opcode.go
1 // Copyright (c) 2013-2017 The btcsuite developers 2 // Use of this source code is governed by an ISC 3 // license that can be found in the LICENSE file. 4 5 package txscript 6 7 import ( 8 "bytes" 9 "crypto/sha1" 10 "crypto/sha256" 11 "encoding/binary" 12 "fmt" 13 "hash" 14 15 "golang.org/x/crypto/ripemd160" 16 17 "github.com/btcsuite/btcd/btcec" 18 "github.com/btcsuite/btcd/chaincfg/chainhash" 19 "github.com/btcsuite/btcd/wire" 20 ) 21 22 // An opcode defines the information related to a txscript opcode. opfunc, if 23 // present, is the function to call to perform the opcode on the script. The 24 // current script is passed in as a slice with the first member being the opcode 25 // itself. 26 type opcode struct { 27 value byte 28 name string 29 length int 30 opfunc func(*parsedOpcode, *Engine) error 31 } 32 33 // These constants are the values of the official opcodes used on the btc wiki, 34 // in bitcoin core and in most if not all other references and software related 35 // to handling BTC scripts. 36 const ( 37 OP_0 = 0x00 // 0 38 OP_FALSE = 0x00 // 0 - AKA OP_0 39 OP_DATA_1 = 0x01 // 1 40 OP_DATA_2 = 0x02 // 2 41 OP_DATA_3 = 0x03 // 3 42 OP_DATA_4 = 0x04 // 4 43 OP_DATA_5 = 0x05 // 5 44 OP_DATA_6 = 0x06 // 6 45 OP_DATA_7 = 0x07 // 7 46 OP_DATA_8 = 0x08 // 8 47 OP_DATA_9 = 0x09 // 9 48 OP_DATA_10 = 0x0a // 10 49 OP_DATA_11 = 0x0b // 11 50 OP_DATA_12 = 0x0c // 12 51 OP_DATA_13 = 0x0d // 13 52 OP_DATA_14 = 0x0e // 14 53 OP_DATA_15 = 0x0f // 15 54 OP_DATA_16 = 0x10 // 16 55 OP_DATA_17 = 0x11 // 17 56 OP_DATA_18 = 0x12 // 18 57 OP_DATA_19 = 0x13 // 19 58 OP_DATA_20 = 0x14 // 20 59 OP_DATA_21 = 0x15 // 21 60 OP_DATA_22 = 0x16 // 22 61 OP_DATA_23 = 0x17 // 23 62 OP_DATA_24 = 0x18 // 24 63 OP_DATA_25 = 0x19 // 25 64 OP_DATA_26 = 0x1a // 26 65 OP_DATA_27 = 0x1b // 27 66 OP_DATA_28 = 0x1c // 28 67 OP_DATA_29 = 0x1d // 29 68 OP_DATA_30 = 0x1e // 30 69 OP_DATA_31 = 0x1f // 31 70 OP_DATA_32 = 0x20 // 32 71 OP_DATA_33 = 0x21 // 33 72 OP_DATA_34 = 0x22 // 34 73 OP_DATA_35 = 0x23 // 35 74 OP_DATA_36 = 0x24 // 36 75 OP_DATA_37 = 0x25 // 37 76 OP_DATA_38 = 0x26 // 38 77 OP_DATA_39 = 0x27 // 39 78 OP_DATA_40 = 0x28 // 40 79 OP_DATA_41 = 0x29 // 41 80 OP_DATA_42 = 0x2a // 42 81 OP_DATA_43 = 0x2b // 43 82 OP_DATA_44 = 0x2c // 44 83 OP_DATA_45 = 0x2d // 45 84 OP_DATA_46 = 0x2e // 46 85 OP_DATA_47 = 0x2f // 47 86 OP_DATA_48 = 0x30 // 48 87 OP_DATA_49 = 0x31 // 49 88 OP_DATA_50 = 0x32 // 50 89 OP_DATA_51 = 0x33 // 51 90 OP_DATA_52 = 0x34 // 52 91 OP_DATA_53 = 0x35 // 53 92 OP_DATA_54 = 0x36 // 54 93 OP_DATA_55 = 0x37 // 55 94 OP_DATA_56 = 0x38 // 56 95 OP_DATA_57 = 0x39 // 57 96 OP_DATA_58 = 0x3a // 58 97 OP_DATA_59 = 0x3b // 59 98 OP_DATA_60 = 0x3c // 60 99 OP_DATA_61 = 0x3d // 61 100 OP_DATA_62 = 0x3e // 62 101 OP_DATA_63 = 0x3f // 63 102 OP_DATA_64 = 0x40 // 64 103 OP_DATA_65 = 0x41 // 65 104 OP_DATA_66 = 0x42 // 66 105 OP_DATA_67 = 0x43 // 67 106 OP_DATA_68 = 0x44 // 68 107 OP_DATA_69 = 0x45 // 69 108 OP_DATA_70 = 0x46 // 70 109 OP_DATA_71 = 0x47 // 71 110 OP_DATA_72 = 0x48 // 72 111 OP_DATA_73 = 0x49 // 73 112 OP_DATA_74 = 0x4a // 74 113 OP_DATA_75 = 0x4b // 75 114 OP_PUSHDATA1 = 0x4c // 76 115 OP_PUSHDATA2 = 0x4d // 77 116 OP_PUSHDATA4 = 0x4e // 78 117 OP_1NEGATE = 0x4f // 79 118 OP_RESERVED = 0x50 // 80 119 OP_1 = 0x51 // 81 - AKA OP_TRUE 120 OP_TRUE = 0x51 // 81 121 OP_2 = 0x52 // 82 122 OP_3 = 0x53 // 83 123 OP_4 = 0x54 // 84 124 OP_5 = 0x55 // 85 125 OP_6 = 0x56 // 86 126 OP_7 = 0x57 // 87 127 OP_8 = 0x58 // 88 128 OP_9 = 0x59 // 89 129 OP_10 = 0x5a // 90 130 OP_11 = 0x5b // 91 131 OP_12 = 0x5c // 92 132 OP_13 = 0x5d // 93 133 OP_14 = 0x5e // 94 134 OP_15 = 0x5f // 95 135 OP_16 = 0x60 // 96 136 OP_NOP = 0x61 // 97 137 OP_VER = 0x62 // 98 138 OP_IF = 0x63 // 99 139 OP_NOTIF = 0x64 // 100 140 OP_VERIF = 0x65 // 101 141 OP_VERNOTIF = 0x66 // 102 142 OP_ELSE = 0x67 // 103 143 OP_ENDIF = 0x68 // 104 144 OP_VERIFY = 0x69 // 105 145 OP_RETURN = 0x6a // 106 146 OP_TOALTSTACK = 0x6b // 107 147 OP_FROMALTSTACK = 0x6c // 108 148 OP_2DROP = 0x6d // 109 149 OP_2DUP = 0x6e // 110 150 OP_3DUP = 0x6f // 111 151 OP_2OVER = 0x70 // 112 152 OP_2ROT = 0x71 // 113 153 OP_2SWAP = 0x72 // 114 154 OP_IFDUP = 0x73 // 115 155 OP_DEPTH = 0x74 // 116 156 OP_DROP = 0x75 // 117 157 OP_DUP = 0x76 // 118 158 OP_NIP = 0x77 // 119 159 OP_OVER = 0x78 // 120 160 OP_PICK = 0x79 // 121 161 OP_ROLL = 0x7a // 122 162 OP_ROT = 0x7b // 123 163 OP_SWAP = 0x7c // 124 164 OP_TUCK = 0x7d // 125 165 OP_CAT = 0x7e // 126 166 OP_SUBSTR = 0x7f // 127 167 OP_LEFT = 0x80 // 128 168 OP_RIGHT = 0x81 // 129 169 OP_SIZE = 0x82 // 130 170 OP_INVERT = 0x83 // 131 171 OP_AND = 0x84 // 132 172 OP_OR = 0x85 // 133 173 OP_XOR = 0x86 // 134 174 OP_EQUAL = 0x87 // 135 175 OP_EQUALVERIFY = 0x88 // 136 176 OP_RESERVED1 = 0x89 // 137 177 OP_RESERVED2 = 0x8a // 138 178 OP_1ADD = 0x8b // 139 179 OP_1SUB = 0x8c // 140 180 OP_2MUL = 0x8d // 141 181 OP_2DIV = 0x8e // 142 182 OP_NEGATE = 0x8f // 143 183 OP_ABS = 0x90 // 144 184 OP_NOT = 0x91 // 145 185 OP_0NOTEQUAL = 0x92 // 146 186 OP_ADD = 0x93 // 147 187 OP_SUB = 0x94 // 148 188 OP_MUL = 0x95 // 149 189 OP_DIV = 0x96 // 150 190 OP_MOD = 0x97 // 151 191 OP_LSHIFT = 0x98 // 152 192 OP_RSHIFT = 0x99 // 153 193 OP_BOOLAND = 0x9a // 154 194 OP_BOOLOR = 0x9b // 155 195 OP_NUMEQUAL = 0x9c // 156 196 OP_NUMEQUALVERIFY = 0x9d // 157 197 OP_NUMNOTEQUAL = 0x9e // 158 198 OP_LESSTHAN = 0x9f // 159 199 OP_GREATERTHAN = 0xa0 // 160 200 OP_LESSTHANOREQUAL = 0xa1 // 161 201 OP_GREATERTHANOREQUAL = 0xa2 // 162 202 OP_MIN = 0xa3 // 163 203 OP_MAX = 0xa4 // 164 204 OP_WITHIN = 0xa5 // 165 205 OP_RIPEMD160 = 0xa6 // 166 206 OP_SHA1 = 0xa7 // 167 207 OP_SHA256 = 0xa8 // 168 208 OP_HASH160 = 0xa9 // 169 209 OP_HASH256 = 0xaa // 170 210 OP_CODESEPARATOR = 0xab // 171 211 OP_CHECKSIG = 0xac // 172 212 OP_CHECKSIGVERIFY = 0xad // 173 213 OP_CHECKMULTISIG = 0xae // 174 214 OP_CHECKMULTISIGVERIFY = 0xaf // 175 215 OP_NOP1 = 0xb0 // 176 216 OP_NOP2 = 0xb1 // 177 217 OP_CHECKLOCKTIMEVERIFY = 0xb1 // 177 - AKA OP_NOP2 218 OP_NOP3 = 0xb2 // 178 219 OP_CHECKSEQUENCEVERIFY = 0xb2 // 178 - AKA OP_NOP3 220 OP_NOP4 = 0xb3 // 179 221 OP_NOP5 = 0xb4 // 180 222 OP_NOP6 = 0xb5 // 181 223 OP_NOP7 = 0xb6 // 182 224 OP_NOP8 = 0xb7 // 183 225 OP_NOP9 = 0xb8 // 184 226 OP_NOP10 = 0xb9 // 185 227 OP_UNKNOWN186 = 0xba // 186 228 OP_UNKNOWN187 = 0xbb // 187 229 OP_UNKNOWN188 = 0xbc // 188 230 OP_UNKNOWN189 = 0xbd // 189 231 OP_UNKNOWN190 = 0xbe // 190 232 OP_UNKNOWN191 = 0xbf // 191 233 OP_UNKNOWN192 = 0xc0 // 192 234 OP_UNKNOWN193 = 0xc1 // 193 235 OP_UNKNOWN194 = 0xc2 // 194 236 OP_UNKNOWN195 = 0xc3 // 195 237 OP_UNKNOWN196 = 0xc4 // 196 238 OP_UNKNOWN197 = 0xc5 // 197 239 OP_UNKNOWN198 = 0xc6 // 198 240 OP_UNKNOWN199 = 0xc7 // 199 241 OP_UNKNOWN200 = 0xc8 // 200 242 OP_UNKNOWN201 = 0xc9 // 201 243 OP_UNKNOWN202 = 0xca // 202 244 OP_UNKNOWN203 = 0xcb // 203 245 OP_UNKNOWN204 = 0xcc // 204 246 OP_UNKNOWN205 = 0xcd // 205 247 OP_UNKNOWN206 = 0xce // 206 248 OP_UNKNOWN207 = 0xcf // 207 249 OP_UNKNOWN208 = 0xd0 // 208 250 OP_UNKNOWN209 = 0xd1 // 209 251 OP_UNKNOWN210 = 0xd2 // 210 252 OP_UNKNOWN211 = 0xd3 // 211 253 OP_UNKNOWN212 = 0xd4 // 212 254 OP_UNKNOWN213 = 0xd5 // 213 255 OP_UNKNOWN214 = 0xd6 // 214 256 OP_UNKNOWN215 = 0xd7 // 215 257 OP_UNKNOWN216 = 0xd8 // 216 258 OP_UNKNOWN217 = 0xd9 // 217 259 OP_UNKNOWN218 = 0xda // 218 260 OP_UNKNOWN219 = 0xdb // 219 261 OP_UNKNOWN220 = 0xdc // 220 262 OP_UNKNOWN221 = 0xdd // 221 263 OP_UNKNOWN222 = 0xde // 222 264 OP_UNKNOWN223 = 0xdf // 223 265 OP_UNKNOWN224 = 0xe0 // 224 266 OP_UNKNOWN225 = 0xe1 // 225 267 OP_UNKNOWN226 = 0xe2 // 226 268 OP_UNKNOWN227 = 0xe3 // 227 269 OP_UNKNOWN228 = 0xe4 // 228 270 OP_UNKNOWN229 = 0xe5 // 229 271 OP_UNKNOWN230 = 0xe6 // 230 272 OP_UNKNOWN231 = 0xe7 // 231 273 OP_UNKNOWN232 = 0xe8 // 232 274 OP_UNKNOWN233 = 0xe9 // 233 275 OP_UNKNOWN234 = 0xea // 234 276 OP_UNKNOWN235 = 0xeb // 235 277 OP_UNKNOWN236 = 0xec // 236 278 OP_UNKNOWN237 = 0xed // 237 279 OP_UNKNOWN238 = 0xee // 238 280 OP_UNKNOWN239 = 0xef // 239 281 OP_UNKNOWN240 = 0xf0 // 240 282 OP_UNKNOWN241 = 0xf1 // 241 283 OP_UNKNOWN242 = 0xf2 // 242 284 OP_UNKNOWN243 = 0xf3 // 243 285 OP_UNKNOWN244 = 0xf4 // 244 286 OP_UNKNOWN245 = 0xf5 // 245 287 OP_UNKNOWN246 = 0xf6 // 246 288 OP_UNKNOWN247 = 0xf7 // 247 289 OP_UNKNOWN248 = 0xf8 // 248 290 OP_UNKNOWN249 = 0xf9 // 249 291 OP_SMALLINTEGER = 0xfa // 250 - bitcoin core internal 292 OP_PUBKEYS = 0xfb // 251 - bitcoin core internal 293 OP_UNKNOWN252 = 0xfc // 252 294 OP_PUBKEYHASH = 0xfd // 253 - bitcoin core internal 295 OP_PUBKEY = 0xfe // 254 - bitcoin core internal 296 OP_INVALIDOPCODE = 0xff // 255 - bitcoin core internal 297 ) 298 299 // Conditional execution constants. 300 const ( 301 OpCondFalse = 0 302 OpCondTrue = 1 303 OpCondSkip = 2 304 ) 305 306 // opcodeArray holds details about all possible opcodes such as how many bytes 307 // the opcode and any associated data should take, its human-readable name, and 308 // the handler function. 309 var opcodeArray = [256]opcode{ 310 // Data push opcodes. 311 OP_FALSE: {OP_FALSE, "OP_0", 1, opcodeFalse}, 312 OP_DATA_1: {OP_DATA_1, "OP_DATA_1", 2, opcodePushData}, 313 OP_DATA_2: {OP_DATA_2, "OP_DATA_2", 3, opcodePushData}, 314 OP_DATA_3: {OP_DATA_3, "OP_DATA_3", 4, opcodePushData}, 315 OP_DATA_4: {OP_DATA_4, "OP_DATA_4", 5, opcodePushData}, 316 OP_DATA_5: {OP_DATA_5, "OP_DATA_5", 6, opcodePushData}, 317 OP_DATA_6: {OP_DATA_6, "OP_DATA_6", 7, opcodePushData}, 318 OP_DATA_7: {OP_DATA_7, "OP_DATA_7", 8, opcodePushData}, 319 OP_DATA_8: {OP_DATA_8, "OP_DATA_8", 9, opcodePushData}, 320 OP_DATA_9: {OP_DATA_9, "OP_DATA_9", 10, opcodePushData}, 321 OP_DATA_10: {OP_DATA_10, "OP_DATA_10", 11, opcodePushData}, 322 OP_DATA_11: {OP_DATA_11, "OP_DATA_11", 12, opcodePushData}, 323 OP_DATA_12: {OP_DATA_12, "OP_DATA_12", 13, opcodePushData}, 324 OP_DATA_13: {OP_DATA_13, "OP_DATA_13", 14, opcodePushData}, 325 OP_DATA_14: {OP_DATA_14, "OP_DATA_14", 15, opcodePushData}, 326 OP_DATA_15: {OP_DATA_15, "OP_DATA_15", 16, opcodePushData}, 327 OP_DATA_16: {OP_DATA_16, "OP_DATA_16", 17, opcodePushData}, 328 OP_DATA_17: {OP_DATA_17, "OP_DATA_17", 18, opcodePushData}, 329 OP_DATA_18: {OP_DATA_18, "OP_DATA_18", 19, opcodePushData}, 330 OP_DATA_19: {OP_DATA_19, "OP_DATA_19", 20, opcodePushData}, 331 OP_DATA_20: {OP_DATA_20, "OP_DATA_20", 21, opcodePushData}, 332 OP_DATA_21: {OP_DATA_21, "OP_DATA_21", 22, opcodePushData}, 333 OP_DATA_22: {OP_DATA_22, "OP_DATA_22", 23, opcodePushData}, 334 OP_DATA_23: {OP_DATA_23, "OP_DATA_23", 24, opcodePushData}, 335 OP_DATA_24: {OP_DATA_24, "OP_DATA_24", 25, opcodePushData}, 336 OP_DATA_25: {OP_DATA_25, "OP_DATA_25", 26, opcodePushData}, 337 OP_DATA_26: {OP_DATA_26, "OP_DATA_26", 27, opcodePushData}, 338 OP_DATA_27: {OP_DATA_27, "OP_DATA_27", 28, opcodePushData}, 339 OP_DATA_28: {OP_DATA_28, "OP_DATA_28", 29, opcodePushData}, 340 OP_DATA_29: {OP_DATA_29, "OP_DATA_29", 30, opcodePushData}, 341 OP_DATA_30: {OP_DATA_30, "OP_DATA_30", 31, opcodePushData}, 342 OP_DATA_31: {OP_DATA_31, "OP_DATA_31", 32, opcodePushData}, 343 OP_DATA_32: {OP_DATA_32, "OP_DATA_32", 33, opcodePushData}, 344 OP_DATA_33: {OP_DATA_33, "OP_DATA_33", 34, opcodePushData}, 345 OP_DATA_34: {OP_DATA_34, "OP_DATA_34", 35, opcodePushData}, 346 OP_DATA_35: {OP_DATA_35, "OP_DATA_35", 36, opcodePushData}, 347 OP_DATA_36: {OP_DATA_36, "OP_DATA_36", 37, opcodePushData}, 348 OP_DATA_37: {OP_DATA_37, "OP_DATA_37", 38, opcodePushData}, 349 OP_DATA_38: {OP_DATA_38, "OP_DATA_38", 39, opcodePushData}, 350 OP_DATA_39: {OP_DATA_39, "OP_DATA_39", 40, opcodePushData}, 351 OP_DATA_40: {OP_DATA_40, "OP_DATA_40", 41, opcodePushData}, 352 OP_DATA_41: {OP_DATA_41, "OP_DATA_41", 42, opcodePushData}, 353 OP_DATA_42: {OP_DATA_42, "OP_DATA_42", 43, opcodePushData}, 354 OP_DATA_43: {OP_DATA_43, "OP_DATA_43", 44, opcodePushData}, 355 OP_DATA_44: {OP_DATA_44, "OP_DATA_44", 45, opcodePushData}, 356 OP_DATA_45: {OP_DATA_45, "OP_DATA_45", 46, opcodePushData}, 357 OP_DATA_46: {OP_DATA_46, "OP_DATA_46", 47, opcodePushData}, 358 OP_DATA_47: {OP_DATA_47, "OP_DATA_47", 48, opcodePushData}, 359 OP_DATA_48: {OP_DATA_48, "OP_DATA_48", 49, opcodePushData}, 360 OP_DATA_49: {OP_DATA_49, "OP_DATA_49", 50, opcodePushData}, 361 OP_DATA_50: {OP_DATA_50, "OP_DATA_50", 51, opcodePushData}, 362 OP_DATA_51: {OP_DATA_51, "OP_DATA_51", 52, opcodePushData}, 363 OP_DATA_52: {OP_DATA_52, "OP_DATA_52", 53, opcodePushData}, 364 OP_DATA_53: {OP_DATA_53, "OP_DATA_53", 54, opcodePushData}, 365 OP_DATA_54: {OP_DATA_54, "OP_DATA_54", 55, opcodePushData}, 366 OP_DATA_55: {OP_DATA_55, "OP_DATA_55", 56, opcodePushData}, 367 OP_DATA_56: {OP_DATA_56, "OP_DATA_56", 57, opcodePushData}, 368 OP_DATA_57: {OP_DATA_57, "OP_DATA_57", 58, opcodePushData}, 369 OP_DATA_58: {OP_DATA_58, "OP_DATA_58", 59, opcodePushData}, 370 OP_DATA_59: {OP_DATA_59, "OP_DATA_59", 60, opcodePushData}, 371 OP_DATA_60: {OP_DATA_60, "OP_DATA_60", 61, opcodePushData}, 372 OP_DATA_61: {OP_DATA_61, "OP_DATA_61", 62, opcodePushData}, 373 OP_DATA_62: {OP_DATA_62, "OP_DATA_62", 63, opcodePushData}, 374 OP_DATA_63: {OP_DATA_63, "OP_DATA_63", 64, opcodePushData}, 375 OP_DATA_64: {OP_DATA_64, "OP_DATA_64", 65, opcodePushData}, 376 OP_DATA_65: {OP_DATA_65, "OP_DATA_65", 66, opcodePushData}, 377 OP_DATA_66: {OP_DATA_66, "OP_DATA_66", 67, opcodePushData}, 378 OP_DATA_67: {OP_DATA_67, "OP_DATA_67", 68, opcodePushData}, 379 OP_DATA_68: {OP_DATA_68, "OP_DATA_68", 69, opcodePushData}, 380 OP_DATA_69: {OP_DATA_69, "OP_DATA_69", 70, opcodePushData}, 381 OP_DATA_70: {OP_DATA_70, "OP_DATA_70", 71, opcodePushData}, 382 OP_DATA_71: {OP_DATA_71, "OP_DATA_71", 72, opcodePushData}, 383 OP_DATA_72: {OP_DATA_72, "OP_DATA_72", 73, opcodePushData}, 384 OP_DATA_73: {OP_DATA_73, "OP_DATA_73", 74, opcodePushData}, 385 OP_DATA_74: {OP_DATA_74, "OP_DATA_74", 75, opcodePushData}, 386 OP_DATA_75: {OP_DATA_75, "OP_DATA_75", 76, opcodePushData}, 387 OP_PUSHDATA1: {OP_PUSHDATA1, "OP_PUSHDATA1", -1, opcodePushData}, 388 OP_PUSHDATA2: {OP_PUSHDATA2, "OP_PUSHDATA2", -2, opcodePushData}, 389 OP_PUSHDATA4: {OP_PUSHDATA4, "OP_PUSHDATA4", -4, opcodePushData}, 390 OP_1NEGATE: {OP_1NEGATE, "OP_1NEGATE", 1, opcode1Negate}, 391 OP_RESERVED: {OP_RESERVED, "OP_RESERVED", 1, opcodeReserved}, 392 OP_TRUE: {OP_TRUE, "OP_1", 1, opcodeN}, 393 OP_2: {OP_2, "OP_2", 1, opcodeN}, 394 OP_3: {OP_3, "OP_3", 1, opcodeN}, 395 OP_4: {OP_4, "OP_4", 1, opcodeN}, 396 OP_5: {OP_5, "OP_5", 1, opcodeN}, 397 OP_6: {OP_6, "OP_6", 1, opcodeN}, 398 OP_7: {OP_7, "OP_7", 1, opcodeN}, 399 OP_8: {OP_8, "OP_8", 1, opcodeN}, 400 OP_9: {OP_9, "OP_9", 1, opcodeN}, 401 OP_10: {OP_10, "OP_10", 1, opcodeN}, 402 OP_11: {OP_11, "OP_11", 1, opcodeN}, 403 OP_12: {OP_12, "OP_12", 1, opcodeN}, 404 OP_13: {OP_13, "OP_13", 1, opcodeN}, 405 OP_14: {OP_14, "OP_14", 1, opcodeN}, 406 OP_15: {OP_15, "OP_15", 1, opcodeN}, 407 OP_16: {OP_16, "OP_16", 1, opcodeN}, 408 409 // Control opcodes. 410 OP_NOP: {OP_NOP, "OP_NOP", 1, opcodeNop}, 411 OP_VER: {OP_VER, "OP_VER", 1, opcodeReserved}, 412 OP_IF: {OP_IF, "OP_IF", 1, opcodeIf}, 413 OP_NOTIF: {OP_NOTIF, "OP_NOTIF", 1, opcodeNotIf}, 414 OP_VERIF: {OP_VERIF, "OP_VERIF", 1, opcodeReserved}, 415 OP_VERNOTIF: {OP_VERNOTIF, "OP_VERNOTIF", 1, opcodeReserved}, 416 OP_ELSE: {OP_ELSE, "OP_ELSE", 1, opcodeElse}, 417 OP_ENDIF: {OP_ENDIF, "OP_ENDIF", 1, opcodeEndif}, 418 OP_VERIFY: {OP_VERIFY, "OP_VERIFY", 1, opcodeVerify}, 419 OP_RETURN: {OP_RETURN, "OP_RETURN", 1, opcodeReturn}, 420 OP_CHECKLOCKTIMEVERIFY: {OP_CHECKLOCKTIMEVERIFY, "OP_CHECKLOCKTIMEVERIFY", 1, opcodeCheckLockTimeVerify}, 421 OP_CHECKSEQUENCEVERIFY: {OP_CHECKSEQUENCEVERIFY, "OP_CHECKSEQUENCEVERIFY", 1, opcodeCheckSequenceVerify}, 422 423 // Stack opcodes. 424 OP_TOALTSTACK: {OP_TOALTSTACK, "OP_TOALTSTACK", 1, opcodeToAltStack}, 425 OP_FROMALTSTACK: {OP_FROMALTSTACK, "OP_FROMALTSTACK", 1, opcodeFromAltStack}, 426 OP_2DROP: {OP_2DROP, "OP_2DROP", 1, opcode2Drop}, 427 OP_2DUP: {OP_2DUP, "OP_2DUP", 1, opcode2Dup}, 428 OP_3DUP: {OP_3DUP, "OP_3DUP", 1, opcode3Dup}, 429 OP_2OVER: {OP_2OVER, "OP_2OVER", 1, opcode2Over}, 430 OP_2ROT: {OP_2ROT, "OP_2ROT", 1, opcode2Rot}, 431 OP_2SWAP: {OP_2SWAP, "OP_2SWAP", 1, opcode2Swap}, 432 OP_IFDUP: {OP_IFDUP, "OP_IFDUP", 1, opcodeIfDup}, 433 OP_DEPTH: {OP_DEPTH, "OP_DEPTH", 1, opcodeDepth}, 434 OP_DROP: {OP_DROP, "OP_DROP", 1, opcodeDrop}, 435 OP_DUP: {OP_DUP, "OP_DUP", 1, opcodeDup}, 436 OP_NIP: {OP_NIP, "OP_NIP", 1, opcodeNip}, 437 OP_OVER: {OP_OVER, "OP_OVER", 1, opcodeOver}, 438 OP_PICK: {OP_PICK, "OP_PICK", 1, opcodePick}, 439 OP_ROLL: {OP_ROLL, "OP_ROLL", 1, opcodeRoll}, 440 OP_ROT: {OP_ROT, "OP_ROT", 1, opcodeRot}, 441 OP_SWAP: {OP_SWAP, "OP_SWAP", 1, opcodeSwap}, 442 OP_TUCK: {OP_TUCK, "OP_TUCK", 1, opcodeTuck}, 443 444 // Splice opcodes. 445 OP_CAT: {OP_CAT, "OP_CAT", 1, opcodeDisabled}, 446 OP_SUBSTR: {OP_SUBSTR, "OP_SUBSTR", 1, opcodeDisabled}, 447 OP_LEFT: {OP_LEFT, "OP_LEFT", 1, opcodeDisabled}, 448 OP_RIGHT: {OP_RIGHT, "OP_RIGHT", 1, opcodeDisabled}, 449 OP_SIZE: {OP_SIZE, "OP_SIZE", 1, opcodeSize}, 450 451 // Bitwise logic opcodes. 452 OP_INVERT: {OP_INVERT, "OP_INVERT", 1, opcodeDisabled}, 453 OP_AND: {OP_AND, "OP_AND", 1, opcodeDisabled}, 454 OP_OR: {OP_OR, "OP_OR", 1, opcodeDisabled}, 455 OP_XOR: {OP_XOR, "OP_XOR", 1, opcodeDisabled}, 456 OP_EQUAL: {OP_EQUAL, "OP_EQUAL", 1, opcodeEqual}, 457 OP_EQUALVERIFY: {OP_EQUALVERIFY, "OP_EQUALVERIFY", 1, opcodeEqualVerify}, 458 OP_RESERVED1: {OP_RESERVED1, "OP_RESERVED1", 1, opcodeReserved}, 459 OP_RESERVED2: {OP_RESERVED2, "OP_RESERVED2", 1, opcodeReserved}, 460 461 // Numeric related opcodes. 462 OP_1ADD: {OP_1ADD, "OP_1ADD", 1, opcode1Add}, 463 OP_1SUB: {OP_1SUB, "OP_1SUB", 1, opcode1Sub}, 464 OP_2MUL: {OP_2MUL, "OP_2MUL", 1, opcodeDisabled}, 465 OP_2DIV: {OP_2DIV, "OP_2DIV", 1, opcodeDisabled}, 466 OP_NEGATE: {OP_NEGATE, "OP_NEGATE", 1, opcodeNegate}, 467 OP_ABS: {OP_ABS, "OP_ABS", 1, opcodeAbs}, 468 OP_NOT: {OP_NOT, "OP_NOT", 1, opcodeNot}, 469 OP_0NOTEQUAL: {OP_0NOTEQUAL, "OP_0NOTEQUAL", 1, opcode0NotEqual}, 470 OP_ADD: {OP_ADD, "OP_ADD", 1, opcodeAdd}, 471 OP_SUB: {OP_SUB, "OP_SUB", 1, opcodeSub}, 472 OP_MUL: {OP_MUL, "OP_MUL", 1, opcodeDisabled}, 473 OP_DIV: {OP_DIV, "OP_DIV", 1, opcodeDisabled}, 474 OP_MOD: {OP_MOD, "OP_MOD", 1, opcodeDisabled}, 475 OP_LSHIFT: {OP_LSHIFT, "OP_LSHIFT", 1, opcodeDisabled}, 476 OP_RSHIFT: {OP_RSHIFT, "OP_RSHIFT", 1, opcodeDisabled}, 477 OP_BOOLAND: {OP_BOOLAND, "OP_BOOLAND", 1, opcodeBoolAnd}, 478 OP_BOOLOR: {OP_BOOLOR, "OP_BOOLOR", 1, opcodeBoolOr}, 479 OP_NUMEQUAL: {OP_NUMEQUAL, "OP_NUMEQUAL", 1, opcodeNumEqual}, 480 OP_NUMEQUALVERIFY: {OP_NUMEQUALVERIFY, "OP_NUMEQUALVERIFY", 1, opcodeNumEqualVerify}, 481 OP_NUMNOTEQUAL: {OP_NUMNOTEQUAL, "OP_NUMNOTEQUAL", 1, opcodeNumNotEqual}, 482 OP_LESSTHAN: {OP_LESSTHAN, "OP_LESSTHAN", 1, opcodeLessThan}, 483 OP_GREATERTHAN: {OP_GREATERTHAN, "OP_GREATERTHAN", 1, opcodeGreaterThan}, 484 OP_LESSTHANOREQUAL: {OP_LESSTHANOREQUAL, "OP_LESSTHANOREQUAL", 1, opcodeLessThanOrEqual}, 485 OP_GREATERTHANOREQUAL: {OP_GREATERTHANOREQUAL, "OP_GREATERTHANOREQUAL", 1, opcodeGreaterThanOrEqual}, 486 OP_MIN: {OP_MIN, "OP_MIN", 1, opcodeMin}, 487 OP_MAX: {OP_MAX, "OP_MAX", 1, opcodeMax}, 488 OP_WITHIN: {OP_WITHIN, "OP_WITHIN", 1, opcodeWithin}, 489 490 // Crypto opcodes. 491 OP_RIPEMD160: {OP_RIPEMD160, "OP_RIPEMD160", 1, opcodeRipemd160}, 492 OP_SHA1: {OP_SHA1, "OP_SHA1", 1, opcodeSha1}, 493 OP_SHA256: {OP_SHA256, "OP_SHA256", 1, opcodeSha256}, 494 OP_HASH160: {OP_HASH160, "OP_HASH160", 1, opcodeHash160}, 495 OP_HASH256: {OP_HASH256, "OP_HASH256", 1, opcodeHash256}, 496 OP_CODESEPARATOR: {OP_CODESEPARATOR, "OP_CODESEPARATOR", 1, opcodeCodeSeparator}, 497 OP_CHECKSIG: {OP_CHECKSIG, "OP_CHECKSIG", 1, opcodeCheckSig}, 498 OP_CHECKSIGVERIFY: {OP_CHECKSIGVERIFY, "OP_CHECKSIGVERIFY", 1, opcodeCheckSigVerify}, 499 OP_CHECKMULTISIG: {OP_CHECKMULTISIG, "OP_CHECKMULTISIG", 1, opcodeCheckMultiSig}, 500 OP_CHECKMULTISIGVERIFY: {OP_CHECKMULTISIGVERIFY, "OP_CHECKMULTISIGVERIFY", 1, opcodeCheckMultiSigVerify}, 501 502 // Reserved opcodes. 503 OP_NOP1: {OP_NOP1, "OP_NOP1", 1, opcodeNop}, 504 OP_NOP4: {OP_NOP4, "OP_NOP4", 1, opcodeNop}, 505 OP_NOP5: {OP_NOP5, "OP_NOP5", 1, opcodeNop}, 506 OP_NOP6: {OP_NOP6, "OP_NOP6", 1, opcodeNop}, 507 OP_NOP7: {OP_NOP7, "OP_NOP7", 1, opcodeNop}, 508 OP_NOP8: {OP_NOP8, "OP_NOP8", 1, opcodeNop}, 509 OP_NOP9: {OP_NOP9, "OP_NOP9", 1, opcodeNop}, 510 OP_NOP10: {OP_NOP10, "OP_NOP10", 1, opcodeNop}, 511 512 // Undefined opcodes. 513 OP_UNKNOWN186: {OP_UNKNOWN186, "OP_UNKNOWN186", 1, opcodeInvalid}, 514 OP_UNKNOWN187: {OP_UNKNOWN187, "OP_UNKNOWN187", 1, opcodeInvalid}, 515 OP_UNKNOWN188: {OP_UNKNOWN188, "OP_UNKNOWN188", 1, opcodeInvalid}, 516 OP_UNKNOWN189: {OP_UNKNOWN189, "OP_UNKNOWN189", 1, opcodeInvalid}, 517 OP_UNKNOWN190: {OP_UNKNOWN190, "OP_UNKNOWN190", 1, opcodeInvalid}, 518 OP_UNKNOWN191: {OP_UNKNOWN191, "OP_UNKNOWN191", 1, opcodeInvalid}, 519 OP_UNKNOWN192: {OP_UNKNOWN192, "OP_UNKNOWN192", 1, opcodeInvalid}, 520 OP_UNKNOWN193: {OP_UNKNOWN193, "OP_UNKNOWN193", 1, opcodeInvalid}, 521 OP_UNKNOWN194: {OP_UNKNOWN194, "OP_UNKNOWN194", 1, opcodeInvalid}, 522 OP_UNKNOWN195: {OP_UNKNOWN195, "OP_UNKNOWN195", 1, opcodeInvalid}, 523 OP_UNKNOWN196: {OP_UNKNOWN196, "OP_UNKNOWN196", 1, opcodeInvalid}, 524 OP_UNKNOWN197: {OP_UNKNOWN197, "OP_UNKNOWN197", 1, opcodeInvalid}, 525 OP_UNKNOWN198: {OP_UNKNOWN198, "OP_UNKNOWN198", 1, opcodeInvalid}, 526 OP_UNKNOWN199: {OP_UNKNOWN199, "OP_UNKNOWN199", 1, opcodeInvalid}, 527 OP_UNKNOWN200: {OP_UNKNOWN200, "OP_UNKNOWN200", 1, opcodeInvalid}, 528 OP_UNKNOWN201: {OP_UNKNOWN201, "OP_UNKNOWN201", 1, opcodeInvalid}, 529 OP_UNKNOWN202: {OP_UNKNOWN202, "OP_UNKNOWN202", 1, opcodeInvalid}, 530 OP_UNKNOWN203: {OP_UNKNOWN203, "OP_UNKNOWN203", 1, opcodeInvalid}, 531 OP_UNKNOWN204: {OP_UNKNOWN204, "OP_UNKNOWN204", 1, opcodeInvalid}, 532 OP_UNKNOWN205: {OP_UNKNOWN205, "OP_UNKNOWN205", 1, opcodeInvalid}, 533 OP_UNKNOWN206: {OP_UNKNOWN206, "OP_UNKNOWN206", 1, opcodeInvalid}, 534 OP_UNKNOWN207: {OP_UNKNOWN207, "OP_UNKNOWN207", 1, opcodeInvalid}, 535 OP_UNKNOWN208: {OP_UNKNOWN208, "OP_UNKNOWN208", 1, opcodeInvalid}, 536 OP_UNKNOWN209: {OP_UNKNOWN209, "OP_UNKNOWN209", 1, opcodeInvalid}, 