86 lines
2.2 KiB
Go
86 lines
2.2 KiB
Go
package vm
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import (
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"crypto/sha256"
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"github.com/tendermint/tendermint/Godeps/_workspace/src/code.google.com/p/go.crypto/ripemd160"
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. "github.com/tendermint/tendermint/common"
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"github.com/tendermint/tendermint/vm/secp256k1"
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"github.com/tendermint/tendermint/vm/sha3"
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)
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var nativeContracts = make(map[Word256]NativeContract)
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func init() {
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nativeContracts[Int64ToWord256(1)] = ecrecoverFunc
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nativeContracts[Int64ToWord256(2)] = sha256Func
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nativeContracts[Int64ToWord256(3)] = ripemd160Func
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nativeContracts[Int64ToWord256(4)] = identityFunc
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}
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//-----------------------------------------------------------------------------
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type NativeContract func(input []byte, gas *int64) (output []byte, err error)
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func ecrecoverFunc(input []byte, gas *int64) (output []byte, err error) {
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// Deduct gas
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gasRequired := GasEcRecover
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if *gas < gasRequired {
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return nil, ErrInsufficientGas
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} else {
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*gas -= gasRequired
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}
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// Recover
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hash := input[:32]
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v := byte(input[32] - 27) // ignore input[33:64], v is small.
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sig := append(input[64:], v)
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recovered, err := secp256k1.RecoverPubkey(hash, sig)
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if err != nil {
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return nil, err
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}
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hashed := sha3.Sha3(recovered[1:])
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return LeftPadBytes(hashed, 32), nil
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}
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func sha256Func(input []byte, gas *int64) (output []byte, err error) {
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// Deduct gas
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gasRequired := int64((len(input)+31)/32)*GasSha256Word + GasSha256Base
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if *gas < gasRequired {
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return nil, ErrInsufficientGas
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} else {
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*gas -= gasRequired
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}
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// Hash
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hasher := sha256.New()
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// CONTRACT: this does not err
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hasher.Write(input)
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return hasher.Sum(nil), nil
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}
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func ripemd160Func(input []byte, gas *int64) (output []byte, err error) {
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// Deduct gas
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gasRequired := int64((len(input)+31)/32)*GasRipemd160Word + GasRipemd160Base
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if *gas < gasRequired {
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return nil, ErrInsufficientGas
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} else {
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*gas -= gasRequired
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}
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// Hash
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hasher := ripemd160.New()
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// CONTRACT: this does not err
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hasher.Write(input)
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return LeftPadBytes(hasher.Sum(nil), 32), nil
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}
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func identityFunc(input []byte, gas *int64) (output []byte, err error) {
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// Deduct gas
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gasRequired := int64((len(input)+31)/32)*GasIdentityWord + GasIdentityBase
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if *gas < gasRequired {
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return nil, ErrInsufficientGas
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} else {
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*gas -= gasRequired
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}
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// Return identity
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return input, nil
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}
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