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[ewasm] Terminate on out-of-bounds access in EwasmInterpreter

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This commit is contained in:
Alex Beregszaszi 2020-10-28 14:31:49 +00:00
parent f42280f5c9
commit bcd31daf94
2 changed files with 41 additions and 47 deletions
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85
test/tools/yulInterpreter/EwasmBuiltinInterpreter.cpp
View File

@ -115,8 +115,6 @@ uint64_t popcnt(uint64_t _v)
} }
using u512 = boost::multiprecision::number<boost::multiprecision::cpp_int_backend<512, 256, boost::multiprecision::unsigned_magnitude, boost::multiprecision::unchecked, void>>;
u256 EwasmBuiltinInterpreter::evalBuiltin( u256 EwasmBuiltinInterpreter::evalBuiltin(
YulString _functionName, YulString _functionName,
vector<Expression> const& _arguments, vector<Expression> const& _arguments,
@ -144,14 +142,14 @@ u256 EwasmBuiltinInterpreter::evalBuiltin(
else if (fun == "datacopy") else if (fun == "datacopy")
{ {
// This is identical to codecopy. // This is identical to codecopy.
if (accessMemory(_evaluatedArguments.at(0), _evaluatedArguments.at(2))) accessMemory(_evaluatedArguments.at(0), _evaluatedArguments.at(2));
copyZeroExtended( copyZeroExtended(
m_state.memory, m_state.memory,
m_state.code, m_state.code,
static_cast<size_t>(_evaluatedArguments.at(0)), static_cast<size_t>(_evaluatedArguments.at(0)),
static_cast<size_t>(_evaluatedArguments.at(1) & numeric_limits<size_t>::max()), static_cast<size_t>(_evaluatedArguments.at(1) & numeric_limits<size_t>::max()),
static_cast<size_t>(_evaluatedArguments.at(2)) static_cast<size_t>(_evaluatedArguments.at(2))
); );
return 0; return 0;
} }
else if (fun == "i32.drop" || fun == "i64.drop" || fun == "nop") else if (fun == "i32.drop" || fun == "i64.drop" || fun == "nop")
@ -324,11 +322,11 @@ u256 EwasmBuiltinInterpreter::evalEthBuiltin(string const& _fun, vector<uint64_t
{ {
if (arg[1] + arg[2] < arg[1] || arg[1] + arg[2] > m_state.calldata.size()) if (arg[1] + arg[2] < arg[1] || arg[1] + arg[2] > m_state.calldata.size())
throw ExplicitlyTerminated(); throw ExplicitlyTerminated();
if (accessMemory(arg[0], arg[2])) accessMemory(arg[0], arg[2]);
copyZeroExtended( copyZeroExtended(
m_state.memory, m_state.calldata, m_state.memory, m_state.calldata,
size_t(arg[0]), size_t(arg[1]), size_t(arg[2]) size_t(arg[0]), size_t(arg[1]), size_t(arg[2])
); );
return {}; return {};
} }
else if (_fun == "getCallDataSize") else if (_fun == "getCallDataSize")
@ -377,11 +375,11 @@ u256 EwasmBuiltinInterpreter::evalEthBuiltin(string const& _fun, vector<uint64_t
} }
else if (_fun == "codeCopy") else if (_fun == "codeCopy")
{ {
if (accessMemory(arg[0], arg[2])) accessMemory(arg[0], arg[2]);
copyZeroExtended( copyZeroExtended(
m_state.memory, m_state.code, m_state.memory, m_state.code,
size_t(arg[0]), size_t(arg[1]), size_t(arg[2]) size_t(arg[0]), size_t(arg[1]), size_t(arg[2])
); );
return 0; return 0;
} }
else if (_fun == "getCodeSize") else if (_fun == "getCodeSize")
@ -407,12 +405,12 @@ u256 EwasmBuiltinInterpreter::evalEthBuiltin(string const& _fun, vector<uint64_t
else if (_fun == "externalCodeCopy") else if (_fun == "externalCodeCopy")
{ {
readAddress(arg[0]); readAddress(arg[0]);
if (accessMemory(arg[1], arg[3])) accessMemory(arg[1], arg[3]);
// TODO this way extcodecopy and codecopy do the same thing. // TODO this way extcodecopy and codecopy do the same thing.
copyZeroExtended( copyZeroExtended(
m_state.memory, m_state.code, m_state.memory, m_state.code,
