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Merge #10481: Decodehextx scripts sanity check

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ac4e438 Sanity check transaction scripts in DecodeHexTx (Andrew Chow)
5b75c47 Add a valid opcode sanity check to CScript (Andrew Chow)

Tree-SHA512: a516e95c274c9d131123150c798cae8bed75925e8a4d59469967dd7f1d49f7f8161e26afb61024b821bd8dcdffdfd0d19b8dcad20b39b1106820326d8d56904d
This commit is contained in:
Wladimir J. van der Laan 2017-06-08 12:48:46 +02:00
commit 9c248e39f2
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GPG key ID: 1E4AED62986CD25D
4 changed files with 59 additions and 3 deletions
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29
src/core_read.cpp
View file

@ -88,10 +88,32 @@ CScript ParseScript(const std::string& s)
return result;
}
// Check that all of the input and output scripts of a transaction contains valid opcodes
bool CheckTxScriptsSanity(const CMutableTransaction& tx)
{
// Check input scripts for non-coinbase txs
if (!CTransaction(tx).IsCoinBase()) {
for (unsigned int i = 0; i < tx.vin.size(); i++) {
if (!tx.vin[i].scriptSig.HasValidOps() || tx.vin[i].scriptSig.size() > MAX_SCRIPT_SIZE) {
return false;
}
}
}
// Check output scripts
for (unsigned int i = 0; i < tx.vout.size(); i++) {
if (!tx.vout[i].scriptPubKey.HasValidOps() || tx.vout[i].scriptPubKey.size() > MAX_SCRIPT_SIZE) {
return false;
}
}
return true;
}
bool DecodeHexTx(CMutableTransaction& tx, const std::string& strHexTx, bool fTryNoWitness)
{
if (!IsHex(strHexTx))
if (!IsHex(strHexTx)) {
return false;
}
std::vector<unsigned char> txData(ParseHex(strHexTx));
@ -99,7 +121,7 @@ bool DecodeHexTx(CMutableTransaction& tx, const std::string& strHexTx, bool fTry
CDataStream ssData(txData, SER_NETWORK, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS);
try {
ssData >> tx;
if (ssData.eof()) {
if (ssData.eof() && CheckTxScriptsSanity(tx)) {
return true;
}
}
@ -111,8 +133,9 @@ bool DecodeHexTx(CMutableTransaction& tx, const std::string& strHexTx, bool fTry
CDataStream ssData(txData, SER_NETWORK, PROTOCOL_VERSION);
try {
ssData >> tx;
if (!ssData.empty())
if (!ssData.empty()) {
return false;
}
}
catch (const std::exception&) {
return false;

13
src/script/script.cpp
View file

@ -267,3 +267,16 @@ std::string CScriptWitness::ToString() const
}
return ret + ")";
}
bool CScript::HasValidOps() const
{
CScript::const_iterator it = begin();
while (it < end()) {
opcodetype opcode;
std::vector<unsigned char> item;
if (!GetOp(it, opcode, item) || opcode > MAX_OPCODE || item.size() > MAX_SCRIPT_ELEMENT_SIZE) {
return false;
}
}
return true;
}

6
src/script/script.h
View file

@ -190,6 +190,9 @@ enum opcodetype
OP_INVALIDOPCODE = 0xff,
};
// Maximum value that an opcode can be
static const unsigned int MAX_OPCODE = OP_NOP10;
const char* GetOpName(opcodetype opcode);
class scriptnum_error : public std::runtime_error
@ -630,6 +633,9 @@ public:
bool IsPushOnly(const_iterator pc) const;
bool IsPushOnly() const;
/** Check if the script contains valid OP_CODES */
bool HasValidOps() const;
/**
* Returns whether the script is guaranteed to fail at execution,
* regardless of the initial stack. This allows outputs to be pruned

14
src/test/script_tests.cpp
View file

@ -1438,4 +1438,18 @@ BOOST_AUTO_TEST_CASE(script_FindAndDelete)
BOOST_CHECK(s == expect);
}
BOOST_AUTO_TEST_CASE(script_HasValidOps)
{
// Exercise the HasValidOps functionality
CScript script;
script = ScriptFromHex("76a9141234567890abcdefa1a2a3a4a5a6a7a8a9a0aaab88ac"); // Normal script
BOOST_CHECK(script.HasValidOps());
script = ScriptFromHex("76a914ff34567890abcdefa1a2a3a4a5a6a7a8a9a0aaab88ac");
BOOST_CHECK(script.HasValidOps());
script = ScriptFromHex("ff88ac"); // Script with OP_INVALIDOPCODE explicit
BOOST_CHECK(!script.HasValidOps());
script = ScriptFromHex("88acc0"); // Script with undefined opcode
BOOST_CHECK(!script.HasValidOps());
}
BOOST_AUTO_TEST_SUITE_END()