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1133 | @pytest.mark.parametrize(
"opcode",
[
Op.EXTCALL,
Op.EXTDELEGATECALL,
Op.EXTSTATICCALL,
],
)
def test_eof_calls_msg_depth(
state_test: StateTestFiller,
pre: Alloc,
sender: EOA,
opcode: Op,
):
"""
Test EOF contracts calls handle msg depth limit correctly (1024).
NOTE: due to block gas limit and the 63/64th rule this limit is unlikely to be hit
on mainnet.
"""
# Not a precise gas_limit formula, but enough to exclude risk of gas causing the failure.
gas_limit = int(200000 * (64 / 63) ** 1024)
env = Environment(gas_limit=gas_limit)
# Flow of the test:
# `callee_code` is recursively calling itself, passing msg depth as calldata
# (kept with the `MSTORE(0, ADD(...))`). When maximum msg depth is reached
# the call fails and starts returning. The deep-most frame returns:
# - current reached msg depth (expected to be the maximum 1024), with the
# `MSTORE(32, ADD(...))`
# - the respective return code of the EXT*CALL (expected to be 1 - light failure), with the
# `MSTORE(64, NOOP)`. Note the `NOOP` is just to appease the `Op.MSTORE` call, the return
# code value is actually coming from the `Op.DUP1`
# When unwinding the msg call stack, the intermediate frames return whatever the deeper callee
# returned with the `RETURNDATACOPY` instruction.
# Memory offsets layout:
# - 0 - input - msg depth
# - 32 - output - msg depth
# - 64 - output - call result
returndatacopy_block = Op.RETURNDATACOPY(32, 0, 64) + Op.RETURN(32, 64)
deep_most_result_block = (
Op.MSTORE(32, Op.ADD(Op.CALLDATALOAD(0), 1)) + Op.MSTORE(64, Op.NOOP) + Op.RETURN(32, 64)
)
rjump_offset = len(returndatacopy_block)
callee_code = Container.Code(
# current stack depth in memory bytes 0-31
Op.MSTORE(0, Op.ADD(Op.CALLDATALOAD(0), 1))
# pass it along deeper as calldata
+ opcode(address=Op.ADDRESS, args_size=32)
# duplicate return code for the `returndatacopy_block` below
+ Op.DUP1
# if return code was:
# - 1, we're in the deep-most frame, `deep_most_result_block` returns the actual result
# - 0, we're in an intermediate frame, `returndatacopy_block` only passes on the result
+ Op.RJUMPI[rjump_offset]
+ returndatacopy_block
+ deep_most_result_block
)
callee_address = pre.deploy_contract(callee_code)
calling_contract_address = pre.deploy_contract(
Container.Code(
Op.MSTORE(0, Op.CALLDATALOAD(0))
+ Op.EXTCALL(address=callee_address, args_size=32)
+ Op.SSTORE(slot_max_depth, Op.RETURNDATALOAD(0))
+ Op.SSTORE(slot_call_result, Op.RETURNDATALOAD(32))
+ Op.SSTORE(slot_code_worked, value_code_worked)
+ Op.STOP
)
)
tx = Transaction(
sender=sender,
to=calling_contract_address,
gas_limit=gas_limit,
)
calling_storage = {
slot_max_depth: 1024,
slot_code_worked: value_code_worked,
slot_call_result: EXTCALL_REVERT,
}
post = {
calling_contract_address: Account(storage=calling_storage),
}
state_test(
env=env,
pre=pre,
post=post,
tx=tx,
)
|