src/apps/homescreen: implement {Initialize,Features}.state field, implement ClearSession handling

src/apps/common/cache.py

@@ -1,6 +1,18 @@
 seed = None
 
 
+def get_state():
+    global seed
+    if seed is None:
+        return None
+    else:
+        from trezor.crypto import bip32
+        from trezor.crypto.hashlib import blake2s
+        node = bip32.from_seed(seed, 'secp256k1')
+        state = blake2s(node.public_key()).digest()
+        return state
+
+
 def clear():
     global seed
     seed = None

src/apps/homescreen/__init__.py

@@ -1,14 +1,18 @@
 from trezor import config
 from trezor.wire import register, protobuf_workflow
 from trezor.utils import unimport
-from trezor.messages.wire_types import Initialize, GetFeatures, Ping
+from trezor.messages.wire_types import Initialize, GetFeatures, Ping, ClearSession
 
 
 @unimport
 async def respond_Features(ctx, msg):
-    from apps.common import storage, coins
+    from apps.common import storage, coins, cache
     from trezor.messages.Features import Features
 
+    if msg.__qualname__ == 'Initialize':
+        if not hasattr(msg, 'state') or msg.state != cache.get_state():
+            cache.clear()
+
     f = Features()
     f.vendor = 'trezor.io'
     f.revision = '0123456789'
@@ -26,6 +30,8 @@ async def respond_Features(ctx, msg):
     f.pin_protection = config.has_pin()
     f.language = 'english'
 
+    f.state = cache.get_state()
+
     return f
 
 
@@ -50,7 +56,16 @@ async def respond_Pong(ctx, msg):
     return s
 
 
+@unimport
+async def respond_ClearSession(ctx, msg):
+    from apps.common import cache
+    from trezor.messages.Success import Success
+    cache.clear()
+    return Success(message='Session cleared')
+
+
 def boot():
     register(Initialize, protobuf_workflow, respond_Features)
     register(GetFeatures, protobuf_workflow, respond_Features)
     register(Ping, protobuf_workflow, respond_Pong)
+    register(ClearSession, protobuf_workflow, respond_ClearSession)

src/trezor/messages/Features.py

@@ -26,5 +26,11 @@ class Features(p.MessageType):
         19: ('needs_backup', p.BoolType, 0),
         20: ('flags', p.UVarintType, 0),
         21: ('model', p.UnicodeType, 0),
+        22: ('fw_major', p.UVarintType, 0),
+        23: ('fw_minor', p.UVarintType, 0),
+        24: ('fw_patch', p.UVarintType, 0),
+        25: ('fw_vendor', p.UnicodeType, 0),
+        26: ('fw_vendor_keys', p.BytesType, 0),
+        27: ('state', p.BytesType, 0),
     }
     MESSAGE_WIRE_TYPE = 17

src/trezor/messages/Initialize.py

@@ -3,4 +3,7 @@ import protobuf as p
 
 
 class Initialize(p.MessageType):
+    FIELDS = {
+        1: ('state', p.BytesType, 0),
+    }
     MESSAGE_WIRE_TYPE = 0

vendor/trezor-common

@@ -1 +1 @@
-Subproject commit 8652df0c692ea4f13042539dcb6bde57b79137bc
+Subproject commit c7dcca60c724c32ca3a688a6f20a055b0b4b3b1f