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-rw-r--r--src/script/interpreter.cpp89
1 files changed, 82 insertions, 7 deletions
diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp
index 901f901f01..4e87006f57 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)
@@ -1120,27 +1157,33 @@ bool TransactionSignatureChecker::CheckSig(const vector<unsigned char>& vchSigIn
return true;
}
-bool TransactionSignatureChecker::CheckLockTime(const CScriptNum& nLockTime) const
+static bool VerifyLockTime(int64_t txToLockTime, int64_t nThreshold, const CScriptNum& nLockTime)
{
// There are two kinds of nLockTime: lock-by-blockheight
// and lock-by-blocktime, distinguished by whether
- // nLockTime < LOCKTIME_THRESHOLD.
+ // nLockTime < nThreshold (either LOCKTIME_THRESHOLD or
+ // CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG).
//
// 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)
+ (txToLockTime < nThreshold && nLockTime < nThreshold) ||
+ (txToLockTime >= nThreshold && nLockTime >= nThreshold)
))
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)
+ if (nLockTime > txToLockTime)
return false;
- // Finally the nLockTime feature can be disabled and thus
+ return true;
+}
+
+bool TransactionSignatureChecker::CheckLockTime(const CScriptNum& nLockTime) const
+{
+ // 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
@@ -1153,6 +1196,38 @@ bool TransactionSignatureChecker::CheckLockTime(const CScriptNum& nLockTime) con
if (CTxIn::SEQUENCE_FINAL == txTo->vin[nIn].nSequence)
return false;
+ if (!::VerifyLockTime((int64_t)txTo->nLockTime, LOCKTIME_THRESHOLD, nLockTime))
+ 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 of ::VerifyLockTime.
+ const uint32_t nLockTimeMask = CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG
+ | CTxIn::SEQUENCE_LOCKTIME_MASK;
+
+ if (!::VerifyLockTime(txToSequence & nLockTimeMask, CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG, nSequence & nLockTimeMask))
+ return false;
+
return true;
}