core/evm: RANDOM opcode (EIP-4399) (ethereum#24141)

* core: implement eip-4399 random opcode

* core: make vmconfig threadsafe

* core: miner: pass vmConfig by value not reference

* all: enable 4399 by Rules

* core: remove diff (f)

* tests: set proper difficulty (f)

* smaller diff (f)

* eth/catalyst: nit

* core: make RANDOM a pointer which is only set post-merge

* cmd/evm/internal/t8ntool: fix t8n tracing of 4399

* tests: set difficulty

* cmd/evm/internal/t8ntool: check that baserules are london before applying the merge chainrules

cmd/evm/internal/t8ntool/execution.go

@@ -67,6 +67,7 @@ type ommer struct {
 type stEnv struct {
 	Coinbase         common.Address                      `json:"currentCoinbase"   gencodec:"required"`
 	Difficulty       *big.Int                            `json:"currentDifficulty"`
+	Random           *big.Int                            `json:"currentRandom"`
 	ParentDifficulty *big.Int                            `json:"parentDifficulty"`
 	GasLimit         uint64                              `json:"currentGasLimit"   gencodec:"required"`
 	Number           uint64                              `json:"currentNumber"     gencodec:"required"`
@@ -81,6 +82,7 @@ type stEnv struct {
 type stEnvMarshaling struct {
 	Coinbase         common.UnprefixedAddress
 	Difficulty       *math.HexOrDecimal256
+	Random           *math.HexOrDecimal256
 	ParentDifficulty *math.HexOrDecimal256
 	GasLimit         math.HexOrDecimal64
 	Number           math.HexOrDecimal64
@@ -139,6 +141,11 @@ func (pre *Prestate) Apply(vmConfig vm.Config, chainConfig *params.ChainConfig,
 	if pre.Env.BaseFee != nil {
 		vmContext.BaseFee = new(big.Int).Set(pre.Env.BaseFee)
 	}
+	// If random is defined, add it to the vmContext.
+	if pre.Env.Random != nil {
+		rnd := common.BigToHash(pre.Env.Random)
+		vmContext.Random = &rnd
+	}
 	// If DAO is supported/enabled, we need to handle it here. In geth 'proper', it's
 	// done in StateProcessor.Process(block, ...), right before transactions are applied.
 	if chainConfig.DAOForkSupport &&

cmd/evm/internal/t8ntool/transition.go

@@ -252,6 +252,10 @@ func Transition(ctx *cli.Context) error {
 			return NewError(ErrorConfig, errors.New("EIP-1559 config but missing 'currentBaseFee' in env section"))
 		}
 	}
+	// Sanity check, to not `panic` in state_transition
+	if prestate.Env.Random != nil && !chainConfig.IsLondon(big.NewInt(int64(prestate.Env.Number))) {
+		return NewError(ErrorConfig, errors.New("can only apply RANDOM on top of London chainrules"))
+	}
 	if env := prestate.Env; env.Difficulty == nil {
 		// If difficulty was not provided by caller, we need to calculate it.
 		switch {

consensus/beacon/consensus.go

@@ -43,7 +43,6 @@ var (
 // error types into the consensus package.
 var (
 	errTooManyUncles    = errors.New("too many uncles")
-	errInvalidMixDigest = errors.New("invalid mix digest")
 	errInvalidNonce     = errors.New("invalid nonce")
 	errInvalidUncleHash = errors.New("invalid uncle hash")
 )
@@ -182,10 +181,7 @@ func (beacon *Beacon) verifyHeader(chain consensus.ChainHeaderReader, header, pa
 	if len(header.Extra) > 32 {
 		return fmt.Errorf("extra-data longer than 32 bytes (%d)", len(header.Extra))
 	}
-	// Verify the seal parts. Ensure the mixhash, nonce and uncle hash are the expected value.
-	if header.MixDigest != (common.Hash{}) {
-		return errInvalidMixDigest
-	}
+	// Verify the seal parts. Ensure the nonce and uncle hash are the expected value.
 	if header.Nonce != beaconNonce {
 		return errInvalidNonce
 	}

core/evm.go

@@ -40,6 +40,7 @@ func NewEVMBlockContext(header *types.Header, chain ChainContext, author *common
 	var (
 		beneficiary common.Address
 		baseFee     *big.Int
+		random      *common.Hash
 	)
 
