Merge #18422: [consensus] MOVEONLY: Move single-sig checking EvalScript code to EvalChecksig

14e8cf974a [consensus] MOVEONLY: Move single-sig checking EvalScript code to EvalChecksig (Pieter Wuille)

Pull request description:

  This is another small refactor pulled out of the Schnorr/Taproot PR #17977.

  This is in preparation for adding different signature verification rules,
  specifically tapscript (BIP 342), which interprets opcode 0xac and 0xad
  as Schnorr signature verifications.

ACKs for top commit:
  sipa:
    ACK 14e8cf974a, verified move-only.
  MarcoFalke:
    ACK 14e8cf974a, reviewed with "git show 14e8cf974a --color-moved=dimmed-zebra --color-moved-ws=ignore-all-space -W" 👆
  fjahr:
    Code-review ACK 14e8cf974a, verified that it's move-only.
  instagibbs:
    code review ACK 14e8cf974a, verified move-only
  theStack:
    Code-Review ACK 14e8cf974a
  jonatack:
    ACK 14e8cf974a

Tree-SHA512: af2efce9ae39d5ec01db5b9ef0ff383fe252ef5f33b3483927308ae17d91a619266cb45951f32ea1ce54807a4c0f052bcdefb47e244465d3a726393221c227b1
This commit is contained in:
MarcoFalke 2020-04-10 12:59:22 -04:00
commit a9213bbe75
No known key found for this signature in database
GPG key ID: CE2B75697E69A548

View file

@ -342,6 +342,35 @@ public:
};
}
/** Helper for OP_CHECKSIG and OP_CHECKSIGVERIFY
*
* A return value of false means the script fails entirely. When true is returned, the
* fSuccess variable indicates whether the signature check itself succeeded.
*/
static bool EvalChecksig(const valtype& vchSig, const valtype& vchPubKey, CScript::const_iterator pbegincodehash, CScript::const_iterator pend, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror, bool& fSuccess)
{
// Subset of script starting at the most recent codeseparator
CScript scriptCode(pbegincodehash, pend);
// Drop the signature in pre-segwit scripts but not segwit scripts
if (sigversion == SigVersion::BASE) {
int found = FindAndDelete(scriptCode, CScript() << vchSig);
if (found > 0 && (flags & SCRIPT_VERIFY_CONST_SCRIPTCODE))
return set_error(serror, SCRIPT_ERR_SIG_FINDANDDELETE);
}
if (!CheckSignatureEncoding(vchSig, flags, serror) || !CheckPubKeyEncoding(vchPubKey, flags, sigversion, serror)) {
//serror is set
return false;
}
fSuccess = checker.CheckSig(vchSig, vchPubKey, scriptCode, sigversion);
if (!fSuccess && (flags & SCRIPT_VERIFY_NULLFAIL) && vchSig.size())
return set_error(serror, SCRIPT_ERR_SIG_NULLFAIL);
return true;
}
bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror)
{
static const CScriptNum bnZero(0);
@ -985,25 +1014,8 @@ bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript&
valtype& vchSig = stacktop(-2);
valtype& vchPubKey = stacktop(-1);
// Subset of script starting at the most recent codeseparator
CScript scriptCode(pbegincodehash, pend);
// Drop the signature in pre-segwit scripts but not segwit scripts
if (sigversion == SigVersion::BASE) {
int found = FindAndDelete(scriptCode, CScript() << vchSig);
if (found > 0 && (flags & SCRIPT_VERIFY_CONST_SCRIPTCODE))
return set_error(serror, SCRIPT_ERR_SIG_FINDANDDELETE);
}
if (!CheckSignatureEncoding(vchSig, flags, serror) || !CheckPubKeyEncoding(vchPubKey, flags, sigversion, serror)) {
//serror is set
return false;
}
bool fSuccess = checker.CheckSig(vchSig, vchPubKey, scriptCode, sigversion);
if (!fSuccess && (flags & SCRIPT_VERIFY_NULLFAIL) && vchSig.size())
return set_error(serror, SCRIPT_ERR_SIG_NULLFAIL);
bool fSuccess = true;
if (!EvalChecksig(vchSig, vchPubKey, pbegincodehash, pend, flags, checker, sigversion, serror, fSuccess)) return false;
popstack(stack);
popstack(stack);
stack.push_back(fSuccess ? vchTrue : vchFalse);