implement Milestone 19: Security Testing Suite with fuzzer (141 tests pass)

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2026-01-18 16:45:09 +01:00
parent 372a293bd0
commit 1b163891e0
6 changed files with 903 additions and 1 deletions

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// lua_fuzzer.cpp - Random Lua code generator for security testing
// Milestone 19: Security Testing Suite
#include "lua_fuzzer.h"
#include "lua_sandbox.h"
#include <sstream>
#include <chrono>
namespace mosis {
LuaFuzzer::LuaFuzzer(uint32_t seed) {
if (seed == 0) {
seed = static_cast<uint32_t>(
std::chrono::steady_clock::now().time_since_epoch().count());
}
m_rng.seed(seed);
}
LuaFuzzer::~LuaFuzzer() = default;
int LuaFuzzer::RandomInt(int min, int max) {
std::uniform_int_distribution<int> dist(min, max);
return dist(m_rng);
}
bool LuaFuzzer::RandomBool() {
return RandomInt(0, 1) == 1;
}
char LuaFuzzer::RandomChar() {
static const char chars[] = "abcdefghijklmnopqrstuvwxyz_";
return chars[RandomInt(0, sizeof(chars) - 2)];
}
std::string LuaFuzzer::GenerateIdentifier() {
int len = RandomInt(1, 8);
std::string id;
id += RandomChar(); // First char must be letter or underscore
for (int i = 1; i < len; i++) {
if (RandomBool()) {
id += RandomChar();
} else {
id += static_cast<char>('0' + RandomInt(0, 9));
}
}
return id;
}
std::string LuaFuzzer::GenerateLiteral() {
int type = RandomInt(0, 4);
switch (type) {
case 0: // nil
return "nil";
case 1: // boolean
return RandomBool() ? "true" : "false";
case 2: // integer
return std::to_string(RandomInt(-1000, 1000));
case 3: // float
return std::to_string(RandomInt(-100, 100)) + "." +
std::to_string(RandomInt(0, 99));
case 4: // string
{
int len = RandomInt(0, 20);
std::string s = "\"";
for (int i = 0; i < len; i++) {
char c = static_cast<char>(RandomInt(32, 126));
if (c == '"' || c == '\\') {
s += '\\';
}
s += c;
}
s += "\"";
return s;
}
default:
return "nil";
}
}
std::string LuaFuzzer::GenerateOperator() {
static const char* ops[] = {
"+", "-", "*", "/", "//", "%", "^",
"==", "~=", "<", ">", "<=", ">=",
"and", "or", ".."
};
return ops[RandomInt(0, sizeof(ops)/sizeof(ops[0]) - 1)];
}
std::string LuaFuzzer::GenerateTableConstructor(int depth) {
if (depth > static_cast<int>(m_max_nesting)) {
return "{}";
}
int count = RandomInt(0, 5);
if (count == 0) {
return "{}";
}
std::ostringstream ss;
ss << "{";
for (int i = 0; i < count; i++) {
if (i > 0) ss << ", ";
int style = RandomInt(0, 2);
switch (style) {
case 0: // array style
ss << GenerateExpression(depth + 1);
break;
case 1: // record style
ss << GenerateIdentifier() << " = " << GenerateExpression(depth + 1);
break;
case 2: // general style
ss << "[" << GenerateExpression(depth + 1) << "] = "
<< GenerateExpression(depth + 1);
break;
}
}
ss << "}";
return ss.str();
}
std::string LuaFuzzer::GenerateFunctionCall(int depth) {
// Use only very safe built-in functions
static const char* funcs[] = {
"tostring", "tonumber", "type"
};
std::ostringstream ss;
ss << funcs[RandomInt(0, sizeof(funcs)/sizeof(funcs[0]) - 1)];
ss << "(";
ss << GenerateLiteral(); // Just use literals, not recursive expressions
ss << ")";
return ss.str();
}
std::string LuaFuzzer::GenerateExpression(int depth) {
if (depth > static_cast<int>(m_max_nesting)) {
return GenerateLiteral();
}
int type = RandomInt(0, 7);
switch (type) {
case 0:
case 1:
return GenerateLiteral();
case 2:
return GenerateIdentifier();
case 3: // binary op
return "(" + GenerateExpression(depth + 1) + " " +
GenerateOperator() + " " + GenerateExpression(depth + 1) + ")";
case 4: // unary op
{
static const char* unary[] = {"-", "not ", "#"};
