Beispiel #1
0
// checkInputsStandard performs a series of checks on a transaction's inputs
// to ensure they are "standard".  A standard transaction input within the
// context of this function is one whose referenced public key script is of a
// standard form and, for pay-to-script-hash, does not have more than
// maxStandardP2SHSigOps signature operations.  However, it should also be noted
// that standard inputs also are those which have a clean stack after execution
// and only contain pushed data in their signature scripts.  This function does
// not perform those checks because the script engine already does this more
// accurately and concisely via the txscript.ScriptVerifyCleanStack and
// txscript.ScriptVerifySigPushOnly flags.
func checkInputsStandard(tx *btcutil.Tx, utxoView *blockchain.UtxoViewpoint) error {
	// NOTE: The reference implementation also does a coinbase check here,
	// but coinbases have already been rejected prior to calling this
	// function so no need to recheck.

	for i, txIn := range tx.MsgTx().TxIn {
		// It is safe to elide existence and index checks here since
		// they have already been checked prior to calling this
		// function.
		prevOut := txIn.PreviousOutPoint
		entry := utxoView.LookupEntry(&prevOut.Hash)
		originPkScript := entry.PkScriptByIndex(prevOut.Index)
		switch txscript.GetScriptClass(originPkScript) {
		case txscript.ScriptHashTy:
			numSigOps := txscript.GetPreciseSigOpCount(
				txIn.SignatureScript, originPkScript, true)
			if numSigOps > maxStandardP2SHSigOps {
				str := fmt.Sprintf("transaction input #%d has "+
					"%d signature operations which is more "+
					"than the allowed max amount of %d",
					i, numSigOps, maxStandardP2SHSigOps)
				return txRuleError(wire.RejectNonstandard, str)
			}

		case txscript.NonStandardTy:
			str := fmt.Sprintf("transaction input #%d has a "+
				"non-standard script form", i)
			return txRuleError(wire.RejectNonstandard, str)
		}
	}

	return nil
}
Beispiel #2
0
// isNonstandardTransaction determines whether a transaction contains any
// scripts which are not one of the standard types.
func isNonstandardTransaction(tx *btcutil.Tx) bool {
	// Check all of the output public key scripts for non-standard scripts.
	for _, txOut := range tx.MsgTx().TxOut {
		scriptClass := txscript.GetScriptClass(txOut.PkScript)
		if scriptClass == txscript.NonStandardTy {
			return true
		}
	}
	return false
}
// isNonstandardTransaction determines whether a transaction contains any
// scripts which are not one of the standard types.
func isNonstandardTransaction(tx *btcutil.Tx) bool {
	// TODO(davec): Should there be checks for the input signature scripts?

	// Check all of the output public key scripts for non-standard scripts.
	for _, txOut := range tx.MsgTx().TxOut {
		scriptClass := txscript.GetScriptClass(txOut.PkScript)
		if scriptClass == txscript.NonStandardTy {
			return true
		}
	}
	return false
}
Beispiel #4
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// maybeAddOutpoint potentially adds the passed outpoint to the bloom filter
// depending on the bloom update flags and the type of the passed public key
// script.
//
// This function MUST be called with the filter lock held.
func (bf *Filter) maybeAddOutpoint(pkScript []byte, outHash *wire.ShaHash, outIdx uint32) {
	switch bf.msgFilterLoad.Flags {
	case wire.BloomUpdateAll:
		outpoint := wire.NewOutPoint(outHash, outIdx)
		bf.addOutPoint(outpoint)
	case wire.BloomUpdateP2PubkeyOnly:
		class := txscript.GetScriptClass(pkScript)
		if class == txscript.PubKeyTy || class == txscript.MultiSigTy {
			outpoint := wire.NewOutPoint(outHash, outIdx)
			bf.addOutPoint(outpoint)
		}
	}
}
Beispiel #5
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// TestScriptClass ensures all the scripts in scriptClassTests have the expected
// class.
func TestScriptClass(t *testing.T) {
	t.Parallel()

	for _, test := range scriptClassTests {
		script := mustParseShortForm(test.script)
		class := txscript.GetScriptClass(script)
		if class != test.class {
			t.Errorf("%s: expected %s got %s", test.name,
				test.class, class)
			return
		}
	}
}
Beispiel #6
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// IsDustOutput determines whether a transaction output is considered dust.
// Transactions with dust outputs are not standard and are rejected by mempools
// with default policies.
func IsDustOutput(output *wire.TxOut, relayFeePerKb btcutil.Amount) bool {
	// Unspendable outputs which solely carry data are not checked for dust.
	if txscript.GetScriptClass(output.PkScript) == txscript.NullDataTy {
		return false
	}