537 OP_UNKNOWN210: {OP_UNKNOWN210, "OP_UNKNOWN210", 1, opcodeInvalid}, 538 OP_UNKNOWN211: {OP_UNKNOWN211, "OP_UNKNOWN211", 1, opcodeInvalid}, 539 OP_UNKNOWN212: {OP_UNKNOWN212, "OP_UNKNOWN212", 1, opcodeInvalid}, 540 OP_UNKNOWN213: {OP_UNKNOWN213, "OP_UNKNOWN213", 1, opcodeInvalid}, 541 OP_UNKNOWN214: {OP_UNKNOWN214, "OP_UNKNOWN214", 1, opcodeInvalid}, 542 OP_UNKNOWN215: {OP_UNKNOWN215, "OP_UNKNOWN215", 1, opcodeInvalid}, 543 OP_UNKNOWN216: {OP_UNKNOWN216, "OP_UNKNOWN216", 1, opcodeInvalid}, 544 OP_UNKNOWN217: {OP_UNKNOWN217, "OP_UNKNOWN217", 1, opcodeInvalid}, 545 OP_UNKNOWN218: {OP_UNKNOWN218, "OP_UNKNOWN218", 1, opcodeInvalid}, 546 OP_UNKNOWN219: {OP_UNKNOWN219, "OP_UNKNOWN219", 1, opcodeInvalid}, 547 OP_UNKNOWN220: {OP_UNKNOWN220, "OP_UNKNOWN220", 1, opcodeInvalid}, 548 OP_UNKNOWN221: {OP_UNKNOWN221, "OP_UNKNOWN221", 1, opcodeInvalid}, 549 OP_UNKNOWN222: {OP_UNKNOWN222, "OP_UNKNOWN222", 1, opcodeInvalid}, 550 OP_UNKNOWN223: {OP_UNKNOWN223, "OP_UNKNOWN223", 1, opcodeInvalid}, 551 OP_UNKNOWN224: {OP_UNKNOWN224, "OP_UNKNOWN224", 1, opcodeInvalid}, 552 OP_UNKNOWN225: {OP_UNKNOWN225, "OP_UNKNOWN225", 1, opcodeInvalid}, 553 OP_UNKNOWN226: {OP_UNKNOWN226, "OP_UNKNOWN226", 1, opcodeInvalid}, 554 OP_UNKNOWN227: {OP_UNKNOWN227, "OP_UNKNOWN227", 1, opcodeInvalid}, 555 OP_UNKNOWN228: {OP_UNKNOWN228, "OP_UNKNOWN228", 1, opcodeInvalid}, 556 OP_UNKNOWN229: {OP_UNKNOWN229, "OP_UNKNOWN229", 1, opcodeInvalid}, 557 OP_UNKNOWN230: {OP_UNKNOWN230, "OP_UNKNOWN230", 1, opcodeInvalid}, 558 OP_UNKNOWN231: {OP_UNKNOWN231, "OP_UNKNOWN231", 1, opcodeInvalid}, 559 OP_UNKNOWN232: {OP_UNKNOWN232, "OP_UNKNOWN232", 1, opcodeInvalid}, 560 OP_UNKNOWN233: {OP_UNKNOWN233, "OP_UNKNOWN233", 1, opcodeInvalid}, 561 OP_UNKNOWN234: {OP_UNKNOWN234, "OP_UNKNOWN234", 1, opcodeInvalid}, 562 OP_UNKNOWN235: {OP_UNKNOWN235, "OP_UNKNOWN235", 1, opcodeInvalid}, 563 OP_UNKNOWN236: {OP_UNKNOWN236, "OP_UNKNOWN236", 1, opcodeInvalid}, 564 OP_UNKNOWN237: {OP_UNKNOWN237, "OP_UNKNOWN237", 1, opcodeInvalid}, 565 OP_UNKNOWN238: {OP_UNKNOWN238, "OP_UNKNOWN238", 1, opcodeInvalid}, 566 OP_UNKNOWN239: {OP_UNKNOWN239, "OP_UNKNOWN239", 1, opcodeInvalid}, 567 OP_UNKNOWN240: {OP_UNKNOWN240, "OP_UNKNOWN240", 1, opcodeInvalid}, 568 OP_UNKNOWN241: {OP_UNKNOWN241, "OP_UNKNOWN241", 1, opcodeInvalid}, 569 OP_UNKNOWN242: {OP_UNKNOWN242, "OP_UNKNOWN242", 1, opcodeInvalid}, 570 OP_UNKNOWN243: {OP_UNKNOWN243, "OP_UNKNOWN243", 1, opcodeInvalid}, 571 OP_UNKNOWN244: {OP_UNKNOWN244, "OP_UNKNOWN244", 1, opcodeInvalid}, 572 OP_UNKNOWN245: {OP_UNKNOWN245, "OP_UNKNOWN245", 1, opcodeInvalid}, 573 OP_UNKNOWN246: {OP_UNKNOWN246, "OP_UNKNOWN246", 1, opcodeInvalid}, 574 OP_UNKNOWN247: {OP_UNKNOWN247, "OP_UNKNOWN247", 1, opcodeInvalid}, 575 OP_UNKNOWN248: {OP_UNKNOWN248, "OP_UNKNOWN248", 1, opcodeInvalid}, 576 OP_UNKNOWN249: {OP_UNKNOWN249, "OP_UNKNOWN249", 1, opcodeInvalid}, 577 578 // Bitcoin Core internal use opcode. Defined here for completeness. 579 OP_SMALLINTEGER: {OP_SMALLINTEGER, "OP_SMALLINTEGER", 1, opcodeInvalid}, 580 OP_PUBKEYS: {OP_PUBKEYS, "OP_PUBKEYS", 1, opcodeInvalid}, 581 OP_UNKNOWN252: {OP_UNKNOWN252, "OP_UNKNOWN252", 1, opcodeInvalid}, 582 OP_PUBKEYHASH: {OP_PUBKEYHASH, "OP_PUBKEYHASH", 1, opcodeInvalid}, 583 OP_PUBKEY: {OP_PUBKEY, "OP_PUBKEY", 1, opcodeInvalid}, 584 585 OP_INVALIDOPCODE: {OP_INVALIDOPCODE, "OP_INVALIDOPCODE", 1, opcodeInvalid}, 586 } 587 588 // opcodeOnelineRepls defines opcode names which are replaced when doing a 589 // one-line disassembly. This is done to match the output of the reference 590 // implementation while not changing the opcode names in the nicer full 591 // disassembly. 592 var opcodeOnelineRepls = map[string]string{ 593 "OP_1NEGATE": "-1", 594 "OP_0": "0", 595 "OP_1": "1", 596 "OP_2": "2", 597 "OP_3": "3", 598 "OP_4": "4", 599 "OP_5": "5", 600 "OP_6": "6", 601 "OP_7": "7", 602 "OP_8": "8", 603 "OP_9": "9", 604 "OP_10": "10", 605 "OP_11": "11", 606 "OP_12": "12", 607 "OP_13": "13", 608 "OP_14": "14", 609 "OP_15": "15", 610 "OP_16": "16", 611 } 612 613 // parsedOpcode represents an opcode that has been parsed and includes any 614 // potential data associated with it. 615 type parsedOpcode struct { 616 opcode *opcode 617 data []byte 618 } 619 620 // isDisabled returns whether or not the opcode is disabled and thus is always 621 // bad to see in the instruction stream (even if turned off by a conditional). 622 func (pop *parsedOpcode) isDisabled() bool { 623 switch pop.opcode.value { 624 case OP_CAT: 625 return true 626 case OP_SUBSTR: 627 return true 628 case OP_LEFT: 629 return true 630 case OP_RIGHT: 631 return true 632 case OP_INVERT: 633 return true 634 case OP_AND: 635 return true 636 case OP_OR: 637 return true 638 case OP_XOR: 639 return true 640 case OP_2MUL: 641 return true 642 case OP_2DIV: 643 return true 644 case OP_MUL: 645 return true 646 case OP_DIV: 647 return true 648 case OP_MOD: 649 return true 650 case OP_LSHIFT: 651 return true 652 case OP_RSHIFT: 653 return true 654 default: 655 return false 656 } 657 } 658 659 // alwaysIllegal returns whether or not the opcode is always illegal when passed 660 // over by the program counter even if in a non-executed branch (it isn't a 661 // coincidence that they are conditionals). 662 func (pop *parsedOpcode) alwaysIllegal() bool { 663 switch pop.opcode.value { 664 case OP_VERIF: 665 return true 666 case OP_VERNOTIF: 667 return true 668 default: 669 return false 670 } 671 } 672 673 // isConditional returns whether or not the opcode is a conditional opcode which 674 // changes the conditional execution stack when executed. 675 func (pop *parsedOpcode) isConditional() bool { 676 switch pop.opcode.value { 677 case OP_IF: 678 return true 679 case OP_NOTIF: 680 return true 681 case OP_ELSE: 682 return true 683 case OP_ENDIF: 684 return true 685 default: 686 return false 687 } 688 } 689 690 // checkMinimalDataPush returns whether or not the current data push uses the 691 // smallest possible opcode to represent it. For example, the value 15 could 692 // be pushed with OP_DATA_1 15 (among other variations); however, OP_15 is a 693 // single opcode that represents the same value and is only a single byte versus 694 // two bytes. 695 func (pop *parsedOpcode) checkMinimalDataPush() error { 696 data := pop.data 697 dataLen := len(data) 698 opcode := pop.opcode.value 699 700 if dataLen == 0 && opcode != OP_0 { 701 str := fmt.Sprintf("zero length data push is encoded with "+ 702 "opcode %s instead of OP_0", pop.opcode.name) 703 return scriptError(ErrMinimalData, str) 704 } else if dataLen == 1 && data[0] >= 1 && data[0] <= 16 { 705 if opcode != OP_1+data[0]-1 { 706 // Should have used OP_1 .. OP_16 707 str := fmt.Sprintf("data push of the value %d encoded "+ 708 "with opcode %s instead of OP_%d", data[0], 709 pop.opcode.name, data[0]) 710 return scriptError(ErrMinimalData, str) 711 } 712 } else if dataLen == 1 && data[0] == 0x81 { 713 if opcode != OP_1NEGATE { 714 str := fmt.Sprintf("data push of the value -1 encoded "+ 715 "with opcode %s instead of OP_1NEGATE", 716 pop.opcode.name) 717 return scriptError(ErrMinimalData, str) 718 } 719 } else if dataLen <= 75 { 720 if int(opcode) != dataLen { 721 // Should have used a direct push 722 str := fmt.Sprintf("data push of %d bytes encoded "+ 723 "with opcode %s instead of OP_DATA_%d", dataLen, 724 pop.opcode.name, dataLen) 725 return scriptError(ErrMinimalData, str) 726 } 727 } else if dataLen <= 255 { 728 if opcode != OP_PUSHDATA1 { 729 str := fmt.Sprintf("data push of %d bytes encoded "+ 730 "with opcode %s instead of OP_PUSHDATA1", 731 dataLen, pop.opcode.name) 732 return scriptError(ErrMinimalData, str) 733 } 734 } else if dataLen <= 65535 { 735 if opcode != OP_PUSHDATA2 { 736 str := fmt.Sprintf("data push of %d bytes encoded "+ 737 "with opcode %s instead of OP_PUSHDATA2", 738 dataLen, pop.opcode.name) 739 return scriptError(ErrMinimalData, str) 740 } 741 } 742 return nil 743 } 744 745 // print returns a human-readable string representation of the opcode for use 746 // in script disassembly. 747 func (pop *parsedOpcode) print(oneline bool) string { 748 // The reference implementation one-line disassembly replaces opcodes 749 // which represent values (e.g. OP_0 through OP_16 and OP_1NEGATE) 750 // with the raw value. However, when not doing a one-line dissassembly, 751 // we prefer to show the actual opcode names. Thus, only replace the 752 // opcodes in question when the oneline flag is set. 753 opcodeName := pop.opcode.name 754 if oneline { 755 if replName, ok := opcodeOnelineRepls[opcodeName]; ok { 756 opcodeName = replName 757 } 758 759 // Nothing more to do for non-data push opcodes. 760 if pop.opcode.length == 1 { 761 return opcodeName 762 } 763 764 return fmt.Sprintf("%x", pop.data) 765 } 766 767 // Nothing more to do for non-data push opcodes. 768 if pop.opcode.length == 1 { 769 return opcodeName 770 } 771 772 // Add length for the OP_PUSHDATA# opcodes. 773 retString := opcodeName 774 switch pop.opcode.length { 775 case -1: 776 retString += fmt.Sprintf(" 0x%02x", len(pop.data)) 777 case -2: 778 retString += fmt.Sprintf(" 0x%04x", len(pop.data)) 779 case -4: 780 retString += fmt.Sprintf(" 0x%08x", len(pop.data)) 781 } 782 783 return fmt.Sprintf("%s 0x%02x", retString, pop.data) 784 } 785 786 // bytes returns any data associated with the opcode encoded as it would be in 787 // a script. This is used for unparsing scripts from parsed opcodes. 788 func (pop *parsedOpcode) bytes() ([]byte, error) { 789 var retbytes []byte 790 if pop.opcode.length > 0 { 791 retbytes = make([]byte, 1, pop.opcode.length) 792 } else { 793 retbytes = make([]byte, 1, 1+len(pop.data)- 794 pop.opcode.length) 795 } 796 797 retbytes[0] = pop.opcode.value 798 if pop.opcode.length == 1 { 799 if len(pop.data) != 0 { 800 str := fmt.Sprintf("internal consistency error - "+ 801 "parsed opcode %s has data length %d when %d "+ 802 "was expected", pop.opcode.name, len(pop.data), 803 0) 804 return nil, scriptError(ErrInternal, str) 805 } 806 return retbytes, nil 807 } 808 nbytes := pop.opcode.length 809 if pop.opcode.length < 0 { 810 l := len(pop.data) 811 // tempting just to hardcode to avoid the complexity here. 812 switch pop.opcode.length { 813 case -1: 814 retbytes = append(retbytes, byte(l)) 815 nbytes = int(retbytes[1]) + len(retbytes) 816 case -2: 817 retbytes = append(retbytes, byte(l&0xff), 818 byte(l>>8&0xff)) 819 nbytes = int(binary.LittleEndian.Uint16(retbytes[1:])) + 820 len(retbytes) 821 case -4: 822 retbytes = append(retbytes, byte(l&0xff), 823 byte((l>>8)&0xff), byte((l>>16)&0xff), 824 byte((l>>24)&0xff)) 825 nbytes = int(binary.LittleEndian.Uint32(retbytes[1:])) + 826 len(retbytes) 827 } 828 } 829 830 retbytes = append(retbytes, pop.data...) 831 832 if len(retbytes) != nbytes { 833 str := fmt.Sprintf("internal consistency error - "+ 834 "parsed opcode %s has data length %d when %d was "+ 835 "expected", pop.opcode.name, len(retbytes), nbytes) 836 return nil, scriptError(ErrInternal, str) 837 } 838 839 return retbytes, nil 840 } 841 842 // ******************************************* 843 // Opcode implementation functions start here. 844 // ******************************************* 845 846 // opcodeDisabled is a common handler for disabled opcodes. It returns an 847 // appropriate error indicating the opcode is disabled. While it would 848 // ordinarily make more sense to detect if the script contains any disabled 849 // opcodes before executing in an initial parse step, the consensus rules 850 // dictate the script doesn't fail until the program counter passes over a 851 // disabled opcode (even when they appear in a branch that is not executed). 