Add CHECKLOCKTIMEVERIFY support using Viacoin https://github.com/viac…

…oin/viacoin/pull/23/files#diff-b81dfdd8a5bd80fe9f82b5a40c4c991eR89 Conflicts: src/script/interpreter.cpp src/script/standard.h
supcoin · Feb 6, 2015 · 81e19c1 · 81e19c1
1 parent 2b856a3
commit 81e19c1
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Showing 11 changed files with 239 additions and 21 deletions.
diff --git a/src/main.h b/src/main.h
@@ -72,8 +72,6 @@ static const unsigned int BLOCKFILE_CHUNK_SIZE = 0x1000000; // 16 MiB
 static const unsigned int UNDOFILE_CHUNK_SIZE = 0x100000; // 1 MiB
 /** Coinbase transaction outputs can only be spent after this number of new blocks (network rule) */
 static const int COINBASE_MATURITY = 100;
-/** Threshold for nLockTime: below this value it is interpreted as block number, otherwise as UNIX timestamp. */
-static const unsigned int LOCKTIME_THRESHOLD = 500000000; // Tue Nov  5 00:53:20 1985 UTC
 /** Maximum number of script-checking threads allowed */
 static const int MAX_SCRIPTCHECK_THREADS = 16;
 /** -par default (number of script-checking threads, 0 = auto) */

diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp
@@ -337,7 +337,48 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un
                 case OP_NOP:
                 break;
 
-                case OP_NOP1: case OP_NOP2: case OP_NOP3: case OP_NOP4: case OP_NOP5:
+                case OP_CHECKLOCKTIMEVERIFY:
+                {
+                    if (!(flags & SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY)) {
+                        // not enabled; treat as a NOP2 (note: should always be enabled)
+                        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**32-1, the
+                    // same limit as 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_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)
@@ -1057,6 +1098,42 @@ uint256 SignatureHash(const CScript& scriptCode, const CTransaction& txTo, unsig
     return ss.GetHash();
 }
 
+bool SignatureChecker::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 TransactionSignatureChecker::VerifySignature(const std::vector<unsigned char>& vchSig, const CPubKey& pubkey, const uint256& sighash) const
 {
     return pubkey.Verify(sighash, vchSig);

diff --git a/src/script/interpreter.h b/src/script/interpreter.h
@@ -12,6 +12,7 @@
 #include <vector>
 #include <stdint.h>
 #include <string>
+#include "script.h"
 
 class CPubKey;
 class CScript;
@@ -68,7 +69,11 @@ enum
     // discouraged NOPs fails the script. This verification flag will never be
     // a mandatory flag applied to scripts in a block. NOPs that are not
     // executed, e.g.  within an unexecuted IF ENDIF block, are *not* rejected.
-    SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS  = (1U << 7)
+    SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS  = (1U << 7),
+    // Verify CHECKLOCKTIMEVERIFY (BIP65)
+    //
+    SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY = (1U << 8)
+
 
 };
 
@@ -81,7 +86,10 @@ class BaseSignatureChecker
     {
         return false;
     }
-
+    virtual bool CheckLockTime(const CScriptNum& nLockTime) const
+    {
+         return false;
+    }
     virtual ~BaseSignatureChecker() {}
 };
 
@@ -97,6 +105,7 @@ class TransactionSignatureChecker : public BaseSignatureChecker
 public:
     TransactionSignatureChecker(const CTransaction* txToIn, unsigned int nInIn) : txTo(txToIn), nIn(nInIn) {}
     bool CheckSig(const std::vector<unsigned char>& scriptSig, const std::vector<unsigned char>& vchPubKey, const CScript& scriptCode) const;
+    bool CheckLockTime(const CScriptNum& nLockTime) const;
 };
 
 class MutableTransactionSignatureChecker : public TransactionSignatureChecker

diff --git a/src/script/script.h b/src/script/script.h
@@ -15,6 +15,9 @@
 #include <string>
 #include <vector>
 
