Merge pull request #3206 from ethereum/btec-fork-version

MUST use `GENESIS_FORK_VERSION` to sign `BLSToExecutionChange` message

specs/capella/beacon-chain.md

@@ -472,7 +472,8 @@ def process_bls_to_execution_change(state: BeaconState,
     assert validator.withdrawal_credentials[:1] == BLS_WITHDRAWAL_PREFIX
     assert validator.withdrawal_credentials[1:] == hash(address_change.from_bls_pubkey)[1:]
 
-    domain = get_domain(state, DOMAIN_BLS_TO_EXECUTION_CHANGE)
+    # Fork-agnostic domain since address changes are valid across forks
+    domain = compute_domain(DOMAIN_BLS_TO_EXECUTION_CHANGE, genesis_validators_root=state.genesis_validators_root)
     signing_root = compute_signing_root(address_change, domain)
     assert bls.Verify(address_change.from_bls_pubkey, signing_root, signed_address_change.signature)
 

specs/capella/p2p-interface.md

@@ -61,6 +61,8 @@ This topic is used to propagate signed bls to execution change messages to be in
 
 The following validations MUST pass before forwarding the `signed_bls_to_execution_change` on the network:
 
+- _[IGNORE]_ `current_epoch >= CAPELLA_FORK_EPOCH`,
+  where `current_epoch` is defined by the current wall-clock time.
 - _[IGNORE]_ The `signed_bls_to_execution_change` is the first valid signed bls to execution change received
   for the validator with index `signed_bls_to_execution_change.message.validator_index`.
 - _[REJECT]_ All of the conditions within `process_bls_to_execution_change` pass validation.

tests/core/pyspec/eth2spec/test/capella/block_processing/test_process_bls_to_execution_change.py

@@ -177,16 +177,21 @@ def test_invalid_bad_signature(spec, state):
 @with_capella_and_later
 @spec_state_test
 @always_bls
-def test_current_fork_version(spec, state):
-    """
-    It should be identical to the `test_success` test case.
-    It is just for comparing with `test_invalid_previous_fork_version`.
-    """
-    signed_address_change = get_signed_address_change(spec, state, fork_version=state.fork.current_version)
+def test_genesis_fork_version(spec, state):
+    signed_address_change = get_signed_address_change(spec, state, fork_version=spec.config.GENESIS_FORK_VERSION)
 
     yield from run_bls_to_execution_change_processing(spec, state, signed_address_change)
 
 
+@with_capella_and_later
+@spec_state_test
+@always_bls
+def test_invalid_current_fork_version(spec, state):
+    signed_address_change = get_signed_address_change(spec, state, fork_version=state.fork.current_version)
+
+    yield from run_bls_to_execution_change_processing(spec, state, signed_address_change, valid=False)
+
+
 @with_capella_and_later
 @spec_state_test
 @always_bls
@@ -194,3 +199,12 @@ def test_invalid_previous_fork_version(spec, state):
     signed_address_change = get_signed_address_change(spec, state, fork_version=state.fork.previous_version)
 
     yield from run_bls_to_execution_change_processing(spec, state, signed_address_change, valid=False)
+
+
+@with_capella_and_later
+@spec_state_test
+@always_bls
+def test_invalid_genesis_validators_root(spec, state):
+    signed_address_change = get_signed_address_change(spec, state, genesis_validators_root=b'\x99' * 32)
+
+    yield from run_bls_to_execution_change_processing(spec, state, signed_address_change, valid=False)

tests/core/pyspec/eth2spec/test/helpers/bls_to_execution_changes.py

@@ -2,8 +2,12 @@ from eth2spec.utils import bls
 from eth2spec.test.helpers.keys import pubkeys, privkeys, pubkey_to_privkey
 
 
-def get_signed_address_change(spec, state, validator_index=None, withdrawal_pubkey=None, to_execution_address=None,
-                              fork_version=None):
+def get_signed_address_change(spec, state,
+                              validator_index=None,
+                              withdrawal_pubkey=None,
+                              to_execution_address=None,
+                              fork_version=None,
+                              genesis_validators_root=None):
     if validator_index is None:
         validator_index = 0
 
@@ -17,10 +21,14 @@ def get_signed_address_change(spec, state, validator_index=None, withdrawal_pubk
     if to_execution_address is None:
         to_execution_address = b'\x42' * 20
 
-    if fork_version is None:
-        domain = spec.get_domain(state, spec.DOMAIN_BLS_TO_EXECUTION_CHANGE)
-    else:
-        domain = spec.compute_domain(spec.DOMAIN_BLS_TO_EXECUTION_CHANGE, fork_version, state.genesis_validators_root)
+    if genesis_validators_root is None:
+        genesis_validators_root = state.genesis_validators_root
+
+    domain = spec.compute_domain(
+        spec.DOMAIN_BLS_TO_EXECUTION_CHANGE,
+        fork_version=fork_version,
+        genesis_validators_root=genesis_validators_root,
+    )
 
     address_change = spec.BLSToExecutionChange(
         validator_index=validator_index,