management/recovery_device/homescreen.py

@@ -1,6 +1,6 @@
 from trezor import loop, utils, wire
+from trezor.crypto import slip39
 from trezor.crypto.hashlib import sha256
-from trezor.crypto.slip39 import MAX_SHARE_COUNT
 from trezor.errors import MnemonicError
 from trezor.messages import BackupType
 from trezor.messages.Success import Success
@@ -209,14 +209,18 @@ async def _show_remaining_groups_and_shares(ctx: wire.Context) -> None:
     identifiers = []
     first_entered_index = -1
     for i in range(len(shares_remaining)):
-        if shares_remaining[i] < MAX_SHARE_COUNT:
+        if shares_remaining[i] < slip39.MAX_SHARE_COUNT:
             first_entered_index = i
 
+    share = None
     for i, r in enumerate(shares_remaining):
-        if 0 < r < MAX_SHARE_COUNT:
-            identifier = storage.recovery_shares.fetch_group(i)[0].split(" ")[0:3]
+        if 0 < r < slip39.MAX_SHARE_COUNT:
+            if not share:
+                m = storage.recovery_shares.fetch_group(i)[0]
+                share = slip39.decode_mnemonic(m)
+            identifier = mnemonic.split(" ")[0:3]
             identifiers.append([r, identifier])
-        elif r == MAX_SHARE_COUNT:
+        elif r == slip39.MAX_SHARE_COUNT:
             identifier = storage.recovery_shares.fetch_group(first_entered_index)[
                 0
             ].split(" ")[0:2]
@@ -226,4 +230,6 @@ async def _show_remaining_groups_and_shares(ctx: wire.Context) -> None:
             except ValueError:
                 identifiers.append([r, identifier])
 
-    return await layout.show_remaining_shares(ctx, identifiers, shares_remaining)
+    return await layout.show_remaining_shares(
+        ctx, identifiers, shares_remaining, share.group_threshold
+    )

core/src/apps/management/recovery_device/layout.py

@@ -154,8 +154,8 @@ async def show_remaining_shares(
     ctx: wire.Context,
     groups: List[int, List[str]],  # remaining + list 3 words
     shares_remaining: List[int],
+    group_threshold: int,
 ) -> None:
-    group_threshold = storage.recovery.get_slip39_group_threshold()
     pages = []
     for remaining, group in groups:
         if 0 < remaining < MAX_SHARE_COUNT:

core/src/apps/management/recovery_device/recover.py

@@ -35,7 +35,6 @@ def process_slip39(words: str) -> Tuple[Optional[bytes], slip39.Share]:
     # if this is the first share, parse and store metadata
     if not remaining:
         storage.recovery.set_slip39_group_count(share.group_count)
-        storage.recovery.set_slip39_group_threshold(share.group_threshold)
         storage.recovery.set_slip39_iteration_exponent(share.iteration_exponent)
         storage.recovery.set_slip39_identifier(share.identifier)
         storage.recovery.set_slip39_threshold(share.threshold)