 	// If we don't have an explicit author (i.e. not mining), extract from the header
@@ -51,6 +52,9 @@ func NewEVMBlockContext(header *types.Header, chain ChainContext, author *common
 	if header.BaseFee != nil {
 		baseFee = new(big.Int).Set(header.BaseFee)
 	}
+	if header.Difficulty.Cmp(common.Big0) == 0 {
+		random = &header.MixDigest
+	}
 	return vm.BlockContext{
 		CanTransfer: CanTransfer,
 		Transfer:    Transfer,
@@ -61,6 +65,7 @@ func NewEVMBlockContext(header *types.Header, chain ChainContext, author *common
 		Difficulty:  new(big.Int).Set(header.Difficulty),
 		BaseFee:     baseFee,
 		GasLimit:    header.GasLimit,
+		Random:      random,
 	}
 }
 

core/genesis.go

@@ -294,7 +294,7 @@ func (g *Genesis) ToBlock(db ethdb.Database) *types.Block {
 	if g.GasLimit == 0 {
 		head.GasLimit = params.GenesisGasLimit
 	}
-	if g.Difficulty == nil {
+	if g.Difficulty == nil && g.Mixhash == (common.Hash{}) {
 		head.Difficulty = params.GenesisDifficulty
 	}
 	if g.Config != nil && g.Config.IsLondon(common.Big0) {

core/state_transition.go

@@ -310,7 +310,7 @@ func (st *StateTransition) TransitionDb() (*ExecutionResult, error) {
 	}
 
 	// Set up the initial access list.
-	if rules := st.evm.ChainConfig().Rules(st.evm.Context.BlockNumber); rules.IsBerlin {
+	if rules := st.evm.ChainConfig().Rules(st.evm.Context.BlockNumber, st.evm.Context.Random != nil); rules.IsBerlin {
 		st.state.PrepareAccessList(msg.From(), msg.To(), vm.ActivePrecompiles(rules), msg.AccessList())
 	}
 	var (

core/vm/evm.go

@@ -75,6 +75,7 @@ type BlockContext struct {
 	Time        *big.Int       // Provides information for TIME
 	Difficulty  *big.Int       // Provides information for DIFFICULTY
 	BaseFee     *big.Int       // Provides information for BASEFEE
+	Random      *common.Hash   // Provides information for RANDOM
 }
 
 // TxContext provides the EVM with information about a transaction.
@@ -131,7 +132,7 @@ func NewEVM(blockCtx BlockContext, txCtx TxContext, statedb StateDB, chainConfig
 		StateDB:     statedb,
 		Config:      config,
 		chainConfig: chainConfig,
-		chainRules:  chainConfig.Rules(blockCtx.BlockNumber),
+		chainRules:  chainConfig.Rules(blockCtx.BlockNumber, blockCtx.Random != nil),
 	}
 	evm.interpreter = NewEVMInterpreter(evm, config)
 	return evm

core/vm/instructions.go

@@ -477,6 +477,12 @@ func opDifficulty(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext)
 	return nil, nil
 }
 
