1  // Copyright (c) 2009-2022 The Bitcoin Core developers
  2  // Distributed under the MIT software license, see the accompanying
  3  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  4  
  5  #include <core_io.h>
  6  
  7  #include <primitives/block.h>
  8  #include <primitives/transaction.h>
  9  #include <script/script.h>
 10  #include <script/sign.h>
 11  #include <serialize.h>
 12  #include <streams.h>
 13  #include <util/result.h>
 14  #include <util/strencodings.h>
 15  
 16  #include <algorithm>
 17  #include <string>
 18  
 19  using util::SplitString;
 20  
 21  namespace {
 22  class OpCodeParser
 23  {
 24  private:
 25      std::map<std::string, opcodetype> mapOpNames;
 26  
 27  public:
 28      OpCodeParser()
 29      {
 30          for (unsigned int op = 0; op <= MAX_OPCODE; ++op) {
 31              // Allow OP_RESERVED to get into mapOpNames
 32              if (op < OP_NOP && op != OP_RESERVED) {
 33                  continue;
 34              }
 35  
 36              std::string strName = GetOpName(static_cast<opcodetype>(op));
 37              if (strName == "OP_UNKNOWN") {
 38                  continue;
 39              }
 40              mapOpNames[strName] = static_cast<opcodetype>(op);
 41              // Convenience: OP_ADD and just ADD are both recognized:
 42              if (strName.starts_with("OP_")) {
 43                  mapOpNames[strName.substr(3)] = static_cast<opcodetype>(op);
 44              }
 45          }
 46      }
 47      opcodetype Parse(const std::string& s) const
 48      {
 49          auto it = mapOpNames.find(s);
 50          if (it == mapOpNames.end()) throw std::runtime_error("script parse error: unknown opcode");
 51          return it->second;
 52      }
 53  };
 54  
 55  opcodetype ParseOpCode(const std::string& s)
 56  {
 57      static const OpCodeParser ocp;
 58      return ocp.Parse(s);
 59  }
 60  
 61  } // namespace
 62  
 63  CScript ParseScript(const std::string& s)
 64  {
 65      CScript result;
 66  
 67      std::vector<std::string> words = SplitString(s, " \t\n");
 68  
 69      for (const std::string& w : words) {
 70          if (w.empty()) {
 71              // Empty string, ignore. (SplitString doesn't combine multiple separators)
 72          } else if (std::all_of(w.begin(), w.end(), ::IsDigit) ||
 73                     (w.front() == '-' && w.size() > 1 && std::all_of(w.begin() + 1, w.end(), ::IsDigit)))
 74          {
 75              // Number
 76              const auto num{ToIntegral<int64_t>(w)};
 77  
 78              // limit the range of numbers ParseScript accepts in decimal
 79              // since numbers outside -0xFFFFFFFF...0xFFFFFFFF are illegal in scripts
 80              if (!num.has_value() || num > int64_t{0xffffffff} || num < -1 * int64_t{0xffffffff}) {
 81                  throw std::runtime_error("script parse error: decimal numeric value only allowed in the "
 82                                           "range -0xFFFFFFFF...0xFFFFFFFF");
 83              }
 84  
 85              result << num.value();
 86          } else if (w.starts_with("0x") && w.size() > 2 && IsHex(std::string(w.begin() + 2, w.end()))) {
 87              // Raw hex data, inserted NOT pushed onto stack:
 88              std::vector<unsigned char> raw = ParseHex(std::string(w.begin() + 2, w.end()));
 89              result.insert(result.end(), raw.begin(), raw.end());
 90          } else if (w.size() >= 2 && w.front() == '\'' && w.back() == '\'') {
 91              // Single-quoted string, pushed as data. NOTE: this is poor-man's
 92              // parsing, spaces/tabs/newlines in single-quoted strings won't work.
 93              std::vector<unsigned char> value(w.begin() + 1, w.end() - 1);
 94              result << value;
 95          } else {
 96              // opcode, e.g. OP_ADD or ADD:
 97              result << ParseOpCode(w);
 98          }
 99      }
100  
101      return result;
102  }
103  
104  // Check that all of the input and output scripts of a transaction contains valid opcodes
105  static bool CheckTxScriptsSanity(const CMutableTransaction& tx)
106  {
107      // Check input scripts for non-coinbase txs
108      if (!CTransaction(tx).IsCoinBase()) {
109          for (unsigned int i = 0; i < tx.vin.size(); i++) {
110              if (!tx.vin[i].scriptSig.HasValidOps() || tx.vin[i].scriptSig.size() > MAX_SCRIPT_SIZE) {
111                  return false;
112              }
113          }
114      }
115      // Check output scripts
116      for (unsigned int i = 0; i < tx.vout.size(); i++) {
117          if (!tx.vout[i].scriptPubKey.HasValidOps() || tx.vout[i].scriptPubKey.size() > MAX_SCRIPT_SIZE) {
118              return false;
119          }
120      }
121  
122      return true;
123  }
124  
125  static bool DecodeTx(CMutableTransaction& tx, const std::vector<unsigned char>& tx_data, bool try_no_witness, bool try_witness)
126  {
127      // General strategy:
128      // - Decode both with extended serialization (which interprets the 0x0001 tag as a marker for
129      //   the presence of witnesses) and with legacy serialization (which interprets the tag as a
130      //   0-input 1-output incomplete transaction).
