src/script/standard.cpp

   1 // Copyright (c) 2009-2010 Satoshi Nakamoto
   2 // Copyright (c) 2009-2016 The Bitcoin Core developers
   3 // Distributed under the MIT software license, see the accompanying
   4 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
   5
   6 #include "script/standard.h"
   7
   8 #include "pubkey.h"
   9 #include "script/script.h"
  10 #include "util.h"
  11 #include "utilstrencodings.h"
  12
  13
  14 typedef std::vector<unsigned char> valtype;
  15
  16 bool fAcceptDatacarrier = DEFAULT_ACCEPT_DATACARRIER;
  17 unsigned nMaxDatacarrierBytes = MAX_OP_RETURN_RELAY;
  18
  19 CScriptID::CScriptID(const CScript& in) : uint160(Hash160(in.begin(), in.end())) {}
  20
  21 const char* GetTxnOutputType(txnouttype t)
  22 {
  23     switch (t)
  24     {
  25     case TX_NONSTANDARD: return "nonstandard";
  26     case TX_PUBKEY: return "pubkey";
  27     case TX_PUBKEYHASH: return "pubkeyhash";
  28     case TX_SCRIPTHASH: return "scripthash";
  29     case TX_MULTISIG: return "multisig";
  30     case TX_NULL_DATA: return "nulldata";
  31     case TX_WITNESS_V0_KEYHASH: return "witness_v0_keyhash";
  32     case TX_WITNESS_V0_SCRIPTHASH: return "witness_v0_scripthash";
  33     case TX_WITNESS_UNKNOWN: return "witness_unknown";
  34     }
  35     return nullptr;
  36 }
  37
  38 bool Solver(const CScript& scriptPubKey, txnouttype& typeRet, std::vector<std::vector<unsigned char> >& vSolutionsRet)
  39 {
  40     // Templates
  41     static std::multimap<txnouttype, CScript> mTemplates;
  42     if (mTemplates.empty())
  43     {
  44         // Standard tx, sender provides pubkey, receiver adds signature
  45         mTemplates.insert(std::make_pair(TX_PUBKEY, CScript() << OP_PUBKEY << OP_CHECKSIG));
  46
  47         // Bitcoin address tx, sender provides hash of pubkey, receiver provides signature and pubkey
  48         mTemplates.insert(std::make_pair(TX_PUBKEYHASH, CScript() << OP_DUP << OP_HASH160 << OP_PUBKEYHASH << OP_EQUALVERIFY << OP_CHECKSIG));
  49
  50         // Sender provides N pubkeys, receivers provides M signatures
  51         mTemplates.insert(std::make_pair(TX_MULTISIG, CScript() << OP_SMALLINTEGER << OP_PUBKEYS << OP_SMALLINTEGER << OP_CHECKMULTISIG));
  52     }
  53
  54     vSolutionsRet.clear();
  55
  56     // Shortcut for pay-to-script-hash, which are more constrained than the other types:
  57     // it is always OP_HASH160 20 [20 byte hash] OP_EQUAL
  58     if (scriptPubKey.IsPayToScriptHash())
  59     {
  60         typeRet = TX_SCRIPTHASH;
  61         std::vector<unsigned char> hashBytes(scriptPubKey.begin()+2, scriptPubKey.begin()+22);
  62         vSolutionsRet.push_back(hashBytes);
  63         return true;
  64     }
  65
  66     int witnessversion;
  67     std::vector<unsigned char> witnessprogram;
  68     if (scriptPubKey.IsWitnessProgram(witnessversion, witnessprogram)) {
  69         if (witnessversion == 0 && witnessprogram.size() == 20) {
  70             typeRet = TX_WITNESS_V0_KEYHASH;
  71             vSolutionsRet.push_back(witnessprogram);
  72             return true;
  73         }
  74         if (witnessversion == 0 && witnessprogram.size() == 32) {
  75             typeRet = TX_WITNESS_V0_SCRIPTHASH;
  76             vSolutionsRet.push_back(witnessprogram);
  77             return true;
  78         }
  79         if (witnessversion != 0) {
  80             typeRet = TX_WITNESS_UNKNOWN;
  81             vSolutionsRet.push_back(std::vector<unsigned char>{(unsigned char)witnessversion});
  82             vSolutionsRet.push_back(std::move(witnessprogram));
  83             return true;
  84         }
  85         return false;
  86     }
  87
  88     // Provably prunable, data-carrying output
  89     //
  90     // So long as script passes the IsUnspendable() test and all but the first
  91     // byte passes the IsPushOnly() test we don't care what exactly is in the
  92     // script.
