From 81a7f463851e308e9427959c8d6f40b00b8c75aa Mon Sep 17 00:00:00 2001
From: CJentzsch <jentzsch.software@gmail.com>
Date: Tue, 2 Jun 2015 10:13:12 +0200
Subject: [PATCH] forbid uncle to be your brother

---
 libethcore/Exceptions.h | 15 ++++++++-------
 libethereum/State.cpp   |  8 ++++++++
 2 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/libethcore/Exceptions.h b/libethcore/Exceptions.h
index 8b73c96fe..9362e4fed 100644
--- a/libethcore/Exceptions.h
+++ b/libethcore/Exceptions.h
@@ -49,27 +49,28 @@ struct FeeTooSmall: virtual dev::Exception {};
 struct TooMuchGasUsed: virtual dev::Exception {};
 struct ExtraDataTooBig: virtual dev::Exception {};
 struct InvalidSignature: virtual dev::Exception {};
-class InvalidBlockFormat: virtual public dev::Exception {};
+struct InvalidBlockFormat: virtual dev::Exception {};
 struct InvalidUnclesHash: virtual dev::Exception {};
 struct InvalidUncle: virtual dev::Exception {};
 struct TooManyUncles: virtual dev::Exception {};
 struct UncleTooOld: virtual dev::Exception {};
-class UncleInChain: virtual public dev::Exception {};
+struct UncleIsBrother: virtual dev::Exception {};
+struct UncleInChain: virtual dev::Exception {};
 struct DuplicateUncleNonce: virtual dev::Exception {};
 struct InvalidStateRoot: virtual dev::Exception {};
 struct InvalidGasUsed: virtual dev::Exception {};
-class InvalidTransactionsHash: virtual public dev::Exception {};
+struct InvalidTransactionsHash: virtual dev::Exception {};
 struct InvalidTransaction: virtual dev::Exception {};
 struct InvalidDifficulty: virtual dev::Exception {};
-class InvalidGasLimit: virtual public dev::Exception {};
+struct InvalidGasLimit: virtual dev::Exception {};
 struct InvalidTransactionGasUsed: virtual dev::Exception {};
 struct InvalidTransactionsStateRoot: virtual dev::Exception {};
 struct InvalidReceiptsStateRoot: virtual dev::Exception {};
 struct InvalidTimestamp: virtual dev::Exception {};
 struct InvalidLogBloom: virtual dev::Exception {};
-class InvalidNonce: virtual public dev::Exception {};
-class InvalidBlockHeaderItemCount: virtual public dev::Exception {};
-class InvalidBlockNonce: virtual public dev::Exception {};
+struct InvalidNonce: virtual dev::Exception {};
+struct InvalidBlockHeaderItemCount: virtual dev::Exception {};
+struct InvalidBlockNonce: virtual dev::Exception {};
 struct InvalidParentHash: virtual dev::Exception {};
 struct InvalidNumber: virtual dev::Exception {};
 struct InvalidContractAddress: virtual public dev::Exception {};
diff --git a/libethereum/State.cpp b/libethereum/State.cpp
index b35ef98ce..09765d9ee 100644
--- a/libethereum/State.cpp
+++ b/libethereum/State.cpp
@@ -726,6 +726,14 @@ u256 State::enact(bytesConstRef _block, BlockChain const& _bc, ImportRequirement
 			cwarn << "  Block number: " << m_currentBlock.number;
 			BOOST_THROW_EXCEPTION(UncleTooOld());
 		}
+		else if (uncle.number == m_currentBlock.number)
+		{
+			badBlock(_block, "Uncle is brother");
+			cwarn << "  Uncle number: " << uncle.number;
+			cwarn << "  Uncle parent number: " << uncleParent.number;
+			cwarn << "  Block number: " << m_currentBlock.number;
+			BOOST_THROW_EXCEPTION(UncleIsBrother());
+		}
 		uncle.verifyParent(uncleParent);
 
 //		tdIncrease += uncle.difficulty;