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Record witness access in EXTCODEHASH #370

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merged 4 commits into from
Feb 15, 2024
Merged

Record witness access in EXTCODEHASH #370

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77c4345
instructions: add access witness recording for EXTCODEHASH
jsign Feb 8, 2024
c977e63
add test for EXTCODEHASH witness recording
jsign Feb 8, 2024
92fadfe
add test for access witness EXTCODEHASH
jsign Feb 8, 2024
e400860
do not touch version
jsign Feb 9, 2024
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133 changes: 133 additions & 0 deletions core/state_processor_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -37,6 +37,7 @@ import (
"github.com/ethereum/go-ethereum/core/vm"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/params"
"github.com/ethereum/go-ethereum/trie/utils"

//"github.com/ethereum/go-ethereum/rlp"
"github.com/ethereum/go-ethereum/trie"
Expand Down Expand Up @@ -794,3 +795,135 @@ func TestProcessVerkleContractWithEmptyCode(t *testing.T) {
}
}
}

func TestProcessVerklExtCodeHashOpcode(t *testing.T) {
var (
config = &params.ChainConfig{
ChainID: big.NewInt(69421),
HomesteadBlock: big.NewInt(0),
EIP150Block: big.NewInt(0),
EIP155Block: big.NewInt(0),
EIP158Block: big.NewInt(0),
ByzantiumBlock: big.NewInt(0),
ConstantinopleBlock: big.NewInt(0),
PetersburgBlock: big.NewInt(0),
IstanbulBlock: big.NewInt(0),
MuirGlacierBlock: big.NewInt(0),
BerlinBlock: big.NewInt(0),
LondonBlock: big.NewInt(0),
Ethash: new(params.EthashConfig),
ShanghaiTime: u64(0),
PragueTime: u64(0),
TerminalTotalDifficulty: common.Big0,
TerminalTotalDifficultyPassed: true,
ProofInBlocks: true,
}
signer = types.LatestSigner(config)
testKey, _ = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
bcdb = rawdb.NewMemoryDatabase() // Database for the blockchain
gendb = rawdb.NewMemoryDatabase() // Database for the block-generation code, they must be separate as they are path-based.
coinbase = common.HexToAddress("0x71562b71999873DB5b286dF957af199Ec94617F7")
account1 = common.HexToAddress("0x687704DB07e902e9A8B3754031D168D46E3D586e")
account2 = common.HexToAddress("0x6177843db3138ae69679A54b95cf345ED759450d")
gspec = &Genesis{
Config: config,
Alloc: GenesisAlloc{
coinbase: GenesisAccount{
Balance: big.NewInt(1000000000000000000), // 1 ether
Nonce: 0,
},
account1: GenesisAccount{
Balance: big.NewInt(1000000000000000000), // 1 ether
Nonce: 0,
},
account2: GenesisAccount{
Balance: big.NewInt(1000000000000000000), // 1 ether
Nonce: 3,
},
},
}
)
// Verkle trees use the snapshot, which must be enabled before the
// data is saved into the tree+database.
genesis := gspec.MustCommit(bcdb)

// Commit the genesis block to the block-generation database as it
// is now independent of the blockchain database.
gspec.MustCommit(gendb)

dummyContract := []byte{
0x60, 2, // PUSH1 2
0x60, 12, // PUSH1 12
0x60, 0x00, // PUSH1 0
0x39, // CODECOPY

0x60, 2, // PUSH1 2
0x60, 0x00, // PUSH1 0
0xF3, // RETURN

// Contract that auto-calls EXTCODEHASH
0x60, 42, // PUSH1 42
}
Comment on lines +854 to +866
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Deploy dummyContract so we have some contract to use EXTCODEHASH later.

dummyContractAddr := common.HexToAddress("3a220f351252089d385b29beca14e27f204c296a")
extCodeHashContract := []byte{
0x60, 22, // PUSH1 22
0x60, 12, // PUSH1 12
0x60, 0x00, // PUSH1 0
0x39, // CODECOPY

0x60, 22, // PUSH1 22
0x60, 0x00, // PUSH1 0
0xF3, // RETURN

// Contract that auto-calls EXTCODEHASH
0x73, // PUSH20
0x3a, 0x22, 0x0f, 0x35, 0x12, 0x52, 0x08, 0x9d, 0x38, 0x5b, 0x29, 0xbe, 0xca, 0x14, 0xe2, 0x7f, 0x20, 0x4c, 0x29, 0x6a,
0x3F, // EXTCODEHASH
}
Comment on lines +868 to +882
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Deploy another contract that actually makes the EXTCODEHASH to the previously deployed contract.

