src/script.cpp

   1 // Copyright (c) 2009-2010 Satoshi Nakamoto
   2 // Copyright (c) 2009-2012 The Bitcoin developers
   3 // Distributed under the MIT/X11 software license, see the accompanying
   4 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
   5 #include <boost/foreach.hpp>
   6 #include <boost/tuple/tuple.hpp>
   7
   8 using namespace std;
   9 using namespace boost;
  10
  11 #include "script.h"
  12 #include "keystore.h"
  13 #include "bignum.h"
  14 #include "key.h"
  15 #include "main.h"
  16 #include "sync.h"
  17 #include "util.h"
  18
  19 bool CheckSig(vector<unsigned char> vchSig, vector<unsigned char> vchPubKey, CScript scriptCode, const CTransaction& txTo, unsigned int nIn, int nHashType);
  20
  21
  22
  23 typedef vector<unsigned char> valtype;
  24 static const valtype vchFalse(0);
  25 static const valtype vchZero(0);
  26 static const valtype vchTrue(1, 1);
  27 static const CBigNum bnZero(0);
  28 static const CBigNum bnOne(1);
  29 static const CBigNum bnFalse(0);
  30 static const CBigNum bnTrue(1);
  31 static const size_t nMaxNumSize = 4;
  32
  33
  34 CBigNum CastToBigNum(const valtype& vch)
  35 {
  36     if (vch.size() > nMaxNumSize)
  37         throw runtime_error("CastToBigNum() : overflow");
  38     // Get rid of extra leading zeros
  39     return CBigNum(CBigNum(vch).getvch());
  40 }
  41
  42 bool CastToBool(const valtype& vch)
  43 {
  44     for (unsigned int i = 0; i < vch.size(); i++)
  45     {
  46         if (vch[i] != 0)
  47         {
  48             // Can be negative zero
  49             if (i == vch.size()-1 && vch[i] == 0x80)
  50                 return false;
  51             return true;
  52         }
  53     }
  54     return false;
  55 }
  56
  57 void MakeSameSize(valtype& vch1, valtype& vch2)
  58 {
  59     // Lengthen the shorter one
  60     if (vch1.size() < vch2.size())
  61         vch1.resize(vch2.size(), 0);
  62     if (vch2.size() < vch1.size())
  63         vch2.resize(vch1.size(), 0);
  64 }
  65
  66
  67
  68 //
  69 // Script is a stack machine (like Forth) that evaluates a predicate
  70 // returning a bool indicating valid or not.  There are no loops.
  71 //
  72 #define stacktop(i)  (stack.at(stack.size()+(i)))
  73 #define altstacktop(i)  (altstack.at(altstack.size()+(i)))
  74 static inline void popstack(vector<valtype>& stack)
  75 {
  76     if (stack.empty())
  77         throw runtime_error("popstack() : stack empty");
  78     stack.pop_back();
  79 }
  80
  81
  82 const char* GetTxnOutputType(txnouttype t)
  83 {
  84     switch (t)
  85     {
  86     case TX_NONSTANDARD: return "nonstandard";
  87     case TX_PUBKEY: return "pubkey";
  88     case TX_PUBKEYHASH: return "pubkeyhash";
  89     case TX_SCRIPTHASH: return "scripthash";
  90     case TX_MULTISIG: return "multisig";
  91     }
  92     return NULL;
  93 }
  94
  95
  96 const char* GetOpName(opcodetype opcode)
  97 {
  98     switch (opcode)
  99     {
 100     // push value
 101     case OP_0                      : return "0";
 102     case OP_PUSHDATA1              : return "OP_PUSHDATA1";
 103     case OP_PUSHDATA2              : return "OP_PUSHDATA2";
 104     case OP_PUSHDATA4              : return "OP_PUSHDATA4";
 105     case OP_1NEGATE                : return "-1";
 106     case OP_RESERVED               : return "OP_RESERVED";
 107     case OP_1                      : return "1";
 108     case OP_2                      : return "2";
 109     case OP_3                      : return "3";
 110     case OP_4                      : return "4";
 111     case OP_5                      : return "5";
 112     case OP_6                      : return "6";
 113     case OP_7                      : return "7";
 114     case OP_8                      : return "8";
 115     case OP_9                      : return "9";
 116     case OP_10                     : return "10";
 117     case OP_11                     : return "11";
 118     case OP_12                     : return "12";
 119     case OP_13                     : return "13";
 120     case OP_14                     : return "14";
 121     case OP_15                     : return "15";
 122     case OP_16                     : return "16";
 123
 124     // control
 125     case OP_NOP                    : return "OP_NOP";
 126     case OP_VER                    : return "OP_VER";
 127     case OP_IF                     : return "OP_IF";
 128     case OP_NOTIF                  : return "OP_NOTIF";
 129     case OP_VERIF                  : return "OP_VERIF";
 130     case OP_VERNOTIF               : return "OP_VERNOTIF";
 131     case OP_ELSE                   : return "OP_ELSE";
 132     case OP_ENDIF                  : return "OP_ENDIF";
 133     case OP_VERIFY                 : return "OP_VERIFY";
 134     case OP_RETURN                 : return "OP_RETURN";
 135
 136     // stack ops
 137     case OP_TOALTSTACK             : return "OP_TOALTSTACK";
 138     case OP_FROMALTSTACK           : return "OP_FROMALTSTACK";
 139     case OP_2DROP                  : return "OP_2DROP";
 140     case OP_2DUP                   : return "OP_2DUP";
 141     case OP_3DUP                   : return "OP_3DUP";
 142     case OP_2OVER                  : return "OP_2OVER";
 143     case OP_2ROT                   : return "OP_2ROT";
 144     case OP_2SWAP                  : return "OP_2SWAP";
 145     case OP_IFDUP                  : return "OP_IFDUP";
 146     case OP_DEPTH                  : return "OP_DEPTH";
 147     case OP_DROP                   : return "OP_DROP";
 148     case OP_DUP                    : return "OP_DUP";
 149     case OP_NIP                    : return "OP_NIP";
 150     case OP_OVER                   : return "OP_OVER";
 151     case OP_PICK                   : return "OP_PICK";
 152     case OP_ROLL                   : return "OP_ROLL";
 153     case OP_ROT                    : return "OP_ROT";
 154     case OP_SWAP                   : return "OP_SWAP";
 155     case OP_TUCK                   : return "OP_TUCK";
 156
 157     // splice ops
 158     case OP_CAT                    : return "OP_CAT";
 159     case OP_SUBSTR                 : return "OP_SUBSTR";
 160     case OP_LEFT                   : return "OP_LEFT";
 161     case OP_RIGHT                  : return "OP_RIGHT";
 162     case OP_SIZE                   : return "OP_SIZE";
 163
 164     // bit logic
 165     case OP_INVERT                 : return "OP_INVERT";
 166     case OP_AND                    : return "OP_AND";
 167     case OP_OR                     : return "OP_OR";
 168     case OP_XOR                    : return "OP_XOR";
 169     case OP_EQUAL                  : return "OP_EQUAL";
 170     case OP_EQUALVERIFY            : return "OP_EQUALVERIFY";
 171     case OP_RESERVED1              : return "OP_RESERVED1";
 172     case OP_RESERVED2              : return "OP_RESERVED2";
 173
 174     // numeric
 175     case OP_1ADD                   : return "OP_1ADD";
 176     case OP_1SUB                   : return "OP_1SUB";
 177     case OP_2MUL                   : return "OP_2MUL";
 178     case OP_2DIV                   : return "OP_2DIV";
 179     case OP_NEGATE                 : return "OP_NEGATE";
 180     case OP_ABS                    : return "OP_ABS";
 181     case OP_NOT                    : return "OP_NOT";
 182     case OP_0NOTEQUAL              : return "OP_0NOTEQUAL";
 183     case OP_ADD                    : return "OP_ADD";
 184     case OP_SUB                    : return "OP_SUB";
 185     case OP_MUL                    : return "OP_MUL";
 186     case OP_DIV                    : return "OP_DIV";
 187     case OP_MOD                    : return "OP_MOD";
 188     case OP_LSHIFT                 : return "OP_LSHIFT";
 189     case OP_RSHIFT                 : return "OP_RSHIFT";
 190     case OP_BOOLAND                : return "OP_BOOLAND";
 191     case OP_BOOLOR                 : return "OP_BOOLOR";
 192     case OP_NUMEQUAL               : return "OP_NUMEQUAL";
 193     case OP_NUMEQUALVERIFY         : return "OP_NUMEQUALVERIFY";
 194     case OP_NUMNOTEQUAL            : return "OP_NUMNOTEQUAL";
 195     case OP_LESSTHAN               : return "OP_LESSTHAN";
 196     case OP_GREATERTHAN            : return "OP_GREATERTHAN";
 197     case OP_LESSTHANOREQUAL        : return "OP_LESSTHANOREQUAL";
 198     case OP_GREATERTHANOREQUAL     : return "OP_GREATERTHANOREQUAL";
 199     case OP_MIN                    : return "OP_MIN";
 200     case OP_MAX                    : return "OP_MAX";
 201     case OP_WITHIN                 : return "OP_WITHIN";
 202
 203     // crypto
 204     case OP_RIPEMD160              : return "OP_RIPEMD160";
 205     case OP_SHA1                   : return "OP_SHA1";
 206     case OP_SHA256                 : return "OP_SHA256";
 207     case OP_HASH160                : return "OP_HASH160";
 208     case OP_HASH256                : return "OP_HASH256";
 209     case OP_CODESEPARATOR          : return "OP_CODESEPARATOR";
 210     case OP_CHECKSIG               : return "OP_CHECKSIG";
 211     case OP_CHECKSIGVERIFY         : return "OP_CHECKSIGVERIFY";
 212     case OP_CHECKMULTISIG          : return "OP_CHECKMULTISIG";
 213     case OP_CHECKMULTISIGVERIFY    : return "OP_CHECKMULTISIGVERIFY";
 214
 215     // expanson
 216     case OP_NOP1                   : return "OP_NOP1";
 217     case OP_NOP2                   : return "OP_NOP2";
 218     case OP_NOP3                   : return "OP_NOP3";
 219     case OP_NOP4                   : return "OP_NOP4";