+// Threshold for nLockTime: below this value it is interpreted as block number,
+// otherwise as UNIX timestamp.
+static const unsigned int LOCKTIME_THRESHOLD = 500000000; // Tue Nov  5 00:53:20 1985 UTC
 static const unsigned int MAX_SCRIPT_ELEMENT_SIZE = 520; // bytes
 
 template <typename T>
@@ -149,6 +152,7 @@ enum opcodetype
     // expansion
     OP_NOP1 = 0xb0,
     OP_NOP2 = 0xb1,
+    OP_CHECKLOCKTIMEVERIFY = OP_NOP2,
     OP_NOP3 = 0xb2,
     OP_NOP4 = 0xb3,
     OP_NOP5 = 0xb4,
@@ -193,8 +197,9 @@ class CScriptNum
     {
         m_value = n;
     }
-
-    explicit CScriptNum(const std::vector<unsigned char>& vch, bool fRequireMinimal)
+    static const size_t nDefaultMaxNumSize = 4;
+    explicit CScriptNum(const std::vector<unsigned char>& vch, bool fRequireMinimal,
+                        const size_t nMaxNumSize = nDefaultMaxNumSize)
     {
         if (vch.size() > nMaxNumSize) {
             throw scriptnum_error("script number overflow");
@@ -317,7 +322,6 @@ class CScriptNum
         return result;
     }
 
-    static const size_t nMaxNumSize = 4;
 
 private:
     static int64_t set_vch(const std::vector<unsigned char>& vch)

diff --git a/src/script/script_error.cpp b/src/script/script_error.cpp
@@ -47,6 +47,10 @@ const char* ScriptErrorString(const ScriptError serror)
             return "OP_RETURN was encountered";
         case SCRIPT_ERR_UNBALANCED_CONDITIONAL:
             return "Invalid OP_IF construction";
+        case SCRIPT_ERR_NEGATIVE_LOCKTIME:
+            return "Negative locktime";
+        case SCRIPT_ERR_UNSATISFIED_LOCKTIME:
+            return "Locktime requirement not satisfied";
         case SCRIPT_ERR_SIG_HASHTYPE:
             return "Signature hash type missing or not understood";
         case SCRIPT_ERR_SIG_DER:

diff --git a/src/script/script_error.h b/src/script/script_error.h
@@ -35,6 +35,9 @@ typedef enum ScriptError_t
     SCRIPT_ERR_INVALID_ALTSTACK_OPERATION,
     SCRIPT_ERR_UNBALANCED_CONDITIONAL,
 
+    /* OP_CHECKLOCKTIMEVERIFY */
+    SCRIPT_ERR_NEGATIVE_LOCKTIME,
+    SCRIPT_ERR_UNSATISFIED_LOCKTIME,
     /* BIP62 */
     SCRIPT_ERR_SIG_HASHTYPE,
     SCRIPT_ERR_SIG_DER,

diff --git a/src/script/standard.h b/src/script/standard.h
@@ -37,19 +37,25 @@ extern unsigned nMaxDatacarrierBytes;
  * Failing one of these tests may trigger a DoS ban - see CheckInputs() for
  * details.
  */
-static const unsigned int MANDATORY_SCRIPT_VERIFY_FLAGS = SCRIPT_VERIFY_P2SH;
 
-/**
- * Standard script verification flags that standard transactions will comply
- * with. However scripts violating these flags may still be present in valid
- * blocks and we must accept those blocks.
- */
-static const unsigned int STANDARD_SCRIPT_VERIFY_FLAGS = MANDATORY_SCRIPT_VERIFY_FLAGS |
+static const unsigned int MANDATORY_SCRIPT_VERIFY_FLAGS = SCRIPT_VERIFY_P2SH |
+                                                          SCRIPT_VERIFY_STRICTENC |
+                                                          SCRIPT_VERIFY_DERSIG |
+                                                          SCRIPT_VERIFY_LOW_S |
+                                                          SCRIPT_VERIFY_NULLDUMMY |
+                                                          SCRIPT_VERIFY_SIGPUSHONLY | 
+                                                          SCRIPT_VERIFY_MINIMALDATA |
+                                                          SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS |
+                                                          SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY;
+
+
+ /**
+  * Standard script verification flags that standard transactions will comply
+  * with. However scripts violating these flags may still be present in valid
+  * blocks and we must accept those blocks.
+  */
+static const unsigned int STANDARD_SCRIPT_VERIFY_FLAGS = MANDATORY_SCRIPT_VERIFY_FLAGS;
                                                          SCRIPT_VERIFY_DERSIG |
-                                                         SCRIPT_VERIFY_STRICTENC |
-                                                         SCRIPT_VERIFY_MINIMALDATA |
-                                                         SCRIPT_VERIFY_NULLDUMMY |
-                                                         SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS;
 
