// checkPkScriptStandard performs a series of checks on a transaction ouput
// script (public key script) to ensure it is a "standard" public key script.
// A standard public key script is one that is a recognized form, and for
// multi-signature scripts, only contains from 1 to maxStandardMultiSigKeys
// public keys.
func checkPkScriptStandard(version uint16, pkScript []byte,
scriptClass txscript.ScriptClass) error {
// Only default Bitcoin-style script is standard except for
// null data outputs.
if version != wire.DefaultPkScriptVersion {
str := fmt.Sprintf("versions other than default pkscript version " +
"are currently non-standard except for provably unspendable " +
"outputs")
return txRuleError(wire.RejectNonstandard, str)
}
switch scriptClass {
case txscript.MultiSigTy:
numPubKeys, numSigs, err := txscript.CalcMultiSigStats(pkScript)
if err != nil {
str := fmt.Sprintf("multi-signature script parse "+
"failure: %v", err)
return txRuleError(wire.RejectNonstandard, str)
}
// A standard multi-signature public key script must contain
// from 1 to maxStandardMultiSigKeys public keys.
if numPubKeys < 1 {
str := "multi-signature script with no pubkeys"
return txRuleError(wire.RejectNonstandard, str)
}
if numPubKeys > maxStandardMultiSigKeys {
str := fmt.Sprintf("multi-signature script with %d "+
"public keys which is more than the allowed "+
"max of %d", numPubKeys, maxStandardMultiSigKeys)
return txRuleError(wire.RejectNonstandard, str)
}
// A standard multi-signature public key script must have at
// least 1 signature and no more signatures than available
// public keys.
if numSigs < 1 {
return txRuleError(wire.RejectNonstandard,
"multi-signature script with no signatures")
}
if numSigs > numPubKeys {
str := fmt.Sprintf("multi-signature script with %d "+
"signatures which is more than the available "+
"%d public keys", numSigs, numPubKeys)
return txRuleError(wire.RejectNonstandard, str)
}
case txscript.NonStandardTy:
return txRuleError(wire.RejectNonstandard,
"non-standard script form")
}
return nil
}
// TestCalcMultiSigStats ensures the CalcMutliSigStats function returns the
// expected errors.
func TestCalcMultiSigStats(t *testing.T) {
t.Parallel()
tests := []struct {
name string
script string
err error
}{
{
name: "short script",
script: "0x046708afdb0fe5548271967f1a67130b7105cd6a828" +
"e03909a67962e0ea1f61d",
err: txscript.ErrStackShortScript,
},
{
name: "stack underflow",
script: "RETURN DATA_41 0x046708afdb0fe5548271967f1a" +
"67130b7105cd6a828e03909a67962e0ea1f61deb649f6" +
"bc3f4cef308",
err: txscript.ErrStackUnderflow,
},
{
name: "multisig script",
script: "0 DATA_72 0x30450220106a3e4ef0b51b764a2887226" +
"2ffef55846514dacbdcbbdd652c849d395b4384022100" +
"e03ae554c3cbb40600d31dd46fc33f25e47bf8525b1fe" +
"07282e3b6ecb5f3bb2801 CODESEPARATOR 1 DATA_33 " +
"0x0232abdc893e7f0631364d7fd01cb33d24da45329a0" +
"0357b3a7886211ab414d55a 1 CHECKMULTISIG",
err: nil,
},
}
for i, test := range tests {
script := mustParseShortForm(test.script)
if _, _, err := txscript.CalcMultiSigStats(script); err != test.err {
t.Errorf("CalcMultiSigStats #%d (%s) unexpected "+
"error\ngot: %v\nwant: %v", i, test.name, err,
test.err)
}
}
}