dogecoin/src/core_read.cpp
Pieter Wuille 1caa32e3f2 Improve heuristic hex transaction decoding
Whenever both encodings are permitted, try both, and if only one succeeds,
return that one. Otherwise prefer the one for which the heuristic sanity
check passes. If that is the case for neither or for both, return the
extended-permitting deserialization.

Github-Pull: #20595
Rebased-From: 39c42c442044aef611d03ee7053d2dd6df63deb7
2020-12-10 11:37:53 +01:00

273 lines
9.3 KiB
C++

// Copyright (c) 2009-2020 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include <core_io.h>
#include <primitives/block.h>
#include <primitives/transaction.h>
#include <script/script.h>
#include <script/sign.h>
#include <serialize.h>
#include <streams.h>
#include <univalue.h>
#include <util/strencodings.h>
#include <version.h>
#include <boost/algorithm/string/classification.hpp>
#include <boost/algorithm/string/replace.hpp>
#include <boost/algorithm/string/split.hpp>
#include <algorithm>
#include <string>
CScript ParseScript(const std::string& s)
{
CScript result;
static std::map<std::string, opcodetype> mapOpNames;
if (mapOpNames.empty())
{
for (unsigned int op = 0; op <= MAX_OPCODE; op++)
{
// Allow OP_RESERVED to get into mapOpNames
if (op < OP_NOP && op != OP_RESERVED)
continue;
std::string strName = GetOpName(static_cast<opcodetype>(op));
if (strName == "OP_UNKNOWN")
continue;
mapOpNames[strName] = static_cast<opcodetype>(op);
// Convenience: OP_ADD and just ADD are both recognized:
boost::algorithm::replace_first(strName, "OP_", "");
mapOpNames[strName] = static_cast<opcodetype>(op);
}
}
std::vector<std::string> words;
boost::algorithm::split(words, s, boost::algorithm::is_any_of(" \t\n"), boost::algorithm::token_compress_on);
for (std::vector<std::string>::const_iterator w = words.begin(); w != words.end(); ++w)
{
if (w->empty())
{
// Empty string, ignore. (boost::split given '' will return one word)
}
else if (std::all_of(w->begin(), w->end(), ::IsDigit) ||
(w->front() == '-' && w->size() > 1 && std::all_of(w->begin()+1, w->end(), ::IsDigit)))
{
// Number
int64_t n = atoi64(*w);
//limit the range of numbers ParseScript accepts in decimal
//since numbers outside -0xFFFFFFFF...0xFFFFFFFF are illegal in scripts
if (n > int64_t{0xffffffff} || n < -1 * int64_t{0xffffffff}) {
throw std::runtime_error("script parse error: decimal numeric value only allowed in the "
"range -0xFFFFFFFF...0xFFFFFFFF");
}
result << n;
}
else if (w->substr(0,2) == "0x" && w->size() > 2 && IsHex(std::string(w->begin()+2, w->end())))
{
// Raw hex data, inserted NOT pushed onto stack:
std::vector<unsigned char> raw = ParseHex(std::string(w->begin()+2, w->end()));
result.insert(result.end(), raw.begin(), raw.end());
}
else if (w->size() >= 2 && w->front() == '\'' && w->back() == '\'')
{
// Single-quoted string, pushed as data. NOTE: this is poor-man's
// parsing, spaces/tabs/newlines in single-quoted strings won't work.
std::vector<unsigned char> value(w->begin()+1, w->end()-1);
result << value;
}
else if (mapOpNames.count(*w))
{
// opcode, e.g. OP_ADD or ADD:
result << mapOpNames[*w];
}
else
{
throw std::runtime_error("script parse error");
}
}
return result;
}
// Check that all of the input and output scripts of a transaction contains valid opcodes
static 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;
}
static bool DecodeTx(CMutableTransaction& tx, const std::vector<unsigned char>& tx_data, bool try_no_witness, bool try_witness)
{
// General strategy:
// - Decode both with extended serialization (which interprets the 0x0001 tag as a marker for
// the presense of witnesses) and with legacy serialization (which interprets the tag as a
// 0-input 1-output incomplete transaction).
// - Restricted by try_no_witness (which disables legacy if false) and try_witness (which
// disables extended if false).
// - Ignore serializations that do not fully consume the hex string.
// - If neither succeeds, fail.
// - If only one succeeds, return that one.