852 func opcodeDisabled(op *parsedOpcode, vm *Engine) error { 853 str := fmt.Sprintf("attempt to execute disabled opcode %s", 854 op.opcode.name) 855 return scriptError(ErrDisabledOpcode, str) 856 } 857 858 // opcodeReserved is a common handler for all reserved opcodes. It returns an 859 // appropriate error indicating the opcode is reserved. 860 func opcodeReserved(op *parsedOpcode, vm *Engine) error { 861 str := fmt.Sprintf("attempt to execute reserved opcode %s", 862 op.opcode.name) 863 return scriptError(ErrReservedOpcode, str) 864 } 865 866 // opcodeInvalid is a common handler for all invalid opcodes. It returns an 867 // appropriate error indicating the opcode is invalid. 868 func opcodeInvalid(op *parsedOpcode, vm *Engine) error { 869 str := fmt.Sprintf("attempt to execute invalid opcode %s", 870 op.opcode.name) 871 return scriptError(ErrReservedOpcode, str) 872 } 873 874 // opcodeFalse pushes an empty array to the data stack to represent false. Note 875 // that 0, when encoded as a number according to the numeric encoding consensus 876 // rules, is an empty array. 877 func opcodeFalse(op *parsedOpcode, vm *Engine) error { 878 vm.dstack.PushByteArray(nil) 879 return nil 880 } 881 882 // opcodePushData is a common handler for the vast majority of opcodes that push 883 // raw data (bytes) to the data stack. 884 func opcodePushData(op *parsedOpcode, vm *Engine) error { 885 vm.dstack.PushByteArray(op.data) 886 return nil 887 } 888 889 // opcode1Negate pushes -1, encoded as a number, to the data stack. 890 func opcode1Negate(op *parsedOpcode, vm *Engine) error { 891 vm.dstack.PushInt(scriptNum(-1)) 892 return nil 893 } 894 895 // opcodeN is a common handler for the small integer data push opcodes. It 896 // pushes the numeric value the opcode represents (which will be from 1 to 16) 897 // onto the data stack. 898 func opcodeN(op *parsedOpcode, vm *Engine) error { 899 // The opcodes are all defined consecutively, so the numeric value is 900 // the difference. 901 vm.dstack.PushInt(scriptNum((op.opcode.value - (OP_1 - 1)))) 902 return nil 903 } 904 905 // opcodeNop is a common handler for the NOP family of opcodes. As the name 906 // implies it generally does nothing, however, it will return an error when 907 // the flag to discourage use of NOPs is set for select opcodes. 908 func opcodeNop(op *parsedOpcode, vm *Engine) error { 909 switch op.opcode.value { 910 case OP_NOP1, OP_NOP4, OP_NOP5, 911 OP_NOP6, OP_NOP7, OP_NOP8, OP_NOP9, OP_NOP10: 912 if vm.hasFlag(ScriptDiscourageUpgradableNops) { 913 str := fmt.Sprintf("OP_NOP%d reserved for soft-fork "+ 914 "upgrades", op.opcode.value-(OP_NOP1-1)) 915 return scriptError(ErrDiscourageUpgradableNOPs, str) 916 } 917 } 918 return nil 919 } 920 921 // popIfBool enforces the "minimal if" policy during script execution if the 922 // particular flag is set. If so, in order to eliminate an additional source 923 // of nuisance malleability, post-segwit for version 0 witness programs, we now 924 // require the following: for OP_IF and OP_NOT_IF, the top stack item MUST 925 // either be an empty byte slice, or [0x01]. Otherwise, the item at the top of 926 // the stack will be popped and interpreted as a boolean. 927 func popIfBool(vm *Engine) (bool, error) { 928 // When not in witness execution mode, not executing a v0 witness 929 // program, or the minimal if flag isn't set pop the top stack item as 930 // a normal bool. 931 if !vm.isWitnessVersionActive(0) || !vm.hasFlag(ScriptVerifyMinimalIf) { 932 return vm.dstack.PopBool() 933 } 934 935 // At this point, a v0 witness program is being executed and the minimal 936 // if flag is set, so enforce additional constraints on the top stack 937 // item. 938 so, err := vm.dstack.PopByteArray() 939 if err != nil { 940 return false, err 941 } 942 943 // The top element MUST have a length of at least one. 944 if len(so) > 1 { 945 str := fmt.Sprintf("minimal if is active, top element MUST "+ 946 "have a length of at least, instead length is %v", 947 len(so)) 948 return false, scriptError(ErrMinimalIf, str) 949 } 950 951 // Additionally, if the length is one, then the value MUST be 0x01. 952 if len(so) == 1 && so[0] != 0x01 { 953 str := fmt.Sprintf("minimal if is active, top stack item MUST "+ 954 "be an empty byte array or 0x01, is instead: %v", 955 so[0]) 956 return false, scriptError(ErrMinimalIf, str) 957 } 958 959 return asBool(so), nil 960 } 961 962 // opcodeIf treats the top item on the data stack as a boolean and removes it. 963 // 964 // An appropriate entry is added to the conditional stack depending on whether 965 // the boolean is true and whether this if is on an executing branch in order 966 // to allow proper execution of further opcodes depending on the conditional 967 // logic. When the boolean is true, the first branch will be executed (unless 968 // this opcode is nested in a non-executed branch). 969 // 970 // <expression> if [statements] [else [statements]] endif 971 // 972 // Note that, unlike for all non-conditional opcodes, this is executed even when 973 // it is on a non-executing branch so proper nesting is maintained. 974 // 975 // Data stack transformation: [... bool] -> [...] 976 // Conditional stack transformation: [...] -> [... OpCondValue] 977 func opcodeIf(op *parsedOpcode, vm *Engine) error { 978 condVal := OpCondFalse 979 if vm.isBranchExecuting() { 980 ok, err := popIfBool(vm) 981 if err != nil { 982 return err 983 } 984 985 if ok { 986 condVal = OpCondTrue 987 } 988 } else { 989 condVal = OpCondSkip 990 } 991 vm.condStack = append(vm.condStack, condVal) 992 return nil 993 } 994 995 // opcodeNotIf treats the top item on the data stack as a boolean and removes 996 // it. 997 // 998 // An appropriate entry is added to the conditional stack depending on whether 999 // the boolean is true and whether this if is on an executing branch in order 1000 // to allow proper execution of further opcodes depending on the conditional 1001 // logic. When the boolean is false, the first branch will be executed (unless 1002 // this opcode is nested in a non-executed branch). 1003 // 1004 // <expression> notif [statements] [else [statements]] endif 1005 // 1006 // Note that, unlike for all non-conditional opcodes, this is executed even when 1007 // it is on a non-executing branch so proper nesting is maintained. 1008 // 1009 // Data stack transformation: [... bool] -> [...] 1010 // Conditional stack transformation: [...] -> [... OpCondValue] 1011 func opcodeNotIf(op *parsedOpcode, vm *Engine) error { 1012 condVal := OpCondFalse 1013 if vm.isBranchExecuting() { 1014 ok, err := popIfBool(vm) 1015 if err != nil { 1016 return err 1017 } 1018 1019 if !ok { 1020 condVal = OpCondTrue 1021 } 1022 } else { 1023 condVal = OpCondSkip 1024 } 1025 vm.condStack = append(vm.condStack, condVal) 1026 return nil 1027 } 1028 1029 // opcodeElse inverts conditional execution for other half of if/else/endif. 1030 // 1031 // An error is returned if there has not already been a matching OP_IF. 1032 // 1033 // Conditional stack transformation: [... OpCondValue] -> [... !OpCondValue] 1034 func opcodeElse(op *parsedOpcode, vm *Engine) error { 1035 if len(vm.condStack) == 0 { 1036 str := fmt.Sprintf("encountered opcode %s with no matching "+ 1037 "opcode to begin conditional execution", op.opcode.name) 1038 return scriptError(ErrUnbalancedConditional, str) 1039 } 1040 1041 conditionalIdx := len(vm.condStack) - 1 1042 switch vm.condStack[conditionalIdx] { 1043 case OpCondTrue: 1044 vm.condStack[conditionalIdx] = OpCondFalse 1045 case OpCondFalse: 1046 vm.condStack[conditionalIdx] = OpCondTrue 1047 case OpCondSkip: 1048 // Value doesn't change in skip since it indicates this opcode 1049 // is nested in a non-executed branch. 1050 } 1051 return nil 1052 } 1053 1054 // opcodeEndif terminates a conditional block, removing the value from the 1055 // conditional execution stack. 1056 // 1057 // An error is returned if there has not already been a matching OP_IF. 1058 // 1059 // Conditional stack transformation: [... OpCondValue] -> [...] 1060 func opcodeEndif(op *parsedOpcode, vm *Engine) error { 1061 if len(vm.condStack) == 0 { 1062 str := fmt.Sprintf("encountered opcode %s with no matching "+ 1063 "opcode to begin conditional execution", op.opcode.name) 1064 return scriptError(ErrUnbalancedConditional, str) 1065 } 1066 1067 vm.condStack = vm.condStack[:len(vm.condStack)-1] 1068 return nil 1069 } 1070 1071 // abstractVerify examines the top item on the data stack as a boolean value and 1072 // verifies it evaluates to true. An error is returned either when there is no 1073 // item on the stack or when that item evaluates to false. In the latter case 1074 // where the verification fails specifically due to the top item evaluating 1075 // to false, the returned error will use the passed error code. 1076 func abstractVerify(op *parsedOpcode, vm *Engine, c ErrorCode) error { 1077 verified, err := vm.dstack.PopBool() 1078 if err != nil { 1079 return err 1080 } 1081 1082 if !verified { 1083 str := fmt.Sprintf("%s failed", op.opcode.name) 1084 return scriptError(c, str) 1085 } 1086 return nil 1087 } 1088 1089 // opcodeVerify examines the top item on the data stack as a boolean value and 1090 // verifies it evaluates to true. An error is returned if it does not. 1091 func opcodeVerify(op *parsedOpcode, vm *Engine) error { 1092 return abstractVerify(op, vm, ErrVerify) 1093 } 1094 1095 // opcodeReturn returns an appropriate error since it is always an error to 1096 // return early from a script. 1097 func opcodeReturn(op *parsedOpcode, vm *Engine) error { 1098 return scriptError(ErrEarlyReturn, "script returned early") 1099 } 1100 1101 // verifyLockTime is a helper function used to validate locktimes. 1102 func verifyLockTime(txLockTime, threshold, lockTime int64) error { 1103 // The lockTimes in both the script and transaction must be of the same 1104 // type. 1105 if !((txLockTime < threshold && lockTime < threshold) || 1106 (txLockTime >= threshold && lockTime >= threshold)) { 1107 str := fmt.Sprintf("mismatched locktime types -- tx locktime "+ 1108 "%d, stack locktime %d", txLockTime, lockTime) 1109 return scriptError(ErrUnsatisfiedLockTime, str) 1110 } 1111 1112 if lockTime > txLockTime { 1113 str := fmt.Sprintf("locktime requirement not satisfied -- "+ 1114 "locktime is greater than the transaction locktime: "+ 1115 "%d > %d", lockTime, txLockTime) 1116 return scriptError(ErrUnsatisfiedLockTime, str) 1117 } 1118 1119 return nil 1120 } 1121 1122 // opcodeCheckLockTimeVerify compares the top item on the data stack to the 1123 // LockTime field of the transaction containing the script signature 1124 // validating if the transaction outputs are spendable yet. If flag 1125 // ScriptVerifyCheckLockTimeVerify is not set, the code continues as if OP_NOP2 1126 // were executed. 