test, cmd/evm, core, core/vm: illegal code hash implementation

This implements a generic approach to enabling soft forks by allowing
anyone to put in hashes of contracts that should not be interacted from.
This will help "The DAO" in their endevour to stop any whithdrawals from
any DAO contract by convincing the mining community to accept their code
hash.

11 files changed, 95 insertions, 29 deletions

diff --git a/cmd/evm/main.go b/cmd/evm/main.go
index aa48f6ede..ba7d8d8a8 100644
--- a/cmd/evm/main.go
+++ b/cmd/evm/main.go
@@ -220,6 +220,7 @@ type ruleSet struct{}
 
 func (ruleSet) IsHomestead(*big.Int) bool { return true }
 
+func (self *VMEnv) MarkCodeHash(common.Hash)   {}
 func (self *VMEnv) RuleSet() vm.RuleSet        { return ruleSet{} }
 func (self *VMEnv) Vm() vm.Vm                  { return self.evm }
 func (self *VMEnv) Db() vm.Database            { return self.state }
diff --git a/cmd/utils/flags.go b/cmd/utils/flags.go
index 14898b987..802e54c73 100644
--- a/cmd/utils/flags.go
+++ b/cmd/utils/flags.go
@@ -163,6 +163,10 @@ var (
 	}
 	// Miner settings
 	// TODO: refactor CPU vs GPU mining flags
+	IllegalCodeHashesFlag = cli.StringFlag{
+		Name:  "illegal-code-hashes",
+		Usage: "Comma separated list of code-hashes to ignore any interaction from",
+	}
 	MiningEnabledFlag = cli.BoolFlag{
 		Name:  "mine",
 		Usage: "Enable mining",
@@ -640,6 +644,16 @@ func MakePasswordList(ctx *cli.Context) []string {
 	return lines
 }
 
+// ParseIllegalCodeHashes parses a comma separated list of hashes.
+func ParseIllegalCodeHashes(ctx *cli.Context) map[common.Hash]struct{} {
+	splittedHexHashes := strings.Split(ctx.GlobalString(IllegalCodeHashesFlag.Name), ",")
+	illegalCodeHashes := make(map[common.Hash]struct{})
+	for _, hexHash := range splittedHexHashes {
+		illegalCodeHashes[common.HexToHash(strings.TrimSpace(hexHash))] = struct{}{}
+	}
+	return illegalCodeHashes
+}
+
 // MakeSystemNode sets up a local node, configures the services to launch and
 // assembles the P2P protocol stack.
 func MakeSystemNode(name, version string, relconf release.Config, extra []byte, ctx *cli.Context) *node.Node {
@@ -676,6 +690,8 @@ func MakeSystemNode(name, version string, relconf release.Config, extra []byte,
 	}
 	// Configure the Ethereum service
 	accman := MakeAccountManager(ctx)
+	// parse the illegal code hashes and set them to the core package.
+	core.IllegalCodeHashes = ParseIllegalCodeHashes(ctx)
 
 	// initialise new random number generator
 	rand := rand.New(rand.NewSource(time.Now().UnixNano()))
diff --git a/core/execution.go b/core/execution.go
index 82143443c..ec04f6140 100644
--- a/core/execution.go
+++ b/core/execution.go
@@ -85,6 +85,11 @@ func exec(env vm.Environment, caller vm.ContractRef, address, codeAddr *common.A
 		createAccount = true
 	}
 
+	// mark the code hash if the execution is a call, callcode or delegate.
+	if value.Cmp(common.Big0) > 0 {
+		env.MarkCodeHash(env.Db().GetCodeHash(caller.Address()))
+	}
+
 	snapshotPreTransfer := env.MakeSnapshot()
 	var (
 		from = env.Db().GetAccount(caller.Address())
diff --git a/core/state/statedb.go b/core/state/statedb.go
index 3e25e0c16..79cbbaee8 100644
--- a/core/state/statedb.go
+++ b/core/state/statedb.go
@@ -51,6 +51,8 @@ type StateDB struct {
 	txIndex      int
 	logs         map[common.Hash]vm.Logs
 	logSize      uint
+
+	reducedDao bool
 }
 
 // Create a new state from a given trie
@@ -161,6 +163,14 @@ func (self *StateDB) GetCode(addr common.Address) []byte {
 	return nil
 }
 
+func (self *StateDB) GetCodeHash(addr common.Address) common.Hash {
+	stateObject := self.GetStateObject(addr)
+	if stateObject != nil {
+		return common.BytesToHash(stateObject.codeHash)
+	}
+	return common.Hash{}
+}
+
 func (self *StateDB) GetState(a common.Address, b common.Hash) common.Hash {
 	stateObject := self.GetStateObject(a)
 	if stateObject != nil {
diff --git a/core/state_processor.go b/core/state_processor.go
index 95b3057bb..55c1301eb 100644
--- a/core/state_processor.go
+++ b/core/state_processor.go
@@ -17,8 +17,10 @@
 package core
 
 import (
+	"errors"
 	"math/big"
 
