go-ethereum/core/vm/contracts.libevm_test.go
Arran Schlosberg 38eaaab96c
feat!: RulesHooks.CanCreateContract() accepts and returns gas (#28)
* refactor!: `RulesHooks.CanCreateContract()` via `defer`

`TestCanCreateContract` is unchanged and merely moved to the appropriate file.

* feat!: `RulesHooks.CanCreateContract()` accepts and returns gas

* chore: move `TestCanCreateContract` to original file

Simplifies code review

* chore: pacify linter

* refactor!: revert to non-deferred call (not at start)
2024-09-17 12:14:17 -04:00

354 lines
10 KiB
Go

package vm_test
import (
"fmt"
"math/big"
"testing"
"github.com/holiman/uint256"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
"golang.org/x/exp/rand"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/vm"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/libevm"
"github.com/ethereum/go-ethereum/libevm/ethtest"
"github.com/ethereum/go-ethereum/libevm/hookstest"
"github.com/ethereum/go-ethereum/params"
)
type precompileStub struct {
requiredGas uint64
returnData []byte
}
func (s *precompileStub) RequiredGas([]byte) uint64 { return s.requiredGas }
func (s *precompileStub) Run([]byte) ([]byte, error) { return s.returnData, nil }
func TestPrecompileOverride(t *testing.T) {
type test struct {
name string
addr common.Address
requiredGas uint64
stubData []byte
}
const gasLimit = uint64(1e7)
tests := []test{
{
name: "arbitrary values",
addr: common.Address{'p', 'r', 'e', 'c', 'o', 'm', 'p', 'i', 'l', 'e'},
requiredGas: 314159,
stubData: []byte("the return data"),
},
}
rng := rand.New(rand.NewSource(42))
for _, addr := range vm.PrecompiledAddressesCancun {
tests = append(tests, test{
name: fmt.Sprintf("existing precompile %v", addr),
addr: addr,
requiredGas: rng.Uint64n(gasLimit),
stubData: addr[:],
})
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
hooks := &hookstest.Stub{
PrecompileOverrides: map[common.Address]libevm.PrecompiledContract{
tt.addr: &precompileStub{
requiredGas: tt.requiredGas,
returnData: tt.stubData,
},
},
}
hooks.Register(t)
t.Run(fmt.Sprintf("%T.Call([overridden precompile address = %v])", &vm.EVM{}, tt.addr), func(t *testing.T) {
_, evm := ethtest.NewZeroEVM(t)
gotData, gotGasLeft, err := evm.Call(vm.AccountRef{}, tt.addr, nil, gasLimit, uint256.NewInt(0))
require.NoError(t, err)
assert.Equal(t, tt.stubData, gotData, "contract's return data")
assert.Equal(t, gasLimit-tt.requiredGas, gotGasLeft, "gas left")
})
})
}
}
func TestNewStatefulPrecompile(t *testing.T) {
rng := ethtest.NewPseudoRand(314159)
precompile := rng.Address()
slot := rng.Hash()
const gasLimit = 1e6
gasCost := rng.Uint64n(gasLimit)
makeOutput := func(caller, self common.Address, input []byte, stateVal common.Hash, readOnly bool) []byte {
return []byte(fmt.Sprintf(
"Caller: %v Precompile: %v State: %v Read-only: %t, Input: %#x",
caller, self, stateVal, readOnly, input,
))
}
run := func(env vm.PrecompileEnvironment, input []byte) ([]byte, error) {
if got, want := env.StateDB() != nil, !env.ReadOnly(); got != want {
return nil, fmt.Errorf("PrecompileEnvironment().StateDB() must be non-nil i.f.f. not read-only; got non-nil? %t; want %t", got, want)
}
addrs := env.Addresses()
val := env.ReadOnlyState().GetState(precompile, slot)
return makeOutput(addrs.Caller, addrs.Self, input, val, env.ReadOnly()), nil
}
hooks := &hookstest.Stub{
PrecompileOverrides: map[common.Address]libevm.PrecompiledContract{
