mirror of
https://github.com/nspcc-dev/neo-go.git
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0aecddea10
Ref. https://github.com/nspcc-dev/neo-go/pull/3402#discussion_r1577879141. Signed-off-by: Anna Shaleva <shaleva.ann@nspcc.ru>
202 lines
5.7 KiB
Go
202 lines
5.7 KiB
Go
package oracle
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import (
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"errors"
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"fmt"
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gio "io"
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"unicode/utf8"
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"github.com/nspcc-dev/neo-go/pkg/core/fee"
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"github.com/nspcc-dev/neo-go/pkg/core/interop"
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"github.com/nspcc-dev/neo-go/pkg/core/native/nativehashes"
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"github.com/nspcc-dev/neo-go/pkg/core/transaction"
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"github.com/nspcc-dev/neo-go/pkg/crypto/hash"
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"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
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"github.com/nspcc-dev/neo-go/pkg/io"
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"github.com/nspcc-dev/neo-go/pkg/smartcontract/callflag"
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"github.com/nspcc-dev/neo-go/pkg/smartcontract/trigger"
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"go.uber.org/zap"
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)
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func (o *Oracle) getResponse(reqID uint64, create bool) *incompleteTx {
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o.respMtx.Lock()
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defer o.respMtx.Unlock()
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incTx, ok := o.responses[reqID]
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if !ok && create && !o.removed[reqID] {
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incTx = newIncompleteTx()
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o.responses[reqID] = incTx
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}
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return incTx
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}
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// AddResponse handles an oracle response (transaction signature for some identified request) signed by the given key.
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// sig is a response transaction signature.
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func (o *Oracle) AddResponse(pub *keys.PublicKey, reqID uint64, txSig []byte) {
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incTx := o.getResponse(reqID, true)
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if incTx == nil {
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return
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}
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incTx.Lock()
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isBackup := false
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if incTx.tx != nil {
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ok := pub.VerifyHashable(txSig, uint32(o.Network), incTx.tx)
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if !ok {
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ok = pub.VerifyHashable(txSig, uint32(o.Network), incTx.backupTx)
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if !ok {
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o.Log.Debug("invalid response signature",
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zap.String("pub", pub.StringCompressed()))
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incTx.Unlock()
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return
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}
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isBackup = true
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}
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}
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incTx.addResponse(pub, txSig, isBackup)
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readyTx, ready := incTx.finalize(o.getOracleNodes(), false)
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if ready {
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ready = !incTx.isSent
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incTx.isSent = true
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}
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incTx.Unlock()
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if ready {
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o.sendTx(readyTx)
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}
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}
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// ErrResponseTooLarge is returned when a response exceeds the max allowed size.
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var ErrResponseTooLarge = errors.New("too big response")
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func (o *Oracle) readResponse(rc gio.Reader, url string) ([]byte, transaction.OracleResponseCode) {
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const limit = transaction.MaxOracleResultSize
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buf := make([]byte, limit+1)
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n, err := gio.ReadFull(rc, buf)
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if errors.Is(err, gio.ErrUnexpectedEOF) && n <= limit {
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res, err := checkUTF8(buf[:n])
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return o.handleResponseError(res, err, url)
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}
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if err == nil || n > limit {
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return o.handleResponseError(nil, ErrResponseTooLarge, url)
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}
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return o.handleResponseError(nil, err, url)
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}
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func (o *Oracle) handleResponseError(data []byte, err error, url string) ([]byte, transaction.OracleResponseCode) {
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if err != nil {
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o.Log.Warn("failed to read data for oracle request", zap.String("url", url), zap.Error(err))
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if errors.Is(err, ErrResponseTooLarge) {
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return nil, transaction.ResponseTooLarge
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}
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return nil, transaction.Error
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}
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return data, transaction.Success
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}
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func checkUTF8(v []byte) ([]byte, error) {
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if !utf8.Valid(v) {
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return nil, errors.New("invalid UTF-8")
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}
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return v, nil
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}
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// CreateResponseTx creates an unsigned oracle response transaction.