1127 func opcodeCheckLockTimeVerify(op *parsedOpcode, vm *Engine) error { 1128 // If the ScriptVerifyCheckLockTimeVerify script flag is not set, treat 1129 // opcode as OP_NOP2 instead. 1130 if !vm.hasFlag(ScriptVerifyCheckLockTimeVerify) { 1131 if vm.hasFlag(ScriptDiscourageUpgradableNops) { 1132 return scriptError(ErrDiscourageUpgradableNOPs, 1133 "OP_NOP2 reserved for soft-fork upgrades") 1134 } 1135 return nil 1136 } 1137 1138 // The current transaction locktime is a uint32 resulting in a maximum 1139 // locktime of 2^32-1 (the year 2106). However, scriptNums are signed 1140 // and therefore a standard 4-byte scriptNum would only support up to a 1141 // maximum of 2^31-1 (the year 2038). Thus, a 5-byte scriptNum is used 1142 // here since it will support up to 2^39-1 which allows dates beyond the 1143 // current locktime limit. 1144 // 1145 // PeekByteArray is used here instead of PeekInt because we do not want 1146 // to be limited to a 4-byte integer for reasons specified above. 1147 so, err := vm.dstack.PeekByteArray(0) 1148 if err != nil { 1149 return err 1150 } 1151 lockTime, err := makeScriptNum(so, vm.dstack.verifyMinimalData, 5) 1152 if err != nil { 1153 return err 1154 } 1155 1156 // In the rare event that the argument needs to be < 0 due to some 1157 // arithmetic being done first, you can always use 1158 // 0 OP_MAX OP_CHECKLOCKTIMEVERIFY. 1159 if lockTime < 0 { 1160 str := fmt.Sprintf("negative lock time: %d", lockTime) 1161 return scriptError(ErrNegativeLockTime, str) 1162 } 1163 1164 // The lock time field of a transaction is either a block height at 1165 // which the transaction is finalized or a timestamp depending on if the 1166 // value is before the txscript.LockTimeThreshold. When it is under the 1167 // threshold it is a block height. 1168 err = verifyLockTime(int64(vm.tx.LockTime), LockTimeThreshold, 1169 int64(lockTime)) 1170 if err != nil { 1171 return err 1172 } 1173 1174 // The lock time feature can also be disabled, thereby bypassing 1175 // OP_CHECKLOCKTIMEVERIFY, if every transaction input has been finalized by 1176 // setting its sequence to the maximum value (wire.MaxTxInSequenceNum). This 1177 // condition would result in the transaction being allowed into the blockchain 1178 // making the opcode ineffective. 1179 // 1180 // This condition is prevented by enforcing that the input being used by 1181 // the opcode is unlocked (its sequence number is less than the max 1182 // value). This is sufficient to prove correctness without having to 1183 // check every input. 1184 // 1185 // NOTE: This implies that even if the transaction is not finalized due to 1186 // another input being unlocked, the opcode execution will still fail when the 1187 // input being used by the opcode is locked. 1188 if vm.tx.TxIn[vm.txIdx].Sequence == wire.MaxTxInSequenceNum { 1189 return scriptError(ErrUnsatisfiedLockTime, 1190 "transaction input is finalized") 1191 } 1192 1193 return nil 1194 } 1195 1196 // opcodeCheckSequenceVerify compares the top item on the data stack to the 1197 // LockTime field of the transaction containing the script signature 1198 // validating if the transaction outputs are spendable yet. If flag 1199 // ScriptVerifyCheckSequenceVerify is not set, the code continues as if OP_NOP3 1200 // were executed. 1201 func opcodeCheckSequenceVerify(op *parsedOpcode, vm *Engine) error { 1202 // If the ScriptVerifyCheckSequenceVerify script flag is not set, treat 1203 // opcode as OP_NOP3 instead. 1204 if !vm.hasFlag(ScriptVerifyCheckSequenceVerify) { 1205 if vm.hasFlag(ScriptDiscourageUpgradableNops) { 1206 return scriptError(ErrDiscourageUpgradableNOPs, 1207 "OP_NOP3 reserved for soft-fork upgrades") 1208 } 1209 return nil 1210 } 1211 1212 // The current transaction sequence is a uint32 resulting in a maximum 1213 // sequence of 2^32-1. However, scriptNums are signed and therefore a 1214 // standard 4-byte scriptNum would only support up to a maximum of 1215 // 2^31-1. Thus, a 5-byte scriptNum is used here since it will support 1216 // up to 2^39-1 which allows sequences beyond the current sequence 1217 // limit. 1218 // 1219 // PeekByteArray is used here instead of PeekInt because we do not want 1220 // to be limited to a 4-byte integer for reasons specified above. 1221 so, err := vm.dstack.PeekByteArray(0) 1222 if err != nil { 1223 return err 1224 } 1225 stackSequence, err := makeScriptNum(so, vm.dstack.verifyMinimalData, 5) 1226 if err != nil { 1227 return err 1228 } 1229 1230 // In the rare event that the argument needs to be < 0 due to some 1231 // arithmetic being done first, you can always use 1232 // 0 OP_MAX OP_CHECKSEQUENCEVERIFY. 1233 if stackSequence < 0 { 1234 str := fmt.Sprintf("negative sequence: %d", stackSequence) 1235 return scriptError(ErrNegativeLockTime, str) 1236 } 1237 1238 sequence := int64(stackSequence) 1239 1240 // To provide for future soft-fork extensibility, if the 1241 // operand has the disabled lock-time flag set, 1242 // CHECKSEQUENCEVERIFY behaves as a NOP. 1243 if sequence&int64(wire.SequenceLockTimeDisabled) != 0 { 1244 return nil 1245 } 1246 1247 // Transaction version numbers not high enough to trigger CSV rules must 1248 // fail. 1249 if vm.tx.Version < 2 { 1250 str := fmt.Sprintf("invalid transaction version: %d", 1251 vm.tx.Version) 1252 return scriptError(ErrUnsatisfiedLockTime, str) 1253 } 1254 1255 // Sequence numbers with their most significant bit set are not 1256 // consensus constrained. Testing that the transaction's sequence 1257 // number does not have this bit set prevents using this property 1258 // to get around a CHECKSEQUENCEVERIFY check. 1259 txSequence := int64(vm.tx.TxIn[vm.txIdx].Sequence) 1260 if txSequence&int64(wire.SequenceLockTimeDisabled) != 0 { 1261 str := fmt.Sprintf("transaction sequence has sequence "+ 1262 "locktime disabled bit set: 0x%x", txSequence) 1263 return scriptError(ErrUnsatisfiedLockTime, str) 1264 } 1265 1266 // Mask off non-consensus bits before doing comparisons. 1267 lockTimeMask := int64(wire.SequenceLockTimeIsSeconds | 1268 wire.SequenceLockTimeMask) 1269 return verifyLockTime(txSequence&lockTimeMask, 1270 wire.SequenceLockTimeIsSeconds, sequence&lockTimeMask) 1271 } 1272 1273 // opcodeToAltStack removes the top item from the main data stack and pushes it 1274 // onto the alternate data stack. 1275 // 1276 // Main data stack transformation: [... x1 x2 x3] -> [... x1 x2] 1277 // Alt data stack transformation: [... y1 y2 y3] -> [... y1 y2 y3 x3] 1278 func opcodeToAltStack(op *parsedOpcode, vm *Engine) error { 1279 so, err := vm.dstack.PopByteArray() 1280 if err != nil { 1281 return err 1282 } 1283 vm.astack.PushByteArray(so) 1284 1285 return nil 1286 } 1287 1288 // opcodeFromAltStack removes the top item from the alternate data stack and 1289 // pushes it onto the main data stack. 1290 // 1291 // Main data stack transformation: [... x1 x2 x3] -> [... x1 x2 x3 y3] 1292 // Alt data stack transformation: [... y1 y2 y3] -> [... y1 y2] 1293 func opcodeFromAltStack(op *parsedOpcode, vm *Engine) error { 1294 so, err := vm.astack.PopByteArray() 1295 if err != nil { 1296 return err 1297 } 1298 vm.dstack.PushByteArray(so) 1299 1300 return nil 1301 } 1302 1303 // opcode2Drop removes the top 2 items from the data stack. 1304 // 1305 // Stack transformation: [... x1 x2 x3] -> [... x1] 1306 func opcode2Drop(op *parsedOpcode, vm *Engine) error { 1307 return vm.dstack.DropN(2) 1308 } 1309 1310 // opcode2Dup duplicates the top 2 items on the data stack. 1311 // 1312 // Stack transformation: [... x1 x2 x3] -> [... x1 x2 x3 x2 x3] 1313 func opcode2Dup(op *parsedOpcode, vm *Engine) error { 1314 return vm.dstack.DupN(2) 1315 } 1316 1317 // opcode3Dup duplicates the top 3 items on the data stack. 1318 // 1319 // Stack transformation: [... x1 x2 x3] -> [... x1 x2 x3 x1 x2 x3] 1320 func opcode3Dup(op *parsedOpcode, vm *Engine) error { 1321 return vm.dstack.DupN(3) 1322 } 1323 1324 // opcode2Over duplicates the 2 items before the top 2 items on the data stack. 1325 // 1326 // Stack transformation: [... x1 x2 x3 x4] -> [... x1 x2 x3 x4 x1 x2] 1327 func opcode2Over(op *parsedOpcode, vm *Engine) error { 1328 return vm.dstack.OverN(2) 1329 } 1330 1331 // opcode2Rot rotates the top 6 items on the data stack to the left twice. 1332 // 1333 // Stack transformation: [... x1 x2 x3 x4 x5 x6] -> [... x3 x4 x5 x6 x1 x2] 1334 func opcode2Rot(op *parsedOpcode, vm *Engine) error { 1335 return vm.dstack.RotN(2) 1336 } 1337 1338 // opcode2Swap swaps the top 2 items on the data stack with the 2 that come 1339 // before them. 1340 // 1341 // Stack transformation: [... x1 x2 x3 x4] -> [... x3 x4 x1 x2] 1342 func opcode2Swap(op *parsedOpcode, vm *Engine) error { 1343 return vm.dstack.SwapN(2) 1344 } 1345 1346 // opcodeIfDup duplicates the top item of the stack if it is not zero. 1347 // 1348 // Stack transformation (x1==0): [... x1] -> [... x1] 1349 // Stack transformation (x1!=0): [... x1] -> [... x1 x1] 1350 func opcodeIfDup(op *parsedOpcode, vm *Engine) error { 1351 so, err := vm.dstack.PeekByteArray(0) 1352 if err != nil { 1353 return err 1354 } 1355 1356 // Push copy of data iff it isn't zero 1357 if asBool(so) { 1358 vm.dstack.PushByteArray(so) 1359 } 1360 1361 return nil 1362 } 1363 1364 // opcodeDepth pushes the depth of the data stack prior to executing this 1365 // opcode, encoded as a number, onto the data stack. 1366 // 1367 // Stack transformation: [...] -> [... <num of items on the stack>] 1368 // Example with 2 items: [x1 x2] -> [x1 x2 2] 1369 // Example with 3 items: [x1 x2 x3] -> [x1 x2 x3 3] 1370 func opcodeDepth(op *parsedOpcode, vm *Engine) error { 1371 vm.dstack.PushInt(scriptNum(vm.dstack.Depth())) 1372 return nil 1373 } 1374 1375 // opcodeDrop removes the top item from the data stack. 1376 // 1377 // Stack transformation: [... x1 x2 x3] -> [... x1 x2] 1378 func opcodeDrop(op *parsedOpcode, vm *Engine) error { 1379 return vm.dstack.DropN(1) 1380 } 1381 1382 // opcodeDup duplicates the top item on the data stack. 1383 // 1384 // Stack transformation: [... x1 x2 x3] -> [... x1 x2 x3 x3] 1385 func opcodeDup(op *parsedOpcode, vm *Engine) error { 1386 return vm.dstack.DupN(1) 1387 } 1388 1389 // opcodeNip removes the item before the top item on the data stack. 1390 // 1391 // Stack transformation: [... x1 x2 x3] -> [... x1 x3] 1392 func opcodeNip(op *parsedOpcode, vm *Engine) error { 1393 return vm.dstack.NipN(1) 1394 } 1395 1396 // opcodeOver duplicates the item before the top item on the data stack. 