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Fix max stack growth overflow #219

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merged 2 commits into from
Dec 3, 2019
Merged

Fix max stack growth overflow #219

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2b0c332
test: Add unit test for block stack max growth overflow
chfast Dec 2, 2019
27601a9
Fix block max stack growth overflow
chfast Dec 2, 2019
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10 changes: 6 additions & 4 deletions lib/evmone/analysis.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -23,13 +23,15 @@ struct block_analysis
explicit block_analysis(size_t index) noexcept : begin_block_index{index} {}

/// Close the current block by producing compressed information about the block.
block_info close() const noexcept
[[nodiscard]] block_info close() const noexcept
{
static constexpr auto stack_req_max = std::numeric_limits<int16_t>::max();
static constexpr auto stack_param_max = std::numeric_limits<int16_t>::max();

const auto final_stack_req =
stack_req <= stack_req_max ? static_cast<int16_t>(stack_req) : stack_req_max;
const auto final_stack_max_growth = static_cast<int16_t>(stack_max_growth);
stack_req <= stack_param_max ? static_cast<int16_t>(stack_req) : stack_param_max;
const auto final_stack_max_growth = stack_max_growth <= stack_param_max ?
static_cast<int16_t>(stack_max_growth) :
stack_param_max;
return {gas_cost, final_stack_req, final_stack_max_growth};
}
};
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26 changes: 26 additions & 0 deletions test/unittests/evm_other_test.cpp
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Expand Up @@ -35,6 +35,32 @@ TEST_F(evm_other, evmone_block_stack_req_overflow)
EXPECT_STATUS(EVMC_STACK_UNDERFLOW);
}

TEST_F(evm_other, evmone_block_max_stack_growth_overflow)
{
// This tests constructs a code with single basic block which stack max growth is > int16 max.
// Such basic block can cause int16_t overflow during analysis.

constexpr auto test_max_code_size = 1024 * 1024u + 1;

bytes code_buffer(test_max_code_size, uint8_t{OP_MSIZE});

for (auto max_stack_growth : {32767u, 32768u, 65535u, 65536u, test_max_code_size - 1})
{
execute({code_buffer.data(), max_stack_growth});
EXPECT_STATUS(EVMC_STACK_OVERFLOW);

code_buffer[max_stack_growth] = OP_JUMPDEST;
execute({code_buffer.data(), max_stack_growth + 1});
EXPECT_STATUS(EVMC_STACK_OVERFLOW);

code_buffer[max_stack_growth] = OP_STOP;
execute({code_buffer.data(), max_stack_growth + 1});
EXPECT_STATUS(EVMC_STACK_OVERFLOW);

code_buffer[max_stack_growth] = OP_MSIZE; // Restore original opcode.
}
}

TEST_F(evm_other, loop_full_of_jumpdests)
{
// The code is a simple loop with a counter taken from the input or a constant (325) if the
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