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func (o *Oracle) CreateResponseTx(gasForResponse int64, vub uint32, resp *transaction.OracleResponse) (*transaction.Transaction, error) {
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var respScript []byte
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o.oracleInfoLock.RLock()
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respScript = o.oracleResponse
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o.oracleInfoLock.RUnlock()
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tx := transaction.New(respScript, 0)
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tx.Nonce = uint32(resp.ID)
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tx.ValidUntilBlock = vub
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tx.Attributes = []transaction.Attribute{{
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Type: transaction.OracleResponseT,
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Value: resp,
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}}
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oracleSignContract := o.getOracleSignContract()
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tx.Signers = []transaction.Signer{
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{
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Account: nativehashes.OracleContract,
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Scopes: transaction.None,
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},
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{
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Account: hash.Hash160(oracleSignContract),
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Scopes: transaction.None,
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},
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}
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tx.Scripts = []transaction.Witness{
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{}, // native contract witness is fixed, second witness is set later.
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}
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// Calculate network fee.
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size := io.GetVarSize(tx)
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tx.Scripts = append(tx.Scripts, transaction.Witness{VerificationScript: oracleSignContract})
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gasConsumed, ok, err := o.testVerify(tx)
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if err != nil {
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return nil, fmt.Errorf("failed to prepare `verify` invocation: %w", err)
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}
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if !ok {
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return nil, errors.New("can't verify transaction")
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}
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tx.NetworkFee += gasConsumed
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netFee, sizeDelta := fee.Calculate(o.Chain.GetBaseExecFee(), tx.Scripts[1].VerificationScript)
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tx.NetworkFee += netFee
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size += sizeDelta
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currNetFee := tx.NetworkFee + int64(size)*o.Chain.FeePerByte()
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if currNetFee > gasForResponse {
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attrSize := io.GetVarSize(tx.Attributes)
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resp.Code = transaction.InsufficientFunds
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resp.Result = nil
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size = size - attrSize + io.GetVarSize(tx.Attributes)
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}
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tx.NetworkFee += int64(size) * o.Chain.FeePerByte() // 233
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// Calculate system fee.
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tx.SystemFee = gasForResponse - tx.NetworkFee
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return tx, nil
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}
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func (o *Oracle) testVerify(tx *transaction.Transaction) (int64, bool, error) {
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// (*Blockchain).GetTestVM calls Hash() method of the provided transaction; once being called, this
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// method caches transaction hash, but tx building is not yet completed and hash will be changed.
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// So, make a copy of the tx to avoid wrong hash caching.
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cp := *tx
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ic, err := o.Chain.GetTestVM(trigger.Verification, &cp, nil)
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if err != nil {
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return 0, false, fmt.Errorf("failed to create test VM: %w", err)
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}
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ic.VM.GasLimit = o.Chain.GetMaxVerificationGAS()
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o.oracleInfoLock.RLock()
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ic.VM.LoadScriptWithHash(o.oracleScript, nativehashes.OracleContract, callflag.ReadOnly)
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ic.VM.Context().Jump(o.verifyOffset)
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o.oracleInfoLock.RUnlock()
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ok := isVerifyOk(ic)
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return ic.VM.GasConsumed(), ok, nil
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}
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func isVerifyOk(ic *interop.Context) bool {
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defer ic.Finalize()
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if err := ic.VM.Run(); err != nil {
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return false
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}
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if ic.VM.Estack().Len() != 1 {
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return false
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}
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ok, err := ic.VM.Estack().Pop().Item().TryBool()
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return err == nil && ok
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}
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func getFailedResponse(id uint64) *transaction.OracleResponse {
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return &transaction.OracleResponse{
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ID: id,
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Code: transaction.Error,
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}
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}
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