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-rw-r--r--src/script/standard.cpp46
1 files changed, 39 insertions, 7 deletions
diff --git a/src/script/standard.cpp b/src/script/standard.cpp
index 700155c8d4..e6f99f3034 100644
--- a/src/script/standard.cpp
+++ b/src/script/standard.cpp
@@ -88,21 +88,53 @@ static constexpr bool IsSmallInteger(opcodetype opcode)
return opcode >= OP_1 && opcode <= OP_16;
}
-static bool MatchMultisig(const CScript& script, unsigned int& required, std::vector<valtype>& pubkeys)
+static constexpr bool IsPushdataOp(opcodetype opcode)
+{
+ return opcode > OP_FALSE && opcode <= OP_PUSHDATA4;
+}
+
+static constexpr bool IsValidMultisigKeyCount(int n_keys)
+{
+ return n_keys > 0 && n_keys <= MAX_PUBKEYS_PER_MULTISIG;
+}
+
+static bool GetMultisigKeyCount(opcodetype opcode, valtype data, int& count)
+{
+ if (IsSmallInteger(opcode)) {
+ count = CScript::DecodeOP_N(opcode);
+ return IsValidMultisigKeyCount(count);
+ }
+
+ if (IsPushdataOp(opcode)) {
+ if (!CheckMinimalPush(data, opcode)) return false;
+ try {
+ count = CScriptNum(data, /* fRequireMinimal = */ true).getint();
+ return IsValidMultisigKeyCount(count);
+ } catch (const scriptnum_error&) {
+ return false;
+ }
+ }
+
+ return false;
+}
+
+static bool MatchMultisig(const CScript& script, int& required_sigs, std::vector<valtype>& pubkeys)
{
opcodetype opcode;
valtype data;
+ int num_keys;
+
CScript::const_iterator it = script.begin();
if (script.size() < 1 || script.back() != OP_CHECKMULTISIG) return false;
- if (!script.GetOp(it, opcode, data) || !IsSmallInteger(opcode)) return false;
- required = CScript::DecodeOP_N(opcode);
+ if (!script.GetOp(it, opcode, data) || !GetMultisigKeyCount(opcode, data, required_sigs)) return false;
while (script.GetOp(it, opcode, data) && CPubKey::ValidSize(data)) {
pubkeys.emplace_back(std::move(data));
}
- if (!IsSmallInteger(opcode)) return false;
- unsigned int keys = CScript::DecodeOP_N(opcode);
- if (pubkeys.size() != keys || keys < required) return false;
+ if (!GetMultisigKeyCount(opcode, data, num_keys)) return false;
+
+ if (pubkeys.size() != static_cast<unsigned long>(num_keys) || num_keys < required_sigs) return false;
+
return (it + 1 == script.end());
}
@@ -163,7 +195,7 @@ TxoutType Solver(const CScript& scriptPubKey, std::vector<std::vector<unsigned c
return TxoutType::PUBKEYHASH;
}
- unsigned int required;
+ int required;
std::vector<std::vector<unsigned char>> keys;
if (MatchMultisig(scriptPubKey, required, keys)) {
vSolutionsRet.push_back({static_cast<unsigned char>(required)}); // safe as required is in range 1..16