This was required to be super clear about witness checks. Initially, I made the dummy contract "auto call" EXTCODEHASH, but then is hard to distinguish why the witness have the contract code hash (e.g: from deployment or from EXTCODEHASH exec).

extCodeHashContractAddr := common.HexToAddress("db7d6ab1f17c6b31909ae466702703daef9269cf")
_, _, _, statediff := GenerateVerkleChain(gspec.Config, genesis, beacon.New(ethash.NewFaker()), gendb, 2, func(i int, gen *BlockGen) {
gen.SetPoS()

if i == 0 {
// Create dummy contract.
tx, _ := types.SignTx(types.NewContractCreation(0, big.NewInt(0), 100_000, big.NewInt(875000000), dummyContract), signer, testKey)
gen.AddTx(tx)

// Create contract with EXTCODEHASH opcode.
tx, _ = types.SignTx(types.NewContractCreation(1, big.NewInt(0), 100_000, big.NewInt(875000000), extCodeHashContract), signer, testKey)
gen.AddTx(tx)
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In the first block deploy both contracts.

} else {
tx, _ := types.SignTx(types.NewTransaction(2, extCodeHashContractAddr, big.NewInt(0), 100_000, big.NewInt(875000000), nil), signer, testKey)
gen.AddTx(tx)
Comment on lines +896 to +897
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In the next block do the actual execution, so if the witness shows the contract code hash address then we know its' from EXTCODEHASH execution and not contract deployments.

}

})

contractKeccakTreeKey := utils.GetTreeKeyCodeKeccak(dummyContractAddr[:])

var stateDiffIdx = -1
for i, stemStateDiff := range statediff[1] {
if bytes.Equal(stemStateDiff.Stem[:], contractKeccakTreeKey[:31]) {
stateDiffIdx = i
break
}
}
if stateDiffIdx == -1 {
t.Fatalf("no state diff found for stem")
}

codeHashStateDiff := statediff[1][stateDiffIdx].SuffixDiffs[0]
if codeHashStateDiff.Suffix != utils.CodeKeccakLeafKey {
t.Fatalf("code hash invalid suffix")
}
if codeHashStateDiff.CurrentValue == nil {
t.Fatalf("codeHash.CurrentValue must not be empty")
}
expCodeHash := crypto.Keccak256Hash(dummyContract[12:])
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Avoiding magical hashes, so we know it's correct.

if *codeHashStateDiff.CurrentValue != expCodeHash {
t.Fatalf("codeHash.CurrentValue unexpected code hash")
}
if codeHashStateDiff.NewValue != nil {
t.Fatalf("codeHash.NewValue must be nil")
}
}
7 changes: 7 additions & 0 deletions core/vm/instructions.go
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Original file line number Diff line number Diff line change
Expand Up @@ -485,6 +485,13 @@ func opExtCodeCopy(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext)
func opExtCodeHash(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
slot := scope.Stack.peek()
address := common.Address(slot.Bytes20())
if interpreter.evm.chainRules.IsPrague {
statelessGas := interpreter.evm.Accesses.TouchAddressOnReadAndComputeGas(slot.Bytes(), uint256.Int{}, trieUtils.CodeKeccakLeafKey)
if !scope.Contract.UseGas(statelessGas) {
scope.Contract.Gas = 0
return nil, ErrOutOfGas
}
}
if interpreter.evm.StateDB.Empty(address) {
slot.Clear()
} else {
Expand Down
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