ensure random is validated for all payloads including transition

specs/merge/beacon-chain.md

@@ -298,12 +298,14 @@ def is_valid_gas_limit(payload: ExecutionPayload, parent: ExecutionPayloadHeader
 
 ```python
 def process_execution_payload(state: BeaconState, payload: ExecutionPayload, execution_engine: ExecutionEngine) -> None:
-    # Verify consistency of the parent hash, block number, random, base fee per gas and gas limit
+    # Verify consistency of the parent hash, block number, base fee per gas and gas limit
+    # with respect to the previous execution payload header
     if is_merge_complete(state):
         assert payload.parent_hash == state.latest_execution_payload_header.block_hash
         assert payload.block_number == state.latest_execution_payload_header.block_number + uint64(1)
-        assert payload.random == get_randao_mix(state, get_current_epoch(state))
         assert is_valid_gas_limit(payload, state.latest_execution_payload_header)
+    # Verify random
+    assert payload.random == get_randao_mix(state, get_current_epoch(state))
     # Verify timestamp
     assert payload.timestamp == compute_timestamp_at_slot(state, state.slot)
     # Verify the execution payload is valid

tests/core/pyspec/eth2spec/test/merge/block_processing/test_process_execution_payload.py

@@ -144,6 +144,34 @@ def test_bad_parent_hash_regular_payload(spec, state):
     yield from run_execution_payload_processing(spec, state, execution_payload, valid=False)
 
 
+@with_merge_and_later
+@spec_state_test
+def test_bad_random_first_payload(spec, state):
+    # pre-state
+    state = build_state_with_incomplete_transition(spec, state)
+    next_slot(spec, state)
+
+    # execution payload
+    execution_payload = build_empty_execution_payload(spec, state)
+    execution_payload.random = b'\x42' * 32
+
+    yield from run_execution_payload_processing(spec, state, execution_payload, valid=False)
+
+
+@with_merge_and_later
+@spec_state_test
+def test_bad_random_regular_payload(spec, state):
+    # pre-state
+    state = build_state_with_complete_transition(spec, state)
+    next_slot(spec, state)
+
+    # execution payload
+    execution_payload = build_empty_execution_payload(spec, state)
+    execution_payload.random = b'\x04' * 32
+
+    yield from run_execution_payload_processing(spec, state, execution_payload, valid=False)
+
+
 @with_merge_and_later
 @spec_state_test
 def test_bad_number_regular_payload(spec, state):