return std::string(unary[RandomInt(0, 2)]) +
"(" + GenerateExpression(depth + 1) + ")";
}
case 5:
return GenerateTableConstructor(depth + 1);
case 6:
return GenerateFunctionCall(depth + 1);
case 7: // table access
return GenerateIdentifier() + "[" + GenerateExpression(depth + 1) + "]";
default:
return GenerateLiteral();
}
}
std::string LuaFuzzer::GenerateStatement(int depth) {
if (depth > static_cast<int>(m_max_nesting)) {
return "local _ = nil";
}
int type = RandomInt(0, 5);
std::ostringstream ss;
switch (type) {
case 0: // local assignment
ss << "local " << GenerateIdentifier() << " = " << GenerateLiteral();
break;
case 1: // assignment (to local)
ss << "local " << GenerateIdentifier() << " = " << GenerateExpression(depth + 1);
break;
case 2: // function call statement
ss << GenerateFunctionCall(depth + 1);
break;
case 3: // if statement (simple)
ss << "if " << GenerateLiteral() << " then\n"
<< " local _ = " << GenerateLiteral() << "\n"
<< "end";
break;
case 4: // for numeric (small)
ss << "for " << GenerateIdentifier() << " = 1, " << RandomInt(1, 5) << " do\n"
<< " local _ = " << GenerateLiteral() << "\n"
<< "end";
break;
case 5: // do block
ss << "do\n"
<< " local " << GenerateIdentifier() << " = " << GenerateLiteral() << "\n"
<< "end";
break;
default:
ss << "local _ = nil";
}
return ss.str();
}
std::string LuaFuzzer::GenerateRandomCode() {
std::ostringstream ss;
// Generate 1-5 statements
int count = RandomInt(1, 5);
for (int i = 0; i < count; i++) {
ss << GenerateStatement(0) << "\n";
}
// Optionally add a return
if (RandomBool()) {
ss << "return " << GenerateExpression(0) << "\n";
}
return ss.str();
}
bool LuaFuzzer::VerifySandboxIntegrity() {
// Create a fresh sandbox and verify basic operations work
SandboxContext ctx{
.app_id = "fuzzer.verify",
.app_path = ".",
.permissions = {},
.is_system_app = false
};
LuaSandbox sandbox(ctx);
// Test basic arithmetic
if (!sandbox.LoadString("return 1 + 1", "verify1")) {
return false;
}
// Test string operations
if (!sandbox.LoadString("return string.len('test')", "verify2")) {
return false;
}
// Test table operations
if (!sandbox.LoadString("local t = {1,2,3}; return #t", "verify3")) {
return false;
}
// Verify dangerous functions are still blocked
if (sandbox.LoadString("return os.execute", "verify_os")) {
return false; // os.execute should not exist
}
if (sandbox.LoadString("return io.open", "verify_io")) {
return false; // io.open should not exist
}
return true;
}
FuzzResult LuaFuzzer::Run(size_t iterations) {
FuzzResult result;
result.iterations = iterations;
for (size_t i = 0; i < iterations; i++) {
m_total_runs++;
// Generate random code
std::string code = GenerateRandomCode();
// Create sandbox with limits
SandboxContext ctx{
.app_id = "fuzzer.test",
.app_path = ".",
.permissions = {},
.is_system_app = false
};
SandboxLimits limits;
limits.memory_bytes = 10 * 1024 * 1024; // 10MB limit
limits.instructions_per_call = 100000; // 100k instruction limit
try {
LuaSandbox sandbox(ctx, limits);
// Execute
bool ok = sandbox.LoadString(code, "fuzz_" + std::to_string(i));
if (!ok) {
m_errors_caught++;
result.errors_caught++;
// This is expected - random code often has errors
}
} catch (const std::exception& e) {
// Caught exception - not a crash, but unexpected
m_errors_caught++;
result.errors_caught++;
result.error = std::string("Exception: ") + e.what();
} catch (...) {
// Unknown exception - this is bad
m_crashes++;
result.crashed = true;
result.error = "Unknown exception caught";
return result;
}
}
// Verify sandbox is still working correctly
result.sandbox_intact = VerifySandboxIntegrity();
return result;
}
} // namespace mosis