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Merge/generalize IsValidMultisigKeyCount/GetMultisigKeyCount

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This commit is contained in:
Pieter Wuille
2022-01-12 11:03:17 -05:00
parent 16781e1bc9
commit 25e95f9ff8
1 changed files with 18 additions and 20 deletions
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38
src/script/standard.cpp
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@@ -96,47 +96,45 @@ static constexpr bool IsPushdataOp(opcodetype opcode)
return opcode > OP_FALSE && opcode <= OP_PUSHDATA4; return opcode > OP_FALSE && opcode <= OP_PUSHDATA4;
} }
static constexpr bool IsValidMultisigKeyCount(int n_keys) /** Retrieve a minimally-encoded number in range [min,max] from an (opcode, data) pair,
{ * whether it's OP_n or through a push. */
return n_keys > 0 && n_keys <= MAX_PUBKEYS_PER_MULTISIG; static std::optional<int> GetScriptNumber(opcodetype opcode, valtype data, int min, int max)
}
static bool GetMultisigKeyCount(opcodetype opcode, valtype data, int& count)
{ {
int count;
if (IsSmallInteger(opcode)) { if (IsSmallInteger(opcode)) {
count = CScript::DecodeOP_N(opcode); count = CScript::DecodeOP_N(opcode);
return IsValidMultisigKeyCount(count); } else if (IsPushdataOp(opcode)) {
} if (!CheckMinimalPush(data, opcode)) return {};
if (IsPushdataOp(opcode)) {
if (!CheckMinimalPush(data, opcode)) return false;
try { try {
count = CScriptNum(data, /* fRequireMinimal = */ true).getint(); count = CScriptNum(data, /* fRequireMinimal = */ true).getint();
return IsValidMultisigKeyCount(count);
} catch (const scriptnum_error&) { } catch (const scriptnum_error&) {
return false; return {};
} }
} else {
return {};
} }
if (count < min || count > max) return {};
return false; return count;
} }
static bool MatchMultisig(const CScript& script, int& required_sigs, std::vector<valtype>& pubkeys) static bool MatchMultisig(const CScript& script, int& required_sigs, std::vector<valtype>& pubkeys)
{ {
opcodetype opcode; opcodetype opcode;
valtype data; valtype data;
int num_keys;
CScript::const_iterator it = script.begin(); CScript::const_iterator it = script.begin();
if (script.size() < 1 || script.back() != OP_CHECKMULTISIG) return false; if (script.size() < 1 || script.back() != OP_CHECKMULTISIG) return false;
if (!script.GetOp(it, opcode, data) || !GetMultisigKeyCount(opcode, data, required_sigs)) return false; if (!script.GetOp(it, opcode, data)) return false;
auto req_sigs = GetScriptNumber(opcode, data, 1, MAX_PUBKEYS_PER_MULTISIG);
if (!req_sigs) return false;
required_sigs = *req_sigs;
while (script.GetOp(it, opcode, data) && CPubKey::ValidSize(data)) { while (script.GetOp(it, opcode, data) && CPubKey::ValidSize(data)) {
pubkeys.emplace_back(std::move(data)); pubkeys.emplace_back(std::move(data));
} }
if (!GetMultisigKeyCount(opcode, data, num_keys)) return false; auto num_keys = GetScriptNumber(opcode, data, required_sigs, MAX_PUBKEYS_PER_MULTISIG);
if (!num_keys) return false;
if (pubkeys.size() != static_cast<unsigned long>(num_keys) || num_keys < required_sigs) return false; if (pubkeys.size() != static_cast<unsigned long>(*num_keys)) return false;
return (it + 1 == script.end()); return (it + 1 == script.end());
} }