 220     case OP_NOP5                   : return "OP_NOP5";
 221     case OP_NOP6                   : return "OP_NOP6";
 222     case OP_NOP7                   : return "OP_NOP7";
 223     case OP_NOP8                   : return "OP_NOP8";
 224     case OP_NOP9                   : return "OP_NOP9";
 225     case OP_NOP10                  : return "OP_NOP10";
 226
 227
 228
 229     // template matching params
 230     case OP_PUBKEYHASH             : return "OP_PUBKEYHASH";
 231     case OP_PUBKEY                 : return "OP_PUBKEY";
 232
 233     case OP_INVALIDOPCODE          : return "OP_INVALIDOPCODE";
 234     default:
 235         return "OP_UNKNOWN";
 236     }
 237 }
 238
 239 bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, const CTransaction& txTo, unsigned int nIn, int nHashType)
 240 {
 241     CAutoBN_CTX pctx;
 242     CScript::const_iterator pc = script.begin();
 243     CScript::const_iterator pend = script.end();
 244     CScript::const_iterator pbegincodehash = script.begin();
 245     opcodetype opcode;
 246     valtype vchPushValue;
 247     vector<bool> vfExec;
 248     vector<valtype> altstack;
 249     if (script.size() > 10000)
 250         return false;
 251     int nOpCount = 0;
 252
 253
 254     try
 255     {
 256         while (pc < pend)
 257         {
 258             bool fExec = !count(vfExec.begin(), vfExec.end(), false);
 259
 260             //
 261             // Read instruction
 262             //
 263             if (!script.GetOp(pc, opcode, vchPushValue))
 264                 return false;
 265             if (vchPushValue.size() > 520)
 266                 return false;
 267             if (opcode > OP_16 && ++nOpCount > 201)
 268                 return false;
 269
 270             if (opcode == OP_CAT ||
 271                 opcode == OP_SUBSTR ||
 272                 opcode == OP_LEFT ||
 273                 opcode == OP_RIGHT ||
 274                 opcode == OP_INVERT ||
 275                 opcode == OP_AND ||
 276                 opcode == OP_OR ||
 277                 opcode == OP_XOR ||
 278                 opcode == OP_2MUL ||
 279                 opcode == OP_2DIV ||
 280                 opcode == OP_MUL ||
 281                 opcode == OP_DIV ||
 282                 opcode == OP_MOD ||
 283                 opcode == OP_LSHIFT ||
 284                 opcode == OP_RSHIFT)
 285                 return false;
 286
 287             if (fExec && 0 <= opcode && opcode <= OP_PUSHDATA4)
 288                 stack.push_back(vchPushValue);
 289             else if (fExec || (OP_IF <= opcode && opcode <= OP_ENDIF))
 290             switch (opcode)
 291             {
 292                 //
 293                 // Push value
 294                 //
 295                 case OP_1NEGATE:
 296                 case OP_1:
 297                 case OP_2:
 298                 case OP_3:
 299                 case OP_4:
 300                 case OP_5:
 301                 case OP_6:
 302                 case OP_7:
 303                 case OP_8:
 304                 case OP_9:
 305                 case OP_10:
 306                 case OP_11:
 307                 case OP_12:
 308                 case OP_13:
 309                 case OP_14:
 310                 case OP_15:
 311                 case OP_16:
 312                 {
 313                     // ( -- value)
 314                     CBigNum bn((int)opcode - (int)(OP_1 - 1));
 315                     stack.push_back(bn.getvch());
 316                 }
 317                 break;
 318
 319
 320                 //
 321                 // Control
 322                 //
 323                 case OP_NOP:
 324                 case OP_NOP1: case OP_NOP2: case OP_NOP3: case OP_NOP4: case OP_NOP5:
 325                 case OP_NOP6: case OP_NOP7: case OP_NOP8: case OP_NOP9: case OP_NOP10:
 326                 break;
 327
 328                 case OP_IF:
 329                 case OP_NOTIF:
 330                 {
 331                     // <expression> if [statements] [else [statements]] endif
 332                     bool fValue = false;
 333                     if (fExec)
 334                     {
 335                         if (stack.size() < 1)
 336                             return false;
 337                         valtype& vch = stacktop(-1);
 338                         fValue = CastToBool(vch);
 339                         if (opcode == OP_NOTIF)
 340                             fValue = !fValue;
 341                         popstack(stack);
 342                     }
 343                     vfExec.push_back(fValue);
 344                 }
 345                 break;
 346
 347                 case OP_ELSE:
 348                 {
 349                     if (vfExec.empty())
 350                         return false;
 351                     vfExec.back() = !vfExec.back();
 352                 }
 353                 break;
 354
 355                 case OP_ENDIF:
 356                 {
 357                     if (vfExec.empty())
 358                         return false;
 359                     vfExec.pop_back();
 360                 }
 361                 break;
 362
 363                 case OP_VERIFY:
 364                 {
 365                     // (true -- ) or
 366                     // (false -- false) and return
 367                     if (stack.size() < 1)
 368                         return false;
 369                     bool fValue = CastToBool(stacktop(-1));
 370                     if (fValue)
 371                         popstack(stack);
 372                     else
 373                         return false;
 374                 }
 375                 break;
 376
 377                 case OP_RETURN:
 378                 {
 379                     return false;
 380                 }
 381                 break;
 382
 383
 384                 //
 385                 // Stack ops
 386                 //
 387                 case OP_TOALTSTACK:
 388                 {
 389                     if (stack.size() < 1)
 390                         return false;
 391                     altstack.push_back(stacktop(-1));
 392                     popstack(stack);
 393                 }
 394                 break;
 395
 396                 case OP_FROMALTSTACK:
 397                 {
 398                     if (altstack.size() < 1)
 399                         return false;
 400                     stack.push_back(altstacktop(-1));
 401                     popstack(altstack);
 402                 }
 403                 break;
 404
 405                 case OP_2DROP:
 406                 {
 407                     // (x1 x2 -- )
 408                     if (stack.size() < 2)
 409                         return false;
 410                     popstack(stack);
 411                     popstack(stack);
 412                 }
 413                 break;
 414
 415                 case OP_2DUP:
 416                 {
 417                     // (x1 x2 -- x1 x2 x1 x2)
 418                     if (stack.size() < 2)
 419                         return false;
 420                     valtype vch1 = stacktop(-2);
 421                     valtype vch2 = stacktop(-1);
 422                     stack.push_back(vch1);
 423                     stack.push_back(vch2);
 424                 }
 425                 break;
 426
 427                 case OP_3DUP:
 428                 {
 429                     // (x1 x2 x3 -- x1 x2 x3 x1 x2 x3)
 430                     if (stack.size() < 3)
 431                         return false;
 432                     valtype vch1 = stacktop(-3);
 433                     valtype vch2 = stacktop(-2);
 434                     valtype vch3 = stacktop(-1);
 435                     stack.push_back(vch1);
 436                     stack.push_back(vch2);
 437                     stack.push_back(vch3);
 438                 }
 439                 break;
 440
 441                 case OP_2OVER:
 442                 {
 443                     // (x1 x2 x3 x4 -- x1 x2 x3 x4 x1 x2)
 444                     if (stack.size() < 4)
 445                         return false;
 446                     valtype vch1 = stacktop(-4);
 447                     valtype vch2 = stacktop(-3);
 448                     stack.push_back(vch1);
 449                     stack.push_back(vch2);
 450                 }
 451                 break;
 452
 453                 case OP_2ROT:
 454                 {
 455                     // (x1 x2 x3 x4 x5 x6 -- x3 x4 x5 x6 x1 x2)
 456                     if (stack.size() < 6)
 457                         return false;
 458                     valtype vch1 = stacktop(-6);
 459                     valtype vch2 = stacktop(-5);
 460                     stack.erase(stack.end()-6, stack.end()-4);
 461                     stack.push_back(vch1);
 462                     stack.push_back(vch2);
 463                 }
 464                 break;
 465
 466                 case OP_2SWAP:
 467                 {
 468                     // (x1 x2 x3 x4 -- x3 x4 x1 x2)
 469                     if (stack.size() < 4)
 470                         return false;
 471                     swap(stacktop(-4), stacktop(-2));
 472                     swap(stacktop(-3), stacktop(-1));
 473                 }
 474                 break;
 475
 476                 case OP_IFDUP:
 477                 {
 478                     // (x - 0 | x x)
 479                     if (stack.size() < 1)
 480                         return false;
