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Fix zero size memory expansion semantics in the yul interpreter.

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This commit is contained in:
Bhargava Shastry
2022-11-21 11:53:42 +01:00
parent 0b4b1045cf
commit 2c27405cbb
3 changed files with 37 additions and 7 deletions
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test/tools/yulInterpreter/EVMInstructionInterpreter.cpp
+15 -4
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@@ -499,13 +499,15 @@ u256 EVMInstructionInterpreter::evalBuiltin(
bool EVMInstructionInterpreter::accessMemory(u256 const& _offset, u256 const& _size)
{
if (((_offset + _size) >= _offset) && ((_offset + _size + 0x1f) >= (_offset + _size)))
if (_size == 0)
return true;
else if (((_offset + _size) >= _offset) && ((_offset + _size + 0x1f) >= (_offset + _size)))
{
u256 newSize = (_offset + _size + 0x1f) & ~u256(0x1f);
m_state.msize = max(m_state.msize, newSize);
// We only record accesses to contiguous memory chunks that are at most 0xffff bytes
// in size and at an offset of at most numeric_limits<size_t>::max() - 0xffff
return _size <= 0xffff && _offset <= u256(numeric_limits<size_t>::max() - 0xffff);
// We only record accesses to contiguous memory chunks that are at most s_maxRangeSize bytes
// in size and at an offset of at most numeric_limits<size_t>::max() - s_maxRangeSize
return _size <= s_maxRangeSize && _offset <= u256(numeric_limits<size_t>::max() - s_maxRangeSize);
}
else
m_state.msize = u256(-1);
@@ -513,6 +515,15 @@ bool EVMInstructionInterpreter::accessMemory(u256 const& _offset, u256 const& _s
return false;
}
bytes EVMInstructionInterpreter::readMemory(u256 const& _offset, u256 const& _size)
{
yulAssert(_size <= s_maxRangeSize, "Too large read.");
bytes data(size_t(_size), uint8_t(0));
for (size_t i = 0; i < data.size(); ++i)
data[i] = m_state.memory[_offset + i];
return data;
}
u256 EVMInstructionInterpreter::readMemoryWord(u256 const& _offset)
{
return u256(h256(m_state.readMemory(_offset, 32)));