	// All other unspendable outputs are considered dust.
	if txscript.IsUnspendable(output.PkScript) {
		return true
	}

	return IsDustAmount(btcutil.Amount(output.Value), len(output.PkScript),
		relayFeePerKb)
}
Beispiel #7
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// checkTransactionStandard performs a series of checks on a transaction to
// ensure it is a "standard" transaction.  A standard transaction is one that
// conforms to several additional limiting cases over what is considered a
// "sane" transaction such as having a version in the supported range, being
// finalized, conforming to more stringent size constraints, having scripts
// of recognized forms, and not containing "dust" outputs (those that are
// so small it costs more to process them than they are worth).
func checkTransactionStandard(tx *btcutil.Tx, height int32,
	medianTimePast time.Time, minRelayTxFee btcutil.Amount,
	maxTxVersion int32) error {

	// The transaction must be a currently supported version.
	msgTx := tx.MsgTx()
	if msgTx.Version > maxTxVersion || msgTx.Version < 1 {
		str := fmt.Sprintf("transaction version %d is not in the "+
			"valid range of %d-%d", msgTx.Version, 1,
			maxTxVersion)
		return txRuleError(wire.RejectNonstandard, str)
	}

	// The transaction must be finalized to be standard and therefore
	// considered for inclusion in a block.
	if !blockchain.IsFinalizedTransaction(tx, height, medianTimePast) {
		return txRuleError(wire.RejectNonstandard,
			"transaction is not finalized")
	}

	// Since extremely large transactions with a lot of inputs can cost
	// almost as much to process as the sender fees, limit the maximum
	// size of a transaction.  This also helps mitigate CPU exhaustion
	// attacks.
	serializedLen := msgTx.SerializeSize()
	if serializedLen > MaxStandardTxSize {
		str := fmt.Sprintf("transaction size of %v is larger than max "+
			"allowed size of %v", serializedLen, MaxStandardTxSize)
		return txRuleError(wire.RejectNonstandard, str)
	}

	for i, txIn := range msgTx.TxIn {
		// Each transaction input signature script must not exceed the
		// maximum size allowed for a standard transaction.  See
		// the comment on maxStandardSigScriptSize for more details.
		sigScriptLen := len(txIn.SignatureScript)
		if sigScriptLen > maxStandardSigScriptSize {
			str := fmt.Sprintf("transaction input %d: signature "+
				"script size of %d bytes is large than max "+
				"allowed size of %d bytes", i, sigScriptLen,
				maxStandardSigScriptSize)
			return txRuleError(wire.RejectNonstandard, str)
		}

		// Each transaction input signature script must only contain
		// opcodes which push data onto the stack.
		if !txscript.IsPushOnlyScript(txIn.SignatureScript) {
			str := fmt.Sprintf("transaction input %d: signature "+
				"script is not push only", i)
			return txRuleError(wire.RejectNonstandard, str)
		}
	}

	// None of the output public key scripts can be a non-standard script or
	// be "dust" (except when the script is a null data script).
	numNullDataOutputs := 0
	for i, txOut := range msgTx.TxOut {
		scriptClass := txscript.GetScriptClass(txOut.PkScript)
		err := checkPkScriptStandard(txOut.PkScript, scriptClass)
		if err != nil {
			// Attempt to extract a reject code from the error so
			// it can be retained.  When not possible, fall back to
			// a non standard error.
			rejectCode := wire.RejectNonstandard
			if rejCode, found := extractRejectCode(err); found {
				rejectCode = rejCode
			}
			str := fmt.Sprintf("transaction output %d: %v", i, err)
			return txRuleError(rejectCode, str)
		}

		// Accumulate the number of outputs which only carry data.  For
		// all other script types, ensure the output value is not
		// "dust".
		if scriptClass == txscript.NullDataTy {
			numNullDataOutputs++
		} else if isDust(txOut, minRelayTxFee) {
			str := fmt.Sprintf("transaction output %d: payment "+
				"of %d is dust", i, txOut.Value)
			return txRuleError(wire.RejectDust, str)
		}
	}