precompile: vm.NewStatefulPrecompile(
run,
func(b []byte) uint64 {
return gasCost
},
),
},
}
hooks.Register(t)
caller := rng.Address()
input := rng.Bytes(8)
value := rng.Hash()
state, evm := ethtest.NewZeroEVM(t)
state.SetState(precompile, slot, value)
tests := []struct {
name string
call func() ([]byte, uint64, error)
// Note that this only covers evm.readWrite being set to forceReadOnly,
// via StaticCall(). See TestInheritReadOnly for alternate case.
wantReadOnly bool
}{
{
name: "EVM.Call()",
call: func() ([]byte, uint64, error) {
return evm.Call(vm.AccountRef(caller), precompile, input, gasLimit, uint256.NewInt(0))
},
wantReadOnly: false,
},
{
name: "EVM.CallCode()",
call: func() ([]byte, uint64, error) {
return evm.CallCode(vm.AccountRef(caller), precompile, input, gasLimit, uint256.NewInt(0))
},
wantReadOnly: false,
},
{
name: "EVM.DelegateCall()",
call: func() ([]byte, uint64, error) {
return evm.DelegateCall(vm.AccountRef(caller), precompile, input, gasLimit)
},
wantReadOnly: false,
},
{
name: "EVM.StaticCall()",
call: func() ([]byte, uint64, error) {
return evm.StaticCall(vm.AccountRef(caller), precompile, input, gasLimit)
},
wantReadOnly: true,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
wantReturnData := makeOutput(caller, precompile, input, value, tt.wantReadOnly)
wantGasLeft := gasLimit - gasCost
gotReturnData, gotGasLeft, err := tt.call()
require.NoError(t, err)
assert.Equal(t, string(wantReturnData), string(gotReturnData))
assert.Equal(t, wantGasLeft, gotGasLeft)
})
}
}
func TestInheritReadOnly(t *testing.T) {
// The regular test of stateful precompiles only checks the read-only state
// when called directly via vm.EVM.*Call*() methods. That approach will not
// result in a read-only state via inheritance, which occurs when already in
// a read-only environment there is a non-static call to a precompile.
//
// Test strategy:
//
// 1. Create a precompile that echoes its read-only status in the return
// data. We MUST NOT assert inside the precompile as we need proof that
// the precompile was actually called.
//
// 2. Create a bytecode contract that calls the precompile with CALL and
// propagates the return data. Using CALL (i.e. not STATICCALL) means
// that we know for certain that [forceReadOnly] isn't being used and,
// instead, the read-only state is being read from
// evm.interpreter.readOnly.
//
// 3. Assert that the returned input is as expected for the read-only state.
// (1)
var precompile common.Address
const precompileAddr = 255
precompile[common.AddressLength-1] = precompileAddr
const (
ifReadOnly = iota + 1 // see contract bytecode for rationale
ifNotReadOnly
)
hooks := &hookstest.Stub{
PrecompileOverrides: map[common.Address]libevm.PrecompiledContract{
precompile: vm.NewStatefulPrecompile(
func(env vm.PrecompileEnvironment, input []byte) ([]byte, error) {
if env.ReadOnly() {
return []byte{ifReadOnly}, nil
}
return []byte{ifNotReadOnly}, nil
},
func([]byte) uint64 { return 0 },
),
},
}
hookstest.Register(t, params.Extras[*hookstest.Stub, *hookstest.Stub]{
NewRules: func(_ *params.ChainConfig, r *params.Rules, _ *hookstest.Stub, blockNum *big.Int, isMerge bool, timestamp uint64) *hookstest.Stub {
r.IsCancun = true // enable PUSH0
return hooks
},
})
// (2)
// See CALL signature: https://www.evm.codes/#f1?fork=cancun
const p0 = vm.PUSH0