size_t(arg[1]), size_t(arg[2]), size_t(arg[3]) size_t(arg[1]), size_t(arg[2]), size_t(arg[3])
); );
return 0; return 0;
} }
else if (_fun == "getExternalCodeSize") else if (_fun == "getExternalCodeSize")
@ -454,16 +452,16 @@ u256 EwasmBuiltinInterpreter::evalEthBuiltin(string const& _fun, vector<uint64_t
else if (_fun == "finish") else if (_fun == "finish")
{ {
bytes data; bytes data;
if (accessMemory(arg[0], arg[1])) accessMemory(arg[0], arg[1]);
data = readMemory(arg[0], arg[1]); data = readMemory(arg[0], arg[1]);
logTrace(evmasm::Instruction::RETURN, {}, data); logTrace(evmasm::Instruction::RETURN, {}, data);
throw ExplicitlyTerminated(); throw ExplicitlyTerminated();
} }
else if (_fun == "revert") else if (_fun == "revert")
{ {
bytes data; bytes data;
if (accessMemory(arg[0], arg[1])) accessMemory(arg[0], arg[1]);
data = readMemory(arg[0], arg[1]); data = readMemory(arg[0], arg[1]);
logTrace(evmasm::Instruction::REVERT, {}, data); logTrace(evmasm::Instruction::REVERT, {}, data);
throw ExplicitlyTerminated(); throw ExplicitlyTerminated();
} }
@ -473,11 +471,11 @@ u256 EwasmBuiltinInterpreter::evalEthBuiltin(string const& _fun, vector<uint64_t
{ {
if (arg[1] + arg[2] < arg[1] || arg[1] + arg[2] > m_state.returndata.size()) if (arg[1] + arg[2] < arg[1] || arg[1] + arg[2] > m_state.returndata.size())
throw ExplicitlyTerminated(); throw ExplicitlyTerminated();
if (accessMemory(arg[0], arg[2])) accessMemory(arg[0], arg[2]);
copyZeroExtended( copyZeroExtended(
m_state.memory, m_state.calldata, m_state.memory, m_state.calldata,
size_t(arg[0]), size_t(arg[1]), size_t(arg[2]) size_t(arg[0]), size_t(arg[1]), size_t(arg[2])
); );
return {}; return {};
} }
else if (_fun == "selfDestruct") else if (_fun == "selfDestruct")
@ -494,18 +492,15 @@ u256 EwasmBuiltinInterpreter::evalEthBuiltin(string const& _fun, vector<uint64_t
return 0; return 0;
} }
bool EwasmBuiltinInterpreter::accessMemory(u256 const& _offset, u256 const& _size) void EwasmBuiltinInterpreter::accessMemory(u256 const& _offset, u256 const& _size)
{ {
if (((_offset + _size) >= _offset) && ((_offset + _size + 0x1f) >= (_offset + _size))) // Single WebAssembly page.
{ // TODO: Support expansion in this interpreter.
u256 newSize = (_offset + _size + 0x1f) & ~u256(0x1f); m_state.msize = 65536;
m_state.msize = max(m_state.msize, newSize);
return _size <= 0xffff;
}
else
m_state.msize = u256(-1);
return false; if (((_offset + _size) < _offset) || ((_offset + _size) > m_state.msize))
// Ewasm throws out of bounds exception as opposed to the EVM.
throw ExplicitlyTerminated();
} }
bytes EwasmBuiltinInterpreter::readMemory(uint64_t _offset, uint64_t _size) bytes EwasmBuiltinInterpreter::readMemory(uint64_t _offset, uint64_t _size)

3
test/tools/yulInterpreter/EwasmBuiltinInterpreter.h
View File

@ -91,8 +91,7 @@ private:
/// Checks if the memory access is not too large for the interpreter and adjusts /// Checks if the memory access is not too large for the interpreter and adjusts
/// msize accordingly. /// msize accordingly.
/// @returns false if the amount of bytes read is lager than 0xffff void accessMemory(u256 const& _offset, u256 const& _size = 32);
bool accessMemory(u256 const& _offset, u256 const& _size = 32);
/// @returns the memory contents at the provided address. /// @returns the memory contents at the provided address.
/// Does not adjust msize, use @a accessMemory for that /// Does not adjust msize, use @a accessMemory for that
bytes readMemory(uint64_t _offset, uint64_t _size = 32); bytes readMemory(uint64_t _offset, uint64_t _size = 32);