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Accept any sequence of PUSHDATAs in OP_RETURN outputs

Previously only one PUSHDATA was allowed, needlessly limiting
applications such as matching OP_RETURN contents with bloom filters that
operate on a per-PUSHDATA level. Now any combination that passes
IsPushOnly() is allowed, so long as the total size of the scriptPubKey
is less than 42 bytes. (unchanged modulo non-minimal PUSHDATA encodings)

Also, this fixes the odd bug where previously the PUSHDATA could be
replaced by any single opcode, even sigops consuming opcodes such as
CHECKMULTISIG. (20 sigops!)
tags/v0.15.1
Peter Todd 7 years ago
parent
commit
da894ab5da

+ 3
- 1
src/policy/policy.cpp View File

@@ -49,7 +49,9 @@ bool IsStandard(const CScript& scriptPubKey, txnouttype& whichType)
return false;
if (m < 1 || m > n)
return false;
}
} else if (whichType == TX_NULL_DATA &&
(!GetBoolArg("-datacarrier", true) || scriptPubKey.size() > nMaxDatacarrierBytes))
return false;

return whichType != TX_NONSTANDARD;
}

+ 1
- 1
src/script/script.cpp View File

@@ -144,7 +144,7 @@ const char* GetOpName(opcodetype opcode)
case OP_INVALIDOPCODE : return "OP_INVALIDOPCODE";

// Note:
// The template matching params OP_SMALLDATA/etc are defined in opcodetype enum
// The template matching params OP_SMALLINTEGER/etc are defined in opcodetype enum
// as kind of implementation hack, they are *NOT* real opcodes. If found in real
// Script, just let the default: case deal with them.


+ 0
- 1
src/script/script.h View File

@@ -167,7 +167,6 @@ enum opcodetype


// template matching params
OP_SMALLDATA = 0xf9,
OP_SMALLINTEGER = 0xfa,
OP_PUBKEYS = 0xfb,
OP_PUBKEYHASH = 0xfd,

+ 10
- 11
src/script/standard.cpp View File

@@ -51,11 +51,6 @@ bool Solver(const CScript& scriptPubKey, txnouttype& typeRet, vector<vector<unsi

// Sender provides N pubkeys, receivers provides M signatures
mTemplates.insert(make_pair(TX_MULTISIG, CScript() << OP_SMALLINTEGER << OP_PUBKEYS << OP_SMALLINTEGER << OP_CHECKMULTISIG));

// Empty, provably prunable, data-carrying output
if (GetBoolArg("-datacarrier", true))
mTemplates.insert(make_pair(TX_NULL_DATA, CScript() << OP_RETURN << OP_SMALLDATA));
mTemplates.insert(make_pair(TX_NULL_DATA, CScript() << OP_RETURN));
}

vSolutionsRet.clear();
@@ -70,6 +65,16 @@ bool Solver(const CScript& scriptPubKey, txnouttype& typeRet, vector<vector<unsi
return true;
}

// Provably prunable, data-carrying output
//
// So long as script passes the IsUnspendable() test and all but the first
// byte passes the IsPushOnly() test we don't care what exactly is in the
// script.
if (scriptPubKey.size() >= 1 && scriptPubKey[0] == OP_RETURN && scriptPubKey.IsPushOnly(scriptPubKey.begin()+1)) {
typeRet = TX_NULL_DATA;
return true;
}

// Scan templates
const CScript& script1 = scriptPubKey;
BOOST_FOREACH(const PAIRTYPE(txnouttype, CScript)& tplate, mTemplates)
@@ -142,12 +147,6 @@ bool Solver(const CScript& scriptPubKey, txnouttype& typeRet, vector<vector<unsi
else
break;
}
else if (opcode2 == OP_SMALLDATA)
{
// small pushdata, <= nMaxDatacarrierBytes
if (vch1.size() > nMaxDatacarrierBytes)
break;
}
else if (opcode1 != opcode2 || vch1 != vch2)
{
// Others must match exactly

+ 1
- 1
src/script/standard.h View File

@@ -25,7 +25,7 @@ public:
CScriptID(const uint160& in) : uint160(in) {}
};

static const unsigned int MAX_OP_RETURN_RELAY = 80; //! bytes
static const unsigned int MAX_OP_RETURN_RELAY = 83; //! bytes (+1 for OP_RETURN, +2 for the pushdata opcodes)
extern unsigned nMaxDatacarrierBytes;

/**

+ 19
- 2
src/test/transaction_tests.cpp View File

@@ -351,12 +351,29 @@ BOOST_AUTO_TEST_CASE(test_IsStandard)
t.vout[0].scriptPubKey = CScript() << OP_1;
BOOST_CHECK(!IsStandardTx(t, reason));

// 80-byte TX_NULL_DATA (standard)
// MAX_OP_RETURN_RELAY-byte TX_NULL_DATA (standard)
t.vout[0].scriptPubKey = CScript() << OP_RETURN << ParseHex("04678afdb0fe5548271967f1a67130b7105cd6a828e03909a67962e0ea1f61deb649f6bc3f4cef3804678afdb0fe5548271967f1a67130b7105cd6a828e03909a67962e0ea1f61deb649f6bc3f4cef38");
BOOST_CHECK_EQUAL(MAX_OP_RETURN_RELAY, t.vout[0].scriptPubKey.size());
BOOST_CHECK(IsStandardTx(t, reason));

// 81-byte TX_NULL_DATA (non-standard)
// MAX_OP_RETURN_RELAY+1-byte TX_NULL_DATA (non-standard)
t.vout[0].scriptPubKey = CScript() << OP_RETURN << ParseHex("04678afdb0fe5548271967f1a67130b7105cd6a828e03909a67962e0ea1f61deb649f6bc3f4cef3804678afdb0fe5548271967f1a67130b7105cd6a828e03909a67962e0ea1f61deb649f6bc3f4cef3800");
BOOST_CHECK_EQUAL(MAX_OP_RETURN_RELAY + 1, t.vout[0].scriptPubKey.size());
BOOST_CHECK(!IsStandardTx(t, reason));

// Data payload can be encoded in any way...
t.vout[0].scriptPubKey = CScript() << OP_RETURN << ParseHex("");
BOOST_CHECK(IsStandardTx(t, reason));
t.vout[0].scriptPubKey = CScript() << OP_RETURN << ParseHex("00") << ParseHex("01");
BOOST_CHECK(IsStandardTx(t, reason));
// OP_RESERVED *is* considered to be a PUSHDATA type opcode by IsPushOnly()!
t.vout[0].scriptPubKey = CScript() << OP_RETURN << OP_RESERVED << -1 << 0 << ParseHex("01") << 2 << 3 << 4 << 5 << 6 << 7 << 8 << 9 << 10 << 11 << 12 << 13 << 14 << 15 << 16;
BOOST_CHECK(IsStandardTx(t, reason));
t.vout[0].scriptPubKey = CScript() << OP_RETURN << 0 << ParseHex("01") << 2 << ParseHex("ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff");
BOOST_CHECK(IsStandardTx(t, reason));

// ...so long as it only contains PUSHDATA's
t.vout[0].scriptPubKey = CScript() << OP_RETURN << OP_RETURN;
BOOST_CHECK(!IsStandardTx(t, reason));

// TX_NULL_DATA w/o PUSHDATA

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