131      //   - Restricted by try_no_witness (which disables legacy if false) and try_witness (which
132      //     disables extended if false).
133      //   - Ignore serializations that do not fully consume the hex string.
134      // - If neither succeeds, fail.
135      // - If only one succeeds, return that one.
136      // - If both decode attempts succeed:
137      //   - If only one passes the CheckTxScriptsSanity check, return that one.
138      //   - If neither or both pass CheckTxScriptsSanity, return the extended one.
139  
140      CMutableTransaction tx_extended, tx_legacy;
141      bool ok_extended = false, ok_legacy = false;
142  
143      // Try decoding with extended serialization support, and remember if the result successfully
144      // consumes the entire input.
145      if (try_witness) {
146          DataStream ssData(tx_data);
147          try {
148              ssData >> TX_WITH_WITNESS(tx_extended);
149              if (ssData.empty()) ok_extended = true;
150          } catch (const std::exception&) {
151              // Fall through.
152          }
153      }
154  
155      // Optimization: if extended decoding succeeded and the result passes CheckTxScriptsSanity,
156      // don't bother decoding the other way.
157      if (ok_extended && CheckTxScriptsSanity(tx_extended)) {
158          tx = std::move(tx_extended);
159          return true;
160      }
161  
162      // Try decoding with legacy serialization, and remember if the result successfully consumes the entire input.
163      if (try_no_witness) {
164          DataStream ssData(tx_data);
165          try {
166              ssData >> TX_NO_WITNESS(tx_legacy);
167              if (ssData.empty()) ok_legacy = true;
168          } catch (const std::exception&) {
169              // Fall through.
170          }
171      }
172  
173      // If legacy decoding succeeded and passes CheckTxScriptsSanity, that's our answer, as we know
174      // at this point that extended decoding either failed or doesn't pass the sanity check.
175      if (ok_legacy && CheckTxScriptsSanity(tx_legacy)) {
176          tx = std::move(tx_legacy);
177          return true;
178      }
179  
180      // If extended decoding succeeded, and neither decoding passes sanity, return the extended one.
181      if (ok_extended) {
182          tx = std::move(tx_extended);
183          return true;
184      }
185  
186      // If legacy decoding succeeded and extended didn't, return the legacy one.
187      if (ok_legacy) {
188          tx = std::move(tx_legacy);
189          return true;
190      }
191  
192      // If none succeeded, we failed.
193      return false;
194  }
195  
196  bool DecodeHexTx(CMutableTransaction& tx, const std::string& hex_tx, bool try_no_witness, bool try_witness)
197  {
198      if (!IsHex(hex_tx)) {
199          return false;
200      }
201  
202      std::vector<unsigned char> txData(ParseHex(hex_tx));
203      return DecodeTx(tx, txData, try_no_witness, try_witness);
204  }
205  
206  bool DecodeHexBlockHeader(CBlockHeader& header, const std::string& hex_header)
207  {
208      if (!IsHex(hex_header)) return false;
209  
210      const std::vector<unsigned char> header_data{ParseHex(hex_header)};
211      DataStream ser_header{header_data};
212      try {
213          ser_header >> header;
214      } catch (const std::exception&) {
215          return false;
216      }
217      return true;
218  }
219  
220  bool DecodeHexBlk(CBlock& block, const std::string& strHexBlk)
221  {
222      if (!IsHex(strHexBlk))
223          return false;
224  
225      std::vector<unsigned char> blockData(ParseHex(strHexBlk));
226      DataStream ssBlock(blockData);
227      try {
228          ssBlock >> TX_WITH_WITNESS(block);
229      }
230      catch (const std::exception&) {
231          return false;
232      }
233  
234      return true;
235  }
236  
237  util::Result<int> SighashFromStr(const std::string& sighash)
238  {
239      static const std::map<std::string, int> map_sighash_values = {
240          {std::string("DEFAULT"), int(SIGHASH_DEFAULT)},
241          {std::string("ALL"), int(SIGHASH_ALL)},
242          {std::string("ALL|ANYONECANPAY"), int(SIGHASH_ALL|SIGHASH_ANYONECANPAY)},
243          {std::string("NONE"), int(SIGHASH_NONE)},
244          {std::string("NONE|ANYONECANPAY"), int(SIGHASH_NONE|SIGHASH_ANYONECANPAY)},
245          {std::string("SINGLE"), int(SIGHASH_SINGLE)},
246          {std::string("SINGLE|ANYONECANPAY"), int(SIGHASH_SINGLE|SIGHASH_ANYONECANPAY)},
247      };
248      const auto& it = map_sighash_values.find(sighash);
249      if (it != map_sighash_values.end()) {
250          return it->second;
251      } else {
252          return util::Error{Untranslated("'" + sighash + "' is not a valid sighash parameter.")};
253      }
254  }