cmd/geth, core: add support for recording SHA3 preimages (#3543)

core/vm/instructions.go

@@ -247,7 +247,12 @@ func opMulmod(pc *uint64, env *EVM, contract *Contract, memory *Memory, stack *S
 
 func opSha3(pc *uint64, env *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
 	offset, size := stack.pop(), stack.pop()
-	hash := crypto.Keccak256(memory.Get(offset.Int64(), size.Int64()))
+	data := memory.Get(offset.Int64(), size.Int64())
+	hash := crypto.Keccak256(data)
+
+	if env.vmConfig.EnablePreimageRecording {
+		env.StateDB.AddPreimage(common.BytesToHash(hash), data)
+	}
 
 	stack.push(common.BytesToBig(hash))
 	return nil, nil

core/vm/interface.go

@@ -60,6 +60,7 @@ type StateDB interface {
 	Snapshot() int
 
 	AddLog(*types.Log)
+	AddPreimage(common.Hash, []byte)
 }
 
 // Account represents a contract or basic ethereum account.

core/vm/noop.go

@@ -67,3 +67,4 @@ func (NoopStateDB) Empty(common.Address) bool                         { return f
 func (NoopStateDB) RevertToSnapshot(int)                              {}
 func (NoopStateDB) Snapshot() int                                     { return 0 }
 func (NoopStateDB) AddLog(*types.Log)                                 {}
+func (NoopStateDB) AddPreimage(common.Hash, []byte)                   {}

core/vm/vm.go

@@ -44,6 +44,8 @@ type Config struct {
 	NoRecursion bool
 	// Disable gas metering
 	DisableGasMetering bool
+	// Enable recording of SHA3/keccak preimages
+	EnablePreimageRecording bool
 	// JumpTable contains the EVM instruction table. This
 	// may me left uninitialised and will be set the default
 	// table.