 /** For convenience, standard but not mandatory verify flags. */
 static const unsigned int STANDARD_NOT_MANDATORY_VERIFY_FLAGS = STANDARD_SCRIPT_VERIFY_FLAGS & ~MANDATORY_SCRIPT_VERIFY_FLAGS;

diff --git a/src/test/data/tx_invalid.json b/src/test/data/tx_invalid.json
@@ -103,5 +103,71 @@
 [[["ad503f72c18df5801ee64d76090afe4c607fb2b822e9b7b63c5826c50e22fc3b", 0, "0x21 0x027c3a97665bf283a102a587a62a30a0c102d4d3b141015e2cae6f64e2543113e5 CHECKSIG NOT"]],
 "01000000013bfc220ec526583cb6b7e922b8b27f604cfe0a09764de61e80f58dc1723f50ad0000000000ffffffff0101000000000000002321027c3a97665bf283a102a587a62a30a0c102d4d3b141015e2cae6f64e2543113e5ac00000000", "P2SH"],
 
+["CHECKLOCKTIMEVERIFY tests"],
+
+["By-height locks, with argument just beyond tx nLockTime"],
+[[["0000000000000000000000000000000000000000000000000000000000000100", 0, "1 NOP2 1"]],
+"010000000100010000000000000000000000000000000000000000000000000000000000000000000000000000000100000000000000000000000000", "P2SH,CHECKLOCKTIMEVERIFY"],
+[[["0000000000000000000000000000000000000000000000000000000000000100", 0, "499999999 NOP2 1"]],
+"0100000001000100000000000000000000000000000000000000000000000000000000000000000000000000000001000000000000000000fe64cd1d", "P2SH,CHECKLOCKTIMEVERIFY"],
+
+["By-time locks, with argument just beyond tx nLockTime (but within numerical boundries)"],
+[[["0000000000000000000000000000000000000000000000000000000000000100", 0, "500000001 NOP2 1"]],
+"01000000010001000000000000000000000000000000000000000000000000000000000000000000000000000000010000000000000000000065cd1d", "P2SH,CHECKLOCKTIMEVERIFY"],
+[[["0000000000000000000000000000000000000000000000000000000000000100", 0, "4294967295 NOP2 1"]],
+"0100000001000100000000000000000000000000000000000000000000000000000000000000000000000000000001000000000000000000feffffff", "P2SH,CHECKLOCKTIMEVERIFY"],
+
+["Argument missing"],
+[[["0000000000000000000000000000000000000000000000000000000000000100", 0, "NOP2 1"]],
+"010000000100010000000000000000000000000000000000000000000000000000000000000000000000000000000100000000000000000000000000", "P2SH,CHECKLOCKTIMEVERIFY"],
+
+["Argument negative with by-blockheight nLockTime=0"],
+[[["0000000000000000000000000000000000000000000000000000000000000100", 0, "-1 NOP2 1"]],
+"010000000100010000000000000000000000000000000000000000000000000000000000000000000000000000000100000000000000000000000000", "P2SH,CHECKLOCKTIMEVERIFY"],
+
+["Argument negative with by-blocktime nLockTime=500,000,000"],
+[[["0000000000000000000000000000000000000000000000000000000000000100", 0, "-1 NOP2 1"]],
+"01000000010001000000000000000000000000000000000000000000000000000000000000000000000000000000010000000000000000000065cd1d", "P2SH,CHECKLOCKTIMEVERIFY"],
+
+["Input locked"],
+[[["0000000000000000000000000000000000000000000000000000000000000100", 0, "0 NOP2 1"]],
+"010000000100010000000000000000000000000000000000000000000000000000000000000000000000ffffffff0100000000000000000000000000", "P2SH,CHECKLOCKTIMEVERIFY"],
+
+["Another input being unlocked isn't sufficient; the CHECKLOCKTIMEVERIFY-using input must be unlocked"],