 481                     valtype vch = stacktop(-1);
 482                     if (CastToBool(vch))
 483                         stack.push_back(vch);
 484                 }
 485                 break;
 486
 487                 case OP_DEPTH:
 488                 {
 489                     // -- stacksize
 490                     CBigNum bn(stack.size());
 491                     stack.push_back(bn.getvch());
 492                 }
 493                 break;
 494
 495                 case OP_DROP:
 496                 {
 497                     // (x -- )
 498                     if (stack.size() < 1)
 499                         return false;
 500                     popstack(stack);
 501                 }
 502                 break;
 503
 504                 case OP_DUP:
 505                 {
 506                     // (x -- x x)
 507                     if (stack.size() < 1)
 508                         return false;
 509                     valtype vch = stacktop(-1);
 510                     stack.push_back(vch);
 511                 }
 512                 break;
 513
 514                 case OP_NIP:
 515                 {
 516                     // (x1 x2 -- x2)
 517                     if (stack.size() < 2)
 518                         return false;
 519                     stack.erase(stack.end() - 2);
 520                 }
 521                 break;
 522
 523                 case OP_OVER:
 524                 {
 525                     // (x1 x2 -- x1 x2 x1)
 526                     if (stack.size() < 2)
 527                         return false;
 528                     valtype vch = stacktop(-2);
 529                     stack.push_back(vch);
 530                 }
 531                 break;
 532
 533                 case OP_PICK:
 534                 case OP_ROLL:
 535                 {
 536                     // (xn ... x2 x1 x0 n - xn ... x2 x1 x0 xn)
 537                     // (xn ... x2 x1 x0 n - ... x2 x1 x0 xn)
 538                     if (stack.size() < 2)
 539                         return false;
 540                     int n = CastToBigNum(stacktop(-1)).getint();
 541                     popstack(stack);
 542                     if (n < 0 || n >= (int)stack.size())
 543                         return false;
 544                     valtype vch = stacktop(-n-1);
 545                     if (opcode == OP_ROLL)
 546                         stack.erase(stack.end()-n-1);
 547                     stack.push_back(vch);
 548                 }
 549                 break;
 550
 551                 case OP_ROT:
 552                 {
 553                     // (x1 x2 x3 -- x2 x3 x1)
 554                     //  x2 x1 x3  after first swap
 555                     //  x2 x3 x1  after second swap
 556                     if (stack.size() < 3)
 557                         return false;
 558                     swap(stacktop(-3), stacktop(-2));
 559                     swap(stacktop(-2), stacktop(-1));
 560                 }
 561                 break;
 562
 563                 case OP_SWAP:
 564                 {
 565                     // (x1 x2 -- x2 x1)
 566                     if (stack.size() < 2)
 567                         return false;
 568                     swap(stacktop(-2), stacktop(-1));
 569                 }
 570                 break;
 571
 572                 case OP_TUCK:
 573                 {
 574                     // (x1 x2 -- x2 x1 x2)
 575                     if (stack.size() < 2)
 576                         return false;
 577                     valtype vch = stacktop(-1);
 578                     stack.insert(stack.end()-2, vch);
 579                 }
 580                 break;
 581
 582
 583                 //
 584                 // Splice ops
 585                 //
 586                 case OP_CAT:
 587                 {
 588                     // (x1 x2 -- out)
 589                     if (stack.size() < 2)
 590                         return false;
 591                     valtype& vch1 = stacktop(-2);
 592                     valtype& vch2 = stacktop(-1);
 593                     vch1.insert(vch1.end(), vch2.begin(), vch2.end());
 594                     popstack(stack);
 595                     if (stacktop(-1).size() > 520)
 596                         return false;
 597                 }
 598                 break;
 599
 600                 case OP_SUBSTR:
 601                 {
 602                     // (in begin size -- out)
 603                     if (stack.size() < 3)
 604                         return false;
 605                     valtype& vch = stacktop(-3);
 606                     int nBegin = CastToBigNum(stacktop(-2)).getint();
 607                     int nEnd = nBegin + CastToBigNum(stacktop(-1)).getint();
 608                     if (nBegin < 0 || nEnd < nBegin)
 609                         return false;
 610                     if (nBegin > (int)vch.size())
 611                         nBegin = vch.size();
 612                     if (nEnd > (int)vch.size())
 613                         nEnd = vch.size();
 614                     vch.erase(vch.begin() + nEnd, vch.end());
 615                     vch.erase(vch.begin(), vch.begin() + nBegin);
 616                     popstack(stack);
 617                     popstack(stack);
 618                 }
 619                 break;
 620
 621                 case OP_LEFT:
 622                 case OP_RIGHT:
 623                 {
 624                     // (in size -- out)
 625                     if (stack.size() < 2)
 626                         return false;
 627                     valtype& vch = stacktop(-2);
 628                     int nSize = CastToBigNum(stacktop(-1)).getint();
 629                     if (nSize < 0)
 630                         return false;
 631                     if (nSize > (int)vch.size())
 632                         nSize = vch.size();
 633                     if (opcode == OP_LEFT)
 634                         vch.erase(vch.begin() + nSize, vch.end());
 635                     else
 636                         vch.erase(vch.begin(), vch.end() - nSize);
 637                     popstack(stack);
 638                 }
 639                 break;
 640
 641                 case OP_SIZE:
 642                 {
 643                     // (in -- in size)
 644                     if (stack.size() < 1)
 645                         return false;
 646                     CBigNum bn(stacktop(-1).size());
 647                     stack.push_back(bn.getvch());
 648                 }
 649                 break;
 650
 651
 652                 //
 653                 // Bitwise logic
 654                 //
 655                 case OP_INVERT:
 656                 {
 657                     // (in - out)
 658                     if (stack.size() < 1)
 659                         return false;
 660                     valtype& vch = stacktop(-1);
 661                     for (unsigned int i = 0; i < vch.size(); i++)
 662                         vch[i] = ~vch[i];
 663                 }
 664                 break;
 665
 666                 case OP_AND:
 667                 case OP_OR:
 668                 case OP_XOR:
 669                 {
 670                     // (x1 x2 - out)
 671                     if (stack.size() < 2)
 672                         return false;
 673                     valtype& vch1 = stacktop(-2);
 674                     valtype& vch2 = stacktop(-1);
 675                     MakeSameSize(vch1, vch2);
 676                     if (opcode == OP_AND)
 677                     {
 678                         for (unsigned int i = 0; i < vch1.size(); i++)
 679                             vch1[i] &= vch2[i];
 680                     }
 681                     else if (opcode == OP_OR)
 682                     {
 683                         for (unsigned int i = 0; i < vch1.size(); i++)
 684                             vch1[i] |= vch2[i];
 685                     }
 686                     else if (opcode == OP_XOR)
 687                     {
 688                         for (unsigned int i = 0; i < vch1.size(); i++)
 689                             vch1[i] ^= vch2[i];
 690                     }
 691                     popstack(stack);
 692                 }
 693                 break;
 694
 695                 case OP_EQUAL:
 696                 case OP_EQUALVERIFY:
 697                 //case OP_NOTEQUAL: // use OP_NUMNOTEQUAL
 698                 {
 699                     // (x1 x2 - bool)
 700                     if (stack.size() < 2)
 701                         return false;
 702                     valtype& vch1 = stacktop(-2);
 703                     valtype& vch2 = stacktop(-1);
 704                     bool fEqual = (vch1 == vch2);
 705                     // OP_NOTEQUAL is disabled because it would be too easy to say
 706                     // something like n != 1 and have some wiseguy pass in 1 with extra
 707                     // zero bytes after it (numerically, 0x01 == 0x0001 == 0x000001)
 708                     //if (opcode == OP_NOTEQUAL)
 709                     //    fEqual = !fEqual;
 710                     popstack(stack);
 711                     popstack(stack);
 712                     stack.push_back(fEqual ? vchTrue : vchFalse);
 713                     if (opcode == OP_EQUALVERIFY)
 714                     {
 715                         if (fEqual)
 716                             popstack(stack);
 717                         else
 718                             return false;
