test(I6): disabling AdvancedMode must revoke the signer, not suspend it

I6 previously MEASURED and documented a gap instead of closing it: turning
AdvancedMode off left the loaded provider in RAM, and the test's own docstring
said so --

    a user who disables AdvancedMode to revoke a provider has not revoked it,
    only suspended it. Re-enabling the policy costs one button press whose
    screen names the policy and never names the signer it silently re-arms.

That also contradicted docs/security/clearsign-provider-tier.md, which lists
"disabling AdvancedMode" among the events that clear identities. One of the two
had to move, and the doc was right: 7.15 is safe without any key-management
programme precisely because trust dies on its own, and a revocation that only
suspends is not one.

The firmware side is four lines in fsm_msgApplyPolicies (firmware PR). This
flips the assertion to match: after the policy round-trip the signer must be
GONE, and the bare-message expected-response list (one ButtonRequest, one
Success) proves trust cannot be restored by a policy toggle at all -- coming
back costs a fresh LoadClearsignSigner consent, which is the screen that names
the alias and fingerprint.

Renamed to say what it now asserts. The atlas entry follows.

Author: BitHighlander

scripts/generate-test-report.py

@@ -2523,25 +2523,25 @@ def _arg_shown(a):
            'Enable Policy: Experimental (marker, four commits)',
            'Enable Policy: AdvancedMode (re-armed after the reboot to isolate the slot)']),
          ('I6', 'test_msg_session_trust_lifetime',
-          'test_disabling_advanced_mode_makes_signer_inert_not_erased',
-          'Disabling AdvancedMode suspends the signer, it does not revoke it',
-          'MEASURED, and it contradicts the shorthand that disabling AdvancedMode clears loaded '
-          'signers. Turning the policy off does make the signer unusable - every consumer in '
-          'signed_metadata.c refuses a runtime slot while the policy is off, so metadata fails closed. '
-          'But nothing erases the slot: storage_setPolicy() flips a bit and only session_clear() calls '
-          'signed_metadata_clear_signers(). Sending the bare ApplyPolicies to turn the policy back on '
-          'brings the old signer straight back to VERIFIED, and the expected-response list asserts '
-          'exactly one ButtonRequest for that - the "Trust CI Test ... NOT verified by KeepKey" consent '
-          'is provably NOT re-shown. The host API hides this because apply_policy() follows every '
-          'policy change with Initialize, and it is the Initialize that clears the slot (I3). Release '
-          'consequence: a user who disables AdvancedMode to drop a provider has suspended it, not '
-          'revoked it, and the screen that re-arms it names the policy but never the signer it silently '
-          'reinstates.',
+          'test_disabling_advanced_mode_revokes_the_signer',
+          'Disabling AdvancedMode revokes the signer, it does not suspend it',
+          'With the policy off, revoking and suspending are indistinguishable: every consumer in '
+          'signed_metadata.c refuses a runtime slot while AdvancedMode is off, so metadata fails '
+          'closed either way. The difference shows on the way back. Suspending would mean '
+          're-enabling the policy silently re-arms a provider the user never re-loaded, on a '
+          'confirmation screen that names the policy and never names the signer - so a user who '
+          'disabled AdvancedMode to drop a provider would not have dropped it. '
+          'fsm_msgApplyPolicies therefore calls signed_metadata_clear_signers() on disable. The '
+          're-enable is sent as the bare ApplyPolicies with an exact expected-response list - one '
+          'ButtonRequest and a Success - so the absence of a trust screen there is proof, not '
+          'observation: trust cannot be restored by a policy toggle at all. Coming back costs a '
+          'fresh LoadClearsignSigner consent, the screen that names the alias and fingerprint.',
           ['Enable Policy: AdvancedMode',
            "Load Clearsigner: Trust 'CI Test' (fingerprint) ... NOT verified by KeepKey",
            'Disable Policy: AdvancedMode',
            'Home screen at the refusal - the metadata message fails closed with no screen',
-           'Enable Policy: AdvancedMode - the ONLY confirm shown on re-arming; no second trust screen']),
+           'Enable Policy: AdvancedMode - the only confirm on re-arming, and the signer does NOT '
+           'come back with it']),
      ]),
     ('L', 'Bitcoin-Only Variant', '7.15.0',
      'KK_BITCOIN_ONLY=ON builds a second shipping product out of the same tree: coins.def keeps '