+[[["0000000000000000000000000000000000000000000000000000000000000100", 0, "0 NOP2 1"] ,
+  ["0000000000000000000000000000000000000000000000000000000000000200", 1, "1"]],
+"010000000200010000000000000000000000000000000000000000000000000000000000000000000000ffffffff00020000000000000000000000000000000000000000000000000000000000000100000000000000000100000000000000000000000000", "P2SH,CHECKLOCKTIMEVERIFY"],
+
+["Argument/tx height/time mismatch, both versions"],
+[[["0000000000000000000000000000000000000000000000000000000000000100", 0, "0 NOP2 1"]],
+"01000000010001000000000000000000000000000000000000000000000000000000000000000000000000000000010000000000000000000065cd1d", "P2SH,CHECKLOCKTIMEVERIFY"],
+[[["0000000000000000000000000000000000000000000000000000000000000100", 0, "499999999 NOP2 1"]],
+"01000000010001000000000000000000000000000000000000000000000000000000000000000000000000000000010000000000000000000065cd1d", "P2SH,CHECKLOCKTIMEVERIFY"],
+[[["0000000000000000000000000000000000000000000000000000000000000100", 0, "500000000 NOP2 1"]],
+"010000000100010000000000000000000000000000000000000000000000000000000000000000000000000000000100000000000000000000000000", "P2SH,CHECKLOCKTIMEVERIFY"],
+[[["0000000000000000000000000000000000000000000000000000000000000100", 0, "500000000 NOP2 1"]],
+"0100000001000100000000000000000000000000000000000000000000000000000000000000000000000000000001000000000000000000ff64cd1d", "P2SH,CHECKLOCKTIMEVERIFY"],
+
+["Argument 2^32 with nLockTime=2^32-1"],
+[[["0000000000000000000000000000000000000000000000000000000000000100", 0, "4294967296 NOP2 1"]],
+"0100000001000100000000000000000000000000000000000000000000000000000000000000000000000000000001000000000000000000ffffffff", "P2SH,CHECKLOCKTIMEVERIFY"],
+
+["Same, but with nLockTime=2^31-1"],
+[[["0000000000000000000000000000000000000000000000000000000000000100", 0, "2147483648 NOP2 1"]],
+"0100000001000100000000000000000000000000000000000000000000000000000000000000000000000000000001000000000000000000ffffff7f", "P2SH,CHECKLOCKTIMEVERIFY"],
+
+["6 byte non-minimally-encoded arguments are invalid even in their contents are valid"],
+[[["0000000000000000000000000000000000000000000000000000000000000100", 0, "0x06 0x000000000000 NOP2 1"]],
+"010000000100010000000000000000000000000000000000000000000000000000000000000000000000000000000100000000000000000000000000", "P2SH,CHECKLOCKTIMEVERIFY"],
+
+["Failure due to failing CHECKLOCKTIMEVERIFY in scriptSig"],
+[[["0000000000000000000000000000000000000000000000000000000000000100", 0, "1"]],
+"01000000010001000000000000000000000000000000000000000000000000000000000000000000000251b1000000000100000000000000000000000000", "P2SH,CHECKLOCKTIMEVERIFY"],
+
+["Failure due to failing CHECKLOCKTIMEVERIFY in redeemScript"],
+[[["0000000000000000000000000000000000000000000000000000000000000100", 0, "HASH160 0x14 0xc5b93064159b3b2d6ab506a41b1f50463771b988 EQUAL"]],
+"0100000001000100000000000000000000000000000000000000000000000000000000000000000000030251b1000000000100000000000000000000000000", "P2SH,CHECKLOCKTIMEVERIFY"],
+
+
 ["Make diffs cleaner by leaving a comment here without comma at the end"]
 ]