// - If both decode attempts succeed:
// - If only one passes the CheckTxScriptsSanity check, return that one.
// - If neither or both pass CheckTxScriptsSanity, return the extended one.
CMutableTransaction tx_extended, tx_legacy;
bool ok_extended = false, ok_legacy = false;
// Try decoding with extended serialization support, and remember if the result successfully
// consumes the entire input.
if (try_witness) {
CDataStream ssData(tx_data, SER_NETWORK, PROTOCOL_VERSION);
try {
ssData >> tx_extended;
if (ssData.empty()) ok_extended = true;
} catch (const std::exception&) {
// Fall through.
}
}
// Optimization: if extended decoding succeeded and the result passes CheckTxScriptsSanity,
// don't bother decoding the other way.
if (ok_extended && CheckTxScriptsSanity(tx_extended)) {
tx = std::move(tx_extended);
return true;
}
// Try decoding with legacy serialization, and remember if the result successfully consumes the entire input.
if (try_no_witness) {
CDataStream ssData(tx_data, SER_NETWORK, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS);
try {
ssData >> tx_legacy;
if (ssData.empty()) ok_legacy = true;
} catch (const std::exception&) {
// Fall through.
}
}
// If legacy decoding succeeded and passes CheckTxScriptsSanity, that's our answer, as we know
// at this point that extended decoding either failed or doesn't pass the sanity check.
if (ok_legacy && CheckTxScriptsSanity(tx_legacy)) {
tx = std::move(tx_legacy);
return true;
}
// If extended decoding succeeded, and neither decoding passes sanity, return the extended one.
if (ok_extended) {
tx = std::move(tx_extended);
return true;
}
// If legacy decoding succeeded and extended didn't, return the legacy one.
if (ok_legacy) {
tx = std::move(tx_legacy);
return true;
}
// If none succeeded, we failed.
return false;
}
bool DecodeHexTx(CMutableTransaction& tx, const std::string& hex_tx, bool try_no_witness, bool try_witness)
{
if (!IsHex(hex_tx)) {
return false;
}
std::vector<unsigned char> txData(ParseHex(hex_tx));
return DecodeTx(tx, txData, try_no_witness, try_witness);
}
bool DecodeHexBlockHeader(CBlockHeader& header, const std::string& hex_header)
{
if (!IsHex(hex_header)) return false;
const std::vector<unsigned char> header_data{ParseHex(hex_header)};
CDataStream ser_header(header_data, SER_NETWORK, PROTOCOL_VERSION);
try {
ser_header >> header;
} catch (const std::exception&) {
return false;
}
return true;
}
bool DecodeHexBlk(CBlock& block, const std::string& strHexBlk)
{
if (!IsHex(strHexBlk))
return false;
std::vector<unsigned char> blockData(ParseHex(strHexBlk));
CDataStream ssBlock(blockData, SER_NETWORK, PROTOCOL_VERSION);
try {
ssBlock >> block;
}
catch (const std::exception&) {
return false;
}
return true;
}
bool ParseHashStr(const std::string& strHex, uint256& result)
{
if ((strHex.size() != 64) || !IsHex(strHex))
return false;
result.SetHex(strHex);
return true;
}
std::vector<unsigned char> ParseHexUV(const UniValue& v, const std::string& strName)
{
std::string strHex;
if (v.isStr())
strHex = v.getValStr();
if (!IsHex(strHex))
throw std::runtime_error(strName + " must be hexadecimal string (not '" + strHex + "')");
return ParseHex(strHex);
}
int ParseSighashString(const UniValue& sighash)
{
int hash_type = SIGHASH_ALL;
if (!sighash.isNull()) {
static std::map<std::string, int> map_sighash_values = {
{std::string("ALL"), int(SIGHASH_ALL)},
{std::string("ALL|ANYONECANPAY"), int(SIGHASH_ALL|SIGHASH_ANYONECANPAY)},
{std::string("NONE"), int(SIGHASH_NONE)},
{std::string("NONE|ANYONECANPAY"), int(SIGHASH_NONE|SIGHASH_ANYONECANPAY)},
{std::string("SINGLE"), int(SIGHASH_SINGLE)},
{std::string("SINGLE|ANYONECANPAY"), int(SIGHASH_SINGLE|SIGHASH_ANYONECANPAY)},
};
std::string strHashType = sighash.get_str();
const auto& it = map_sighash_values.find(strHashType);
if (it != map_sighash_values.end()) {
hash_type = it->second;
} else {
throw std::runtime_error(strHashType + " is not a valid sighash parameter.");
}
}
return hash_type;
}