diff options
Diffstat (limited to 'src/script/interpreter.cpp')
| -rw-r--r-- | src/script/interpreter.cpp | 86 |
1 files changed, 84 insertions, 2 deletions
diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp index 265131ae0d..149a4f0156 100644 --- a/src/script/interpreter.cpp +++ b/src/script/interpreter.cpp @@ -373,7 +373,44 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un break; } - case OP_NOP1: case OP_NOP3: case OP_NOP4: case OP_NOP5: + case OP_CHECKSEQUENCEVERIFY: + { + if (!(flags & SCRIPT_VERIFY_CHECKSEQUENCEVERIFY)) { + // not enabled; treat as a NOP3 + 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); + + // nSequence, like nLockTime, is a 32-bit unsigned integer + // field. See the comment in CHECKLOCKTIMEVERIFY regarding + // 5-byte numeric operands. + const CScriptNum nSequence(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 CHECKSEQUENCEVERIFY. + if (nSequence < 0) + return set_error(serror, SCRIPT_ERR_NEGATIVE_LOCKTIME); + + // To provide for future soft-fork extensibility, if the + // operand has the disabled lock-time flag set, + // CHECKSEQUENCEVERIFY behaves as a NOP. + if ((nSequence & CTxIn::SEQUENCE_LOCKTIME_DISABLE_FLAG) != 0) + break; + + // Compare the specified sequence number with the input. + if (!checker.CheckSequence(nSequence)) + return set_error(serror, SCRIPT_ERR_UNSATISFIED_LOCKTIME); + + break; + } + + case OP_NOP1: 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) @@ -1150,12 +1187,57 @@ bool TransactionSignatureChecker::CheckLockTime(const CScriptNum& nLockTime) con // 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()) + if (CTxIn::SEQUENCE_FINAL == txTo->vin[nIn].nSequence) return false; return true; } +bool TransactionSignatureChecker::CheckSequence(const CScriptNum& nSequence) const +{ + // Relative lock times are supported by comparing the passed + // in operand to the sequence number of the input. + const int64_t txToSequence = (int64_t)txTo->vin[nIn].nSequence; + + // Fail if the transaction's version number is not set high + // enough to trigger BIP 68 rules. + if (static_cast<uint32_t>(txTo->nVersion) < 2) + return false; + + // Sequence numbers with their most significant bit set are not + // consensus constrained. Testing that the transaction's sequence + // number do not have this bit set prevents using this property + // to get around a CHECKSEQUENCEVERIFY check. + if (txToSequence & CTxIn::SEQUENCE_LOCKTIME_DISABLE_FLAG) + return false; + + // Mask off any bits that do not have consensus-enforced meaning + // before doing the integer comparisons + const uint32_t nLockTimeMask = CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG | CTxIn::SEQUENCE_LOCKTIME_MASK; + const int64_t txToSequenceMasked = txToSequence & nLockTimeMask; + const CScriptNum nSequenceMasked = nSequence & nLockTimeMask; + + // There are two kinds of nSequence: lock-by-blockheight + // and lock-by-blocktime, distinguished by whether + // nSequenceMasked < CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG. + // + // We want to compare apples to apples, so fail the script + // unless the type of nSequenceMasked being tested is the same as + // the nSequenceMasked in the transaction. + if (!( + (txToSequenceMasked < CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG && nSequenceMasked < CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG) || + (txToSequenceMasked >= CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG && nSequenceMasked >= CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG) + )) { + return false; + } + + // Now that we know we're comparing apples-to-apples, the + // comparison is a simple numeric one. + if (nSequenceMasked > txToSequenceMasked) + return false; + + return true; +} bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, unsigned int flags, const BaseSignatureChecker& checker, ScriptError* serror) { |