 719                     }
 720                 }
 721                 break;
 722
 723
 724                 //
 725                 // Numeric
 726                 //
 727                 case OP_1ADD:
 728                 case OP_1SUB:
 729                 case OP_2MUL:
 730                 case OP_2DIV:
 731                 case OP_NEGATE:
 732                 case OP_ABS:
 733                 case OP_NOT:
 734                 case OP_0NOTEQUAL:
 735                 {
 736                     // (in -- out)
 737                     if (stack.size() < 1)
 738                         return false;
 739                     CBigNum bn = CastToBigNum(stacktop(-1));
 740                     switch (opcode)
 741                     {
 742                     case OP_1ADD:       bn += bnOne; break;
 743                     case OP_1SUB:       bn -= bnOne; break;
 744                     case OP_2MUL:       bn <<= 1; break;
 745                     case OP_2DIV:       bn >>= 1; break;
 746                     case OP_NEGATE:     bn = -bn; break;
 747                     case OP_ABS:        if (bn < bnZero) bn = -bn; break;
 748                     case OP_NOT:        bn = (bn == bnZero); break;
 749                     case OP_0NOTEQUAL:  bn = (bn != bnZero); break;
 750                     default:            assert(!"invalid opcode"); break;
 751                     }
 752                     popstack(stack);
 753                     stack.push_back(bn.getvch());
 754                 }
 755                 break;
 756
 757                 case OP_ADD:
 758                 case OP_SUB:
 759                 case OP_MUL:
 760                 case OP_DIV:
 761                 case OP_MOD:
 762                 case OP_LSHIFT:
 763                 case OP_RSHIFT:
 764                 case OP_BOOLAND:
 765                 case OP_BOOLOR:
 766                 case OP_NUMEQUAL:
 767                 case OP_NUMEQUALVERIFY:
 768                 case OP_NUMNOTEQUAL:
 769                 case OP_LESSTHAN:
 770                 case OP_GREATERTHAN:
 771                 case OP_LESSTHANOREQUAL:
 772                 case OP_GREATERTHANOREQUAL:
 773                 case OP_MIN:
 774                 case OP_MAX:
 775                 {
 776                     // (x1 x2 -- out)
 777                     if (stack.size() < 2)
 778                         return false;
 779                     CBigNum bn1 = CastToBigNum(stacktop(-2));
 780                     CBigNum bn2 = CastToBigNum(stacktop(-1));
 781                     CBigNum bn;
 782                     switch (opcode)
 783                     {
 784                     case OP_ADD:
 785                         bn = bn1 + bn2;
 786                         break;
 787
 788                     case OP_SUB:
 789                         bn = bn1 - bn2;
 790                         break;
 791
 792                     case OP_MUL:
 793                         if (!BN_mul(&bn, &bn1, &bn2, pctx))
 794                             return false;
 795                         break;
 796
 797                     case OP_DIV:
 798                         if (!BN_div(&bn, NULL, &bn1, &bn2, pctx))
 799                             return false;
 800                         break;
 801
 802                     case OP_MOD:
 803                         if (!BN_mod(&bn, &bn1, &bn2, pctx))
 804                             return false;
 805                         break;
 806
 807                     case OP_LSHIFT:
 808                         if (bn2 < bnZero || bn2 > CBigNum(2048))
 809                             return false;
 810                         bn = bn1 << bn2.getulong();
 811                         break;
 812
 813                     case OP_RSHIFT:
 814                         if (bn2 < bnZero || bn2 > CBigNum(2048))
 815                             return false;
 816                         bn = bn1 >> bn2.getulong();
 817                         break;
 818
 819                     case OP_BOOLAND:             bn = (bn1 != bnZero && bn2 != bnZero); break;
 820                     case OP_BOOLOR:              bn = (bn1 != bnZero || bn2 != bnZero); break;
 821                     case OP_NUMEQUAL:            bn = (bn1 == bn2); break;
 822                     case OP_NUMEQUALVERIFY:      bn = (bn1 == bn2); break;
 823                     case OP_NUMNOTEQUAL:         bn = (bn1 != bn2); break;
 824                     case OP_LESSTHAN:            bn = (bn1 < bn2); break;
 825                     case OP_GREATERTHAN:         bn = (bn1 > bn2); break;
 826                     case OP_LESSTHANOREQUAL:     bn = (bn1 <= bn2); break;
 827                     case OP_GREATERTHANOREQUAL:  bn = (bn1 >= bn2); break;
 828                     case OP_MIN:                 bn = (bn1 < bn2 ? bn1 : bn2); break;
 829                     case OP_MAX:                 bn = (bn1 > bn2 ? bn1 : bn2); break;
 830                     default:                     assert(!"invalid opcode"); break;
 831                     }
 832                     popstack(stack);
 833                     popstack(stack);
 834                     stack.push_back(bn.getvch());
 835
 836                     if (opcode == OP_NUMEQUALVERIFY)
 837                     {
 838                         if (CastToBool(stacktop(-1)))
 839                             popstack(stack);
 840                         else
 841                             return false;
 842                     }
 843                 }
 844                 break;
 845
 846                 case OP_WITHIN:
 847                 {
 848                     // (x min max -- out)
 849                     if (stack.size() < 3)
 850                         return false;
 851                     CBigNum bn1 = CastToBigNum(stacktop(-3));
 852                     CBigNum bn2 = CastToBigNum(stacktop(-2));
 853                     CBigNum bn3 = CastToBigNum(stacktop(-1));
 854                     bool fValue = (bn2 <= bn1 && bn1 < bn3);
 855                     popstack(stack);
 856                     popstack(stack);
 857                     popstack(stack);
 858                     stack.push_back(fValue ? vchTrue : vchFalse);
 859                 }
 860                 break;
 861
 862
 863                 //
 864                 // Crypto
 865                 //
 866                 case OP_RIPEMD160:
 867                 case OP_SHA1:
 868                 case OP_SHA256:
 869                 case OP_HASH160:
 870                 case OP_HASH256:
 871                 {
 872                     // (in -- hash)
 873                     if (stack.size() < 1)
 874                         return false;
 875                     valtype& vch = stacktop(-1);
 876                     valtype vchHash((opcode == OP_RIPEMD160 || opcode == OP_SHA1 || opcode == OP_HASH160) ? 20 : 32);
 877                     if (opcode == OP_RIPEMD160)
 878                         RIPEMD160(&vch[0], vch.size(), &vchHash[0]);
 879                     else if (opcode == OP_SHA1)
 880                         SHA1(&vch[0], vch.size(), &vchHash[0]);
 881                     else if (opcode == OP_SHA256)
 882                         SHA256(&vch[0], vch.size(), &vchHash[0]);
 883                     else if (opcode == OP_HASH160)
 884                     {
 885                         uint160 hash160 = Hash160(vch);
 886                         memcpy(&vchHash[0], &hash160, sizeof(hash160));
 887                     }
 888                     else if (opcode == OP_HASH256)
 889                     {
 890                         uint256 hash = Hash(vch.begin(), vch.end());
 891                         memcpy(&vchHash[0], &hash, sizeof(hash));
 892                     }
 893                     popstack(stack);
 894                     stack.push_back(vchHash);
 895                 }
 896                 break;
 897
 898                 case OP_CODESEPARATOR:
 899                 {
 900                     // Hash starts after the code separator
 901                     pbegincodehash = pc;
 902                 }
 903                 break;
 904
 905                 case OP_CHECKSIG:
 906                 case OP_CHECKSIGVERIFY:
 907                 {
 908                     // (sig pubkey -- bool)
 909                     if (stack.size() < 2)
 910                         return false;
 911
 912                     valtype& vchSig    = stacktop(-2);
 913                     valtype& vchPubKey = stacktop(-1);
 914
 915                     ////// debug print
 916                     //PrintHex(vchSig.begin(), vchSig.end(), "sig: %s\n");
 917                     //PrintHex(vchPubKey.begin(), vchPubKey.end(), "pubkey: %s\n");
 918
 919                     // Subset of script starting at the most recent codeseparator
 920                     CScript scriptCode(pbegincodehash, pend);
 921
 922                     // Drop the signature, since there's no way for a signature to sign itself
 923                     scriptCode.FindAndDelete(CScript(vchSig));
 924
 925                     bool fSuccess = CheckSig(vchSig, vchPubKey, scriptCode, txTo, nIn, nHashType);
 926
 927                     popstack(stack);
 928                     popstack(stack);
 929                     stack.push_back(fSuccess ? vchTrue : vchFalse);
 930                     if (opcode == OP_CHECKSIGVERIFY)
 931                     {
 932                         if (fSuccess)
 933                             popstack(stack);
 934                         else
 935                             return false;
 936                     }
 937                 }
 938                 break;
 939
 940                 case OP_CHECKMULTISIG:
 941                 case OP_CHECKMULTISIGVERIFY:
 942                 {
 943                     // ([sig ...] num_of_signatures [pubkey ...] num_of_pubkeys -- bool)
 944
 945                     int i = 1;
 946                     if ((int)stack.size() < i)
 947                         return false;
 948
 949                     int nKeysCount = CastToBigNum(stacktop(-i)).getint();
 950                     if (nKeysCount < 0 || nKeysCount > 20)
 951                         return false;
 952                     nOpCount += nKeysCount;
 953                     if (nOpCount > 201)
 954                         return false;
 955                     int ikey = ++i;
 956                     i += nKeysCount;
 957                     if ((int)stack.size() < i)
 958                         return false;
 959
 960                     int nSigsCount = CastToBigNum(stacktop(-i)).getint();
 961                     if (nSigsCount < 0 || nSigsCount > nKeysCount)
 962                         return false;
 963                     int isig = ++i;
 964                     i += nSigsCount;
 965                     if ((int)stack.size() < i)
 966                         return false;
 967
 968                     // Subset of script starting at the most recent codeseparator
 969                     CScript scriptCode(pbegincodehash, pend);
 970
 971                     // Drop the signatures, since there's no way for a signature to sign itself
 972                     for (int k = 0; k < nSigsCount; k++)
 973                     {
 974                         valtype& vchSig = stacktop(-isig-k);
 975                         scriptCode.FindAndDelete(CScript(vchSig));
 976                     }
 977
 978                     bool fSuccess = true;
 979                     while (fSuccess && nSigsCount > 0)
 980                     {
 981                         valtype& vchSig    = stacktop(-isig);
 982                         valtype& vchPubKey = stacktop(-ikey);
 983
 984                         // Check signature
 985                         if (CheckSig(vchSig, vchPubKey, scriptCode, txTo, nIn, nHashType))
 986                         {
 987                             isig++;
 988                             nSigsCount--;
 989                         }
 990                         ikey++;
 991                         nKeysCount--;
 992
 993                         // If there are more signatures left than keys left,
 994                         // then too many signatures have failed
 995                         if (nSigsCount > nKeysCount)
 996                             fSuccess = false;
 997                     }
 998
 999                     while (i-- > 0)
1000                         popstack(stack);
1001                     stack.push_back(fSuccess ? vchTrue : vchFalse);
1002
1003                     if (opcode == OP_CHECKMULTISIGVERIFY)
1004                     {
1005                         if (fSuccess)
1006                             popstack(stack);
1007                         else
1008                             return false;
1009                     }
1010                 }
1011                 break;
1012
1013                 default:
1014                     return false;
1015             }
1016
1017             // Size limits
1018             if (stack.size() + altstack.size() > 1000)
1019                 return false;
1020         }
1021     }
1022     catch (...)
1023     {
1024         return false;
1025     }
1026
1027
1028     if (!vfExec.empty())
1029         return false;
1030
1031     return true;
1032 }
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042 uint256 SignatureHash(CScript scriptCode, const CTransaction& txTo, unsigned int nIn, int nHashType)
1043 {
1044     if (nIn >= txTo.vin.size())
1045     {
1046         printf("ERROR: SignatureHash() : nIn=%d out of range\n", nIn);
1047         return 1;
1048     }
1049     CTransaction txTmp(txTo);
1050
1051     // In case concatenating two scripts ends up with two codeseparators,
1052     // or an extra one at the end, this prevents all those possible incompatibilities.
1053     scriptCode.FindAndDelete(CScript(OP_CODESEPARATOR));
1054
1055     // Blank out other inputs' signatures
1056     for (unsigned int i = 0; i < txTmp.vin.size(); i++)
1057         txTmp.vin[i].scriptSig = CScript();
1058     txTmp.vin[nIn].scriptSig = scriptCode;
1059
1060     // Blank out some of the outputs
1061     if ((nHashType & 0x1f) == SIGHASH_NONE)
1062     {
1063         // Wildcard payee
1064         txTmp.vout.clear();
1065
1066         // Let the others update at will
1067         for (unsigned int i = 0; i < txTmp.vin.size(); i++)
1068             if (i != nIn)
1069                 txTmp.vin[i].nSequence = 0;
1070     }
1071     else if ((nHashType & 0x1f) == SIGHASH_SINGLE)
1072     {
1073         // Only lockin the txout payee at same index as txin
1074         unsigned int nOut = nIn;
1075         if (nOut >= txTmp.vout.size())
1076         {
1077             printf("ERROR: SignatureHash() : nOut=%d out of range\n", nOut);
1078             return 1;
1079         }
1080         txTmp.vout.resize(nOut+1);
1081         for (unsigned int i = 0; i < nOut; i++)
1082             txTmp.vout[i].SetNull();
1083
1084         // Let the others update at will
1085         for (unsigned int i = 0; i < txTmp.vin.size(); i++)
1086             if (i != nIn)
1087                 txTmp.vin[i].nSequence = 0;
1088     }
1089
1090     // Blank out other inputs completely, not recommended for open transactions
1091     if (nHashType & SIGHASH_ANYONECANPAY)
1092     {
1093         txTmp.vin[0] = txTmp.vin[nIn];
1094         txTmp.vin.resize(1);
1095     }
1096
1097     // Serialize and hash
1098     CDataStream ss(SER_GETHASH, 0);
1099     ss.reserve(10000);
1100     ss << txTmp << nHashType;
1101     return Hash(ss.begin(), ss.end());
1102 }
1103
1104
1105 // Valid signature cache, to avoid doing expensive ECDSA signature checking
1106 // twice for every transaction (once when accepted into memory pool, and
1107 // again when accepted into the block chain)
1108
1109 class CSignatureCache
1110 {
1111 private:
1112      // sigdata_type is (signature hash, signature, public key):
1113     typedef boost::tuple<uint256, std::vector<unsigned char>, std::vector<unsigned char> > sigdata_type;
1114     std::set< sigdata_type> setValid;
1115     CCriticalSection cs_sigcache;
1116
1117 public:
1118     bool
1119     Get(uint256 hash, const std::vector<unsigned char>& vchSig, const std::vector<unsigned char>& pubKey)
1120     {
1121         LOCK(cs_sigcache);
1122
1123         sigdata_type k(hash, vchSig, pubKey);
1124         std::set<sigdata_type>::iterator mi = setValid.find(k);
1125         if (mi != setValid.end())
1126             return true;
1127         return false;
1128     }
1129
1130     void
1131     Set(uint256 hash, const std::vector<unsigned char>& vchSig, const std::vector<unsigned char>& pubKey)
1132     {
1133         // DoS prevention: limit cache size to less than 10MB
1134         // (~200 bytes per cache entry times 50,000 entries)
1135         // Since there are a maximum of 20,000 signature operations per block
1136         // 50,000 is a reasonable default.
1137         int64 nMaxCacheSize = GetArg("-maxsigcachesize", 50000);
1138         if (nMaxCacheSize <= 0) return;
1139
1140         LOCK(cs_sigcache);
1141
1142         while (static_cast<int64>(setValid.size()) > nMaxCacheSize)
1143         {
1144             // Evict a random entry. Random because that helps
1145             // foil would-be DoS attackers who might try to pre-generate
1146             // and re-use a set of valid signatures just-slightly-greater
1147             // than our cache size.
1148             uint256 randomHash = GetRandHash();
1149             std::vector<unsigned char> unused;
1150             std::set<sigdata_type>::iterator it =
1151                 setValid.lower_bound(sigdata_type(randomHash, unused, unused));
1152             if (it == setValid.end())
1153                 it = setValid.begin();
1154             setValid.erase(*it);
1155         }
1156
1157         sigdata_type k(hash, vchSig, pubKey);
1158         setValid.insert(k);
1159     }
1160 };
1161
1162 bool CheckSig(vector<unsigned char> vchSig, vector<unsigned char> vchPubKey, CScript scriptCode,
1163               const CTransaction& txTo, unsigned int nIn, int nHashType)
1164 {
1165     static CSignatureCache signatureCache;
1166
1167     // Hash type is one byte tacked on to the end of the signature
1168     if (vchSig.empty())
1169         return false;
1170     if (nHashType == 0)
1171         nHashType = vchSig.back();
1172     else if (nHashType != vchSig.back())
1173         return false;
1174     vchSig.pop_back();
1175
1176     uint256 sighash = SignatureHash(scriptCode, txTo, nIn, nHashType);
1177
1178     if (signatureCache.Get(sighash, vchSig, vchPubKey))
1179         return true;
1180
1181     CKey key;
1182     if (!key.SetPubKey(vchPubKey))
1183         return false;
1184
1185     if (!key.Verify(sighash, vchSig))
1186         return false;
1187
1188     signatureCache.Set(sighash, vchSig, vchPubKey);
1189     return true;
1190 }
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200 //
1201 // Return public keys or hashes from scriptPubKey, for 'standard' transaction types.
