From a3db1fc1976e1b2e67aedecb771c288b6dca6b1c Mon Sep 17 00:00:00 2001 From: chriseth Date: Wed, 11 Oct 2017 10:45:24 +0200 Subject: Do not accept truncated function selectors. --- libsolidity/codegen/ContractCompiler.cpp | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) (limited to 'libsolidity/codegen/ContractCompiler.cpp') diff --git a/libsolidity/codegen/ContractCompiler.cpp b/libsolidity/codegen/ContractCompiler.cpp index 429db532..74565ae4 100644 --- a/libsolidity/codegen/ContractCompiler.cpp +++ b/libsolidity/codegen/ContractCompiler.cpp @@ -251,13 +251,10 @@ void ContractCompiler::appendFunctionSelector(ContractDefinition const& _contrac FunctionDefinition const* fallback = _contract.fallbackFunction(); eth::AssemblyItem notFound = m_context.newTag(); - // shortcut messages without data if we have many functions in order to be able to receive - // ether with constant gas - if (interfaceFunctions.size() > 5 || fallback) - { - m_context << Instruction::CALLDATASIZE << Instruction::ISZERO; - m_context.appendConditionalJumpTo(notFound); - } + // directly jump to fallback if the data is too short to contain a function selector + // also guards against short data + m_context << u256(4) << Instruction::CALLDATASIZE << Instruction::LT; + m_context.appendConditionalJumpTo(notFound); // retrieve the function signature hash from the calldata if (!interfaceFunctions.empty()) -- cgit v1.2.3