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Fix the stack_height_required range to accommodate DUPN/SWAPN
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@pdobacz
pdobacz committed Jan 10, 2024
1 parent 896a029 commit 922e9ee
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Showing 4 changed files with 36 additions and 27 deletions.
2 changes: 1 addition & 1 deletion lib/evmone/advanced_analysis.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -149,7 +149,7 @@ struct OpTableEntry
{
instruction_exec_fn fn;
int16_t gas_cost;
int8_t stack_req;
uint8_t stack_req;
int8_t stack_change;
};

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23 changes: 8 additions & 15 deletions lib/evmone/eof.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -364,7 +364,7 @@ std::variant<EOFValidationError, int32_t> validate_max_stack_height(

const auto opcode = static_cast<Opcode>(code[i]);

auto stack_height_required = instr::traits[opcode].stack_height_required;
int stack_height_required = instr::traits[opcode].stack_height_required;
auto stack_height_change = instr::traits[opcode].stack_height_change;

auto stack_height = stack_heights[i];
Expand All @@ -374,7 +374,7 @@ std::variant<EOFValidationError, int32_t> validate_max_stack_height(
{
const auto fid = read_uint16_be(&code[i + 1]);

stack_height_required = static_cast<int8_t>(code_types[fid].inputs);
stack_height_required = code_types[fid].inputs;

if (stack_height + code_types[fid].max_stack_height - stack_height_required >
STACK_SIZE_LIMIT)
Expand All @@ -395,36 +395,29 @@ std::variant<EOFValidationError, int32_t> validate_max_stack_height(

if (code_types[fid].outputs == NON_RETURNING_FUNCITON)
{
stack_height_required = static_cast<int8_t>(code_types[fid].inputs);
stack_height_required = code_types[fid].inputs;
}
else
{
if (code_types[func_index].outputs < code_types[fid].outputs)
return EOFValidationError::jumpf_destination_incompatible_outputs;

stack_height_required =
static_cast<int8_t>(code_types[func_index].outputs + code_types[fid].inputs -
code_types[fid].outputs);
stack_height_required = code_types[func_index].outputs + code_types[fid].inputs -
code_types[fid].outputs;
if (stack_heights[i] > stack_height_required)
return EOFValidationError::stack_higher_than_outputs_required;
}
}
else if (opcode == OP_RETF)
{
stack_height_required = static_cast<int8_t>(code_types[func_index].outputs);
stack_height_required = code_types[func_index].outputs;
if (stack_height > code_types[func_index].outputs)
return EOFValidationError::stack_higher_than_outputs_required;
}
else if (opcode == OP_DUPN)
{
const auto n = static_cast<int8_t>(code[i + 1]);
stack_height_required = n + 1;
}
stack_height_required = code[i + 1] + 1;
else if (opcode == OP_SWAPN)
{
const auto n = static_cast<int8_t>(code[i + 1]);
stack_height_required = n + 2;
}
stack_height_required = code[i + 1] + 2;

if (stack_height < stack_height_required)
return EOFValidationError::stack_underflow;
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2 changes: 1 addition & 1 deletion lib/evmone/instructions_traits.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -204,7 +204,7 @@ struct Traits
bool is_terminating = false;

/// The number of stack items the instruction accesses during execution.
int8_t stack_height_required = 0;
uint8_t stack_height_required = 0;

/// The stack height change caused by the instruction execution. Can be negative.
int8_t stack_height_change = 0;
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36 changes: 26 additions & 10 deletions test/unittests/eof_validation_test.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -962,20 +962,36 @@ TEST(eof_validation, retf_stack_validation)

TEST(eof_validation, dupn_stack_validation)
{
auto pushes = bytecode{};
for (uint64_t i = 1; i <= 20; ++i)
pushes += push(i);
auto code = eof_bytecode(pushes + OP_DUPN + "14" + OP_STOP, 21);
EXPECT_EQ(validate_eof(code), EOFValidationError::stack_underflow);
const auto pushes = 20 * push(1);
EXPECT_EQ(validate_eof(eof_bytecode(pushes + OP_DUPN + "00" + OP_STOP, 21)),
EOFValidationError::success);
EXPECT_EQ(validate_eof(eof_bytecode(pushes + OP_DUPN + "13" + OP_STOP, 21)),
EOFValidationError::success);
EXPECT_EQ(validate_eof(eof_bytecode(pushes + OP_DUPN + "14" + OP_STOP, 21)),
EOFValidationError::stack_underflow);
EXPECT_EQ(validate_eof(eof_bytecode(pushes + OP_DUPN + "d0" + OP_STOP, 21)),
EOFValidationError::stack_underflow);
EXPECT_EQ(validate_eof(eof_bytecode(pushes + OP_DUPN + "fe" + OP_STOP, 21)),
EOFValidationError::stack_underflow);
EXPECT_EQ(validate_eof(eof_bytecode(pushes + OP_DUPN + "ff" + OP_STOP, 21)),
EOFValidationError::stack_underflow);
}

TEST(eof_validation, swapn_stack_validation)
{
auto pushes = bytecode{};
for (uint64_t i = 1; i <= 20; ++i)
pushes += push(i);
auto code = eof_bytecode(pushes + OP_SWAPN + "13" + OP_STOP, 20);
EXPECT_EQ(validate_eof(code), EOFValidationError::stack_underflow);
const auto pushes = 20 * push(1);
EXPECT_EQ(validate_eof(eof_bytecode(pushes + OP_SWAPN + "00" + OP_STOP, 20)),
EOFValidationError::success);
EXPECT_EQ(validate_eof(eof_bytecode(pushes + OP_SWAPN + "12" + OP_STOP, 20)),
EOFValidationError::success);
EXPECT_EQ(validate_eof(eof_bytecode(pushes + OP_SWAPN + "13" + OP_STOP, 20)),
EOFValidationError::stack_underflow);
EXPECT_EQ(validate_eof(eof_bytecode(pushes + OP_SWAPN + "d0" + OP_STOP, 20)),
EOFValidationError::stack_underflow);
EXPECT_EQ(validate_eof(eof_bytecode(pushes + OP_SWAPN + "fe" + OP_STOP, 20)),
EOFValidationError::stack_underflow);
EXPECT_EQ(validate_eof(eof_bytecode(pushes + OP_SWAPN + "ff" + OP_STOP, 20)),
EOFValidationError::stack_underflow);
}

TEST(eof_validation, non_returning_status)
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