1202 //
1203 bool Solver(const CScript& scriptPubKey, txnouttype& typeRet, vector<vector<unsigned char> >& vSolutionsRet)
1204 {
1205     // Templates
1206     static map<txnouttype, CScript> mTemplates;
1207     if (mTemplates.empty())
1208     {
1209         // Standard tx, sender provides pubkey, receiver adds signature
1210         mTemplates.insert(make_pair(TX_PUBKEY, CScript() << OP_PUBKEY << OP_CHECKSIG));
1211
1212         // Bitcoin address tx, sender provides hash of pubkey, receiver provides signature and pubkey
1213         mTemplates.insert(make_pair(TX_PUBKEYHASH, CScript() << OP_DUP << OP_HASH160 << OP_PUBKEYHASH << OP_EQUALVERIFY << OP_CHECKSIG));
1214
1215         // Sender provides N pubkeys, receivers provides M signatures
1216         mTemplates.insert(make_pair(TX_MULTISIG, CScript() << OP_SMALLINTEGER << OP_PUBKEYS << OP_SMALLINTEGER << OP_CHECKMULTISIG));
1217     }
1218
1219     // Shortcut for pay-to-script-hash, which are more constrained than the other types:
1220     // it is always OP_HASH160 20 [20 byte hash] OP_EQUAL
1221     if (scriptPubKey.IsPayToScriptHash())
1222     {
1223         typeRet = TX_SCRIPTHASH;
1224         vector<unsigned char> hashBytes(scriptPubKey.begin()+2, scriptPubKey.begin()+22);
1225         vSolutionsRet.push_back(hashBytes);
1226         return true;
1227     }
1228
1229     // Scan templates
1230     const CScript& script1 = scriptPubKey;
1231     BOOST_FOREACH(const PAIRTYPE(txnouttype, CScript)& tplate, mTemplates)
1232     {
1233         const CScript& script2 = tplate.second;
1234         vSolutionsRet.clear();
1235
1236         opcodetype opcode1, opcode2;
1237         vector<unsigned char> vch1, vch2;
1238
1239         // Compare
1240         CScript::const_iterator pc1 = script1.begin();
1241         CScript::const_iterator pc2 = script2.begin();
1242         loop
1243         {
1244             if (pc1 == script1.end() && pc2 == script2.end())
1245             {
1246                 // Found a match
1247                 typeRet = tplate.first;
1248                 if (typeRet == TX_MULTISIG)
1249                 {
1250                     // Additional checks for TX_MULTISIG:
1251                     unsigned char m = vSolutionsRet.front()[0];
1252                     unsigned char n = vSolutionsRet.back()[0];
1253                     if (m < 1 || n < 1 || m > n || vSolutionsRet.size()-2 != n)
1254                         return false;
1255                 }
1256                 return true;
1257             }
1258             if (!script1.GetOp(pc1, opcode1, vch1))
1259                 break;
1260             if (!script2.GetOp(pc2, opcode2, vch2))
1261                 break;
1262
1263             // Template matching opcodes:
1264             if (opcode2 == OP_PUBKEYS)
1265             {
1266                 while (vch1.size() >= 33 && vch1.size() <= 120)
1267                 {
1268                     vSolutionsRet.push_back(vch1);
1269                     if (!script1.GetOp(pc1, opcode1, vch1))
1270                         break;
1271                 }
1272                 if (!script2.GetOp(pc2, opcode2, vch2))
1273                     break;
1274                 // Normal situation is to fall through
1275                 // to other if/else statments
1276             }
1277
1278             if (opcode2 == OP_PUBKEY)
1279             {
1280                 if (vch1.size() < 33 || vch1.size() > 120)
1281                     break;
1282                 vSolutionsRet.push_back(vch1);
1283             }
1284             else if (opcode2 == OP_PUBKEYHASH)
1285             {
1286                 if (vch1.size() != sizeof(uint160))
1287                     break;
1288                 vSolutionsRet.push_back(vch1);
1289             }
1290             else if (opcode2 == OP_SMALLINTEGER)
1291             {   // Single-byte small integer pushed onto vSolutions
1292                 if (opcode1 == OP_0 ||
1293                     (opcode1 >= OP_1 && opcode1 <= OP_16))
1294                 {
1295                     char n = (char)CScript::DecodeOP_N(opcode1);
1296                     vSolutionsRet.push_back(valtype(1, n));
1297                 }
1298                 else
1299                     break;
1300             }
1301             else if (opcode1 != opcode2 || vch1 != vch2)
1302             {
1303                 // Others must match exactly
1304                 break;
1305             }
1306         }
1307     }
1308
1309     vSolutionsRet.clear();
1310     typeRet = TX_NONSTANDARD;
1311     return false;
1312 }
1313
1314
1315 bool Sign1(const CKeyID& address, const CKeyStore& keystore, uint256 hash, int nHashType, CScript& scriptSigRet)
1316 {
1317     CKey key;
1318     if (!keystore.GetKey(address, key))
1319         return false;
1320
1321     vector<unsigned char> vchSig;
1322     if (!key.Sign(hash, vchSig))
1323         return false;
1324     vchSig.push_back((unsigned char)nHashType);
1325     scriptSigRet << vchSig;
1326
1327     return true;
1328 }
1329
1330 bool SignN(const vector<valtype>& multisigdata, const CKeyStore& keystore, uint256 hash, int nHashType, CScript& scriptSigRet)
1331 {
1332     int nSigned = 0;
1333     int nRequired = multisigdata.front()[0];
1334     for (unsigned int i = 1; i < multisigdata.size()-1 && nSigned < nRequired; i++)
1335     {
1336         const valtype& pubkey = multisigdata[i];
1337         CKeyID keyID = CPubKey(pubkey).GetID();
1338         if (Sign1(keyID, keystore, hash, nHashType, scriptSigRet))
1339             ++nSigned;
1340     }
1341     return nSigned==nRequired;
1342 }
1343
1344 //
1345 // Sign scriptPubKey with private keys stored in keystore, given transaction hash and hash type.
1346 // Signatures are returned in scriptSigRet (or returns false if scriptPubKey can't be signed),
1347 // unless whichTypeRet is TX_SCRIPTHASH, in which case scriptSigRet is the redemption script.
1348 // Returns false if scriptPubKey could not be completely satisified.
