More sophisticated (and correct) BlockHashes handling.

libdevcore/RLP.cpp

@@ -111,10 +111,24 @@ unsigned RLP::actualSize() const
 	return 0;
 }
 
+void RLP::requireGood() const
+{
+	if (isNull())
+		BOOST_THROW_EXCEPTION(BadRLP());
+	byte n = m_data[0];
+	if (n != c_rlpDataImmLenStart + 1)
+		return;
+	if (m_data.size() < 2)
+		BOOST_THROW_EXCEPTION(BadRLP());
+	if (m_data[1] < c_rlpDataImmLenStart)
+		BOOST_THROW_EXCEPTION(BadRLP());
+}
+
 bool RLP::isInt() const
 {
 	if (isNull())
 		return false;
+	requireGood();
 	byte n = m_data[0];
 	if (n < c_rlpDataImmLenStart)
 		return !!n;
@@ -141,6 +155,7 @@ unsigned RLP::length() const
 {
 	if (isNull())
 		return 0;
+	requireGood();
 	unsigned ret = 0;
 	byte n = m_data[0];
 	if (n < c_rlpDataImmLenStart)

libdevcore/RLP.h

@@ -253,6 +253,7 @@ public:
 	/// Converts to int of type given; if isString(), decodes as big-endian bytestream. @returns 0 if not an int or string.
 	template <class _T = unsigned> _T toInt(int _flags = Strict) const
 	{
+		requireGood();
 		if ((!isInt() && !(_flags & AllowNonCanon)) || isList() || isNull())
 			if (_flags & ThrowOnFail)
 				BOOST_THROW_EXCEPTION(BadCast());
@@ -273,6 +274,7 @@ public:
 
 	template <class _N> _N toHash(int _flags = Strict) const
 	{
+		requireGood();
 		if (!isData() || (length() > _N::size && (_flags & FailIfTooBig)) || (length() < _N::size && (_flags & FailIfTooSmall)))
 			if (_flags & ThrowOnFail)
 				BOOST_THROW_EXCEPTION(BadCast());
@@ -290,7 +292,7 @@ public:
 	RLPs toList() const;
 
 	/// @returns the data payload. Valid for all types.
-	bytesConstRef payload() const { return m_data.cropped(payloadOffset()); }
+	bytesConstRef payload() const { auto l = length(); if (l > m_data.size()) throw BadRLP(); return m_data.cropped(payloadOffset(), l); }
 
 	/// @returns the theoretical size of this item.
 	/// @note Under normal circumstances, is equivalent to m_data.size() - use that unless you know it won't work.
@@ -300,6 +302,9 @@ private:
 	/// Disable construction from rvalue
 	explicit RLP(bytes const&&) {}
 
+	/// Throws if is non-canonical data (i.e. single byte done in two bytes that could be done in one).
+	void requireGood() const;
+
 	/// Single-byte data payload.
 	bool isSingleByte() const { return !isNull() && m_data[0] < c_rlpDataImmLenStart; }
 

libethcore/Common.h

@@ -90,8 +90,7 @@ enum class ImportResult
 	AlreadyInChain,
 	AlreadyKnown,
 	Malformed,
-	BadChain,
-	Unknown
+	BadChain
 };
 
 struct ImportRequirements

libethereum/BlockChain.cpp

@@ -310,7 +310,7 @@ tuple<h256s, h256s, bool> BlockChain::sync(BlockQueue& _bq, OverlayDB const& _st
 			fresh += r.first;
 			dead += r.second;
 		}
-		catch (UnknownParent)
+		catch (dev::eth::UnknownParent)
 		{
 			cwarn << "ODD: Import queue contains block with unknown parent." << boost::current_exception_diagnostic_information();
 			// NOTE: don't reimport since the queue should guarantee everything in the right order.

libethereum/BlockQueue.cpp

@@ -169,6 +169,21 @@ template <class T> T advanced(T _t, unsigned _n)
 	return _t;
 }
 
+QueueStatus BlockQueue::blockStatus(h256 const& _h) const
+{
+	ReadGuard l(m_lock);
+	return
+		m_readySet.count(_h) ?
+			QueueStatus::Ready :
+		m_drainingSet.count(_h) ?
+			QueueStatus::Importing :
+		m_unknownSet.count(_h) ?
+			QueueStatus::UnknownParent :
+		m_knownBad.count(_h) ?
+			QueueStatus::Bad :
+			QueueStatus::Unknown;
+}
+
 void BlockQueue::drain(std::vector<bytes>& o_out, unsigned _max)
 {
 	WriteGuard l(m_lock);

libethereum/BlockQueue.h

@@ -46,6 +46,15 @@ struct BlockQueueStatus
 	size_t bad;
 };
 
+enum class QueueStatus
+{
+	Ready,
+	Importing,
+	UnknownParent,
+	Bad,
+	Unknown
+};
+
 /**
  * @brief A queue of blocks. Sits between network or other I/O and the BlockChain.
  * Sorts them ready for blockchain insertion (with the BlockChain::sync() method).
@@ -87,7 +96,7 @@ public:
 	BlockQueueStatus status() const { ReadGuard l(m_lock); return BlockQueueStatus{m_ready.size(), m_future.size(), m_unknown.size(), m_knownBad.size()}; }
 
 	/// Get some infomration on the given block's status regarding us.
-	ImportResult blockStatus(h256 const& _h) const { ReadGuard l(m_lock); return m_readySet.count(_h) || m_drainingSet.count(_h) ? ImportResult::AlreadyKnown : m_unknownSet.count(_h) ? ImportResult::UnknownParent : m_knownBad.count(_h) ? ImportResult::BadChain : ImportResult::Unknown; }
+	QueueStatus blockStatus(h256 const& _h) const;
 
 	template <class T> Handler onReady(T const& _t) { return m_onReady.add(_t); }
 

libethereum/EthereumPeer.cpp

@@ -389,12 +389,19 @@ bool EthereumPeer::interpret(unsigned _id, RLP const& _r)
 		{
 			addRating(1);
 			auto h = _r[i].toHash<h256>();
-			if (host()->m_bq.blockStatus(h) != ImportResult::Unknown || host()->m_chain.isKnown(h))
+			auto status = host()->m_bq.blockStatus(h);
+			if (status == QueueStatus::Importing || status == QueueStatus::Ready || host()->m_chain.isKnown(h))
 			{
 				transition(Asking::Blocks);
 				return true;
 			}
-			else
+			else if (status == QueueStatus::Bad)
+			{
+				cwarn << "BAD hash chain discovered. Ignoring.";
+				transition(Asking::Nothing);
+				return true;
+			}
+			else if (status == QueueStatus::Unknown)
 				m_syncingNeededBlocks.push_back(h);
 		}
 		// run through - ask for more.