+func opRandom(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	v := new(uint256.Int).SetBytes((interpreter.evm.Context.Random.Bytes()))
+	scope.Stack.push(v)
+	return nil, nil
+}
+
 func opGasLimit(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
 	scope.Stack.push(new(uint256.Int).SetUint64(interpreter.evm.Context.GasLimit))
 	return nil, nil

core/vm/instructions_test.go

@@ -21,6 +21,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"io/ioutil"
+	"math/big"
 	"testing"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -654,3 +655,36 @@ func TestCreate2Addreses(t *testing.T) {
 		}
 	}
 }
+
+func TestRandom(t *testing.T) {
+	type testcase struct {
+		name   string
+		random common.Hash
+	}
+
+	for _, tt := range []testcase{
+		{name: "empty hash", random: common.Hash{}},
+		{name: "1", random: common.Hash{0}},
+		{name: "emptyCodeHash", random: emptyCodeHash},
+		{name: "hash(0x010203)", random: crypto.Keccak256Hash([]byte{0x01, 0x02, 0x03})},
+	} {
+		var (
+			env            = NewEVM(BlockContext{Random: &tt.random}, TxContext{}, nil, params.TestChainConfig, Config{})
+			stack          = newstack()
+			pc             = uint64(0)
+			evmInterpreter = env.interpreter
+		)
+		opRandom(&pc, evmInterpreter, &ScopeContext{nil, stack, nil})
+		if len(stack.data) != 1 {
+			t.Errorf("Expected one item on stack after %v, got %d: ", tt.name, len(stack.data))
+		}
+		actual := stack.pop()
+		expected, overflow := uint256.FromBig(new(big.Int).SetBytes(tt.random.Bytes()))
+		if overflow {
+			t.Errorf("Testcase %v: invalid overflow", tt.name)
+		}
+		if actual.Cmp(expected) != 0 {
+			t.Errorf("Testcase %v: expected  %x, got %x", tt.name, expected, actual)
+		}
+	}
+}

core/vm/interpreter.go

@@ -69,6 +69,8 @@ func NewEVMInterpreter(evm *EVM, cfg Config) *EVMInterpreter {
 	// If jump table was not initialised we set the default one.
 	if cfg.JumpTable == nil {
 		switch {
+		case evm.chainRules.IsMerge:
+			cfg.JumpTable = &mergeInstructionSet
 		case evm.chainRules.IsLondon:
 			cfg.JumpTable = &londonInstructionSet
 		case evm.chainRules.IsBerlin:

core/vm/jump_table.go

@@ -54,6 +54,7 @@ var (
 	istanbulInstructionSet         = newIstanbulInstructionSet()
 	berlinInstructionSet           = newBerlinInstructionSet()
 	londonInstructionSet           = newLondonInstructionSet()
+	mergeInstructionSet            = newMergeInstructionSet()
 )
 
 // JumpTable contains the EVM opcodes supported at a given fork.
@@ -77,6 +78,17 @@ func validate(jt JumpTable) JumpTable {
 	return jt
 }
 
+func newMergeInstructionSet() JumpTable {
+	instructionSet := newLondonInstructionSet()
+	instructionSet[RANDOM] = &operation{
+		execute:     opRandom,
+		constantGas: GasQuickStep,
+		minStack:    minStack(0, 1),
+		maxStack:    maxStack(0, 1),
+	}
+	return validate(instructionSet)
+}
+
 // newLondonInstructionSet returns the frontier, homestead, byzantium,
 // contantinople, istanbul, petersburg, berlin and london instructions.
 func newLondonInstructionSet() JumpTable {

core/vm/opcodes.go

@@ -95,6 +95,7 @@ const (
 	TIMESTAMP   OpCode = 0x42
 	NUMBER      OpCode = 0x43
 	DIFFICULTY  OpCode = 0x44
+	RANDOM      OpCode = 0x44 // Same as DIFFICULTY
 	GASLIMIT    OpCode = 0x45
 	CHAINID     OpCode = 0x46
 	SELFBALANCE OpCode = 0x47
@@ -275,7 +276,7 @@ var opCodeToString = map[OpCode]string{
 	COINBASE:    "COINBASE",
 	TIMESTAMP:   "TIMESTAMP",
 	NUMBER:      "NUMBER",
-	DIFFICULTY:  "DIFFICULTY",
+	DIFFICULTY:  "DIFFICULTY", // TODO (MariusVanDerWijden) rename to RANDOM post merge
 	GASLIMIT:    "GASLIMIT",
 	CHAINID:     "CHAINID",
 	SELFBALANCE: "SELFBALANCE",