tests/test_msg_session_trust_lifetime.py

@@ -433,30 +433,27 @@ def test_signer_dropped_by_power_cycle(self):
             CLASSIFICATION_MALFORMED,
             "the signer came back after a power cycle — it was written to flash")
 
-    def test_disabling_advanced_mode_makes_signer_inert_not_erased(self):
-        """MEASURED behaviour, and it is NOT "disabling AdvancedMode clears the
-        signer".
-
-        Turning the policy off does make the signer unusable: every consumer in
-        signed_metadata.c (signed_metadata_process, _verify_attestation,
-        _signer_fingerprint) refuses a runtime slot while AdvancedMode is off,
-        so the metadata message fails closed.  But nothing erases the slot —
-        storage_setPolicy() only flips a policy bit, and only session_clear()
-        calls signed_metadata_clear_signers().  Turn the policy back on and the
-        old signer verifies again, with NO second trust screen: the expected
-        response list below is exactly one ApplyPolicies ButtonRequest and a
-        Success, so the "Trust 'CI Test' (…) NOT verified by KeepKey" consent is
-        provably not re-shown.
-
-        Why the host path looks otherwise: ProtocolMixin.apply_policy() follows
-        every policy change with Initialize, and it is that Initialize — not the
-        policy change — that clears the signer (test_signer_dropped_by_initialize).
-        A host that sends the bare message gets the behaviour asserted here.
-
-        Consequence to weigh at release: a user who disables AdvancedMode to
-        revoke a provider has not revoked it, only suspended it.  Re-enabling
-        the policy costs one button press whose screen names the policy and
-        never names the signer it silently re-arms.
+    def test_disabling_advanced_mode_revokes_the_signer(self):
+        """Turning the policy off DROPS the provider, it does not suspend it.
+
+        Every consumer in signed_metadata.c already refuses a runtime slot
+        while AdvancedMode is off, so with the policy off the two behaviours
+        are indistinguishable — the metadata fails closed either way.  The
+        difference only shows on the way back.
+
+        Suspending would mean re-enabling the policy silently re-arms a
+        provider the user never re-loaded, on a confirmation screen that names
+        the policy and never names the signer.  A user who disabled
+        AdvancedMode to drop a provider would not have dropped it.  So
+        fsm_msgApplyPolicies calls signed_metadata_clear_signers() on disable,
+        and coming back costs a fresh LoadClearsignSigner consent — the screen
+        that names the alias and fingerprint, which is the screen that should
+        appear whenever trust begins.
+
+        The re-enable is sent as the bare message with the exact expected
+        response list: one ApplyPolicies ButtonRequest and a Success.  No trust
+        screen appears there, which is the point — trust cannot be restored by
+        a policy toggle at all.
         """
         self._arm_session()
 
@@ -474,11 +471,10 @@ def test_disabling_advanced_mode_makes_signer_inert_not_erased(self):
             self._apply_policy_raw("AdvancedMode", True)
 
         self._assertClassification(
-            CLASSIFICATION_VERIFIED,
-            "the signer did NOT survive the policy toggle. That is stricter "
-            "than the code path allows today, so something changed: re-read "
-            "storage_setPolicy() and signed_metadata_clear_signers() before "
-            "loosening this assertion")
+            CLASSIFICATION_MALFORMED,
+            "the signer survived disabling AdvancedMode — re-enabling the "
+            "policy re-armed a provider the user never re-loaded, on a screen "
+            "that never named it")
 
 
 if __name__ == '__main__':