	// A standard transaction must not have more than one output script that
	// only carries data.
	if numNullDataOutputs > 1 {
		str := "more than one transaction output in a nulldata script"
		return txRuleError(wire.RejectNonstandard, str)
	}

	return nil
}
Beispiel #8
0
// TestCheckPkScriptStandard tests the checkPkScriptStandard API.
func TestCheckPkScriptStandard(t *testing.T) {
	var pubKeys [][]byte
	for i := 0; i < 4; i++ {
		pk, err := btcec.NewPrivateKey(btcec.S256())
		if err != nil {
			t.Fatalf("TestCheckPkScriptStandard NewPrivateKey failed: %v",
				err)
			return
		}
		pubKeys = append(pubKeys, pk.PubKey().SerializeCompressed())
	}

	tests := []struct {
		name       string // test description.
		script     *txscript.ScriptBuilder
		isStandard bool
	}{
		{
			"key1 and key2",
			txscript.NewScriptBuilder().AddOp(txscript.OP_2).
				AddData(pubKeys[0]).AddData(pubKeys[1]).
				AddOp(txscript.OP_2).AddOp(txscript.OP_CHECKMULTISIG),
			true,
		},
		{
			"key1 or key2",
			txscript.NewScriptBuilder().AddOp(txscript.OP_1).
				AddData(pubKeys[0]).AddData(pubKeys[1]).
				AddOp(txscript.OP_2).AddOp(txscript.OP_CHECKMULTISIG),
			true,
		},
		{
			"escrow",
			txscript.NewScriptBuilder().AddOp(txscript.OP_2).
				AddData(pubKeys[0]).AddData(pubKeys[1]).
				AddData(pubKeys[2]).
				AddOp(txscript.OP_3).AddOp(txscript.OP_CHECKMULTISIG),
			true,
		},
		{
			"one of four",
			txscript.NewScriptBuilder().AddOp(txscript.OP_1).
				AddData(pubKeys[0]).AddData(pubKeys[1]).
				AddData(pubKeys[2]).AddData(pubKeys[3]).
				AddOp(txscript.OP_4).AddOp(txscript.OP_CHECKMULTISIG),
			false,
		},
		{
			"malformed1",
			txscript.NewScriptBuilder().AddOp(txscript.OP_3).
				AddData(pubKeys[0]).AddData(pubKeys[1]).
				AddOp(txscript.OP_2).AddOp(txscript.OP_CHECKMULTISIG),
			false,
		},
		{
			"malformed2",
			txscript.NewScriptBuilder().AddOp(txscript.OP_2).
				AddData(pubKeys[0]).AddData(pubKeys[1]).
				AddOp(txscript.OP_3).AddOp(txscript.OP_CHECKMULTISIG),
			false,
		},
		{
			"malformed3",
			txscript.NewScriptBuilder().AddOp(txscript.OP_0).
				AddData(pubKeys[0]).AddData(pubKeys[1]).
				AddOp(txscript.OP_2).AddOp(txscript.OP_CHECKMULTISIG),
			false,
		},
		{
			"malformed4",
			txscript.NewScriptBuilder().AddOp(txscript.OP_1).
				AddData(pubKeys[0]).AddData(pubKeys[1]).
				AddOp(txscript.OP_0).AddOp(txscript.OP_CHECKMULTISIG),
			false,
		},
		{
			"malformed5",
			txscript.NewScriptBuilder().AddOp(txscript.OP_1).
				AddData(pubKeys[0]).AddData(pubKeys[1]).
				AddOp(txscript.OP_CHECKMULTISIG),
			false,
		},
		{
			"malformed6",
			txscript.NewScriptBuilder().AddOp(txscript.OP_1).
				AddData(pubKeys[0]).AddData(pubKeys[1]),
			false,
		},
	}

	for _, test := range tests {
		script, err := test.script.Script()
		if err != nil {
			t.Fatalf("TestCheckPkScriptStandard test '%s' "+
				"failed: %v", test.name, err)
			continue
		}
		scriptClass := txscript.GetScriptClass(script)
		got := checkPkScriptStandard(script, scriptClass)
		if (test.isStandard && got != nil) ||
			(!test.isStandard && got == nil) {

			t.Fatalf("TestCheckPkScriptStandard test '%s' failed",
				test.name)
			return
		}
	}
}