1397 // 1398 // Stack transformation: [... x1 x2 x3] -> [... x1 x2 x3 x2] 1399 func opcodeOver(op *parsedOpcode, vm *Engine) error { 1400 return vm.dstack.OverN(1) 1401 } 1402 1403 // opcodePick treats the top item on the data stack as an integer and duplicates 1404 // the item on the stack that number of items back to the top. 1405 // 1406 // Stack transformation: [xn ... x2 x1 x0 n] -> [xn ... x2 x1 x0 xn] 1407 // Example with n=1: [x2 x1 x0 1] -> [x2 x1 x0 x1] 1408 // Example with n=2: [x2 x1 x0 2] -> [x2 x1 x0 x2] 1409 func opcodePick(op *parsedOpcode, vm *Engine) error { 1410 val, err := vm.dstack.PopInt() 1411 if err != nil { 1412 return err 1413 } 1414 1415 return vm.dstack.PickN(val.Int32()) 1416 } 1417 1418 // opcodeRoll treats the top item on the data stack as an integer and moves 1419 // the item on the stack that number of items back to the top. 1420 // 1421 // Stack transformation: [xn ... x2 x1 x0 n] -> [... x2 x1 x0 xn] 1422 // Example with n=1: [x2 x1 x0 1] -> [x2 x0 x1] 1423 // Example with n=2: [x2 x1 x0 2] -> [x1 x0 x2] 1424 func opcodeRoll(op *parsedOpcode, vm *Engine) error { 1425 val, err := vm.dstack.PopInt() 1426 if err != nil { 1427 return err 1428 } 1429 1430 return vm.dstack.RollN(val.Int32()) 1431 } 1432 1433 // opcodeRot rotates the top 3 items on the data stack to the left. 1434 // 1435 // Stack transformation: [... x1 x2 x3] -> [... x2 x3 x1] 1436 func opcodeRot(op *parsedOpcode, vm *Engine) error { 1437 return vm.dstack.RotN(1) 1438 } 1439 1440 // opcodeSwap swaps the top two items on the stack. 1441 // 1442 // Stack transformation: [... x1 x2] -> [... x2 x1] 1443 func opcodeSwap(op *parsedOpcode, vm *Engine) error { 1444 return vm.dstack.SwapN(1) 1445 } 1446 1447 // opcodeTuck inserts a duplicate of the top item of the data stack before the 1448 // second-to-top item. 1449 // 1450 // Stack transformation: [... x1 x2] -> [... x2 x1 x2] 1451 func opcodeTuck(op *parsedOpcode, vm *Engine) error { 1452 return vm.dstack.Tuck() 1453 } 1454 1455 // opcodeSize pushes the size of the top item of the data stack onto the data 1456 // stack. 1457 // 1458 // Stack transformation: [... x1] -> [... x1 len(x1)] 1459 func opcodeSize(op *parsedOpcode, vm *Engine) error { 1460 so, err := vm.dstack.PeekByteArray(0) 1461 if err != nil { 1462 return err 1463 } 1464 1465 vm.dstack.PushInt(scriptNum(len(so))) 1466 return nil 1467 } 1468 1469 // opcodeEqual removes the top 2 items of the data stack, compares them as raw 1470 // bytes, and pushes the result, encoded as a boolean, back to the stack. 1471 // 1472 // Stack transformation: [... x1 x2] -> [... bool] 1473 func opcodeEqual(op *parsedOpcode, vm *Engine) error { 1474 a, err := vm.dstack.PopByteArray() 1475 if err != nil { 1476 return err 1477 } 1478 b, err := vm.dstack.PopByteArray() 1479 if err != nil { 1480 return err 1481 } 1482 1483 vm.dstack.PushBool(bytes.Equal(a, b)) 1484 return nil 1485 } 1486 1487 // opcodeEqualVerify is a combination of opcodeEqual and opcodeVerify. 1488 // Specifically, it removes the top 2 items of the data stack, compares them, 1489 // and pushes the result, encoded as a boolean, back to the stack. Then, it 1490 // examines the top item on the data stack as a boolean value and verifies it 1491 // evaluates to true. An error is returned if it does not. 1492 // 1493 // Stack transformation: [... x1 x2] -> [... bool] -> [...] 1494 func opcodeEqualVerify(op *parsedOpcode, vm *Engine) error { 1495 err := opcodeEqual(op, vm) 1496 if err == nil { 1497 err = abstractVerify(op, vm, ErrEqualVerify) 1498 } 1499 return err 1500 } 1501 1502 // opcode1Add treats the top item on the data stack as an integer and replaces 1503 // it with its incremented value (plus 1). 1504 // 1505 // Stack transformation: [... x1 x2] -> [... x1 x2+1] 1506 func opcode1Add(op *parsedOpcode, vm *Engine) error { 1507 m, err := vm.dstack.PopInt() 1508 if err != nil { 1509 return err 1510 } 1511 1512 vm.dstack.PushInt(m + 1) 1513 return nil 1514 } 1515 1516 // opcode1Sub treats the top item on the data stack as an integer and replaces 1517 // it with its decremented value (minus 1). 1518 // 1519 // Stack transformation: [... x1 x2] -> [... x1 x2-1] 1520 func opcode1Sub(op *parsedOpcode, vm *Engine) error { 1521 m, err := vm.dstack.PopInt() 1522 if err != nil { 1523 return err 1524 } 1525 vm.dstack.PushInt(m - 1) 1526 1527 return nil 1528 } 1529 1530 // opcodeNegate treats the top item on the data stack as an integer and replaces 1531 // it with its negation. 1532 // 1533 // Stack transformation: [... x1 x2] -> [... x1 -x2] 1534 func opcodeNegate(op *parsedOpcode, vm *Engine) error { 1535 m, err := vm.dstack.PopInt() 1536 if err != nil { 1537 return err 1538 } 1539 1540 vm.dstack.PushInt(-m) 1541 return nil 1542 } 1543 1544 // opcodeAbs treats the top item on the data stack as an integer and replaces it 1545 // it with its absolute value. 1546 // 1547 // Stack transformation: [... x1 x2] -> [... x1 abs(x2)] 1548 func opcodeAbs(op *parsedOpcode, vm *Engine) error { 1549 m, err := vm.dstack.PopInt() 1550 if err != nil { 1551 return err 1552 } 1553 1554 if m < 0 { 1555 m = -m 1556 } 1557 vm.dstack.PushInt(m) 1558 return nil 1559 } 1560 1561 // opcodeNot treats the top item on the data stack as an integer and replaces 1562 // it with its "inverted" value (0 becomes 1, non-zero becomes 0). 1563 // 1564 // NOTE: While it would probably make more sense to treat the top item as a 1565 // boolean, and push the opposite, which is really what the intention of this 1566 // opcode is, it is extremely important that is not done because integers are 1567 // interpreted differently than booleans and the consensus rules for this opcode 1568 // dictate the item is interpreted as an integer. 1569 // 1570 // Stack transformation (x2==0): [... x1 0] -> [... x1 1] 1571 // Stack transformation (x2!=0): [... x1 1] -> [... x1 0] 1572 // Stack transformation (x2!=0): [... x1 17] -> [... x1 0] 1573 func opcodeNot(op *parsedOpcode, vm *Engine) error { 1574 m, err := vm.dstack.PopInt() 1575 if err != nil { 1576 return err 1577 } 1578 1579 if m == 0 { 1580 vm.dstack.PushInt(scriptNum(1)) 1581 } else { 1582 vm.dstack.PushInt(scriptNum(0)) 1583 } 1584 return nil 1585 } 1586 1587 // opcode0NotEqual treats the top item on the data stack as an integer and 1588 // replaces it with either a 0 if it is zero, or a 1 if it is not zero. 1589 // 1590 // Stack transformation (x2==0): [... x1 0] -> [... x1 0] 1591 // Stack transformation (x2!=0): [... x1 1] -> [... x1 1] 1592 // Stack transformation (x2!=0): [... x1 17] -> [... x1 1] 1593 func opcode0NotEqual(op *parsedOpcode, vm *Engine) error { 1594 m, err := vm.dstack.PopInt() 1595 if err != nil { 1596 return err 1597 } 1598 1599 if m != 0 { 1600 m = 1 1601 } 1602 vm.dstack.PushInt(m) 1603 return nil 1604 } 1605 1606 // opcodeAdd treats the top two items on the data stack as integers and replaces 1607 // them with their sum. 1608 // 1609 // Stack transformation: [... x1 x2] -> [... x1+x2] 1610 func opcodeAdd(op *parsedOpcode, vm *Engine) error { 1611 v0, err := vm.dstack.PopInt() 1612 if err != nil { 1613 return err 1614 } 1615 1616 v1, err := vm.dstack.PopInt() 1617 if err != nil { 1618 return err 1619 } 1620 1621 vm.dstack.PushInt(v0 + v1) 1622 return nil 1623 } 1624 1625 // opcodeSub treats the top two items on the data stack as integers and replaces 1626 // them with the result of subtracting the top entry from the second-to-top 1627 // entry. 1628 // 1629 // Stack transformation: [... x1 x2] -> [... x1-x2] 1630 func opcodeSub(op *parsedOpcode, vm *Engine) error { 1631 v0, err := vm.dstack.PopInt() 1632 if err != nil { 1633 return err 1634 } 1635 1636 v1, err := vm.dstack.PopInt() 1637 if err != nil { 1638 return err 1639 } 1640 1641 vm.dstack.PushInt(v1 - v0) 1642 return nil 1643 } 1644 1645 // opcodeBoolAnd treats the top two items on the data stack as integers. When 1646 // both of them are not zero, they are replaced with a 1, otherwise a 0. 1647 // 1648 // Stack transformation (x1==0, x2==0): [... 0 0] -> [... 0] 1649 // Stack transformation (x1!=0, x2==0): [... 5 0] -> [... 0] 1650 // Stack transformation (x1==0, x2!=0): [... 0 7] -> [... 0] 1651 // Stack transformation (x1!=0, x2!=0): [... 4 8] -> [... 1] 1652 func opcodeBoolAnd(op *parsedOpcode, vm *Engine) error { 1653 v0, err := vm.dstack.PopInt() 1654 if err != nil { 1655 return err 1656 } 1657 1658 v1, err := vm.dstack.PopInt() 1659 if err != nil { 1660 return err 1661 } 1662 1663 if v0 != 0 && v1 != 0 { 1664 vm.dstack.PushInt(scriptNum(1)) 1665 } else { 1666 vm.dstack.PushInt(scriptNum(0)) 1667 } 1668 1669 return nil 1670 } 1671 1672 // opcodeBoolOr treats the top two items on the data stack as integers. When 1673 // either of them are not zero, they are replaced with a 1, otherwise a 0. 1674 // 1675 // Stack transformation (x1==0, x2==0): [... 0 0] -> [... 0] 1676 // Stack transformation (x1!=0, x2==0): [... 5 0] -> [... 1] 1677 // Stack transformation (x1==0, x2!=0): [... 0 7] -> [... 1] 1678 // Stack transformation (x1!=0, x2!=0): [... 4 8] -> [... 1] 1679 func opcodeBoolOr(op *parsedOpcode, vm *Engine) error { 1680 v0, err := vm.dstack.PopInt() 1681 if err != nil { 1682 return err 1683 } 1684 1685 v1, err := vm.dstack.PopInt() 1686 if err != nil { 1687 return err 1688 } 1689 1690 if v0 != 0 || v1 != 0 { 1691 vm.dstack.PushInt(scriptNum(1)) 1692 } else { 1693 vm.dstack.PushInt(scriptNum(0)) 1694 } 1695 1696 return nil 1697 } 1698 1699 // opcodeNumEqual treats the top two items on the data stack as integers. When 1700 // they are equal, they are replaced with a 1, otherwise a 0. 1701 // 1702 // Stack transformation (x1==x2): [... 5 5] -> [... 1] 1703 // Stack transformation (x1!=x2): [... 5 7] -> [... 0] 1704 func opcodeNumEqual(op *parsedOpcode, vm *Engine) error { 1705 v0, err := vm.dstack.PopInt() 1706 if err != nil { 1707 return err 1708 } 1709 1710 v1, err := vm.dstack.PopInt() 1711 if err != nil { 1712 return err 1713 } 1714 1715 if v0 == v1 { 1716 vm.dstack.PushInt(scriptNum(1)) 1717 } else { 1718 vm.dstack.PushInt(scriptNum(0)) 1719 } 1720 1721 return nil 1722 } 1723 1724 // opcodeNumEqualVerify is a combination of opcodeNumEqual and opcodeVerify. 1725 // 1726 // Specifically, treats the top two items on the data stack as integers. When 1727 // they are equal, they are replaced with a 1, otherwise a 0. Then, it examines 1728 // the top item on the data stack as a boolean value and verifies it evaluates 1729 // to true. An error is returned if it does not. 1730 // 1731 // Stack transformation: [... x1 x2] -> [... bool] -> [...] 1732 func opcodeNumEqualVerify(op *parsedOpcode, vm *Engine) error { 1733 err := opcodeNumEqual(op, vm) 1734 if err == nil { 1735 err = abstractVerify(op, vm, ErrNumEqualVerify) 1736 } 1737 return err 1738 } 1739 1740 // opcodeNumNotEqual treats the top two items on the data stack as integers. 1741 // When they are NOT equal, they are replaced with a 1, otherwise a 0. 1742 // 1743 // Stack transformation (x1==x2): [... 5 5] -> [... 0] 1744 // Stack transformation (x1!=x2): [... 5 7] -> [... 