1349 //
1350 bool Solver(const CKeyStore& keystore, const CScript& scriptPubKey, uint256 hash, int nHashType,
1351                   CScript& scriptSigRet, txnouttype& whichTypeRet)
1352 {
1353     scriptSigRet.clear();
1354
1355     vector<valtype> vSolutions;
1356     if (!Solver(scriptPubKey, whichTypeRet, vSolutions))
1357         return false;
1358
1359     CKeyID keyID;
1360     switch (whichTypeRet)
1361     {
1362     case TX_NONSTANDARD:
1363         return false;
1364     case TX_PUBKEY:
1365         keyID = CPubKey(vSolutions[0]).GetID();
1366         return Sign1(keyID, keystore, hash, nHashType, scriptSigRet);
1367     case TX_PUBKEYHASH:
1368         keyID = CKeyID(uint160(vSolutions[0]));
1369         if (!Sign1(keyID, keystore, hash, nHashType, scriptSigRet))
1370             return false;
1371         else
1372         {
1373             CPubKey vch;
1374             keystore.GetPubKey(keyID, vch);
1375             scriptSigRet << vch;
1376         }
1377         return true;
1378     case TX_SCRIPTHASH:
1379         return keystore.GetCScript(uint160(vSolutions[0]), scriptSigRet);
1380
1381     case TX_MULTISIG:
1382         scriptSigRet << OP_0; // workaround CHECKMULTISIG bug
1383         return (SignN(vSolutions, keystore, hash, nHashType, scriptSigRet));
1384     }
1385     return false;
1386 }
1387
1388 int ScriptSigArgsExpected(txnouttype t, const std::vector<std::vector<unsigned char> >& vSolutions)
1389 {
1390     switch (t)
1391     {
1392     case TX_NONSTANDARD:
1393         return -1;
1394     case TX_PUBKEY:
1395         return 1;
1396     case TX_PUBKEYHASH:
1397         return 2;
1398     case TX_MULTISIG:
1399         if (vSolutions.size() < 1 || vSolutions[0].size() < 1)
1400             return -1;
1401         return vSolutions[0][0] + 1;
1402     case TX_SCRIPTHASH:
1403         return 1; // doesn't include args needed by the script
1404     }
1405     return -1;
1406 }
1407
1408 bool IsStandard(const CScript& scriptPubKey)
1409 {
1410     vector<valtype> vSolutions;
1411     txnouttype whichType;
1412     if (!Solver(scriptPubKey, whichType, vSolutions))
1413         return false;
1414
1415     if (whichType == TX_MULTISIG)
1416     {
1417         unsigned char m = vSolutions.front()[0];
1418         unsigned char n = vSolutions.back()[0];
1419         // Support up to x-of-3 multisig txns as standard
1420         if (n < 1 || n > 3)
1421             return false;
1422         if (m < 1 || m > n)
1423             return false;
1424     }
1425
1426     return whichType != TX_NONSTANDARD;
1427 }
1428
1429
1430 unsigned int HaveKeys(const vector<valtype>& pubkeys, const CKeyStore& keystore)
1431 {
1432     unsigned int nResult = 0;
1433     BOOST_FOREACH(const valtype& pubkey, pubkeys)
1434     {
1435         CKeyID keyID = CPubKey(pubkey).GetID();
1436         if (keystore.HaveKey(keyID))
1437             ++nResult;
1438     }
1439     return nResult;
1440 }
1441
1442
1443 class CKeyStoreIsMineVisitor : public boost::static_visitor<bool>
1444 {
1445 private:
1446     const CKeyStore *keystore;
1447 public:
1448     CKeyStoreIsMineVisitor(const CKeyStore *keystoreIn) : keystore(keystoreIn) { }
1449     bool operator()(const CNoDestination &dest) const { return false; }
1450     bool operator()(const CKeyID &keyID) const { return keystore->HaveKey(keyID); }
1451     bool operator()(const CScriptID &scriptID) const { return keystore->HaveCScript(scriptID); }
1452 };
1453
1454 bool IsMine(const CKeyStore &keystore, const CTxDestination &dest)
1455 {
1456     return boost::apply_visitor(CKeyStoreIsMineVisitor(&keystore), dest);
1457 }
1458
1459 bool IsMine(const CKeyStore &keystore, const CScript& scriptPubKey)
1460 {
1461     vector<valtype> vSolutions;
1462     txnouttype whichType;
1463     if (!Solver(scriptPubKey, whichType, vSolutions))
1464         return false;
1465
1466     CKeyID keyID;
1467     switch (whichType)
1468     {
1469     case TX_NONSTANDARD:
1470         return false;
1471     case TX_PUBKEY:
1472         keyID = CPubKey(vSolutions[0]).GetID();
1473         return keystore.HaveKey(keyID);
1474     case TX_PUBKEYHASH:
1475         keyID = CKeyID(uint160(vSolutions[0]));
1476         return keystore.HaveKey(keyID);
1477     case TX_SCRIPTHASH:
1478     {
1479         CScript subscript;
1480         if (!keystore.GetCScript(CScriptID(uint160(vSolutions[0])), subscript))
1481             return false;
1482         return IsMine(keystore, subscript);
1483     }
1484     case TX_MULTISIG:
1485     {
1486         // Only consider transactions "mine" if we own ALL the
1487         // keys involved. multi-signature transactions that are
1488         // partially owned (somebody else has a key that can spend
1489         // them) enable spend-out-from-under-you attacks, especially
1490         // in shared-wallet situations.
1491         vector<valtype> keys(vSolutions.begin()+1, vSolutions.begin()+vSolutions.size()-1);
1492         return HaveKeys(keys, keystore) == keys.size();
1493     }
1494     }
1495     return false;
1496 }
1497
1498 bool ExtractDestination(const CScript& scriptPubKey, CTxDestination& addressRet)
1499 {
1500     vector<valtype> vSolutions;
1501     txnouttype whichType;
1502     if (!Solver(scriptPubKey, whichType, vSolutions))
1503         return false;
1504
1505     if (whichType == TX_PUBKEY)
1506     {
1507         addressRet = CPubKey(vSolutions[0]).GetID();
1508         return true;
1509     }
1510     else if (whichType == TX_PUBKEYHASH)
1511     {
1512         addressRet = CKeyID(uint160(vSolutions[0]));
1513         return true;
1514     }
1515     else if (whichType == TX_SCRIPTHASH)
1516     {
1517         addressRet = CScriptID(uint160(vSolutions[0]));
1518         return true;
1519     }
1520     // Multisig txns have more than one address...
1521     return false;
1522 }
1523
1524 bool ExtractDestinations(const CScript& scriptPubKey, txnouttype& typeRet, vector<CTxDestination>& addressRet, int& nRequiredRet)
1525 {
1526     addressRet.clear();
1527     typeRet = TX_NONSTANDARD;
1528     vector<valtype> vSolutions;
1529     if (!Solver(scriptPubKey, typeRet, vSolutions))
1530         return false;
1531
1532     if (typeRet == TX_MULTISIG)
1533     {
1534         nRequiredRet = vSolutions.front()[0];
1535         for (unsigned int i = 1; i < vSolutions.size()-1; i++)
1536         {
1537             CTxDestination address = CPubKey(vSolutions[i]).GetID();
1538             addressRet.push_back(address);
1539         }
1540     }
1541     else
1542     {
1543         nRequiredRet = 1;
1544         CTxDestination address;
1545         if (!ExtractDestination(scriptPubKey, address))
1546            return false;
1547         addressRet.push_back(address);
1548     }
1549
1550     return true;
1551 }
1552
1553 bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, const CTransaction& txTo, unsigned int nIn,
1554                   bool fValidatePayToScriptHash, int nHashType)
1555 {
1556     vector<vector<unsigned char> > stack, stackCopy;
1557     if (!EvalScript(stack, scriptSig, txTo, nIn, nHashType))
1558         return false;
1559     if (fValidatePayToScriptHash)
1560         stackCopy = stack;
1561     if (!EvalScript(stack, scriptPubKey, txTo, nIn, nHashType))
1562         return false;
1563     if (stack.empty())
1564         return false;
1565
1566     if (CastToBool(stack.back()) == false)
1567         return false;
1568
1569     // Additional validation for spend-to-script-hash transactions:
1570     if (fValidatePayToScriptHash && scriptPubKey.IsPayToScriptHash())
1571     {
1572         if (!scriptSig.IsPushOnly()) // scriptSig must be literals-only
1573             return false;            // or validation fails
1574
1575         const valtype& pubKeySerialized = stackCopy.back();
1576         CScript pubKey2(pubKeySerialized.begin(), pubKeySerialized.end());
1577         popstack(stackCopy);
1578
1579         if (!EvalScript(stackCopy, pubKey2, txTo, nIn, nHashType))
1580             return false;
1581         if (stackCopy.empty())
1582             return false;
1583         return CastToBool(stackCopy.back());
1584     }
1585
1586     return true;
1587 }
1588
1589
1590 bool SignSignature(const CKeyStore &keystore, const CScript& fromPubKey, CTransaction& txTo, unsigned int nIn, int nHashType)
1591 {
1592     assert(nIn < txTo.vin.size());
1593     CTxIn& txin = txTo.vin[nIn];
1594
1595     // Leave out the signature from the hash, since a signature can't sign itself.
1596     // The checksig op will also drop the signatures from its hash.