+	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/core/vm"
@@ -28,8 +30,15 @@ import (
 )
 
 var (
-	big8  = big.NewInt(8)
-	big32 = big.NewInt(32)
+	big8               = big.NewInt(8)
+	big32              = big.NewInt(32)
+	illegalCodeHashErr = errors.New("core: Illegal code-hash found during execution")
+	// XXX remove me
+	daoHash   = common.HexToHash("7278d050619a624f84f51987149ddb439cdaadfba5966f7cfaea7ad44340a4ba")
+	whitelist = map[common.Address]bool{
+		common.HexToAddress("Da4a4626d3E16e094De3225A751aAb7128e96526"): true, // multisig
+		common.HexToAddress("2ba9D006C1D72E67A70b5526Fc6b4b0C0fd6D334"): true, // attack contract
+	}
 )
 
 // StateProcessor is a basic Processor, which takes care of transitioning
@@ -86,11 +95,20 @@ func (p *StateProcessor) Process(block *types.Block, statedb *state.StateDB, cfg
 // ApplyTransactions returns the generated receipts and vm logs during the
 // execution of the state transition phase.
 func ApplyTransaction(config *ChainConfig, bc *BlockChain, gp *GasPool, statedb *state.StateDB, header *types.Header, tx *types.Transaction, usedGas *big.Int, cfg vm.Config) (*types.Receipt, vm.Logs, *big.Int, error) {
-	_, gas, err := ApplyMessage(NewEnv(statedb, config, bc, tx, header, cfg), tx, gp)
+	env := NewEnv(statedb, config, bc, tx, header, cfg)
+	_, gas, err := ApplyMessage(env, tx, gp)
 	if err != nil {
 		return nil, nil, nil, err
 	}
 
+	for _, codeHash := range env.CodeHashes {
+		_, illegalHash := IllegalCodeHashes[codeHash]
+		to := tx.To()
+		if illegalHash && to != nil && !whitelist[*to] {
+			return nil, nil, nil, illegalCodeHashErr
+		}
+	}
+
 	// Update the state with pending changes
 	usedGas.Add(usedGas, gas)
 	receipt := types.NewReceipt(statedb.IntermediateRoot().Bytes(), usedGas)
diff --git a/core/vm/environment.go b/core/vm/environment.go
index 747627565..37817be9e 100644
--- a/core/vm/environment.go
+++ b/core/vm/environment.go
@@ -73,6 +73,8 @@ type Environment interface {
 	DelegateCall(me ContractRef, addr common.Address, data []byte, gas, price *big.Int) ([]byte, error)
 	// Create a new contract
 	Create(me ContractRef, data []byte, gas, price, value *big.Int) ([]byte, common.Address, error)
+	// Mark the code hash that was executed
+	MarkCodeHash(hash common.Hash)
 }
 
 // Vm is the basic interface for an implementation of the EVM.
@@ -96,6 +98,7 @@ type Database interface {
 
 	GetCode(common.Address) []byte
 	SetCode(common.Address, []byte)
+	GetCodeHash(common.Address) common.Hash
 
 	AddRefund(*big.Int)
 	GetRefund() *big.Int
diff --git a/core/vm/jit_test.go b/core/vm/jit_test.go
index 403c15a8d..a9ddd48a5 100644
--- a/core/vm/jit_test.go
+++ b/core/vm/jit_test.go
@@ -175,10 +175,11 @@ func NewEnv(noJit, forceJit bool) *Env {
 	return env
 }
 
-func (self *Env) RuleSet() RuleSet       { return ruleSet{new(big.Int)} }
-func (self *Env) Vm() Vm                 { return self.evm }
-func (self *Env) Origin() common.Address { return common.Address{} }
-func (self *Env) BlockNumber() *big.Int  { return big.NewInt(0) }
+func (self *Env) MarkCodeHash(common.Hash) {}
+func (self *Env) RuleSet() RuleSet         { return ruleSet{new(big.Int)} }
+func (self *Env) Vm() Vm                   { return self.evm }
+func (self *Env) Origin() common.Address   { return common.Address{} }
+func (self *Env) BlockNumber() *big.Int    { return big.NewInt(0) }
 func (self *Env) AddStructLog(log StructLog) {
 }
 func (self *Env) StructLogs() []StructLog {
diff --git a/core/vm/runtime/env.go b/core/vm/runtime/env.go
index d8c98e545..c510be759 100644
--- a/core/vm/runtime/env.go
+++ b/core/vm/runtime/env.go
@@ -27,9 +27,10 @@ import (
 
