new(tests): EOF - EIP-7069: RETURNDATACOPY mem expansion and copy OOG (…

…#671)

* new(tests): RETURNDATACOPY mem expansion and copy oog (EOF)

* Address review comments

---------

Co-authored-by: Andrei Maiboroda <[email protected]>

tests/prague/eip7692_eof_v1/eip7069_extcall/test_returndatacopy_memory_expansion.py

@@ -0,0 +1,271 @@
+"""
+Memory expansion tests for RETURNDATACOPY executing in EOF code
+"""
+
+from typing import Mapping, Tuple
+
+import pytest
+
+from ethereum_test_tools import Account, Address, Alloc, Bytecode, Environment
+from ethereum_test_tools import Opcodes as Op
+from ethereum_test_tools import StateTestFiller, Storage, Transaction, cost_memory_bytes
+from ethereum_test_tools.eof.v1 import Container
+
+from .. import EOF_FORK_NAME
+
+REFERENCE_SPEC_GIT_PATH = "EIPS/eip-7069.md"
+REFERENCE_SPEC_VERSION = "e469fd6c8d736b2a3e1ce632263e3ad36fc8624d"
+
+pytestmark = pytest.mark.valid_from(EOF_FORK_NAME)
+
+
+@pytest.fixture
+def callee_bytecode(dest: int, src: int, length: int) -> Container:
+    """
+    Callee performs a single returndatacopy operation and then returns.
+    """
+    bytecode = Bytecode()
+
+    # Copy the initial memory
+    bytecode += Op.CALLDATACOPY(0x00, 0x00, Op.CALLDATASIZE())
+
+    # Pushes for the return operation
+    bytecode += Op.PUSH1(0x00) + Op.PUSH1(0x00)
+
+    # Perform the returndatacopy operation
+    bytecode += Op.RETURNDATACOPY(dest, src, length)
+
+    bytecode += Op.RETURN
+
+    return Container.Code(code=bytecode)
+
+
+@pytest.fixture
+def subcall_exact_cost(
+    initial_memory: bytes,
+    dest: int,
+    length: int,
+) -> int:
+    """
+    Returns the exact cost of the subcall, based on the initial memory and the length of the copy.
+    """
+    returndatacopy_cost = 3
+    returndatacopy_cost += 3 * ((length + 31) // 32)
+    if length > 0 and dest + length > len(initial_memory):
+        returndatacopy_cost += cost_memory_bytes(dest + length, len(initial_memory))
+
+    calldatacopy_cost = 3
+    calldatacopy_cost += 3 * ((len(initial_memory) + 31) // 32)
+    calldatacopy_cost += cost_memory_bytes(len(initial_memory), 0)
+
+    pushes_cost = 3 * 7
+    calldatasize_cost = 2
+    return returndatacopy_cost + calldatacopy_cost + pushes_cost + calldatasize_cost
+
+
+@pytest.fixture
+def bytecode_storage(
+    subcall_exact_cost: int,
+    successful: bool,
+    memory_expansion_address: Address,
+) -> Tuple[Bytecode, Storage.StorageDictType]:
+    """
+    Prepares the bytecode and storage for the test, based on the expected result of the subcall
+    (whether it succeeds or fails depending on the length of the memory expansion).
+    """
+    bytecode = Bytecode()
+    storage = {}
+
+    # Pass on the calldata
+    bytecode += Op.CALLDATACOPY(0x00, 0x00, Op.CALLDATASIZE())
+
+    subcall_gas = subcall_exact_cost if successful else subcall_exact_cost - 1
+
+    # Perform the subcall and store a one in the result location
+    bytecode += Op.SSTORE(
+        Op.CALL(subcall_gas, memory_expansion_address, 0, 0, Op.CALLDATASIZE(), 0, 0), 1
+    )
+    storage[int(successful)] = 1
+
+    return (bytecode, storage)
+
+
+@pytest.fixture
+def tx_max_fee_per_gas() -> int:  # noqa: D103
+    return 7
+
+
+@pytest.fixture
+def block_gas_limit() -> int:  # noqa: D103
+    return 100_000_000
+
+
+@pytest.fixture
+def tx_gas_limit(  # noqa: D103
+    subcall_exact_cost: int,
+    block_gas_limit: int,
+) -> int:
+    return min(max(500_000, subcall_exact_cost * 2), block_gas_limit)
+
+
+@pytest.fixture
+def env(  # noqa: D103
+    block_gas_limit: int,
+) -> Environment:
+    return Environment(gas_limit=block_gas_limit)
+
+
+@pytest.fixture
+def caller_address(  # noqa: D103
+    pre: Alloc, bytecode_storage: Tuple[bytes, Storage.StorageDictType]
+) -> Address:
+    return pre.deploy_contract(code=bytecode_storage[0])
