auth checks

shared/auth.py

@@ -791,7 +791,8 @@ class ApproveTransaction(UserAuthorizedAction):
     async def interact(self):
         # Prompt user w/ details and get approval
         from glob import dis, hsm_active
-        from ccc import CCCFeature, PolicyViolationException
+        from ccc import CCCFeature
+        from exceptions import CCCPolicyViolationError
 
         # step 1: parse PSBT from PSRAM into in-memory objects.
 
@@ -826,23 +827,12 @@ class ApproveTransaction(UserAuthorizedAction):
 
             dis.progress_bar_show(0.85)
 
-            if CCCFeature.is_enabled():
-                if self.psbt.active_multisig and (ccc_c_xfp in self.psbt.active_multisig.xfp_paths):
-                    CCCFeature.validate_tx(self.psbt)
-                    self.psbt.sign_it(CCCFeature.get_encoded_secret(), ccc_c_xfp)
-
         except FraudulentChangeOutput as exc:
             print('FraudulentChangeOutput: ' + exc.args[0])
             return await self.failure(exc.args[0], title='Change Fraud')
         except FatalPSBTIssue as exc:
             print('FatalPSBTIssue: ' + exc.args[0])
             return await self.failure(exc.args[0])
-        except PolicyViolationException as exc:
-            ch = await ux_show_story(
-                exc.args[0]+"\n\n Would you like to sign with A key?",
-                title='Policy Violation')
-            if ch != "y":
-                return
         except BaseException as exc:
             del self.psbt
             gc.collect()
@@ -855,6 +845,10 @@ class ApproveTransaction(UserAuthorizedAction):
 
             return await self.failure(msg, exc)
 
+        # early test for spending policy; not an error if violates policy
+        # - might add warnings
+        could_ccc_sign, needs_2fa = CCCFeature.could_sign(self.psbt)
+
         # step 2: figure out what we are approving, so we can get sign-off
         # - outputs, amounts
         # - fee 
@@ -954,7 +948,7 @@ class ApproveTransaction(UserAuthorizedAction):
             return await self.failure(msg)
 
         if ch not in 'yb':
-            # they don't want to!
+            # they don't want to sign!
             self.refused = True
 
             await ux_dramatic_pause("Refused.", 1)
@@ -964,11 +958,27 @@ class ApproveTransaction(UserAuthorizedAction):
             self.done()
             return
 
+        if needs_2fa and could_ccc_sign:
+            # They still need to pass web2fa challenge (but it meets other specs ok)
+            try:
+                await CCCFeature.web2fa_challenge()
+            except:
+                could_ccc_sign = False
+                ch = await ux_show_story("Will not add CCC signature. Proceed anyway?")
+                if ch != 'y':
+                    return await self.failure("2FA Failed")
+
         # do the actual signing.
         try:
             dis.fullscreen('Wait...')
             gc.collect()           # visible delay caused by this but also sign_it() below
             self.psbt.sign_it()
+
+            if could_ccc_sign:
+                dis.fullscreen('CCC Sign...')
+                gc.collect()
+                CCCFeature.sign_psbt(self.psbt)
+
         except FraudulentChangeOutput as exc:
             return await self.failure(exc.args[0], title='Change Fraud')
         except MemoryError:

shared/ccc.py

@@ -10,11 +10,9 @@ from menu import MenuSystem, MenuItem
 from seed import seed_words_to_encoded_secret
 from stash import SecretStash, len_to_numwords
 from charcodes import KEY_QR, KEY_CANCEL, KEY_NFC
+from exceptions import CCCPolicyViolationError
 
 
-class PolicyViolationException(Exception):
-    pass
-
 class CCCFeature:
     @classmethod
     def is_enabled(cls):
@@ -44,9 +42,7 @@ class CCCFeature:
     def get_xfp(cls):
         # just the XFP
         ccc = settings.get('ccc')
-        if ccc:
-            return ccc['c_xfp']
-        
+        return ccc['c_xfp'] if ccc else None
 
     @classmethod
     def init_setup(cls, words):
@@ -103,15 +99,79 @@ class CCCFeature:
         settings.save()
 
     @classmethod
-    def validate_tx(cls, psbt):
-        policy = cls.get_policy()
-        magnitude = policy.get("mag", None)
+    async def meets_policy(cls, psbt):
+        # Does policy allow signing this? Else raise why
+        pol = cls.get_policy()
+
+        # mag
+        magnitude = pol.get("mag", None)
         outgoing = psbt.total_value_out - psbt.total_change_value
         if magnitude < 1000:
             # it is a BTC, convert to sats
             magnitude = magnitude * 100000000
+
         if outgoing > magnitude:
-            raise PolicyViolationException("magnitude")
+            raise CCCPolicyViolationError("magnitude")
+
+        # vel
+
+        # whitelist
+
+        # web2fa 
+        # - slow, requires UX, and they might not acheive it...
+        # - wait until about to do signature
+        if pol.get('web2fa', False):
+            psbt.warnings.append(('CCC', 'Web 2FA required.'))
+            return True
+        
+
+    @classmethod
+    def could_sign(cls, psbt):
+        # We are looking at a PSBT: can we sign it, and would we?
+        # - if we **could** but will not, due to policy, add warning msg
+        # - return (we could sign, needs2fa step)
+        if not cls.is_enabled:
+            return False, False
+
+        ms = psbt.active_multisig
+        if not ms:
+            # single-sig CCC not supported
+            return False, False
+
+        xfp = cls.get_xfp()
+        if  (xfp not in ms.xfp_paths):
+            # does not involve us
+            return False, False
+
+        try:
+            # check policy
+            needs_2fa = cls.meets_policy(psbt)
+        except CCCPolicyViolationError:
+            psbt.warning.append(('CCC', "Violates spending policy. Won't sign."))
+            return False, False
+
+        return True, needs_2fa
+
+    @classmethod
+    async def web2fa_challenge(cls):
+        # they are trying to sign something, so make them get our their phone
+        # - at this point they have already ok'ed the details of the txn
+        # - and we have approved other elements of the spending policy.
+        # - TODO: maybe show wallet name? or even txn details?? (but info leak to Coinkite)
+        pol = cls.get_policy()
+        ss = pol.get('web2fa')
+        assert ss
+
+        ok = await web2fa.perform_web2fa('Approve CCC Transaction', ss)
+        if not ok:
+            raise CCCPolicyViolationError
+
+    @classmethod
+    def sign_psbt(cls, psbt):
+        # do the math
+        # TODO: capture the block height if vel is defined; no going back after this pt.
+        psbt.sign_it(cls.get_encoded_secret(), cls.get_xfp())
+
 
 def render_mag_value(mag):
     # handle integer bitcoins, and satoshis in same value
@@ -544,6 +604,7 @@ async def gen_or_import():
     elif ch == '6':
         # pick existing from Seed Vault
         enc = await SeedVaultChooserMenu.pick(words_only=True)
+        if not enc: return None
         words = SecretStash.decode_words(enc)
         await enable_step1(words)
 

shared/exceptions.py

@@ -51,4 +51,8 @@ class QRDecodeExplained(ValueError):
 class UnknownAddressExplained(ValueError):
     pass
 
+# We're not going to co-sign using CCC feature
+class CCCPolicyViolationError(RuntimeError):
+    pass
+
 # EOF