  93     if (scriptPubKey.size() >= 1 && scriptPubKey[0] == OP_RETURN && scriptPubKey.IsPushOnly(scriptPubKey.begin()+1)) {
  94         typeRet = TX_NULL_DATA;
  95         return true;
  96     }
  97
  98     // Scan templates
  99     const CScript& script1 = scriptPubKey;
 100     for (const std::pair<txnouttype, CScript>& tplate : mTemplates)
 101     {
 102         const CScript& script2 = tplate.second;
 103         vSolutionsRet.clear();
 104
 105         opcodetype opcode1, opcode2;
 106         std::vector<unsigned char> vch1, vch2;
 107
 108         // Compare
 109         CScript::const_iterator pc1 = script1.begin();
 110         CScript::const_iterator pc2 = script2.begin();
 111         while (true)
 112         {
 113             if (pc1 == script1.end() && pc2 == script2.end())
 114             {
 115                 // Found a match
 116                 typeRet = tplate.first;
 117                 if (typeRet == TX_MULTISIG)
 118                 {
 119                     // Additional checks for TX_MULTISIG:
 120                     unsigned char m = vSolutionsRet.front()[0];
 121                     unsigned char n = vSolutionsRet.back()[0];
 122                     if (m < 1 || n < 1 || m > n || vSolutionsRet.size()-2 != n)
 123                         return false;
 124                 }
 125                 return true;
 126             }
 127             if (!script1.GetOp(pc1, opcode1, vch1))
 128                 break;
 129             if (!script2.GetOp(pc2, opcode2, vch2))
 130                 break;
 131
 132             // Template matching opcodes:
 133             if (opcode2 == OP_PUBKEYS)
 134             {
 135                 while (vch1.size() >= 33 && vch1.size() <= 65)
 136                 {
 137                     vSolutionsRet.push_back(vch1);
 138                     if (!script1.GetOp(pc1, opcode1, vch1))
 139                         break;
 140                 }
 141                 if (!script2.GetOp(pc2, opcode2, vch2))
 142                     break;
 143                 // Normal situation is to fall through
 144                 // to other if/else statements
 145             }
 146
 147             if (opcode2 == OP_PUBKEY)
 148             {
 149                 if (vch1.size() < 33 || vch1.size() > 65)
 150                     break;
 151                 vSolutionsRet.push_back(vch1);
 152             }
 153             else if (opcode2 == OP_PUBKEYHASH)
 154             {
 155                 if (vch1.size() != sizeof(uint160))
 156                     break;
 157                 vSolutionsRet.push_back(vch1);
 158             }
 159             else if (opcode2 == OP_SMALLINTEGER)
 160             {   // Single-byte small integer pushed onto vSolutions
 161                 if (opcode1 == OP_0 ||
 162                     (opcode1 >= OP_1 && opcode1 <= OP_16))
 163                 {
 164                     char n = (char)CScript::DecodeOP_N(opcode1);
 165                     vSolutionsRet.push_back(valtype(1, n));
 166                 }
 167                 else
 168                     break;
 169             }
 170             else if (opcode1 != opcode2 || vch1 != vch2)
 171             {
 172                 // Others must match exactly
 173                 break;
 174             }
 175         }
 176     }
 177
 178     vSolutionsRet.clear();
 179     typeRet = TX_NONSTANDARD;
 180     return false;
 181 }
 182
 183 bool ExtractDestination(const CScript& scriptPubKey, CTxDestination& addressRet)
 184 {
 185     std::vector<valtype> vSolutions;
 186     txnouttype whichType;
 187     if (!Solver(scriptPubKey, whichType, vSolutions))
 188         return false;
 189
 190     if (whichType == TX_PUBKEY)
 191     {
 192         CPubKey pubKey(vSolutions[0]);
 193         if (!pubKey.IsValid())
 194             return false;
 195
 196         addressRet = pubKey.GetID();
 197         return true;
 198     }
 199     else if (whichType == TX_PUBKEYHASH)
 200     {
 201         addressRet = CKeyID(uint160(vSolutions[0]));
 202         return true;
 203     }
 204     else if (whichType == TX_SCRIPTHASH)
 205     {
 206         addressRet = CScriptID(uint160(vSolutions[0]));
 207         return true;
 208     } else if (whichType == TX_WITNESS_V0_KEYHASH) {
 209         WitnessV0KeyHash hash;
 210         std::copy(vSolutions[0].begin(), vSolutions[0].end(), hash.begin());
 211         addressRet = hash;
 212         return true;
 213     } else if (whichType == TX_WITNESS_V0_SCRIPTHASH) {
 214         WitnessV0ScriptHash hash;
 215         std::copy(vSolutions[0].begin(), vSolutions[0].end(), hash.begin());
 216         addressRet = hash;
 217         return true;
 218     } else if (whichType == TX_WITNESS_UNKNOWN) {
 219         WitnessUnknown unk;
 220         unk.version = vSolutions[0][0];
 221         std::copy(vSolutions[1].begin(), vSolutions[1].end(), unk.program);
 222         unk.length = vSolutions[1].size();
 223         addressRet = unk;
 224         return true;
 225     }
 226     // Multisig txns have more than one address...
