neo-go/pkg/network/payload/notary_request.go

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2020-11-27 10:55:48 +00:00
package payload
import (
"bytes"
"errors"
"github.com/nspcc-dev/neo-go/pkg/config/netmode"
"github.com/nspcc-dev/neo-go/pkg/core/transaction"
"github.com/nspcc-dev/neo-go/pkg/crypto/hash"
"github.com/nspcc-dev/neo-go/pkg/io"
"github.com/nspcc-dev/neo-go/pkg/util"
"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
)
// P2PNotaryRequest contains main and fallback transactions for the Notary service.
type P2PNotaryRequest struct {
MainTransaction *transaction.Transaction
FallbackTransaction *transaction.Transaction
Network netmode.Magic
Witness transaction.Witness
hash util.Uint256
signedHash util.Uint256
}
// Hash returns payload's hash.
func (r *P2PNotaryRequest) Hash() util.Uint256 {
if r.hash.Equals(util.Uint256{}) {
if r.createHash() != nil {
panic("failed to compute hash!")
}
}
return r.hash
}
// GetSignedHash returns a hash of the payload used to verify it.
func (r *P2PNotaryRequest) GetSignedHash() util.Uint256 {
if r.signedHash.Equals(util.Uint256{}) {
if r.createHash() != nil {
panic("failed to compute hash!")
}
}
return r.signedHash
}
// GetSignedPart returns a part of the payload which must be signed.
func (r *P2PNotaryRequest) GetSignedPart() []byte {
buf := io.NewBufBinWriter()
buf.WriteU32LE(uint32(r.Network))
r.encodeHashableFields(buf.BinWriter)
if buf.Err != nil {
return nil
}
return buf.Bytes()
}
// createHash creates hash of the payload.
func (r *P2PNotaryRequest) createHash() error {
b := r.GetSignedPart()
if b == nil {
return errors.New("failed to serialize hashable data")
}
r.updateHashes(b)
return nil
}
// updateHashes updates Payload's hashes based on the given buffer which should
// be a signable data slice.
func (r *P2PNotaryRequest) updateHashes(b []byte) {
r.signedHash = hash.Sha256(b)
r.hash = hash.Sha256(r.signedHash.BytesBE())
}
// DecodeBinaryUnsigned reads payload from w excluding signature.
func (r *P2PNotaryRequest) decodeHashableFields(br *io.BinReader) {
r.MainTransaction = new(transaction.Transaction)
r.FallbackTransaction = new(transaction.Transaction)
r.MainTransaction.DecodeBinary(br)
r.FallbackTransaction.DecodeBinary(br)
if br.Err == nil {
br.Err = r.isValid()
}
if br.Err == nil {
br.Err = r.createHash()
}
}
// DecodeBinary implements io.Serializable interface.
func (r *P2PNotaryRequest) DecodeBinary(br *io.BinReader) {
r.decodeHashableFields(br)
if br.Err == nil {
r.Witness.DecodeBinary(br)
}
}
// encodeHashableFields writes payload to w excluding signature.
func (r *P2PNotaryRequest) encodeHashableFields(bw *io.BinWriter) {
r.MainTransaction.EncodeBinary(bw)
r.FallbackTransaction.EncodeBinary(bw)
}
// EncodeBinary implements Serializable interface.
func (r *P2PNotaryRequest) EncodeBinary(bw *io.BinWriter) {
r.encodeHashableFields(bw)
r.Witness.EncodeBinary(bw)
}
func (r *P2PNotaryRequest) isValid() error {
nKeysMain := r.MainTransaction.GetAttributes(transaction.NotaryAssistedT)
if len(nKeysMain) == 0 {
return errors.New("main transaction should have NotaryAssisted attribute")
}
if nKeysMain[0].Value.(*transaction.NotaryAssisted).NKeys == 0 {
return errors.New("main transaction should have NKeys > 0")
}
if len(r.FallbackTransaction.Signers) != 2 {
return errors.New("fallback transaction should have two signers")
}
if len(r.FallbackTransaction.Scripts) != 2 {
return errors.New("fallback transaction should have dummy Notary witness and valid witness for the second signer")
}
if len(r.FallbackTransaction.Scripts[0].InvocationScript) != 66 ||
len(r.FallbackTransaction.Scripts[0].VerificationScript) != 0 ||
!bytes.HasPrefix(r.FallbackTransaction.Scripts[0].InvocationScript, []byte{byte(opcode.PUSHDATA1), 64}) {
return errors.New("fallback transaction has invalid dummy Notary witness")
}
if !r.FallbackTransaction.HasAttribute(transaction.NotValidBeforeT) {
return errors.New("fallback transactions should have NotValidBefore attribute")
}
conflicts := r.FallbackTransaction.GetAttributes(transaction.ConflictsT)
if len(conflicts) != 1 {
return errors.New("fallback transaction should have one Conflicts attribute")
}
if conflicts[0].Value.(*transaction.Conflicts).Hash != r.MainTransaction.Hash() {
return errors.New("fallback transaction does not conflicts with the main transaction")
}
nKeysFallback := r.FallbackTransaction.GetAttributes(transaction.NotaryAssistedT)
if len(nKeysFallback) == 0 {
return errors.New("fallback transaction should have NotaryAssisted attribute")
}
if nKeysFallback[0].Value.(*transaction.NotaryAssisted).NKeys != 0 {
return errors.New("fallback transaction should have NKeys = 0")
}
if r.MainTransaction.ValidUntilBlock != r.FallbackTransaction.ValidUntilBlock {
return errors.New("both main and fallback transactions should have the same ValidUntil value")
}
return nil
}