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Schnorr sig parsing checks (#4482)

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benthecarman 2022-07-10 16:00:38 -05:00 • committed by GitHub
parent ec599a5c3d
commit 3821060e68
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
1 changed files with 27 additions and 40 deletions
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67
core/src/main/scala/org/bitcoins/core/script/crypto/CryptoInterpreter.scala
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@ -20,6 +20,8 @@ import org.bitcoins.core.util.BitcoinScriptUtil
import org.bitcoins.crypto._
import scodec.bits.ByteVector
import scala.util.Try
/** Created by chris on 1/6/16.
*/
sealed abstract class CryptoInterpreter {
@ -154,33 +156,22 @@ sealed abstract class CryptoInterpreter {
* if the signature is the empty byte vector which trivially
* fails script interpreter validation
*/
private def getSignatureAndHashType(
stack: List[ScriptToken],
isCheckSigAdd: Boolean): Option[(SchnorrDigitalSignature, HashType)] = {
val sigBytes = {
if (isCheckSigAdd) {
stack(2).bytes
} else {
stack.tail.head.bytes
}
}
val sigHashTypeOpt: Option[(SchnorrDigitalSignature, HashType)] = {
if (sigBytes.length == 64) {
val sig = SchnorrDigitalSignature.fromBytes(sigBytes)
Some((sig, HashType.sigHashDefault))
} else if (sigBytes.length == 65) {
val hashTypeByte = sigBytes.last
val hashType = HashType.fromByte(hashTypeByte)
val sig = SchnorrDigitalSignature.fromBytes(sigBytes.dropRight(1))
Some((sig, hashType))
} else if (sigBytes.isEmpty) {
None
} else {
sys.error(
s"Incorrect length for schnorr digital signature, got=${sigBytes.length}, expected 64 or 65 sigBytes=${sigBytes}")
}
}
sigHashTypeOpt
private def getSignatureAndHashType(sigBytes: ByteVector): Either[
ScriptError,
(SchnorrDigitalSignature, HashType)] = {
val parseT = Try(if (sigBytes.length == 64) {
val sig = SchnorrDigitalSignature.fromBytes(sigBytes)
Right((sig, HashType.sigHashDefault))
} else if (sigBytes.length == 65) {
val hashTypeByte = sigBytes.last
val hashType = HashType.fromByte(hashTypeByte)
val sig = SchnorrDigitalSignature.fromBytes(sigBytes.dropRight(1))
Right((sig, hashType))
} else {
Left(ScriptErrorSchnorrSigSize)
})
parseT.getOrElse(Left(ScriptErrorSchnorrSig))
}
private def evalChecksigTapscript(
@ -226,19 +217,15 @@ sealed abstract class CryptoInterpreter {
sys.error(s"Invalid pubkey with 32 bytes in size, got=${xOnlyPubKeyT}")
} else {
val helperE: Either[ScriptError, TapscriptChecksigHelper] = {
val sigHashTypeOpt = getSignatureAndHashType(stack, isCheckSigAdd)
sigHashTypeOpt match {
case Some((signature, hashType)) =>
val restOfStack =
program.stack.tail.tail //remove pubkey, signature
val helper = TapscriptChecksigHelper(pubKey = xOnlyPubKeyT.get,
signature = signature,
hashType = hashType,
restOfStack = restOfStack)
Right(helper)
case None =>
//this is because the signature was empty
Left(ScriptErrorEvalFalse)
val sigHashTypeE = getSignatureAndHashType(sigBytes)
sigHashTypeE.map { case (signature, hashType) =>
val restOfStack =
program.stack.tail.tail //remove pubkey, signature
val helper = TapscriptChecksigHelper(pubKey = xOnlyPubKeyT.get,
signature = signature,
hashType = hashType,
restOfStack = restOfStack)
helper
}
}
helperE match {