1597     uint256 hash = SignatureHash(fromPubKey, txTo, nIn, nHashType);
1598
1599     txnouttype whichType;
1600     if (!Solver(keystore, fromPubKey, hash, nHashType, txin.scriptSig, whichType))
1601         return false;
1602
1603     if (whichType == TX_SCRIPTHASH)
1604     {
1605         // Solver returns the subscript that need to be evaluated;
1606         // the final scriptSig is the signatures from that
1607         // and then the serialized subscript:
1608         CScript subscript = txin.scriptSig;
1609
1610         // Recompute txn hash using subscript in place of scriptPubKey:
1611         uint256 hash2 = SignatureHash(subscript, txTo, nIn, nHashType);
1612
1613         txnouttype subType;
1614         bool fSolved =
1615             Solver(keystore, subscript, hash2, nHashType, txin.scriptSig, subType) && subType != TX_SCRIPTHASH;
1616         // Append serialized subscript whether or not it is completely signed:
1617         txin.scriptSig << static_cast<valtype>(subscript);
1618         if (!fSolved) return false;
1619     }
1620
1621     // Test solution
1622     return VerifyScript(txin.scriptSig, fromPubKey, txTo, nIn, true, 0);
1623 }
1624
1625 bool SignSignature(const CKeyStore &keystore, const CTransaction& txFrom, CTransaction& txTo, unsigned int nIn, int nHashType)
1626 {
1627     assert(nIn < txTo.vin.size());
1628     CTxIn& txin = txTo.vin[nIn];
1629     assert(txin.prevout.n < txFrom.vout.size());
1630     const CTxOut& txout = txFrom.vout[txin.prevout.n];
1631
1632     return SignSignature(keystore, txout.scriptPubKey, txTo, nIn, nHashType);
1633 }
1634
1635 bool VerifySignature(const CTransaction& txFrom, const CTransaction& txTo, unsigned int nIn, bool fValidatePayToScriptHash, int nHashType)
1636 {
1637     assert(nIn < txTo.vin.size());
1638     const CTxIn& txin = txTo.vin[nIn];
1639     if (txin.prevout.n >= txFrom.vout.size())
1640         return false;
1641     const CTxOut& txout = txFrom.vout[txin.prevout.n];
1642
1643     if (txin.prevout.hash != txFrom.GetHash())
1644         return false;
1645
1646     return VerifyScript(txin.scriptSig, txout.scriptPubKey, txTo, nIn, fValidatePayToScriptHash, nHashType);
1647 }
1648
1649 static CScript PushAll(const vector<valtype>& values)
1650 {
1651     CScript result;
1652     BOOST_FOREACH(const valtype& v, values)
1653         result << v;
1654     return result;
1655 }
1656
1657 static CScript CombineMultisig(CScript scriptPubKey, const CTransaction& txTo, unsigned int nIn,
1658                                const vector<valtype>& vSolutions,
1659                                vector<valtype>& sigs1, vector<valtype>& sigs2)
1660 {
1661     // Combine all the signatures we've got:
1662     set<valtype> allsigs;
1663     BOOST_FOREACH(const valtype& v, sigs1)
1664     {
1665         if (!v.empty())
1666             allsigs.insert(v);
1667     }
1668     BOOST_FOREACH(const valtype& v, sigs2)
1669     {
1670         if (!v.empty())
1671             allsigs.insert(v);
1672     }
1673
1674     // Build a map of pubkey -> signature by matching sigs to pubkeys:
1675     assert(vSolutions.size() > 1);
1676     unsigned int nSigsRequired = vSolutions.front()[0];
1677     unsigned int nPubKeys = vSolutions.size()-2;
1678     map<valtype, valtype> sigs;
1679     BOOST_FOREACH(const valtype& sig, allsigs)
1680     {
1681         for (unsigned int i = 0; i < nPubKeys; i++)
1682         {
1683             const valtype& pubkey = vSolutions[i+1];
1684             if (sigs.count(pubkey))
1685                 continue; // Already got a sig for this pubkey
1686
1687             if (CheckSig(sig, pubkey, scriptPubKey, txTo, nIn, 0))
1688             {
1689                 sigs[pubkey] = sig;
1690                 break;
1691             }
1692         }
1693     }
1694     // Now build a merged CScript:
1695     unsigned int nSigsHave = 0;
1696     CScript result; result << OP_0; // pop-one-too-many workaround
1697     for (unsigned int i = 0; i < nPubKeys && nSigsHave < nSigsRequired; i++)
1698     {
1699         if (sigs.count(vSolutions[i+1]))
1700         {
1701             result << sigs[vSolutions[i+1]];
1702             ++nSigsHave;
1703         }
1704     }
1705     // Fill any missing with OP_0:
1706     for (unsigned int i = nSigsHave; i < nSigsRequired; i++)
1707         result << OP_0;
1708
1709     return result;
1710 }
1711
1712 static CScript CombineSignatures(CScript scriptPubKey, const CTransaction& txTo, unsigned int nIn,
1713                                  const txnouttype txType, const vector<valtype>& vSolutions,
1714                                  vector<valtype>& sigs1, vector<valtype>& sigs2)
1715 {
1716     switch (txType)
1717     {
1718     case TX_NONSTANDARD:
1719         // Don't know anything about this, assume bigger one is correct:
1720         if (sigs1.size() >= sigs2.size())
1721             return PushAll(sigs1);
1722         return PushAll(sigs2);
1723     case TX_PUBKEY:
1724     case TX_PUBKEYHASH:
1725         // Signatures are bigger than placeholders or empty scripts:
1726         if (sigs1.empty() || sigs1[0].empty())
1727             return PushAll(sigs2);
1728         return PushAll(sigs1);
1729     case TX_SCRIPTHASH:
1730         if (sigs1.empty() || sigs1.back().empty())
1731             return PushAll(sigs2);
1732         else if (sigs2.empty() || sigs2.back().empty())
1733             return PushAll(sigs1);
1734         else
1735         {
1736             // Recurse to combine:
1737             valtype spk = sigs1.back();
1738             CScript pubKey2(spk.begin(), spk.end());
1739
1740             txnouttype txType2;
1741             vector<vector<unsigned char> > vSolutions2;
1742             Solver(pubKey2, txType2, vSolutions2);
1743             sigs1.pop_back();
1744             sigs2.pop_back();
1745             CScript result = CombineSignatures(pubKey2, txTo, nIn, txType2, vSolutions2, sigs1, sigs2);
1746             result << spk;
1747             return result;
1748         }
1749     case TX_MULTISIG:
1750         return CombineMultisig(scriptPubKey, txTo, nIn, vSolutions, sigs1, sigs2);
1751     }
1752
1753     return CScript();
1754 }
1755
1756 CScript CombineSignatures(CScript scriptPubKey, const CTransaction& txTo, unsigned int nIn,
1757                           const CScript& scriptSig1, const CScript& scriptSig2)
1758 {
1759     txnouttype txType;
1760     vector<vector<unsigned char> > vSolutions;
1761     Solver(scriptPubKey, txType, vSolutions);
1762
1763     vector<valtype> stack1;
1764     EvalScript(stack1, scriptSig1, CTransaction(), 0, 0);
1765     vector<valtype> stack2;
1766     EvalScript(stack2, scriptSig2, CTransaction(), 0, 0);
1767
1768     return CombineSignatures(scriptPubKey, txTo, nIn, txType, vSolutions, stack1, stack2);
1769 }
1770
1771 unsigned int CScript::GetSigOpCount(bool fAccurate) const
1772 {
1773     unsigned int n = 0;
1774     const_iterator pc = begin();
1775     opcodetype lastOpcode = OP_INVALIDOPCODE;
1776     while (pc < end())
1777     {
1778         opcodetype opcode;
1779         if (!GetOp(pc, opcode))
1780             break;
1781         if (opcode == OP_CHECKSIG || opcode == OP_CHECKSIGVERIFY)
1782             n++;
1783         else if (opcode == OP_CHECKMULTISIG || opcode == OP_CHECKMULTISIGVERIFY)
1784         {
1785             if (fAccurate && lastOpcode >= OP_1 && lastOpcode <= OP_16)
1786                 n += DecodeOP_N(lastOpcode);
1787             else
1788                 n += 20;
1789         }
1790         lastOpcode = opcode;
1791     }
1792     return n;
1793 }
1794
1795 unsigned int CScript::GetSigOpCount(const CScript& scriptSig) const
1796 {
1797     if (!IsPayToScriptHash())
1798         return GetSigOpCount(true);
1799
1800     // This is a pay-to-script-hash scriptPubKey;
1801     // get the last item that the scriptSig
1802     // pushes onto the stack:
1803     const_iterator pc = scriptSig.begin();
1804     vector<unsigned char> data;
1805     while (pc < scriptSig.end())
1806     {
1807         opcodetype opcode;
1808         if (!scriptSig.GetOp(pc, opcode, data))
1809             return 0;
1810         if (opcode > OP_16)
1811             return 0;
1812     }
1813
1814     /// ... and return it's opcount:
1815     CScript subscript(data.begin(), data.end());
1816     return subscript.GetSigOpCount(true);
1817 }
1818
1819 bool CScript::IsPayToScriptHash() const
1820 {
1821     // Extra-fast test for pay-to-script-hash CScripts:
1822     return (this->size() == 23 &&
1823             this->at(0) == OP_HASH160 &&
1824             this->at(1) == 0x14 &&
1825             this->at(22) == OP_EQUAL);
1826 }
1827
1828 class CScriptVisitor : public boost::static_visitor<bool>
1829 {
1830 private:
1831     CScript *script;
1832 public:
1833     CScriptVisitor(CScript *scriptin) { script = scriptin; }
1834
1835     bool operator()(const CNoDestination &dest) const {
1836         script->clear();
1837         return false;
1838     }
1839
1840     bool operator()(const CKeyID &keyID) const {
1841         script->clear();
1842         *script << OP_DUP << OP_HASH160 << keyID << OP_EQUALVERIFY << OP_CHECKSIG;
1843         return true;
1844     }
1845
1846     bool operator()(const CScriptID &scriptID) const {
1847         script->clear();
1848         *script << OP_HASH160 << scriptID << OP_EQUAL;
1849         return true;
1850     }
1851 };
1852
1853 void CScript::SetDestination(const CTxDestination& dest)
1854 {
1855     boost::apply_visitor(CScriptVisitor(this), dest);
1856 }
1857
1858 void CScript::SetMultisig(int nRequired, const std::vector<CKey>& keys)
1859 {
1860     this->clear();
1861
1862     *this << EncodeOP_N(nRequired);
1863     BOOST_FOREACH(const CKey& key, keys)
1864         *this << key.GetPubKey();
1865     *this << EncodeOP_N(keys.size()) << OP_CHECKMULTISIG;
1866 }