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Require atomic swap contracts to specify the secret size.

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This allows redeeming parties to audit the secret size and ensure it
will be usable once revealed.
This commit is contained in:
Josh Rickmar 2018-02-16 16:18:43 -05:00
parent 9866016012
commit 1cd648d784
1 changed files with 38 additions and 23 deletions
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61
txscript/standard.go
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@ -629,6 +629,7 @@ type AtomicSwapDataPushes struct {
RecipientHash160 [20]byte RecipientHash160 [20]byte
RefundHash160 [20]byte RefundHash160 [20]byte
SecretHash [32]byte SecretHash [32]byte
SecretSize int64
LockTime int64 LockTime int64
} }
@ -643,47 +644,61 @@ type AtomicSwapDataPushes struct {
// //
// This function is only defined in the txscript package due to API limitations // This function is only defined in the txscript package due to API limitations
// which prevent callers using txscript to parse nonstandard scripts. // which prevent callers using txscript to parse nonstandard scripts.
func ExtractAtomicSwapDataPushes(pkScript []byte) (*AtomicSwapDataPushes, error) { func ExtractAtomicSwapDataPushes(version uint16, pkScript []byte) (*AtomicSwapDataPushes, error) {
pops, err := parseScript(pkScript) pops, err := parseScript(pkScript)
if err != nil { if err != nil {
return nil, err return nil, err
} }
if len(pops) != 17 { if len(pops) != 20 {
return nil, nil return nil, nil
} }
isAtomicSwap := pops[0].opcode.value == OP_IF && isAtomicSwap := pops[0].opcode.value == OP_IF &&
pops[1].opcode.value == OP_SHA256 && pops[1].opcode.value == OP_SIZE &&
pops[2].opcode.value == OP_DATA_32 && canonicalPush(pops[2]) &&
pops[3].opcode.value == OP_EQUALVERIFY && pops[3].opcode.value == OP_EQUALVERIFY &&
pops[4].opcode.value == OP_DUP && pops[4].opcode.value == OP_SHA256 &&
pops[5].opcode.value == OP_HASH160 && pops[5].opcode.value == OP_DATA_32 &&
pops[6].opcode.value == OP_DATA_20 && pops[6].opcode.value == OP_EQUALVERIFY &&
pops[7].opcode.value == OP_ELSE && pops[7].opcode.value == OP_DUP &&
canonicalPush(pops[8]) && pops[8].opcode.value == OP_HASH160 &&
pops[9].opcode.value == OP_CHECKLOCKTIMEVERIFY && pops[9].opcode.value == OP_DATA_20 &&
pops[10].opcode.value == OP_DROP && pops[10].opcode.value == OP_ELSE &&
pops[11].opcode.value == OP_DUP && canonicalPush(pops[11]) &&
pops[12].opcode.value == OP_HASH160 && pops[12].opcode.value == OP_CHECKLOCKTIMEVERIFY &&
pops[13].opcode.value == OP_DATA_20 && pops[13].opcode.value == OP_DROP &&
pops[14].opcode.value == OP_ENDIF && pops[14].opcode.value == OP_DUP &&
pops[15].opcode.value == OP_EQUALVERIFY && pops[15].opcode.value == OP_HASH160 &&
pops[16].opcode.value == OP_CHECKSIG pops[16].opcode.value == OP_DATA_20 &&
pops[17].opcode.value == OP_ENDIF &&
pops[18].opcode.value == OP_EQUALVERIFY &&
pops[19].opcode.value == OP_CHECKSIG
if !isAtomicSwap { if !isAtomicSwap {
return nil, nil return nil, nil
} }
pushes := new(AtomicSwapDataPushes) pushes := new(AtomicSwapDataPushes)
copy(pushes.SecretHash[:], pops[2].data) copy(pushes.SecretHash[:], pops[5].data)
copy(pushes.RecipientHash160[:], pops[6].data) copy(pushes.RecipientHash160[:], pops[9].data)
copy(pushes.RefundHash160[:], pops[13].data) copy(pushes.RefundHash160[:], pops[16].data)
if pops[8].data != nil { if pops[2].data != nil {
locktime, err := makeScriptNum(pops[8].data, true, 5) locktime, err := makeScriptNum(pops[2].data, true, 5)
if err != nil {
return nil, nil
}
pushes.SecretSize = int64(locktime)
} else if op := pops[2].opcode; isSmallInt(op) {
pushes.SecretSize = int64(asSmallInt(op))
} else {
return nil, nil
}
if pops[11].data != nil {
locktime, err := makeScriptNum(pops[11].data, true, 5)
if err != nil { if err != nil {
return nil, nil return nil, nil
} }
pushes.LockTime = int64(locktime) pushes.LockTime = int64(locktime)
} else if op := pops[8].opcode; isSmallInt(op) { } else if op := pops[11].opcode; isSmallInt(op) {
pushes.LockTime = int64(asSmallInt(op)) pushes.LockTime = int64(asSmallInt(op))
} else { } else {
return nil, nil return nil, nil