+
+
+@pytest.fixture
+def memory_expansion_address(pre: Alloc, callee_bytecode: bytes) -> Address:  # noqa: D103
+    return pre.deploy_contract(code=callee_bytecode)
+
+
+@pytest.fixture
+def sender(pre: Alloc, tx_max_fee_per_gas: int, tx_gas_limit: int) -> Address:  # noqa: D103
+    return pre.fund_eoa(tx_max_fee_per_gas * tx_gas_limit)
+
+
+@pytest.fixture
+def tx(  # noqa: D103
+    sender: Address,
+    caller_address: Address,
+    initial_memory: bytes,
+    tx_max_fee_per_gas: int,
+    tx_gas_limit: int,
+) -> Transaction:
+    return Transaction(
+        sender=sender,
+        to=caller_address,
+        data=initial_memory,
+        gas_limit=tx_gas_limit,
+        max_fee_per_gas=tx_max_fee_per_gas,
+        max_priority_fee_per_gas=0,
+    )
+
+
+@pytest.fixture
+def post(  # noqa: D103
+    caller_address: Address, bytecode_storage: Tuple[bytes, Storage.StorageDictType]
+) -> Mapping:
+    return {
+        caller_address: Account(storage=bytecode_storage[1]),
+    }
+
+
+@pytest.mark.parametrize(
+    "dest,src,length",
+    [
+        (0x00, 0x00, 0x01),
+        (0x100, 0x00, 0x01),
+        (0x1F, 0x00, 0x01),
+        (0x20, 0x00, 0x01),
+        (0x1000, 0x00, 0x01),
+        (0x1000, 0x00, 0x40),
+        (0x00, 0x00, 0x00),
+        (2**256 - 1, 0x00, 0x00),
+        (0x00, 2**256 - 1, 0x00),
+        (2**256 - 1, 2**256 - 1, 0x00),
+    ],
+    ids=[
+        "single_byte_expansion",
+        "single_byte_expansion_2",
+        "single_byte_expansion_word_boundary",
+        "single_byte_expansion_word_boundary_2",
+        "multi_word_expansion",
+        "multi_word_expansion_2",
+        "zero_length_expansion",
+        "huge_dest_zero_length",
+        "huge_src_zero_length",
+        "huge_dest_huge_src_zero_length",
+    ],
+)
+@pytest.mark.parametrize("successful", [True, False])
+@pytest.mark.parametrize(
+    "initial_memory",
+    [
+        bytes(range(0x00, 0x100)),
+        bytes(),
+    ],
+    ids=[
+        "from_existent_memory",
+        "from_empty_memory",
+    ],
+)
+def test_returndatacopy_memory_expansion(
+    state_test: StateTestFiller,
+    env: Environment,
+    pre: Alloc,
+    post: Mapping[str, Account],
+    tx: Transaction,
+):
+    """
+    Perform RETURNDATACOPY operations that expand the memory, and verify the gas it costs to do so.
+    """
+    state_test(
+        env=env,
+        pre=pre,
+        post=post,
+        tx=tx,
+    )
+
+
+@pytest.mark.parametrize(
+    "dest,src,length",
+    [
+        (2**256 - 1, 0x00, 0x01),
+        (2**256 - 2, 0x00, 0x01),
+        (2**255 - 1, 0x00, 0x01),
+        (0x00, 0x00, 2**256 - 1),
+        (0x00, 0x00, 2**256 - 2),
+        (0x00, 0x00, 2**255 - 1),
+    ],
+    ids=[
+        "max_dest_single_byte_expansion",
+        "max_dest_minus_one_single_byte_expansion",
+        "half_max_dest_single_byte_expansion",
+        "max_length_expansion",
+        "max_length_minus_one_expansion",
+        "half_max_length_expansion",
+    ],
+)
+@pytest.mark.parametrize(
+    "subcall_exact_cost",
+    [2**128 - 1],
+    ids=[""],
+)  # Limit subcall gas, otherwise it would be impossibly large
+@pytest.mark.parametrize("successful", [False])
+@pytest.mark.parametrize(
+    "initial_memory",
+    [
+        bytes(range(0x00, 0x100)),
+        bytes(),
+    ],
+    ids=[
+        "from_existent_memory",
+        "from_empty_memory",
+    ],
+)
+def test_returndatacopy_huge_memory_expansion(
+    state_test: StateTestFiller,
+    env: Environment,
+    pre: Mapping[str, Account],
+    post: Mapping[str, Account],
+    tx: Transaction,
+):
+    """
+    Perform RETURNDATACOPY operations that expand the memory by huge amounts, and verify that it
+    correctly runs out of gas.
+    """
+    state_test(
+        env=env,
+        pre=pre,
+        post=post,
+        tx=tx,
+    )