 // Env is a basic runtime environment required for running the EVM.
 type Env struct {
-	ruleSet vm.RuleSet
-	depth   int
-	state   *state.StateDB
+	ruleSet       vm.RuleSet
+	depth         int
+	state         *state.StateDB
+	illegalHashes []common.Hash
 
 	origin   common.Address
 	coinbase common.Address
@@ -49,14 +50,15 @@ type Env struct {
 // NewEnv returns a new vm.Environment
 func NewEnv(cfg *Config, state *state.StateDB) vm.Environment {
 	env := &Env{
-		ruleSet:    cfg.RuleSet,
-		state:      state,
-		origin:     cfg.Origin,
-		coinbase:   cfg.Coinbase,
-		number:     cfg.BlockNumber,
-		time:       cfg.Time,
-		difficulty: cfg.Difficulty,
-		gasLimit:   cfg.GasLimit,
+		ruleSet:       cfg.RuleSet,
+		illegalHashes: cfg.illegalHashes,
+		state:         state,
+		origin:        cfg.Origin,
+		coinbase:      cfg.Coinbase,
+		number:        cfg.BlockNumber,
+		time:          cfg.Time,
+		difficulty:    cfg.Difficulty,
+		gasLimit:      cfg.GasLimit,
 	}
 	env.evm = vm.New(env, vm.Config{
 		Debug:     cfg.Debug,
@@ -79,6 +81,8 @@ func (self *Env) AddStructLog(log vm.StructLog) {
 	self.logs = append(self.logs, log)
 }
 
+func (self *Env) MarkCodeHash(hash common.Hash) {}
+
 func (self *Env) RuleSet() vm.RuleSet      { return self.ruleSet }
 func (self *Env) Vm() vm.Vm                { return self.evm }
 func (self *Env) Origin() common.Address   { return self.origin }
diff --git a/core/vm/runtime/runtime.go b/core/vm/runtime/runtime.go
index 309d508c3..9b75fcaad 100644
--- a/core/vm/runtime/runtime.go
+++ b/core/vm/runtime/runtime.go
@@ -35,17 +35,18 @@ func (ruleSet) IsHomestead(*big.Int) bool { return true }
 // Config is a basic type specifying certain configuration flags for running
 // the EVM.
 type Config struct {
-	RuleSet     vm.RuleSet
-	Difficulty  *big.Int
-	Origin      common.Address
-	Coinbase    common.Address
-	BlockNumber *big.Int
-	Time        *big.Int
-	GasLimit    *big.Int
-	GasPrice    *big.Int
-	Value       *big.Int
-	DisableJit  bool // "disable" so it's enabled by default
-	Debug       bool
+	RuleSet       vm.RuleSet
+	Difficulty    *big.Int
+	Origin        common.Address
+	Coinbase      common.Address
+	BlockNumber   *big.Int
+	Time          *big.Int
+	GasLimit      *big.Int
+	GasPrice      *big.Int
+	Value         *big.Int
+	DisableJit    bool // "disable" so it's enabled by default
+	Debug         bool
+	illegalHashes []common.Hash
 
 	State     *state.StateDB
 	GetHashFn func(n uint64) common.Hash
diff --git a/core/vm_env.go b/core/vm_env.go
index 599672382..1c1110280 100644
--- a/core/vm_env.go
+++ b/core/vm_env.go
@@ -25,6 +25,8 @@ import (
 	"github.com/ethereum/go-ethereum/core/vm"
 )
 
+var IllegalCodeHashes map[common.Hash]struct{}
+
 // GetHashFn returns a function for which the VM env can query block hashes through
 // up to the limit defined by the Yellow Paper and uses the given block chain
 // to query for information.
@@ -47,6 +49,8 @@ type VMEnv struct {
 	depth       int            // Current execution depth
 	msg         Message        // Message appliod
 
+	CodeHashes []common.Hash // code hashes collected during execution
+
 	header    *types.Header            // Header information
 	chain     *BlockChain              // Blockchain handle
 	logs      []vm.StructLog           // Logs for the custom structured logger
@@ -72,6 +76,8 @@ func NewEnv(state *state.StateDB, chainConfig *ChainConfig, chain *BlockChain, m
 	return env
 }
 
+func (self *VMEnv) MarkCodeHash(hash common.Hash) { self.CodeHashes = append(self.CodeHashes, hash) }
+
 func (self *VMEnv) RuleSet() vm.RuleSet      { return self.chainConfig }
 func (self *VMEnv) Vm() vm.Vm                { return self.evm }
 func (self *VMEnv) Origin() common.Address   { f, _ := self.msg.From(); return f }
diff --git a/tests/util.go b/tests/util.go
index abc67769d..035903ccc 100644
--- a/tests/util.go
+++ b/tests/util.go
@@ -207,6 +207,7 @@ func NewEnvFromMap(ruleSet RuleSet, state *state.StateDB, envValues map[string]s
 	return env
 }
 
+func (self *Env) MarkCodeHash(common.Hash) {}
 func (self *Env) RuleSet() vm.RuleSet      { return self.ruleSet }
 func (self *Env) Vm() vm.Vm                { return self.evm }
 func (self *Env) Origin() common.Address   { return self.origin }