// OP_CHECKSIG
// OP_CHECKSIGVERIFY
func execCheckSig(ctx *execContext, op Opcode, _ []byte) error {
if ctx.stack.height() < 2 {
return errStackItemMissing
}
pk := ctx.stack.pop()
sig := ctx.stack.pop()
subScript := make([]byte, len(ctx.script)-ctx.separator)
copy(subScript, ctx.script[ctx.separator:])
subScript, err := removeSig(subScript, sig)
if err != nil {
return err
}
err = checkKeySig(ctx.sctx, pk, sig, subScript, ctx.flags)
if op == OP_CHECKSIGVERIFY {
if err != nil {
return errSigVerify
}
} else { // OP_CHECKSIG
b := klib.ScriptInt(1)
if err != nil {
b = 0
}
ctx.stack.push(b.Bytes())
}
return nil
}
func (s *Script) AppendPushInt(v int64) {
if v == int64(OP_1NEGATE) || (v >= 1 && v <= 16) {
s.AppendOp(Opcode(v + int64(OP_1) - 1))
} else {
i := klib.ScriptInt(v)
s.AppendPushData(i.Bytes())
}
}
// OP_CHECKMULTISIG
// OP_CHECKMULTISIGVERIFY
func execCheckMultiSig(ctx *execContext, op Opcode, _ []byte) error {
i := 1
if ctx.stack.height() < i {
return errStackItemMissing
}
kCount := int(klib.ToScriptInt(ctx.stack.top(-i)))
if kCount < 0 || kCount > numbers.MaxMultiSigKeyCount {
return errKeySigCountOutOfRange
}
ctx.opCount += kCount
if ctx.opCount > numbers.MaxOpcodeCount {
return errOpcodeCount
}
i++
iKey := i
i += kCount
if ctx.stack.height() < i {
return errStackItemMissing
}
sCount := int(klib.ToScriptInt(ctx.stack.top(-i)))
if sCount < 0 || sCount > kCount {
return errKeySigCountOutOfRange
}
i++
iSig := i
i += sCount
if ctx.stack.height() < i {
return errStackItemMissing
}
subScript := make([]byte, len(ctx.script)-ctx.separator)
copy(subScript, ctx.script[ctx.separator:])
for k := 0; k < sCount; k++ {
var err error
subScript, err = removeSig(subScript, ctx.stack.top(-(iSig + k)))
if err != nil {
return err
}
}
success := true
for success && (sCount > 0) {
pk := ctx.stack.top(-iKey)
sig := ctx.stack.top(-iSig)
err := checkKeySig(ctx.sctx, pk, sig, subScript, ctx.flags)
if err == nil {
iSig++
sCount--
}
iKey++
kCount--
// If there are more signatures left than keys left,
// then too many signatures have failed
if sCount > kCount {
success = false
}
}
// A Satoshi Bug causes CHECKMULTISIG to consume an extra item on the stack
// We first clear all the "real" arguments
stk := *ctx.stack
*ctx.stack = stk[:len(stk)-i+1]
// The dummy item is still requried
if ctx.stack.empty() {
return errStackItemMissing
}
// Now we check dummy being null when required
si := ctx.stack.pop()
if (ctx.flags&EvalFlagNullDummy) != 0 && len(si) > 0 {
return errDummyArgNotNull
}
if op == OP_CHECKMULTISIGVERIFY {
if !success {
return errSigVerify
}
} else { // OP_CHECKMULTISIG
b := klib.ScriptInt(1)
if !success {
b = 0
}
ctx.stack.push(b.Bytes())
}
return nil
}
func intToStackItem(i int) stackItem {
return klib.ScriptInt(i).Bytes()
}