1] 1745 func opcodeNumNotEqual(op *parsedOpcode, vm *Engine) error { 1746 v0, err := vm.dstack.PopInt() 1747 if err != nil { 1748 return err 1749 } 1750 1751 v1, err := vm.dstack.PopInt() 1752 if err != nil { 1753 return err 1754 } 1755 1756 if v0 != v1 { 1757 vm.dstack.PushInt(scriptNum(1)) 1758 } else { 1759 vm.dstack.PushInt(scriptNum(0)) 1760 } 1761 1762 return nil 1763 } 1764 1765 // opcodeLessThan treats the top two items on the data stack as integers. When 1766 // the second-to-top item is less than the top item, they are replaced with a 1, 1767 // otherwise a 0. 1768 // 1769 // Stack transformation: [... x1 x2] -> [... bool] 1770 func opcodeLessThan(op *parsedOpcode, vm *Engine) error { 1771 v0, err := vm.dstack.PopInt() 1772 if err != nil { 1773 return err 1774 } 1775 1776 v1, err := vm.dstack.PopInt() 1777 if err != nil { 1778 return err 1779 } 1780 1781 if v1 < v0 { 1782 vm.dstack.PushInt(scriptNum(1)) 1783 } else { 1784 vm.dstack.PushInt(scriptNum(0)) 1785 } 1786 1787 return nil 1788 } 1789 1790 // opcodeGreaterThan treats the top two items on the data stack as integers. 1791 // When the second-to-top item is greater than the top item, they are replaced 1792 // with a 1, otherwise a 0. 1793 // 1794 // Stack transformation: [... x1 x2] -> [... bool] 1795 func opcodeGreaterThan(op *parsedOpcode, vm *Engine) error { 1796 v0, err := vm.dstack.PopInt() 1797 if err != nil { 1798 return err 1799 } 1800 1801 v1, err := vm.dstack.PopInt() 1802 if err != nil { 1803 return err 1804 } 1805 1806 if v1 > v0 { 1807 vm.dstack.PushInt(scriptNum(1)) 1808 } else { 1809 vm.dstack.PushInt(scriptNum(0)) 1810 } 1811 return nil 1812 } 1813 1814 // opcodeLessThanOrEqual treats the top two items on the data stack as integers. 1815 // When the second-to-top item is less than or equal to the top item, they are 1816 // replaced with a 1, otherwise a 0. 1817 // 1818 // Stack transformation: [... x1 x2] -> [... bool] 1819 func opcodeLessThanOrEqual(op *parsedOpcode, vm *Engine) error { 1820 v0, err := vm.dstack.PopInt() 1821 if err != nil { 1822 return err 1823 } 1824 1825 v1, err := vm.dstack.PopInt() 1826 if err != nil { 1827 return err 1828 } 1829 1830 if v1 <= v0 { 1831 vm.dstack.PushInt(scriptNum(1)) 1832 } else { 1833 vm.dstack.PushInt(scriptNum(0)) 1834 } 1835 return nil 1836 } 1837 1838 // opcodeGreaterThanOrEqual treats the top two items on the data stack as 1839 // integers. When the second-to-top item is greater than or equal to the top 1840 // item, they are replaced with a 1, otherwise a 0. 1841 // 1842 // Stack transformation: [... x1 x2] -> [... bool] 1843 func opcodeGreaterThanOrEqual(op *parsedOpcode, vm *Engine) error { 1844 v0, err := vm.dstack.PopInt() 1845 if err != nil { 1846 return err 1847 } 1848 1849 v1, err := vm.dstack.PopInt() 1850 if err != nil { 1851 return err 1852 } 1853 1854 if v1 >= v0 { 1855 vm.dstack.PushInt(scriptNum(1)) 1856 } else { 1857 vm.dstack.PushInt(scriptNum(0)) 1858 } 1859 1860 return nil 1861 } 1862 1863 // opcodeMin treats the top two items on the data stack as integers and replaces 1864 // them with the minimum of the two. 1865 // 1866 // Stack transformation: [... x1 x2] -> [... min(x1, x2)] 1867 func opcodeMin(op *parsedOpcode, vm *Engine) error { 1868 v0, err := vm.dstack.PopInt() 1869 if err != nil { 1870 return err 1871 } 1872 1873 v1, err := vm.dstack.PopInt() 1874 if err != nil { 1875 return err 1876 } 1877 1878 if v1 < v0 { 1879 vm.dstack.PushInt(v1) 1880 } else { 1881 vm.dstack.PushInt(v0) 1882 } 1883 1884 return nil 1885 } 1886 1887 // opcodeMax treats the top two items on the data stack as integers and replaces 1888 // them with the maximum of the two. 1889 // 1890 // Stack transformation: [... x1 x2] -> [... max(x1, x2)] 1891 func opcodeMax(op *parsedOpcode, vm *Engine) error { 1892 v0, err := vm.dstack.PopInt() 1893 if err != nil { 1894 return err 1895 } 1896 1897 v1, err := vm.dstack.PopInt() 1898 if err != nil { 1899 return err 1900 } 1901 1902 if v1 > v0 { 1903 vm.dstack.PushInt(v1) 1904 } else { 1905 vm.dstack.PushInt(v0) 1906 } 1907 1908 return nil 1909 } 1910 1911 // opcodeWithin treats the top 3 items on the data stack as integers. When the 1912 // value to test is within the specified range (left inclusive), they are 1913 // replaced with a 1, otherwise a 0. 1914 // 1915 // The top item is the max value, the second-top-item is the minimum value, and 1916 // the third-to-top item is the value to test. 1917 // 1918 // Stack transformation: [... x1 min max] -> [... bool] 1919 func opcodeWithin(op *parsedOpcode, vm *Engine) error { 1920 maxVal, err := vm.dstack.PopInt() 1921 if err != nil { 1922 return err 1923 } 1924 1925 minVal, err := vm.dstack.PopInt() 1926 if err != nil { 1927 return err 1928 } 1929 1930 x, err := vm.dstack.PopInt() 1931 if err != nil { 1932 return err 1933 } 1934 1935 if x >= minVal && x < maxVal { 1936 vm.dstack.PushInt(scriptNum(1)) 1937 } else { 1938 vm.dstack.PushInt(scriptNum(0)) 1939 } 1940 return nil 1941 } 1942 1943 // calcHash calculates the hash of hasher over buf. 1944 func calcHash(buf []byte, hasher hash.Hash) []byte { 1945 hasher.Write(buf) 1946 return hasher.Sum(nil) 1947 } 1948 1949 // opcodeRipemd160 treats the top item of the data stack as raw bytes and 1950 // replaces it with ripemd160(data). 1951 // 1952 // Stack transformation: [... x1] -> [... ripemd160(x1)] 1953 func opcodeRipemd160(op *parsedOpcode, vm *Engine) error { 1954 buf, err := vm.dstack.PopByteArray() 1955 if err != nil { 1956 return err 1957 } 1958 1959 vm.dstack.PushByteArray(calcHash(buf, ripemd160.New())) 1960 return nil 1961 } 1962 1963 // opcodeSha1 treats the top item of the data stack as raw bytes and replaces it 1964 // with sha1(data). 1965 // 1966 // Stack transformation: [... x1] -> [... sha1(x1)] 1967 func opcodeSha1(op *parsedOpcode, vm *Engine) error { 1968 buf, err := vm.dstack.PopByteArray() 1969 if err != nil { 1970 return err 1971 } 1972 1973 hash := sha1.Sum(buf) 1974 vm.dstack.PushByteArray(hash[:]) 1975 return nil 1976 } 1977 1978 // opcodeSha256 treats the top item of the data stack as raw bytes and replaces 1979 // it with sha256(data). 1980 // 1981 // Stack transformation: [... x1] -> [... sha256(x1)] 1982 func opcodeSha256(op *parsedOpcode, vm *Engine) error { 1983 buf, err := vm.dstack.PopByteArray() 1984 if err != nil { 1985 return err 1986 } 1987 1988 hash := sha256.Sum256(buf) 1989 vm.dstack.PushByteArray(hash[:]) 1990 return nil 1991 } 1992 1993 // opcodeHash160 treats the top item of the data stack as raw bytes and replaces 1994 // it with ripemd160(sha256(data)). 1995 // 1996 // Stack transformation: [... x1] -> [... ripemd160(sha256(x1))] 1997 func opcodeHash160(op *parsedOpcode, vm *Engine) error { 1998 buf, err := vm.dstack.PopByteArray() 1999 if err != nil { 2000 return err 2001 } 2002 2003 hash := sha256.Sum256(buf) 2004 vm.dstack.PushByteArray(calcHash(hash[:], ripemd160.New())) 2005 return nil 2006 } 2007 2008 // opcodeHash256 treats the top item of the data stack as raw bytes and replaces 2009 // it with sha256(sha256(data)). 2010 // 2011 // Stack transformation: [... x1] -> [... sha256(sha256(x1))] 2012 func opcodeHash256(op *parsedOpcode, vm *Engine) error { 2013 buf, err := vm.dstack.PopByteArray() 2014 if err != nil { 2015 return err 2016 } 2017 2018 vm.dstack.PushByteArray(chainhash.DoubleHashB(buf)) 2019 return nil 2020 } 2021 2022 // opcodeCodeSeparator stores the current script offset as the most recently 2023 // seen OP_CODESEPARATOR which is used during signature checking. 2024 // 2025 // This opcode does not change the contents of the data stack. 2026 func opcodeCodeSeparator(op *parsedOpcode, vm *Engine) error { 2027 vm.lastCodeSep = vm.scriptOff 2028 return nil 2029 } 2030 2031 // opcodeCheckSig treats the top 2 items on the stack as a public key and a 2032 // signature and replaces them with a bool which indicates if the signature was 2033 // successfully verified. 2034 // 2035 // The process of verifying a signature requires calculating a signature hash in 2036 // the same way the transaction signer did. It involves hashing portions of the 2037 // transaction based on the hash type byte (which is the final byte of the 2038 // signature) and the portion of the script starting from the most recent 2039 // OP_CODESEPARATOR (or the beginning of the script if there are none) to the 2040 // end of the script (with any other OP_CODESEPARATORs removed). Once this 2041 // "script hash" is calculated, the signature is checked using standard 2042 // cryptographic methods against the provided public key. 2043 // 2044 // Stack transformation: [... signature pubkey] -> [... bool] 2045 func opcodeCheckSig(op *parsedOpcode, vm *Engine) error { 2046 pkBytes, err := vm.dstack.PopByteArray() 2047 if err != nil { 2048 return err 2049 } 2050 2051 fullSigBytes, err := vm.dstack.PopByteArray() 2052 if err != nil { 2053 return err 2054 } 2055 2056 // The signature actually needs needs to be longer than this, but at 2057 // least 1 byte is needed for the hash type below. The full length is 2058 // checked depending on the script flags and upon parsing the signature. 2059 if len(fullSigBytes) < 1 { 2060 vm.dstack.PushBool(false) 2061 return nil 2062 } 2063 2064 // Trim off hashtype from the signature string and check if the 2065 // signature and pubkey conform to the strict encoding requirements 2066 // depending on the flags. 2067 // 2068 // NOTE: When the strict encoding flags are set, any errors in the 2069 // signature or public encoding here result in an immediate script error 2070 // (and thus no result bool is pushed to the data stack). This differs 2071 // from the logic below where any errors in parsing the signature is 2072 // treated as the signature failure resulting in false being pushed to 2073 // the data stack. This is required because the more general script 2074 // validation consensus rules do not have the new strict encoding 2075 // requirements enabled by the flags. 2076 hashType := SigHashType(fullSigBytes[len(fullSigBytes)-1]) 2077 sigBytes := fullSigBytes[:len(fullSigBytes)-1] 2078 if err := vm.checkHashTypeEncoding(hashType); err != nil { 2079 return err 2080 } 2081 if err := vm.checkSignatureEncoding(sigBytes); err != nil { 2082 return err 2083 } 2084 if err := vm.checkPubKeyEncoding(pkBytes); err != nil { 2085 return err 2086 } 2087 2088 // Get script starting from the most recent OP_CODESEPARATOR. 2089 subScript := vm.subScript() 2090 2091 // Generate the signature hash based on the signature hash type. 2092 var hash []byte 2093 if vm.isWitnessVersionActive(0) { 2094 var sigHashes *TxSigHashes 2095 if vm.hashCache != nil { 2096 sigHashes = vm.hashCache 2097 } else { 2098 sigHashes = NewTxSigHashes(&vm.tx) 2099 } 2100 2101 hash, err = calcWitnessSignatureHash(subScript, sigHashes, hashType, 2102 &vm.tx, vm.txIdx, vm.inputAmount) 2103 if err != nil { 2104 return err 2105 } 2106 } else { 2107 // Remove the signature since there is no way for a signature 2108 // to sign itself. 