contract := []vm.OpCode{
vm.PUSH1, 1, // retSize (bytes)
p0, // retOffset
p0, // argSize
p0, // argOffset
p0, // value
vm.PUSH1, precompileAddr,
p0, // gas
vm.CALL,
// It's ok to ignore the return status. If the CALL failed then we'll
// return []byte{0} next, and both non-failure return buffers are
// non-zero because of the `iota + 1`.
vm.PUSH1, 1, // size (byte)
p0,
vm.RETURN,
}
state, evm := ethtest.NewZeroEVM(t)
rng := ethtest.NewPseudoRand(42)
contractAddr := rng.Address()
state.CreateAccount(contractAddr)
state.SetCode(contractAddr, contractCode(contract))
// (3)
caller := vm.AccountRef(rng.Address())
tests := []struct {
name string
call func() ([]byte, uint64, error)
want byte
}{
{
name: "EVM.Call()",
call: func() ([]byte, uint64, error) {
return evm.Call(caller, contractAddr, []byte{}, 1e6, uint256.NewInt(0))
},
want: ifNotReadOnly,
},
{
name: "EVM.StaticCall()",
call: func() ([]byte, uint64, error) {
return evm.StaticCall(vm.AccountRef(rng.Address()), contractAddr, []byte{}, 1e6)
},
want: ifReadOnly,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
got, _, err := tt.call()
require.NoError(t, err)
require.Equalf(t, []byte{tt.want}, got, "want %d if read-only, otherwise %d", ifReadOnly, ifNotReadOnly)
})
}
}
// contractCode converts a slice of op codes into a byte buffer for storage as
// contract code.
func contractCode(ops []vm.OpCode) []byte {
ret := make([]byte, len(ops))
for i, o := range ops {
ret[i] = byte(o)
}
return ret
}
func TestCanCreateContract(t *testing.T) {
rng := ethtest.NewPseudoRand(142857)
account := rng.Address()
slot := rng.Hash()
const gasLimit uint64 = 1e6
gasUsage := rng.Uint64n(gasLimit)
makeErr := func(cc *libevm.AddressContext, stateVal common.Hash) error {
return fmt.Errorf("Origin: %v Caller: %v Contract: %v State: %v", cc.Origin, cc.Caller, cc.Self, stateVal)
}
hooks := &hookstest.Stub{
CanCreateContractFn: func(cc *libevm.AddressContext, gas uint64, s libevm.StateReader) (uint64, error) {
return gas - gasUsage, makeErr(cc, s.GetState(account, slot))
},
}
hooks.Register(t)
origin := rng.Address()
caller := rng.Address()
value := rng.Hash()
code := []byte{byte(vm.STOP)}
salt := rng.Hash()
create := crypto.CreateAddress(caller, 0)
create2 := crypto.CreateAddress2(caller, salt, crypto.Keccak256(code))
tests := []struct {
name string
create func(*vm.EVM) ([]byte, common.Address, uint64, error)
wantErr error
}{
{
name: "Create",
create: func(evm *vm.EVM) ([]byte, common.Address, uint64, error) {
return evm.Create(vm.AccountRef(caller), code, gasLimit, uint256.NewInt(0))
},
wantErr: makeErr(&libevm.AddressContext{Origin: origin, Caller: caller, Self: create}, value),
},
{
name: "Create2",
create: func(evm *vm.EVM) ([]byte, common.Address, uint64, error) {
return evm.Create2(vm.AccountRef(caller), code, gasLimit, uint256.NewInt(0), new(uint256.Int).SetBytes(salt[:]))
},
wantErr: makeErr(&libevm.AddressContext{Origin: origin, Caller: caller, Self: create2}, value),
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
state, evm := ethtest.NewZeroEVM(t)
state.SetState(account, slot, value)
evm.TxContext.Origin = origin
_, _, gasRemaining, err := tt.create(evm)
require.EqualError(t, err, tt.wantErr.Error())
// require prints uint64s in hex
require.Equal(t, int(gasLimit-gasUsage), int(gasRemaining), "gas remaining") //nolint:gosec // G115 won't overflow as <= 1e6
})
}
}