core/vm/runtime/runtime.go

@@ -118,7 +118,7 @@ func Execute(code, input []byte, cfg *Config) ([]byte, *state.StateDB, error) {
 		vmenv   = NewEnv(cfg)
 		sender  = vm.AccountRef(cfg.Origin)
 	)
-	if rules := cfg.ChainConfig.Rules(vmenv.Context.BlockNumber); rules.IsBerlin {
+	if rules := cfg.ChainConfig.Rules(vmenv.Context.BlockNumber, vmenv.Context.Random != nil); rules.IsBerlin {
 		cfg.State.PrepareAccessList(cfg.Origin, &address, vm.ActivePrecompiles(rules), nil)
 	}
 	cfg.State.CreateAccount(address)
@@ -150,7 +150,7 @@ func Create(input []byte, cfg *Config) ([]byte, common.Address, uint64, error) {
 		vmenv  = NewEnv(cfg)
 		sender = vm.AccountRef(cfg.Origin)
 	)
-	if rules := cfg.ChainConfig.Rules(vmenv.Context.BlockNumber); rules.IsBerlin {
+	if rules := cfg.ChainConfig.Rules(vmenv.Context.BlockNumber, vmenv.Context.Random != nil); rules.IsBerlin {
 		cfg.State.PrepareAccessList(cfg.Origin, nil, vm.ActivePrecompiles(rules), nil)
 	}
 	// Call the code with the given configuration.
@@ -176,7 +176,7 @@ func Call(address common.Address, input []byte, cfg *Config) ([]byte, uint64, er
 	sender := cfg.State.GetOrNewStateObject(cfg.Origin)
 	statedb := cfg.State
 
-	if rules := cfg.ChainConfig.Rules(vmenv.Context.BlockNumber); rules.IsBerlin {
+	if rules := cfg.ChainConfig.Rules(vmenv.Context.BlockNumber, vmenv.Context.Random != nil); rules.IsBerlin {
 		statedb.PrepareAccessList(cfg.Origin, &address, vm.ActivePrecompiles(rules), nil)
 	}
 	// Call the code with the given configuration.

eth/catalyst/api.go

@@ -133,9 +133,9 @@ type blockExecutionEnv struct {
 }
 
 func (env *blockExecutionEnv) commitTransaction(tx *types.Transaction, coinbase common.Address) error {
-	vmconfig := *env.chain.GetVMConfig()
+	vmConfig := *env.chain.GetVMConfig()
 	snap := env.state.Snapshot()
-	receipt, err := core.ApplyTransaction(env.chain.Config(), env.chain, &coinbase, env.gasPool, env.state, env.header, tx, &env.header.GasUsed, vmconfig)
+	receipt, err := core.ApplyTransaction(env.chain.Config(), env.chain, &coinbase, env.gasPool, env.state, env.header, tx, &env.header.GasUsed, vmConfig)
 	if err != nil {
 		env.state.RevertToSnapshot(snap)
 		return err
@@ -318,6 +318,7 @@ func (api *ConsensusAPI) assembleBlock(parentHash common.Hash, params *PayloadAt
 		GasLimit:   parent.GasLimit(), // Keep the gas limit constant in this prototype
 		Extra:      []byte{},          // TODO (MariusVanDerWijden) properly set extra data
 		Time:       params.Timestamp,
+		MixDigest:  params.Random,
 	}
 	if config := api.eth.BlockChain().Config(); config.IsLondon(header.Number) {
 		header.BaseFee = misc.CalcBaseFee(config, parent.Header())
@@ -432,7 +433,7 @@ func ExecutableDataToBlock(params ExecutableDataV1) (*types.Block, error) {
 		Time:        params.Timestamp,
 		BaseFee:     params.BaseFeePerGas,
 		Extra:       params.ExtraData,
-		// TODO (MariusVanDerWijden) add params.Random to header once required
+		MixDigest:   params.Random,
 	}
 	block := types.NewBlockWithHeader(header).WithBody(txs, nil /* uncles */)
 	if block.Hash() != params.BlockHash {

