diff options
Diffstat (limited to 'src/script/interpreter.cpp')
| -rw-r--r-- | src/script/interpreter.cpp | 83 |
1 files changed, 81 insertions, 2 deletions
diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp index 84a7432fdb..0b78fdf5a8 100644 --- a/src/script/interpreter.cpp +++ b/src/script/interpreter.cpp @@ -335,9 +335,51 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un // Control // case OP_NOP: - break; + break; + + case OP_CHECKLOCKTIMEVERIFY: + { + if (!(flags & SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY)) { + // not enabled; treat as a NOP2 + if (flags & SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS) { + return set_error(serror, SCRIPT_ERR_DISCOURAGE_UPGRADABLE_NOPS); + } + break; + } + + if (stack.size() < 1) + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); + + // Note that elsewhere numeric opcodes are limited to + // operands in the range -2**31+1 to 2**31-1, however it is + // legal for opcodes to produce results exceeding that + // range. This limitation is implemented by CScriptNum's + // default 4-byte limit. + // + // If we kept to that limit we'd have a year 2038 problem, + // even though the nLockTime field in transactions + // themselves is uint32 which only becomes meaningless + // after the year 2106. + // + // Thus as a special case we tell CScriptNum to accept up + // to 5-byte bignums, which are good until 2**39-1, well + // beyond the 2**32-1 limit of the nLockTime field itself. + const CScriptNum nLockTime(stacktop(-1), fRequireMinimal, 5); + + // In the rare event that the argument may be < 0 due to + // some arithmetic being done first, you can always use + // 0 MAX CHECKLOCKTIMEVERIFY. + if (nLockTime < 0) + return set_error(serror, SCRIPT_ERR_NEGATIVE_LOCKTIME); + + // Actually compare the specified lock time with the transaction. + if (!checker.CheckLockTime(nLockTime)) + return set_error(serror, SCRIPT_ERR_UNSATISFIED_LOCKTIME); + + break; + } - case OP_NOP1: case OP_NOP2: case OP_NOP3: case OP_NOP4: case OP_NOP5: + case OP_NOP1: case OP_NOP3: case OP_NOP4: case OP_NOP5: case OP_NOP6: case OP_NOP7: case OP_NOP8: case OP_NOP9: case OP_NOP10: { if (flags & SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS) @@ -1084,6 +1126,43 @@ bool TransactionSignatureChecker::CheckSig(const vector<unsigned char>& vchSigIn return true; } +bool TransactionSignatureChecker::CheckLockTime(const CScriptNum& nLockTime) const +{ + // There are two times of nLockTime: lock-by-blockheight + // and lock-by-blocktime, distinguished by whether + // nLockTime < LOCKTIME_THRESHOLD. + // + // We want to compare apples to apples, so fail the script + // unless the type of nLockTime being tested is the same as + // the nLockTime in the transaction. + if (!( + (txTo->nLockTime < LOCKTIME_THRESHOLD && nLockTime < LOCKTIME_THRESHOLD) || + (txTo->nLockTime >= LOCKTIME_THRESHOLD && nLockTime >= LOCKTIME_THRESHOLD) + )) + return false; + + // Now that we know we're comparing apples-to-apples, the + // comparison is a simple numeric one. + if (nLockTime > (int64_t)txTo->nLockTime) + return false; + + // Finally the nLockTime feature can be disabled and thus + // CHECKLOCKTIMEVERIFY bypassed if every txin has been + // finalized by setting nSequence to maxint. The + // transaction would be allowed into the blockchain, making + // the opcode ineffective. + // + // Testing if this vin is not final is sufficient to + // prevent this condition. Alternatively we could test all + // inputs, but testing just this input minimizes the data + // required to prove correct CHECKLOCKTIMEVERIFY execution. + if (txTo->vin[nIn].IsFinal()) + return false; + + return true; +} + + bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, unsigned int flags, const BaseSignatureChecker& checker, ScriptError* serror) { set_error(serror, SCRIPT_ERR_UNKNOWN_ERROR); |