 227     return false;
 228 }
 229
 230 bool ExtractDestinations(const CScript& scriptPubKey, txnouttype& typeRet, std::vector<CTxDestination>& addressRet, int& nRequiredRet)
 231 {
 232     addressRet.clear();
 233     typeRet = TX_NONSTANDARD;
 234     std::vector<valtype> vSolutions;
 235     if (!Solver(scriptPubKey, typeRet, vSolutions))
 236         return false;
 237     if (typeRet == TX_NULL_DATA){
 238         // This is data, not addresses
 239         return false;
 240     }
 241
 242     if (typeRet == TX_MULTISIG)
 243     {
 244         nRequiredRet = vSolutions.front()[0];
 245         for (unsigned int i = 1; i < vSolutions.size()-1; i++)
 246         {
 247             CPubKey pubKey(vSolutions[i]);
 248             if (!pubKey.IsValid())
 249                 continue;
 250
 251             CTxDestination address = pubKey.GetID();
 252             addressRet.push_back(address);
 253         }
 254
 255         if (addressRet.empty())
 256             return false;
 257     }
 258     else
 259     {
 260         nRequiredRet = 1;
 261         CTxDestination address;
 262         if (!ExtractDestination(scriptPubKey, address))
 263            return false;
 264         addressRet.push_back(address);
 265     }
 266
 267     return true;
 268 }
 269
 270 namespace
 271 {
 272 class CScriptVisitor : public boost::static_visitor<bool>
 273 {
 274 private:
 275     CScript *script;
 276 public:
 277     explicit CScriptVisitor(CScript *scriptin) { script = scriptin; }
 278
 279     bool operator()(const CNoDestination &dest) const {
 280         script->clear();
 281         return false;
 282     }
 283
 284     bool operator()(const CKeyID &keyID) const {
 285         script->clear();
 286         *script << OP_DUP << OP_HASH160 << ToByteVector(keyID) << OP_EQUALVERIFY << OP_CHECKSIG;
 287         return true;
 288     }
 289
 290     bool operator()(const CScriptID &scriptID) const {
 291         script->clear();
 292         *script << OP_HASH160 << ToByteVector(scriptID) << OP_EQUAL;
 293         return true;
 294     }
 295
 296     bool operator()(const WitnessV0KeyHash& id) const
 297     {
 298         script->clear();
 299         *script << OP_0 << ToByteVector(id);
 300         return true;
 301     }
 302
 303     bool operator()(const WitnessV0ScriptHash& id) const
 304     {
 305         script->clear();
 306         *script << OP_0 << ToByteVector(id);
 307         return true;
 308     }
 309
 310     bool operator()(const WitnessUnknown& id) const
 311     {
 312         script->clear();
 313         *script << CScript::EncodeOP_N(id.version) << std::vector<unsigned char>(id.program, id.program + id.length);
 314         return true;
 315     }
 316 };
 317 } // namespace
 318
 319 CScript GetScriptForDestination(const CTxDestination& dest)
 320 {
 321     CScript script;
 322
 323     boost::apply_visitor(CScriptVisitor(&script), dest);
 324     return script;
 325 }
 326
 327 CScript GetScriptForRawPubKey(const CPubKey& pubKey)
 328 {
 329     return CScript() << std::vector<unsigned char>(pubKey.begin(), pubKey.end()) << OP_CHECKSIG;
 330 }
 331
 332 CScript GetScriptForMultisig(int nRequired, const std::vector<CPubKey>& keys)
 333 {
 334     CScript script;
 335
 336     script << CScript::EncodeOP_N(nRequired);
 337     for (const CPubKey& key : keys)
 338         script << ToByteVector(key);
 339     script << CScript::EncodeOP_N(keys.size()) << OP_CHECKMULTISIG;
 340     return script;
 341 }
 342
 343 CScript GetScriptForWitness(const CScript& redeemscript)
 344 {
 345     CScript ret;
 346
 347     txnouttype typ;
 348     std::vector<std::vector<unsigned char> > vSolutions;
 349     if (Solver(redeemscript, typ, vSolutions)) {
 350         if (typ == TX_PUBKEY) {
 351             unsigned char h160[20];
 352             CHash160().Write(&vSolutions[0][0], vSolutions[0].size()).Finalize(h160);
 353             ret << OP_0 << std::vector<unsigned char>(&h160[0], &h160[20]);
 354             return ret;
 355         } else if (typ == TX_PUBKEYHASH) {
 356            ret << OP_0 << vSolutions[0];
 357            return ret;
 358         }
 359     }
 360     uint256 hash;
 361     CSHA256().Write(&redeemscript[0], redeemscript.size()).Finalize(hash.begin());
 362     ret << OP_0 << ToByteVector(hash);
 363     return ret;
 364 }
 365
 366 bool IsValidDestination(const CTxDestination& dest) {
 367     return dest.which() != 0;
 368 }