Sanity check transaction scripts in DecodeHexTx

Make sure that the scripts of decoded transactions are valid scripts.
This commit is contained in:
Andrew Chow 2017-05-30 15:43:07 -07:00
parent 5b75c47784
commit ac4e438229
3 changed files with 31 additions and 4 deletions

View File

@ -88,10 +88,32 @@ CScript ParseScript(const std::string& s)
return result; return result;
} }
// Check that all of the input and output scripts of a transaction contains valid opcodes
bool CheckTxScriptsSanity(const CMutableTransaction& tx)
{
// Check input scripts for non-coinbase txs
if (!CTransaction(tx).IsCoinBase()) {
for (unsigned int i = 0; i < tx.vin.size(); i++) {
if (!tx.vin[i].scriptSig.HasValidOps() || tx.vin[i].scriptSig.size() > MAX_SCRIPT_SIZE) {
return false;
}
}
}
// Check output scripts
for (unsigned int i = 0; i < tx.vout.size(); i++) {
if (!tx.vout[i].scriptPubKey.HasValidOps() || tx.vout[i].scriptPubKey.size() > MAX_SCRIPT_SIZE) {
return false;
}
}
return true;
}
bool DecodeHexTx(CMutableTransaction& tx, const std::string& strHexTx, bool fTryNoWitness) bool DecodeHexTx(CMutableTransaction& tx, const std::string& strHexTx, bool fTryNoWitness)
{ {
if (!IsHex(strHexTx)) if (!IsHex(strHexTx)) {
return false; return false;
}
std::vector<unsigned char> txData(ParseHex(strHexTx)); std::vector<unsigned char> txData(ParseHex(strHexTx));
@ -99,7 +121,7 @@ bool DecodeHexTx(CMutableTransaction& tx, const std::string& strHexTx, bool fTry
CDataStream ssData(txData, SER_NETWORK, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS); CDataStream ssData(txData, SER_NETWORK, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS);
try { try {
ssData >> tx; ssData >> tx;
if (ssData.eof()) { if (ssData.eof() && CheckTxScriptsSanity(tx)) {
return true; return true;
} }
} }
@ -111,8 +133,9 @@ bool DecodeHexTx(CMutableTransaction& tx, const std::string& strHexTx, bool fTry
CDataStream ssData(txData, SER_NETWORK, PROTOCOL_VERSION); CDataStream ssData(txData, SER_NETWORK, PROTOCOL_VERSION);
try { try {
ssData >> tx; ssData >> tx;
if (!ssData.empty()) if (!ssData.empty()) {
return false; return false;
}
} }
catch (const std::exception&) { catch (const std::exception&) {
return false; return false;

View File

@ -273,7 +273,8 @@ bool CScript::HasValidOps() const
CScript::const_iterator it = begin(); CScript::const_iterator it = begin();
while (it < end()) { while (it < end()) {
opcodetype opcode; opcodetype opcode;
if (!GetOp(it, opcode) || opcode > 0xb9) { std::vector<unsigned char> item;
if (!GetOp(it, opcode, item) || opcode > MAX_OPCODE || item.size() > MAX_SCRIPT_ELEMENT_SIZE) {
return false; return false;
} }
} }

View File

@ -190,6 +190,9 @@ enum opcodetype
OP_INVALIDOPCODE = 0xff, OP_INVALIDOPCODE = 0xff,
}; };
// Maximum value that an opcode can be
static const unsigned int MAX_OPCODE = OP_NOP10;
const char* GetOpName(opcodetype opcode); const char* GetOpName(opcodetype opcode);
class scriptnum_error : public std::runtime_error class scriptnum_error : public std::runtime_error