eth/tracers/js/tracer.go

@@ -697,7 +697,7 @@ func (jst *jsTracer) CaptureStart(env *vm.EVM, from common.Address, to common.Ad
 	jst.ctx["block"] = env.Context.BlockNumber.Uint64()
 	jst.dbWrapper.db = env.StateDB
 	// Update list of precompiles based on current block
-	rules := env.ChainConfig().Rules(env.Context.BlockNumber)
+	rules := env.ChainConfig().Rules(env.Context.BlockNumber, env.Context.Random != nil)
 	jst.activePrecompiles = vm.ActivePrecompiles(rules)
 
 	// Compute intrinsic gas

eth/tracers/native/4byte.go

@@ -83,7 +83,7 @@ func (t *fourByteTracer) CaptureStart(env *vm.EVM, from common.Address, to commo
 	t.env = env
 
 	// Update list of precompiles based on current block
-	rules := env.ChainConfig().Rules(env.Context.BlockNumber)
+	rules := env.ChainConfig().Rules(env.Context.BlockNumber, env.Context.Random != nil)
 	t.activePrecompiles = vm.ActivePrecompiles(rules)
 
 	// Save the outer calldata also

internal/ethapi/api.go

@@ -1432,8 +1432,9 @@ func AccessList(ctx context.Context, b Backend, blockNrOrHash rpc.BlockNumberOrH
 	} else {
 		to = crypto.CreateAddress(args.from(), uint64(*args.Nonce))
 	}
+	isPostMerge := header.Difficulty.Cmp(common.Big0) == 0
 	// Retrieve the precompiles since they don't need to be added to the access list
-	precompiles := vm.ActivePrecompiles(b.ChainConfig().Rules(header.Number))
+	precompiles := vm.ActivePrecompiles(b.ChainConfig().Rules(header.Number, isPostMerge))
 
 	// Create an initial tracer
 	prevTracer := logger.NewAccessListTracer(nil, args.from(), to, precompiles)

params/config.go

@@ -267,7 +267,7 @@ var (
 	AllCliqueProtocolChanges = &ChainConfig{big.NewInt(1337), big.NewInt(0), nil, false, big.NewInt(0), common.Hash{}, big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), nil, nil, nil, nil, &CliqueConfig{Period: 0, Epoch: 30000}}
 
 	TestChainConfig = &ChainConfig{big.NewInt(1), big.NewInt(0), nil, false, big.NewInt(0), common.Hash{}, big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), big.NewInt(0), nil, nil, new(EthashConfig), nil}
-	TestRules       = TestChainConfig.Rules(new(big.Int))
+	TestRules       = TestChainConfig.Rules(new(big.Int), false)
 )
 
 // TrustedCheckpoint represents a set of post-processed trie roots (CHT and
@@ -668,10 +668,11 @@ type Rules struct {
 	IsHomestead, IsEIP150, IsEIP155, IsEIP158               bool
 	IsByzantium, IsConstantinople, IsPetersburg, IsIstanbul bool
 	IsBerlin, IsLondon                                      bool
+	IsMerge                                                 bool
 }
 
 // Rules ensures c's ChainID is not nil.
-func (c *ChainConfig) Rules(num *big.Int) Rules {
+func (c *ChainConfig) Rules(num *big.Int, isMerge bool) Rules {
 	chainID := c.ChainID
 	if chainID == nil {
 		chainID = new(big.Int)
@@ -688,5 +689,6 @@ func (c *ChainConfig) Rules(num *big.Int) Rules {
 		IsIstanbul:       c.IsIstanbul(num),
 		IsBerlin:         c.IsBerlin(num),
 		IsLondon:         c.IsLondon(num),
+		IsMerge:          isMerge,
 	}
 }