2109 subScript = removeOpcodeByData(subScript, fullSigBytes) 2110 2111 hash = calcSignatureHash(subScript, hashType, &vm.tx, vm.txIdx) 2112 } 2113 2114 pubKey, err := btcec.ParsePubKey(pkBytes, btcec.S256()) 2115 if err != nil { 2116 vm.dstack.PushBool(false) 2117 return nil 2118 } 2119 2120 var signature *btcec.Signature 2121 if vm.hasFlag(ScriptVerifyStrictEncoding) || 2122 vm.hasFlag(ScriptVerifyDERSignatures) { 2123 2124 signature, err = btcec.ParseDERSignature(sigBytes, btcec.S256()) 2125 } else { 2126 signature, err = btcec.ParseSignature(sigBytes, btcec.S256()) 2127 } 2128 if err != nil { 2129 vm.dstack.PushBool(false) 2130 return nil 2131 } 2132 2133 var valid bool 2134 if vm.sigCache != nil { 2135 var sigHash chainhash.Hash 2136 copy(sigHash[:], hash) 2137 2138 valid = vm.sigCache.Exists(sigHash, signature, pubKey) 2139 if !valid && signature.Verify(hash, pubKey) { 2140 vm.sigCache.Add(sigHash, signature, pubKey) 2141 valid = true 2142 } 2143 } else { 2144 valid = signature.Verify(hash, pubKey) 2145 } 2146 2147 if !valid && vm.hasFlag(ScriptVerifyNullFail) && len(sigBytes) > 0 { 2148 str := "signature not empty on failed checksig" 2149 return scriptError(ErrNullFail, str) 2150 } 2151 2152 vm.dstack.PushBool(valid) 2153 return nil 2154 } 2155 2156 // opcodeCheckSigVerify is a combination of opcodeCheckSig and opcodeVerify. 2157 // The opcodeCheckSig function is invoked followed by opcodeVerify. See the 2158 // documentation for each of those opcodes for more details. 2159 // 2160 // Stack transformation: signature pubkey] -> [... bool] -> [...] 2161 func opcodeCheckSigVerify(op *parsedOpcode, vm *Engine) error { 2162 err := opcodeCheckSig(op, vm) 2163 if err == nil { 2164 err = abstractVerify(op, vm, ErrCheckSigVerify) 2165 } 2166 return err 2167 } 2168 2169 // parsedSigInfo houses a raw signature along with its parsed form and a flag 2170 // for whether or not it has already been parsed. It is used to prevent parsing 2171 // the same signature multiple times when verifying a multisig. 2172 type parsedSigInfo struct { 2173 signature []byte 2174 parsedSignature *btcec.Signature 2175 parsed bool 2176 } 2177 2178 // opcodeCheckMultiSig treats the top item on the stack as an integer number of 2179 // public keys, followed by that many entries as raw data representing the public 2180 // keys, followed by the integer number of signatures, followed by that many 2181 // entries as raw data representing the signatures. 2182 // 2183 // Due to a bug in the original Satoshi client implementation, an additional 2184 // dummy argument is also required by the consensus rules, although it is not 2185 // used. The dummy value SHOULD be an OP_0, although that is not required by 2186 // the consensus rules. When the ScriptStrictMultiSig flag is set, it must be 2187 // OP_0. 2188 // 2189 // All of the aforementioned stack items are replaced with a bool which 2190 // indicates if the requisite number of signatures were successfully verified. 2191 // 2192 // See the opcodeCheckSigVerify documentation for more details about the process 2193 // for verifying each signature. 2194 // 2195 // Stack transformation: 2196 // [... dummy [sig ...] numsigs [pubkey ...] numpubkeys] -> [... bool] 2197 func opcodeCheckMultiSig(op *parsedOpcode, vm *Engine) error { 2198 numKeys, err := vm.dstack.PopInt() 2199 if err != nil { 2200 return err 2201 } 2202 2203 numPubKeys := int(numKeys.Int32()) 2204 if numPubKeys < 0 { 2205 str := fmt.Sprintf("number of pubkeys %d is negative", 2206 numPubKeys) 2207 return scriptError(ErrInvalidPubKeyCount, str) 2208 } 2209 if numPubKeys > MaxPubKeysPerMultiSig { 2210 str := fmt.Sprintf("too many pubkeys: %d > %d", 2211 numPubKeys, MaxPubKeysPerMultiSig) 2212 return scriptError(ErrInvalidPubKeyCount, str) 2213 } 2214 vm.numOps += numPubKeys 2215 if vm.numOps > MaxOpsPerScript { 2216 str := fmt.Sprintf("exceeded max operation limit of %d", 2217 MaxOpsPerScript) 2218 return scriptError(ErrTooManyOperations, str) 2219 } 2220 2221 pubKeys := make([][]byte, 0, numPubKeys) 2222 for i := 0; i < numPubKeys; i++ { 2223 pubKey, err := vm.dstack.PopByteArray() 2224 if err != nil { 2225 return err 2226 } 2227 pubKeys = append(pubKeys, pubKey) 2228 } 2229 2230 numSigs, err := vm.dstack.PopInt() 2231 if err != nil { 2232 return err 2233 } 2234 numSignatures := int(numSigs.Int32()) 2235 if numSignatures < 0 { 2236 str := fmt.Sprintf("number of signatures %d is negative", 2237 numSignatures) 2238 return scriptError(ErrInvalidSignatureCount, str) 2239 2240 } 2241 if numSignatures > numPubKeys { 2242 str := fmt.Sprintf("more signatures than pubkeys: %d > %d", 2243 numSignatures, numPubKeys) 2244 return scriptError(ErrInvalidSignatureCount, str) 2245 } 2246 2247 signatures := make([]*parsedSigInfo, 0, numSignatures) 2248 for i := 0; i < numSignatures; i++ { 2249 signature, err := vm.dstack.PopByteArray() 2250 if err != nil { 2251 return err 2252 } 2253 sigInfo := &parsedSigInfo{signature: signature} 2254 signatures = append(signatures, sigInfo) 2255 } 2256 2257 // A bug in the original Satoshi client implementation means one more 2258 // stack value than should be used must be popped. Unfortunately, this 2259 // buggy behavior is now part of the consensus and a hard fork would be 2260 // required to fix it. 2261 dummy, err := vm.dstack.PopByteArray() 2262 if err != nil { 2263 return err 2264 } 2265 2266 // Since the dummy argument is otherwise not checked, it could be any 2267 // value which unfortunately provides a source of malleability. Thus, 2268 // there is a script flag to force an error when the value is NOT 0. 2269 if vm.hasFlag(ScriptStrictMultiSig) && len(dummy) != 0 { 2270 str := fmt.Sprintf("multisig dummy argument has length %d "+ 2271 "instead of 0", len(dummy)) 2272 return scriptError(ErrSigNullDummy, str) 2273 } 2274 2275 // Get script starting from the most recent OP_CODESEPARATOR. 2276 script := vm.subScript() 2277 2278 // Remove the signature in pre version 0 segwit scripts since there is 2279 // no way for a signature to sign itself. 2280 if !vm.isWitnessVersionActive(0) { 2281 for _, sigInfo := range signatures { 2282 script = removeOpcodeByData(script, sigInfo.signature) 2283 } 2284 } 2285 2286 success := true 2287 numPubKeys++ 2288 pubKeyIdx := -1 2289 signatureIdx := 0 2290 for numSignatures > 0 { 2291 // When there are more signatures than public keys remaining, 2292 // there is no way to succeed since too many signatures are 2293 // invalid, so exit early. 2294 pubKeyIdx++ 2295 numPubKeys-- 2296 if numSignatures > numPubKeys { 2297 success = false 2298 break 2299 } 2300 2301 sigInfo := signatures[signatureIdx] 2302 pubKey := pubKeys[pubKeyIdx] 2303 2304 // The order of the signature and public key evaluation is 2305 // important here since it can be distinguished by an 2306 // OP_CHECKMULTISIG NOT when the strict encoding flag is set. 2307 2308 rawSig := sigInfo.signature 2309 if len(rawSig) == 0 { 2310 // Skip to the next pubkey if signature is empty. 2311 continue 2312 } 2313 2314 // Split the signature into hash type and signature components. 2315 hashType := SigHashType(rawSig[len(rawSig)-1]) 2316 signature := rawSig[:len(rawSig)-1] 2317 2318 // Only parse and check the signature encoding once. 2319 var parsedSig *btcec.Signature 2320 if !sigInfo.parsed { 2321 if err := vm.checkHashTypeEncoding(hashType); err != nil { 2322 return err 2323 } 2324 if err := vm.checkSignatureEncoding(signature); err != nil { 2325 return err 2326 } 2327 2328 // Parse the signature. 2329 var err error 2330 if vm.hasFlag(ScriptVerifyStrictEncoding) || 2331 vm.hasFlag(ScriptVerifyDERSignatures) { 2332 2333 parsedSig, err = btcec.ParseDERSignature(signature, 2334 btcec.S256()) 2335 } else { 2336 parsedSig, err = btcec.ParseSignature(signature, 2337 btcec.S256()) 2338 } 2339 sigInfo.parsed = true 2340 if err != nil { 2341 continue 2342 } 2343 sigInfo.parsedSignature = parsedSig 2344 } else { 2345 // Skip to the next pubkey if the signature is invalid. 2346 if sigInfo.parsedSignature == nil { 2347 continue 2348 } 2349 2350 // Use the already parsed signature. 2351 parsedSig = sigInfo.parsedSignature 2352 } 2353 2354 if err := vm.checkPubKeyEncoding(pubKey); err != nil { 2355 return err 2356 } 2357 2358 // Parse the pubkey. 2359 parsedPubKey, err := btcec.ParsePubKey(pubKey, btcec.S256()) 2360 if err != nil { 2361 continue 2362 } 2363 2364 // Generate the signature hash based on the signature hash type. 2365 var hash []byte 2366 if vm.isWitnessVersionActive(0) { 2367 var sigHashes *TxSigHashes 2368 if vm.hashCache != nil { 2369 sigHashes = vm.hashCache 2370 } else { 2371 sigHashes = NewTxSigHashes(&vm.tx) 2372 } 2373 2374 hash, err = calcWitnessSignatureHash(script, sigHashes, hashType, 2375 &vm.tx, vm.txIdx, vm.inputAmount) 2376 if err != nil { 2377 return err 2378 } 2379 } else { 2380 hash = calcSignatureHash(script, hashType, &vm.tx, vm.txIdx) 2381 } 2382 2383 var valid bool 2384 if vm.sigCache != nil { 2385 var sigHash chainhash.Hash 2386 copy(sigHash[:], hash) 2387 2388 valid = vm.sigCache.Exists(sigHash, parsedSig, parsedPubKey) 2389 if !valid && parsedSig.Verify(hash, parsedPubKey) { 2390 vm.sigCache.Add(sigHash, parsedSig, parsedPubKey) 2391 valid = true 2392 } 2393 } else { 2394 valid = parsedSig.Verify(hash, parsedPubKey) 2395 } 2396 2397 if valid { 2398 // PubKey verified, move on to the next signature. 2399 signatureIdx++ 2400 numSignatures-- 2401 } 2402 } 2403 2404 if !success && vm.hasFlag(ScriptVerifyNullFail) { 2405 for _, sig := range signatures { 2406 if len(sig.signature) > 0 { 2407 str := "not all signatures empty on failed checkmultisig" 2408 return scriptError(ErrNullFail, str) 2409 } 2410 } 2411 } 2412 2413 vm.dstack.PushBool(success) 2414 return nil 2415 } 2416 2417 // opcodeCheckMultiSigVerify is a combination of opcodeCheckMultiSig and 2418 // opcodeVerify. The opcodeCheckMultiSig is invoked followed by opcodeVerify. 2419 // See the documentation for each of those opcodes for more details. 2420 // 2421 // Stack transformation: 2422 // [... dummy [sig ...] numsigs [pubkey ...] numpubkeys] -> [... bool] -> [...] 2423 func opcodeCheckMultiSigVerify(op *parsedOpcode, vm *Engine) error { 2424 err := opcodeCheckMultiSig(op, vm) 2425 if err == nil { 2426 err = abstractVerify(op, vm, ErrCheckMultiSigVerify) 2427 } 2428 return err 2429 } 2430 2431 // OpcodeByName is a map that can be used to lookup an opcode by its 2432 // human-readable name (OP_CHECKMULTISIG, OP_CHECKSIG, etc). 2433 var OpcodeByName = make(map[string]byte) 2434 2435 func init() { 2436 // Initialize the opcode name to value map using the contents of the 2437 // opcode array. Also add entries for "OP_FALSE", "OP_TRUE", and 2438 // "OP_NOP2" since they are aliases for "OP_0", "OP_1", 2439 // and "OP_CHECKLOCKTIMEVERIFY" respectively. 2440 for _, op := range opcodeArray { 2441 OpcodeByName[op.name] = op.value 2442 } 2443 OpcodeByName["OP_FALSE"] = OP_FALSE 2444 OpcodeByName["OP_TRUE"] = OP_TRUE 2445 OpcodeByName["OP_NOP2"] = OP_CHECKLOCKTIMEVERIFY 2446 OpcodeByName["OP_NOP3"] = OP_CHECKSEQUENCEVERIFY 2447 }