// TestHasCanonicalPush ensures the canonicalPush function works as expected.
func TestHasCanonicalPush(t *testing.T) {
t.Parallel()
for i := 0; i < 65535; i++ {
builder := txscript.NewScriptBuilder()
builder.AddInt64(int64(i))
script, err := builder.Script()
if err != nil {
t.Errorf("Script: test #%d unexpected error: %v\n", i,
err)
continue
}
if result := txscript.IsPushOnlyScript(script); !result {
t.Errorf("IsPushOnlyScript: test #%d failed: %x\n", i,
script)
continue
}
pops, err := txscript.TstParseScript(script)
if err != nil {
t.Errorf("TstParseScript: #%d failed: %v", i, err)
continue
}
for _, pop := range pops {
if result := txscript.TstHasCanonicalPushes(pop); !result {
t.Errorf("TstHasCanonicalPushes: test #%d "+
"failed: %x\n", i, script)
break
}
}
}
for i := 0; i <= txscript.MaxScriptElementSize; i++ {
builder := txscript.NewScriptBuilder()
builder.AddData(bytes.Repeat([]byte{0x49}, i))
script, err := builder.Script()
if err != nil {
t.Errorf("StandardPushesTests test #%d unexpected error: %v\n", i, err)
continue
}
if result := txscript.IsPushOnlyScript(script); !result {
t.Errorf("StandardPushesTests IsPushOnlyScript test #%d failed: %x\n", i, script)
continue
}
pops, err := txscript.TstParseScript(script)
if err != nil {
t.Errorf("StandardPushesTests #%d failed to TstParseScript: %v", i, err)
continue
}
for _, pop := range pops {
if result := txscript.TstHasCanonicalPushes(pop); !result {
t.Errorf("StandardPushesTests TstHasCanonicalPushes test #%d failed: %x\n", i, script)
break
}
}
}
}
// TestIsPushOnlyScript ensures the IsPushOnlyScript function returns the
// expected results.
func TestIsPushOnlyScript(t *testing.T) {
t.Parallel()
test := struct {
name string
script []byte
expected bool
}{
name: "does not parse",
script: mustParseShortForm("0x046708afdb0fe5548271967f1a67130" +
"b7105cd6a828e03909a67962e0ea1f61d"),
expected: false,
}
if txscript.IsPushOnlyScript(test.script) != test.expected {
t.Errorf("IsPushOnlyScript (%s) wrong result\ngot: %v\nwant: "+
"%v", test.name, true, test.expected)
}
}
// 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 *dcrutil.Tx, txType stake.TxType, height int64,
timeSource blockchain.MedianTimeSource,
minRelayTxFee dcrutil.Amount) error {
// The transaction must be a currently supported version.
msgTx := tx.MsgTx()
if !wire.IsSupportedMsgTxVersion(msgTx) {
str := fmt.Sprintf("transaction version %d is not in the "+
"valid range of %d-%d", msgTx.Version, 1,
wire.TxVersion)
return txRuleError(wire.RejectNonstandard, str)
}
// The transaction must be finalized to be standard and therefore
// considered for inclusion in a block.
adjustedTime := timeSource.AdjustedTime()
if !blockchain.IsFinalizedTransaction(tx, height, adjustedTime) {
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.Version, txOut.PkScript)
err := checkPkScriptStandard(txOut.Version, 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, found := extractRejectCode(err)
if !found {
rejectCode = wire.RejectNonstandard
}
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) &&
txType != stake.TxTypeSStx {
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. However, certain types of standard stake transactions
// are allowed to have multiple OP_RETURN outputs, so only throw an error here
// if the tx is TxTypeRegular.
if numNullDataOutputs > maxNullDataOutputs && txType == stake.TxTypeRegular {
str := "more than one transaction output in a nulldata script for a " +
"regular type tx"
return txRuleError(wire.RejectNonstandard, str)
}
return nil
}