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zkvm: allow using entire gas in bytecode attack #1575

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Merged
merged 3 commits into from
May 14, 2025
Merged

zkvm: allow using entire gas in bytecode attack #1575

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4056c73
zkvm: full bytecode attack enabling
jsign May 13, 2025
b2f4b2f
set gas limit in ci
jsign May 14, 2025
388276b
add slow mark
jsign May 14, 2025
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4 changes: 2 additions & 2 deletions .github/configs/feature.yaml
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Original file line number Diff line number Diff line change
Expand Up @@ -13,12 +13,12 @@ static:
solc: 0.8.21
zkevm:
evm-type: zkevm
fill-params: --from=Cancun --until=Prague -m zkevm ./tests
fill-params: --from=Cancun --until=Prague --block-gas-limit 36000000 -m zkevm ./tests
solc: 0.8.21
feature_only: true
eip7692:
evm-type: eip7692
fill-params: --fork=EOFv1 ./tests/unscheduled
solc: 0.8.21
eofwrap: true
feature_only: true
feature_only: true
27 changes: 17 additions & 10 deletions tests/zkevm/test_worst_bytecode.py
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Original file line number Diff line number Diff line change
Expand Up @@ -27,9 +27,6 @@
REFERENCE_SPEC_VERSION = "TODO"

MAX_CONTRACT_SIZE = 24 * 1024 # TODO: This could be a fork property
BLOCK_GAS_LIMIT = 36_000_000 # TODO: Parametrize using the (yet to be implemented) block gas limit
# OPCODE_GAS_LIMIT = BLOCK_GAS_LIMIT # TODO: Reduced in order to run the test in a reasonable time
OPCODE_GAS_LIMIT = 100_000

XOR_TABLE_SIZE = 256
XOR_TABLE = [Hash(i).sha256() for i in range(XOR_TABLE_SIZE)]
Expand All @@ -41,12 +38,20 @@
Op.EXTCODESIZE,
],
)
@pytest.mark.parametrize(
"attack_gas_limit",
[
Environment().gas_limit,
],
)
@pytest.mark.slow()
@pytest.mark.valid_from("Cancun")
def test_worst_bytecode_single_opcode(
blockchain_test: BlockchainTestFiller,
pre: Alloc,
fork: Fork,
opcode: Op,
attack_gas_limit: int,
):
"""
Test a block execution where a single opcode execution maxes out the gas limit,
Expand All @@ -60,7 +65,9 @@ def test_worst_bytecode_single_opcode(
The test is performed in the last block of the test, and the entire block gas limit is
consumed by repeated opcode executions.
"""
env = Environment(gas_limit=BLOCK_GAS_LIMIT)
# We use 100G gas limit to be able to deploy a large number of contracts in a single block,
# avoiding bloating the number of preparing blocks in the test.
env = Environment(gas_limit=100_000_000_000)

# The initcode will take its address as a starting point to the input to the keccak
# hash function.
Expand Down Expand Up @@ -126,19 +133,19 @@ def test_worst_bytecode_single_opcode(
)
max_number_of_contract_calls = (
# Base available gas = GAS_LIMIT - intrinsic - (out of loop MSTOREs)
OPCODE_GAS_LIMIT - intrinsic_gas_cost_calc() - gas_costs.G_VERY_LOW * 4
attack_gas_limit - intrinsic_gas_cost_calc() - gas_costs.G_VERY_LOW * 4
) // loop_cost

total_contracts_to_deploy = max_number_of_contract_calls
approximate_gas_per_deployment = 4_970_000 # Obtained from evm tracing
contracts_deployed_per_tx = BLOCK_GAS_LIMIT // approximate_gas_per_deployment
contracts_deployed_per_tx = env.gas_limit // approximate_gas_per_deployment

deploy_txs = []

def generate_deploy_tx(contracts_to_deploy: int):
return Transaction(
to=factory_caller_address,
gas_limit=BLOCK_GAS_LIMIT,
gas_limit=env.gas_limit,
gas_price=10**9, # Bump required due to the amount of full blocks
data=Hash(contracts_deployed_per_tx),
sender=pre.fund_eoa(),
Expand Down Expand Up @@ -171,8 +178,7 @@ def generate_deploy_tx(contracts_to_deploy: int):
+ Op.MSTORE(64, initcode.keccak256())
# Main loop
+ While(
body=Op.POP(Op.EXTCODESIZE(Op.SHA3(32 - 20 - 1, 85)))
+ Op.MSTORE(32, Op.ADD(Op.MLOAD(32), 1)),
body=Op.POP(opcode(Op.SHA3(32 - 20 - 1, 85))) + Op.MSTORE(32, Op.ADD(Op.MLOAD(32), 1)),
)
)

Expand All @@ -185,7 +191,7 @@ def generate_deploy_tx(contracts_to_deploy: int):
opcode_address = pre.deploy_contract(code=opcode_code)
opcode_tx = Transaction(
to=opcode_address,
gas_limit=OPCODE_GAS_LIMIT,
gas_limit=attack_gas_limit,
gas_price=10**9, # Bump required due to the amount of full blocks
sender=pre.fund_eoa(),
)
Expand All @@ -198,4 +204,5 @@ def generate_deploy_tx(contracts_to_deploy: int):
*[Block(txs=[deploy_tx]) for deploy_tx in deploy_txs],
Block(txs=[opcode_tx]),
],
exclude_full_post_state_in_output=True,
)
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