From ded1a739a9d0f5d2d7317156401ba17f100f7544 Mon Sep 17 00:00:00 2001
From: Gav Wood <i@gavwood.com>
Date: Sat, 25 Jul 2015 21:31:06 +0200
Subject: [PATCH] SHA3 gas calc should use bigint to avoid overflow. Fixes
 #2582.

---
 libevm/VM.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libevm/VM.cpp b/libevm/VM.cpp
index f95481c54..9d89ce497 100644
--- a/libevm/VM.cpp
+++ b/libevm/VM.cpp
@@ -103,7 +103,7 @@ void VM::checkRequirements(u256& io_gas, ExtVMFace& _ext, OnOpFunc const& _onOp,
 		newTempSize = memNeed(m_stack.back(), m_stack[m_stack.size() - 2]);
 		break;
 	case Instruction::SHA3:
-		runGas = c_sha3Gas + (m_stack[m_stack.size() - 2] + 31) / 32 * c_sha3WordGas;
+		runGas = c_sha3Gas + ((bigint)m_stack[m_stack.size() - 2] + 31) / 32 * c_sha3WordGas;
 		newTempSize = memNeed(m_stack.back(), m_stack[m_stack.size() - 2]);
 		break;
 	case Instruction::CALLDATACOPY: