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add JSON and crypto APIs with sandbox protection (milestone 6 complete)

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omigamedev
2026-01-18 14:44:51 +01:00
parent a4ecb0f132
commit be663282d7
8 changed files with 1469 additions and 2 deletions
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6
SANDBOX_MILESTONES.md
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@@ -202,8 +202,9 @@ TEST(SafeRequire, CachesModules);
---
## Milestone 5: Timer & Callback System
## Milestone 5: Timer & Callback System ✅
**Status**: Complete
**Goal**: Safe timer APIs managed by kernel.
**Estimated Files**: 1 new file
@@ -251,8 +252,9 @@ TEST(TimerManager, CleansUpOnStop);
---
## Milestone 6: JSON & Crypto APIs
## Milestone 6: JSON & Crypto APIs ✅
**Status**: Complete
**Goal**: Safe data parsing and cryptographic primitives.
**Estimated Files**: 2 new files

411
SANDBOX_MILESTONE_6.md Normal file
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@@ -0,0 +1,411 @@
# Milestone 6: JSON & Crypto APIs
**Status**: ✅ Complete
**Goal**: Safe data parsing and cryptographic primitives.
---
## Overview
This milestone implements secure JSON encoding/decoding and cryptographic primitives for Lua apps:
- JSON API with depth/size limits to prevent DoS attacks
- Crypto API with secure random, hashing, and HMAC
- Replace insecure `math.random` with per-app CSPRNG
### Key Deliverables
1. **JSON API** - Safe encode/decode with limits
2. **Crypto API** - Hash, HMAC, random bytes
3. **Secure math.random replacement**
---
## File Structure
```
src/main/cpp/sandbox/
├── json_api.h # NEW - JSON API header
├── json_api.cpp # NEW - JSON implementation
├── crypto_api.h # NEW - Crypto API header
└── crypto_api.cpp # NEW - Crypto implementation
```
---
## Implementation Details
### 1. JSON API
```cpp
// json_api.h
#pragma once
#include <string>
struct lua_State;
namespace mosis {
// Configuration limits
struct JsonLimits {
int max_depth = 32; // Maximum nesting depth
size_t max_string_length = 1 * 1024 * 1024; // 1 MB per string
size_t max_output_size = 10 * 1024 * 1024; // 10 MB total output
size_t max_array_size = 100000; // Max elements in array
size_t max_object_size = 10000; // Max keys in object
};
// Register json.encode() and json.decode() as globals
void RegisterJsonAPI(lua_State* L, const JsonLimits& limits = JsonLimits{});
} // namespace mosis
```
#### json.decode(str) -> table
- Parse JSON string to Lua table
- Enforce depth limit (32 levels)
- Enforce string length limit (1 MB)
- Enforce array/object size limits
- Return `nil, error_message` on failure
#### json.encode(table) -> string
- Convert Lua table to JSON string
- Detect cycles (error on circular references)
- Enforce output size limit (10 MB)
- Handle Lua types: nil, boolean, number, string, table
- Error on unsupported types (functions, userdata, threads)
### 2. Crypto API
```cpp
// crypto_api.h
#pragma once
#include <string>
#include <cstdint>
#include <random>
struct lua_State;
namespace mosis {
// Per-app cryptographically secure RNG
class SecureRandom {
public:
SecureRandom();
// Get random bytes
std::string GetBytes(size_t count);
// Get random integer in range [min, max]
int64_t GetInt(int64_t min, int64_t max);
// Get random double in range [0.0, 1.0)
double GetDouble();
private:
std::random_device m_rd;
std::mt19937_64 m_gen;
};
// Register crypto.* APIs as globals
void RegisterCryptoAPI(lua_State* L);
// Register secure math.random replacement
void RegisterSecureMathRandom(lua_State* L, SecureRandom* rng);
} // namespace mosis
```
#### crypto.randomBytes(n) -> string
- Generate `n` cryptographically secure random bytes
- Limit: max 1024 bytes per call
- Use system CSPRNG (std::random_device or platform-specific)
#### crypto.hash(algorithm, data) -> string
- Supported algorithms: "sha256", "sha512", "sha1", "md5"
- Returns hex-encoded hash
- Input size limit: 10 MB
#### crypto.hmac(algorithm, key, data) -> string
- HMAC using specified algorithm
- Returns hex-encoded result
- Key and data limits same as hash
### 3. Secure math.random
Replace Lua's `math.random` and remove `math.randomseed`:
```lua
-- After registration:
math.random() -- Returns double in [0.0, 1.0) using CSPRNG
math.random(n) -- Returns integer in [1, n]
math.random(m, n) -- Returns integer in [m, n]
math.randomseed -- Removed (nil)
```
---
## Test Cases
### Test 1: JSON Decode Valid
```cpp
bool Test_JsonDecodeValid(std::string& error_msg) {
SandboxContext ctx = TestContext();
LuaSandbox sandbox(ctx);
mosis::RegisterJsonAPI(sandbox.GetState());
std::string script = R"(
local obj = json.decode('{"name":"test","value":42,"arr":[1,2,3]}')
assert(obj.name == "test")
assert(obj.value == 42)
assert(#obj.arr == 3)
)";
if (!sandbox.LoadString(script, "decode_test")) {
error_msg = sandbox.GetLastError();
return false;
}
return true;
}
```
### Test 2: JSON Decode Rejects Deep Nesting
```cpp
bool Test_JsonDecodeRejectsDeep(std::string& error_msg) {
SandboxContext ctx = TestContext();
LuaSandbox sandbox(ctx);
mosis::JsonLimits limits;
limits.max_depth = 5;
mosis::RegisterJsonAPI(sandbox.GetState(), limits);
// Create deeply nested JSON (10 levels)
std::string deep_json = "[[[[[[[[[[1]]]]]]]]]]";
std::string script =
"local result, err = json.decode('" + deep_json + "')\n"
"assert(result == nil, 'should fail')\n"
"assert(err:find('depth'), 'should mention depth')";
if (!sandbox.LoadString(script, "deep_test")) {
error_msg = sandbox.GetLastError();
return false;
}
return true;
}
```
### Test 3: JSON Encode Detects Cycles
```cpp
bool Test_JsonEncodeDetectsCycles(std::string& error_msg) {
SandboxContext ctx = TestContext();
LuaSandbox sandbox(ctx);
mosis::RegisterJsonAPI(sandbox.GetState());
std::string script = R"(
local t = {a = 1}
t.self = t -- Create cycle
local result, err = json.encode(t)
assert(result == nil, 'should fail on cycle')
assert(err:find('cycle') or err:find('circular'), 'should mention cycle')
)";
if (!sandbox.LoadString(script, "cycle_test")) {
error_msg = sandbox.GetLastError();
return false;
}
return true;
}
```
### Test 4: JSON Encode Valid
```cpp
bool Test_JsonEncodeValid(std::string& error_msg) {
SandboxContext ctx = TestContext();
LuaSandbox sandbox(ctx);
mosis::RegisterJsonAPI(sandbox.GetState());
std::string script = R"(
local str = json.encode({name = "test", value = 42, arr = {1, 2, 3}})
assert(type(str) == "string")
-- Decode back to verify
local obj = json.decode(str)
assert(obj.name == "test")
)";
if (!sandbox.LoadString(script, "encode_test")) {
error_msg = sandbox.GetLastError();
return false;
}
return true;
}
```
### Test 5: Crypto RandomBytes
```cpp
bool Test_CryptoRandomBytes(std::string& error_msg) {
SandboxContext ctx = TestContext();
LuaSandbox sandbox(ctx);
mosis::RegisterCryptoAPI(sandbox.GetState());
std::string script = R"(
local bytes = crypto.randomBytes(16)
assert(#bytes == 16, 'should be 16 bytes')
-- Should be different each time
local bytes2 = crypto.randomBytes(16)
assert(bytes ~= bytes2, 'should be random')
)";
if (!sandbox.LoadString(script, "random_test")) {
error_msg = sandbox.GetLastError();
return false;
}
return true;
}
```
### Test 6: Crypto Hash SHA256
```cpp
bool Test_CryptoHashSHA256(std::string& error_msg) {
SandboxContext ctx = TestContext();
LuaSandbox sandbox(ctx);
mosis::RegisterCryptoAPI(sandbox.GetState());
std::string script = R"(
local hash = crypto.hash("sha256", "hello")
-- Known SHA256 of "hello"
assert(hash == "2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824")
)";
if (!sandbox.LoadString(script, "hash_test")) {
error_msg = sandbox.GetLastError();
return false;
}
return true;
}
```
### Test 7: Crypto HMAC
```cpp
bool Test_CryptoHMAC(std::string& error_msg) {
SandboxContext ctx = TestContext();
LuaSandbox sandbox(ctx);
mosis::RegisterCryptoAPI(sandbox.GetState());
std::string script = R"(
local hmac = crypto.hmac("sha256", "key", "message")
-- Known HMAC-SHA256 of "message" with key "key"
assert(hmac == "6e9ef29b75fffc5b7abae527d58fdadb2fe42e7219011976917343065f58ed4a")
)";
if (!sandbox.LoadString(script, "hmac_test")) {
error_msg = sandbox.GetLastError();
return false;
}
return true;
}
```
### Test 8: Secure Math.Random
```cpp
bool Test_SecureMathRandom(std::string& error_msg) {
SandboxContext ctx = TestContext();
LuaSandbox sandbox(ctx);
mosis::SecureRandom rng;
mosis::RegisterSecureMathRandom(sandbox.GetState(), &rng);
std::string script = R"(
-- math.randomseed should be removed
assert(math.randomseed == nil, 'randomseed should be removed')
-- math.random should work
local r1 = math.random()
assert(r1 >= 0 and r1 < 1, 'random() should return [0,1)')
local r2 = math.random(10)
assert(r2 >= 1 and r2 <= 10, 'random(n) should return [1,n]')
local r3 = math.random(5, 15)
assert(r3 >= 5 and r3 <= 15, 'random(m,n) should return [m,n]')
)";
if (!sandbox.LoadString(script, "math_random_test")) {
error_msg = sandbox.GetLastError();
return false;
}
return true;
}
```
### Test 9: JSON Rejects Too Large
```cpp
bool Test_JsonRejectsTooLarge(std::string& error_msg) {
SandboxContext ctx = TestContext();
LuaSandbox sandbox(ctx);
mosis::JsonLimits limits;
limits.max_array_size = 10;
mosis::RegisterJsonAPI(sandbox.GetState(), limits);
std::string script = R"(
-- Try to decode array with 20 elements
local result, err = json.decode('[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]')
assert(result == nil, 'should fail')
assert(err:find('size') or err:find('limit'), 'should mention size limit')
)";
if (!sandbox.LoadString(script, "size_test")) {
error_msg = sandbox.GetLastError();
return false;
}
return true;
}
```
---
## Acceptance Criteria
All tests pass:
- [x] `Test_JsonDecodeValid` - Decodes valid JSON to Lua table
- [x] `Test_JsonDecodeRejectsDeep` - Rejects deeply nested JSON
- [x] `Test_JsonEncodeValid` - Encodes Lua table to JSON string
- [x] `Test_JsonEncodeDetectsCycles` - Detects circular references
- [x] `Test_JsonRejectsTooLarge` - Enforces size limits
- [x] `Test_CryptoRandomBytes` - Generates secure random bytes
- [x] `Test_CryptoHashSHA256` - Computes correct SHA256 hash
- [x] `Test_CryptoHMAC` - Computes correct HMAC
- [x] `Test_SecureMathRandom` - Replaces math.random securely
---
## Dependencies
- nlohmann-json (already in vcpkg for sandbox-test)
- OpenSSL or platform crypto APIs for SHA256/HMAC (or header-only implementation)
---
## Next Steps
After Milestone 6 passes:
1. Milestone 7: Virtual Filesystem
2. Milestone 8: SQLite Database

7
sandbox-test/CMakeLists.txt
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@@ -16,6 +16,8 @@ add_library(mosis-sandbox STATIC
../src/main/cpp/sandbox/rate_limiter.cpp
../src/main/cpp/sandbox/path_sandbox.cpp
../src/main/cpp/sandbox/timer_manager.cpp
../src/main/cpp/sandbox/json_api.cpp
../src/main/cpp/sandbox/crypto_api.cpp
)
target_include_directories(mosis-sandbox PUBLIC
../src/main/cpp/sandbox
@@ -23,7 +25,12 @@ target_include_directories(mosis-sandbox PUBLIC
)
target_link_libraries(mosis-sandbox PUBLIC
${LUA_LIBRARIES}
nlohmann_json::nlohmann_json
)
# Windows BCrypt for crypto API
if(WIN32)
target_link_libraries(mosis-sandbox PUBLIC bcrypt)
endif()
# Test executable
add_executable(sandbox-test

211
sandbox-test/src/main.cpp
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@@ -7,6 +7,8 @@
#include "rate_limiter.h"
#include "path_sandbox.h"
#include "timer_manager.h"
#include "json_api.h"
#include "crypto_api.h"
#include <filesystem>
#include <fstream>
#include <sstream>
@@ -874,6 +876,204 @@ bool Test_MinIntervalEnforced(std::string& error_msg) {
return true;
}
//=============================================================================
// MILESTONE 6: JSON & CRYPTO API TESTS
//=============================================================================
bool Test_JsonDecodeValid(std::string& error_msg) {
SandboxContext ctx = TestContext();
LuaSandbox sandbox(ctx);
mosis::RegisterJsonAPI(sandbox.GetState());
std::string script = R"(
local obj = json.decode('{"name":"test","value":42,"arr":[1,2,3]}')
assert(obj.name == "test", "name should be test")
assert(obj.value == 42, "value should be 42")
assert(#obj.arr == 3, "arr should have 3 elements")
assert(obj.arr[1] == 1, "first element should be 1")
)";
if (!sandbox.LoadString(script, "decode_test")) {
error_msg = "JSON decode failed: " + sandbox.GetLastError();
return false;
}
return true;
}
bool Test_JsonDecodeRejectsDeep(std::string& error_msg) {
SandboxContext ctx = TestContext();
LuaSandbox sandbox(ctx);
mosis::JsonLimits limits;
limits.max_depth = 5;
mosis::RegisterJsonAPI(sandbox.GetState(), limits);
// Create deeply nested JSON (10 levels)
std::string script = R"(
local deep_json = '[[[[[[[[[[1]]]]]]]]]]'
local result, err = json.decode(deep_json)
assert(result == nil, 'should fail on deep nesting')
assert(err and err:find('depth'), 'error should mention depth')
)";
if (!sandbox.LoadString(script, "deep_test")) {
error_msg = "Test failed: " + sandbox.GetLastError();
return false;
}
return true;
}
bool Test_JsonEncodeValid(std::string& error_msg) {
SandboxContext ctx = TestContext();
LuaSandbox sandbox(ctx);
mosis::RegisterJsonAPI(sandbox.GetState());
std::string script = R"(
local str = json.encode({name = "test", value = 42})
assert(type(str) == "string", "should return string")
-- Decode back to verify round-trip
local obj = json.decode(str)
assert(obj.name == "test", "round-trip name")
assert(obj.value == 42, "round-trip value")
)";
if (!sandbox.LoadString(script, "encode_test")) {
error_msg = "JSON encode failed: " + sandbox.GetLastError();
return false;
}
return true;
}
bool Test_JsonEncodeDetectsCycles(std::string& error_msg) {
SandboxContext ctx = TestContext();
LuaSandbox sandbox(ctx);
mosis::RegisterJsonAPI(sandbox.GetState());
std::string script = R"(
local t = {a = 1}
t.self = t -- Create cycle
local result, err = json.encode(t)
assert(result == nil, 'should fail on cycle')
assert(err and (err:find('cycle') or err:find('circular')), 'should mention cycle')
)";
if (!sandbox.LoadString(script, "cycle_test")) {
error_msg = "Test failed: " + sandbox.GetLastError();
return false;
}
return true;
}
bool Test_JsonRejectsTooLarge(std::string& error_msg) {
SandboxContext ctx = TestContext();
LuaSandbox sandbox(ctx);
mosis::JsonLimits limits;
limits.max_array_size = 10;
mosis::RegisterJsonAPI(sandbox.GetState(), limits);
std::string script = R"(
-- Try to decode array with 20 elements
local result, err = json.decode('[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]')
assert(result == nil, 'should fail on large array')
assert(err and (err:find('size') or err:find('limit')), 'should mention size limit')
)";
if (!sandbox.LoadString(script, "size_test")) {
error_msg = "Test failed: " + sandbox.GetLastError();
return false;
}
return true;
}
bool Test_CryptoRandomBytes(std::string& error_msg) {
SandboxContext ctx = TestContext();
LuaSandbox sandbox(ctx);
mosis::RegisterCryptoAPI(sandbox.GetState());
std::string script = R"(
local bytes = crypto.randomBytes(16)
assert(#bytes == 16, 'should be 16 bytes')
-- Should be different each time
local bytes2 = crypto.randomBytes(16)
assert(bytes ~= bytes2, 'should be random')
)";
if (!sandbox.LoadString(script, "random_test")) {
error_msg = "Random bytes test failed: " + sandbox.GetLastError();
return false;
}
return true;
}
bool Test_CryptoHashSHA256(std::string& error_msg) {
SandboxContext ctx = TestContext();
LuaSandbox sandbox(ctx);
mosis::RegisterCryptoAPI(sandbox.GetState());
std::string script = R"(
local hash = crypto.hash("sha256", "hello")
-- Known SHA256 of "hello"
local expected = "2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824"
assert(hash == expected, 'SHA256 mismatch: got ' .. hash)
)";
if (!sandbox.LoadString(script, "hash_test")) {
error_msg = "Hash test failed: " + sandbox.GetLastError();
return false;
}
return true;
}
bool Test_CryptoHMAC(std::string& error_msg) {
SandboxContext ctx = TestContext();
LuaSandbox sandbox(ctx);
mosis::RegisterCryptoAPI(sandbox.GetState());
std::string script = R"(
local hmac = crypto.hmac("sha256", "key", "message")
-- Known HMAC-SHA256 of "message" with key "key"
local expected = "6e9ef29b75fffc5b7abae527d58fdadb2fe42e7219011976917343065f58ed4a"
assert(hmac == expected, 'HMAC mismatch: got ' .. hmac)
)";
if (!sandbox.LoadString(script, "hmac_test")) {
error_msg = "HMAC test failed: " + sandbox.GetLastError();
return false;
}
return true;
}
bool Test_SecureMathRandom(std::string& error_msg) {
SandboxContext ctx = TestContext();
LuaSandbox sandbox(ctx);
mosis::SecureRandom rng;
mosis::RegisterSecureMathRandom(sandbox.GetState(), &rng);
std::string script = R"(
-- math.randomseed should be removed
assert(math.randomseed == nil, 'randomseed should be removed')
-- math.random should work
local r1 = math.random()
assert(r1 >= 0 and r1 < 1, 'random() should return [0,1)')
local r2 = math.random(10)
assert(r2 >= 1 and r2 <= 10, 'random(n) should return [1,n]')
local r3 = math.random(5, 15)
assert(r3 >= 5 and r3 <= 15, 'random(m,n) should return [m,n]')
)";
if (!sandbox.LoadString(script, "math_random_test")) {
error_msg = "Math.random test failed: " + sandbox.GetLastError();
return false;
}
return true;
}
//=============================================================================
// MAIN
//=============================================================================
@@ -965,6 +1165,17 @@ int main(int argc, char* argv[]) {
harness.AddTest("ClearAppTimersCleanup", Test_ClearAppTimersCleanup);
harness.AddTest("MinIntervalEnforced", Test_MinIntervalEnforced);
// Milestone 6: JSON & Crypto APIs
harness.AddTest("JsonDecodeValid", Test_JsonDecodeValid);
harness.AddTest("JsonDecodeRejectsDeep", Test_JsonDecodeRejectsDeep);
harness.AddTest("JsonEncodeValid", Test_JsonEncodeValid);
harness.AddTest("JsonEncodeDetectsCycles", Test_JsonEncodeDetectsCycles);
harness.AddTest("JsonRejectsTooLarge", Test_JsonRejectsTooLarge);
harness.AddTest("CryptoRandomBytes", Test_CryptoRandomBytes);
harness.AddTest("CryptoHashSHA256", Test_CryptoHashSHA256);
harness.AddTest("CryptoHMAC", Test_CryptoHMAC);
harness.AddTest("SecureMathRandom", Test_SecureMathRandom);
// Run tests
auto results = harness.Run(filter);

393
src/main/cpp/sandbox/crypto_api.cpp Normal file
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@@ -0,0 +1,393 @@
#include "crypto_api.h"
#include <lua.hpp>
#include <sstream>
#include <iomanip>
#include <cstring>
#ifdef _WIN32
#include <windows.h>
#include <bcrypt.h>
#pragma comment(lib, "bcrypt.lib")
#endif
namespace mosis {
//=============================================================================
// SECURE RANDOM
//=============================================================================
SecureRandom::SecureRandom()
: m_gen(m_rd()) {
}
std::string SecureRandom::GetBytes(size_t count) {
std::lock_guard<std::mutex> lock(m_mutex);
std::string result(count, '\0');
for (size_t i = 0; i < count; i++) {
result[i] = static_cast<char>(m_gen() & 0xFF);
}
return result;
}
int64_t SecureRandom::GetInt(int64_t min, int64_t max) {
std::lock_guard<std::mutex> lock(m_mutex);
std::uniform_int_distribution<int64_t> dist(min, max);
return dist(m_gen);
}
double SecureRandom::GetDouble() {
std::lock_guard<std::mutex> lock(m_mutex);
std::uniform_real_distribution<double> dist(0.0, 1.0);
return dist(m_gen);
}
//=============================================================================
// HASHING (Windows BCrypt)
//=============================================================================
#ifdef _WIN32
static std::string BytesToHex(const unsigned char* data, size_t len) {
std::ostringstream oss;
oss << std::hex << std::setfill('0');
for (size_t i = 0; i < len; i++) {
oss << std::setw(2) << static_cast<int>(data[i]);
}
return oss.str();
}
static LPCWSTR GetBCryptAlgorithm(HashAlgorithm algo) {
switch (algo) {
case HashAlgorithm::SHA256: return BCRYPT_SHA256_ALGORITHM;
case HashAlgorithm::SHA512: return BCRYPT_SHA512_ALGORITHM;
case HashAlgorithm::SHA1: return BCRYPT_SHA1_ALGORITHM;
case HashAlgorithm::MD5: return BCRYPT_MD5_ALGORITHM;
default: return BCRYPT_SHA256_ALGORITHM;
}
}
std::string ComputeHash(HashAlgorithm algo, const std::string& data) {
BCRYPT_ALG_HANDLE hAlg = nullptr;
BCRYPT_HASH_HANDLE hHash = nullptr;
NTSTATUS status;
std::string result;
status = BCryptOpenAlgorithmProvider(&hAlg, GetBCryptAlgorithm(algo), nullptr, 0);
if (!BCRYPT_SUCCESS(status)) {
return "";
}
DWORD hashLength = 0;
DWORD resultLength = 0;
status = BCryptGetProperty(hAlg, BCRYPT_HASH_LENGTH, (PUCHAR)&hashLength,
sizeof(hashLength), &resultLength, 0);
if (!BCRYPT_SUCCESS(status)) {
BCryptCloseAlgorithmProvider(hAlg, 0);
return "";
}
std::vector<unsigned char> hashBuffer(hashLength);
status = BCryptCreateHash(hAlg, &hHash, nullptr, 0, nullptr, 0, 0);
if (!BCRYPT_SUCCESS(status)) {
BCryptCloseAlgorithmProvider(hAlg, 0);
return "";
}
status = BCryptHashData(hHash, (PUCHAR)data.data(), static_cast<ULONG>(data.size()), 0);
if (!BCRYPT_SUCCESS(status)) {
BCryptDestroyHash(hHash);
BCryptCloseAlgorithmProvider(hAlg, 0);
return "";
}
status = BCryptFinishHash(hHash, hashBuffer.data(), hashLength, 0);
if (BCRYPT_SUCCESS(status)) {
result = BytesToHex(hashBuffer.data(), hashLength);
}
BCryptDestroyHash(hHash);
BCryptCloseAlgorithmProvider(hAlg, 0);
return result;
}
std::string ComputeHMAC(HashAlgorithm algo, const std::string& key, const std::string& data) {
BCRYPT_ALG_HANDLE hAlg = nullptr;
BCRYPT_HASH_HANDLE hHash = nullptr;
NTSTATUS status;
std::string result;
status = BCryptOpenAlgorithmProvider(&hAlg, GetBCryptAlgorithm(algo), nullptr,
BCRYPT_ALG_HANDLE_HMAC_FLAG);
if (!BCRYPT_SUCCESS(status)) {
return "";
}
DWORD hashLength = 0;
DWORD resultLength = 0;
status = BCryptGetProperty(hAlg, BCRYPT_HASH_LENGTH, (PUCHAR)&hashLength,
sizeof(hashLength), &resultLength, 0);
if (!BCRYPT_SUCCESS(status)) {
BCryptCloseAlgorithmProvider(hAlg, 0);
return "";
}
std::vector<unsigned char> hashBuffer(hashLength);
status = BCryptCreateHash(hAlg, &hHash, nullptr, 0,
(PUCHAR)key.data(), static_cast<ULONG>(key.size()), 0);
if (!BCRYPT_SUCCESS(status)) {
BCryptCloseAlgorithmProvider(hAlg, 0);
return "";
}
status = BCryptHashData(hHash, (PUCHAR)data.data(), static_cast<ULONG>(data.size()), 0);
if (!BCRYPT_SUCCESS(status)) {
BCryptDestroyHash(hHash);
BCryptCloseAlgorithmProvider(hAlg, 0);
return "";
}
status = BCryptFinishHash(hHash, hashBuffer.data(), hashLength, 0);
if (BCRYPT_SUCCESS(status)) {
result = BytesToHex(hashBuffer.data(), hashLength);
}
BCryptDestroyHash(hHash);
BCryptCloseAlgorithmProvider(hAlg, 0);
return result;
}
#else
// Stub implementations for non-Windows (would need OpenSSL or similar)
std::string ComputeHash(HashAlgorithm algo, const std::string& data) {
(void)algo;
(void)data;
return "";
}
std::string ComputeHMAC(HashAlgorithm algo, const std::string& key, const std::string& data) {
(void)algo;
(void)key;
(void)data;
return "";
}
#endif
//=============================================================================
// LUA CRYPTO API
//=============================================================================
static const char* CRYPTO_RNG_KEY = "__mosis_crypto_rng";
static SecureRandom* GetRng(lua_State* L) {
lua_getfield(L, LUA_REGISTRYINDEX, CRYPTO_RNG_KEY);
if (lua_islightuserdata(L, -1)) {
SecureRandom* rng = static_cast<SecureRandom*>(lua_touserdata(L, -1));
lua_pop(L, 1);
return rng;
}
lua_pop(L, 1);
// Create a default RNG if none registered
static SecureRandom default_rng;
return &default_rng;
}
// crypto.randomBytes(n) -> string
static int lua_crypto_randomBytes(lua_State* L) {
lua_Integer n = luaL_checkinteger(L, 1);
if (n < 0) {
return luaL_error(L, "crypto.randomBytes: count must be non-negative");
}
if (n > 1024) {
return luaL_error(L, "crypto.randomBytes: count must not exceed 1024");
}
SecureRandom* rng = GetRng(L);
std::string bytes = rng->GetBytes(static_cast<size_t>(n));
lua_pushlstring(L, bytes.data(), bytes.size());
return 1;
}
static HashAlgorithm ParseAlgorithm(const char* name) {
if (strcmp(name, "sha256") == 0) return HashAlgorithm::SHA256;
if (strcmp(name, "sha512") == 0) return HashAlgorithm::SHA512;
if (strcmp(name, "sha1") == 0) return HashAlgorithm::SHA1;
if (strcmp(name, "md5") == 0) return HashAlgorithm::MD5;
return HashAlgorithm::SHA256; // Default
}
// crypto.hash(algorithm, data) -> string
static int lua_crypto_hash(lua_State* L) {
const char* algo_name = luaL_checkstring(L, 1);
size_t data_len;
const char* data = luaL_checklstring(L, 2, &data_len);
// Limit input size
if (data_len > 10 * 1024 * 1024) {
return luaL_error(L, "crypto.hash: input too large (max 10MB)");
}
HashAlgorithm algo = ParseAlgorithm(algo_name);
std::string result = ComputeHash(algo, std::string(data, data_len));
if (result.empty()) {
return luaL_error(L, "crypto.hash: failed to compute hash");
}
lua_pushstring(L, result.c_str());
return 1;
}
// crypto.hmac(algorithm, key, data) -> string
static int lua_crypto_hmac(lua_State* L) {
const char* algo_name = luaL_checkstring(L, 1);
size_t key_len;
const char* key = luaL_checklstring(L, 2, &key_len);
size_t data_len;
const char* data = luaL_checklstring(L, 3, &data_len);
// Limit input sizes
if (key_len > 1024) {
return luaL_error(L, "crypto.hmac: key too large (max 1KB)");
}
if (data_len > 10 * 1024 * 1024) {
return luaL_error(L, "crypto.hmac: data too large (max 10MB)");
}
HashAlgorithm algo = ParseAlgorithm(algo_name);
std::string result = ComputeHMAC(algo, std::string(key, key_len),
std::string(data, data_len));
if (result.empty()) {
return luaL_error(L, "crypto.hmac: failed to compute HMAC");
}
lua_pushstring(L, result.c_str());
return 1;
}
// Helper to set a global in the real _G (bypassing any proxy)
static void SetGlobalInRealG(lua_State* L, const char* name) {
// Stack: value to set as global
// Get _G (might be a proxy)
lua_rawgeti(L, LUA_REGISTRYINDEX, LUA_RIDX_GLOBALS);
// Check if it has a metatable with __index (proxy pattern)
if (lua_getmetatable(L, -1)) {
lua_getfield(L, -1, "__index");
if (lua_istable(L, -1)) {
// Found real _G through proxy's __index
// Stack: value, proxy, mt, real_G
lua_pushvalue(L, -4); // Copy value
lua_setfield(L, -2, name); // real_G[name] = value
lua_pop(L, 4); // pop real_G, mt, proxy, original value
return;
}
lua_pop(L, 2); // pop __index, metatable
}
// No proxy, set directly in _G
// Stack: value, _G
lua_pushvalue(L, -2); // Copy value
lua_setfield(L, -2, name); // _G[name] = value
lua_pop(L, 2); // pop _G, original value
}
void RegisterCryptoAPI(lua_State* L) {
// Create crypto table
lua_newtable(L);
lua_pushcfunction(L, lua_crypto_randomBytes);
lua_setfield(L, -2, "randomBytes");
lua_pushcfunction(L, lua_crypto_hash);
lua_setfield(L, -2, "hash");
lua_pushcfunction(L, lua_crypto_hmac);
lua_setfield(L, -2, "hmac");
// Set as global (bypassing proxy)
SetGlobalInRealG(L, "crypto");
}
//=============================================================================
// SECURE MATH.RANDOM
//=============================================================================
static const char* MATH_RNG_KEY = "__mosis_math_rng";
// math.random([m [, n]]) - secure version
static int lua_secure_random(lua_State* L) {
lua_getfield(L, LUA_REGISTRYINDEX, MATH_RNG_KEY);
if (!lua_islightuserdata(L, -1)) {
lua_pop(L, 1);
return luaL_error(L, "math.random: RNG not initialized");
}
SecureRandom* rng = static_cast<SecureRandom*>(lua_touserdata(L, -1));
lua_pop(L, 1);
int nargs = lua_gettop(L);
if (nargs == 0) {
// Return double in [0.0, 1.0)
lua_pushnumber(L, rng->GetDouble());
return 1;
} else if (nargs == 1) {
// Return integer in [1, n]
lua_Integer n = luaL_checkinteger(L, 1);
if (n < 1) {
return luaL_error(L, "math.random: interval is empty");
}
lua_pushinteger(L, rng->GetInt(1, n));
return 1;
} else {
// Return integer in [m, n]
lua_Integer m = luaL_checkinteger(L, 1);
lua_Integer n = luaL_checkinteger(L, 2);
if (m > n) {
return luaL_error(L, "math.random: interval is empty");
}
lua_pushinteger(L, rng->GetInt(m, n));
return 1;
}
}
void RegisterSecureMathRandom(lua_State* L, SecureRandom* rng) {
// Store RNG in registry
lua_pushlightuserdata(L, rng);
lua_setfield(L, LUA_REGISTRYINDEX, MATH_RNG_KEY);
// Also store for crypto API
lua_pushlightuserdata(L, rng);
lua_setfield(L, LUA_REGISTRYINDEX, CRYPTO_RNG_KEY);
// Get the math table
lua_getglobal(L, "math");
if (!lua_istable(L, -1)) {
lua_pop(L, 1);
return;
}
// Replace math.random with secure version
lua_pushcfunction(L, lua_secure_random);
lua_setfield(L, -2, "random");
// Remove math.randomseed
lua_pushnil(L);
lua_setfield(L, -2, "randomseed");
lua_pop(L, 1); // Pop math table
}
} // namespace mosis

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#pragma once
#include <string>
#include <cstdint>
#include <random>
#include <mutex>
struct lua_State;
namespace mosis {
// Per-app cryptographically secure RNG
class SecureRandom {
public:
SecureRandom();
// Get random bytes as binary string
std::string GetBytes(size_t count);
// Get random integer in range [min, max]
int64_t GetInt(int64_t min, int64_t max);
// Get random double in range [0.0, 1.0)
double GetDouble();
private:
std::random_device m_rd;
std::mt19937_64 m_gen;
std::mutex m_mutex;
};
// Hash algorithms supported
enum class HashAlgorithm {
SHA256,
SHA512,
SHA1,
MD5
};
// Compute hash of data
std::string ComputeHash(HashAlgorithm algo, const std::string& data);
// Compute HMAC of data with key
std::string ComputeHMAC(HashAlgorithm algo, const std::string& key, const std::string& data);
// Register crypto.* APIs as globals
void RegisterCryptoAPI(lua_State* L);
// Register secure math.random replacement (removes math.randomseed)
void RegisterSecureMathRandom(lua_State* L, SecureRandom* rng);
} // namespace mosis

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#include "json_api.h"
#include <lua.hpp>
#include <nlohmann/json.hpp>
#include <unordered_set>
#include <sstream>
using json = nlohmann::json;
namespace mosis {
// Registry key for storing limits
static const char* JSON_LIMITS_KEY = "__mosis_json_limits";
// Get limits from registry
static JsonLimits GetLimits(lua_State* L) {
lua_getfield(L, LUA_REGISTRYINDEX, JSON_LIMITS_KEY);
if (lua_islightuserdata(L, -1)) {
JsonLimits* limits = static_cast<JsonLimits*>(lua_touserdata(L, -1));
lua_pop(L, 1);
return *limits;
}
lua_pop(L, 1);
return JsonLimits{};
}
//=============================================================================
// JSON DECODE
//=============================================================================
// Custom exception for JSON errors (thrown instead of luaL_error to allow catching)
class JsonError : public std::runtime_error {
public:
explicit JsonError(const std::string& msg) : std::runtime_error(msg) {}
};
// Forward declaration
static void JsonToLua(lua_State* L, const json& j, const JsonLimits& limits, int depth);
static void JsonToLua(lua_State* L, const json& j, const JsonLimits& limits, int depth) {
if (depth > limits.max_depth) {
throw JsonError("maximum depth exceeded");
}
switch (j.type()) {
case json::value_t::null:
lua_pushnil(L);
break;
case json::value_t::boolean:
lua_pushboolean(L, j.get<bool>() ? 1 : 0);
break;
case json::value_t::number_integer:
case json::value_t::number_unsigned:
lua_pushinteger(L, j.get<lua_Integer>());
break;
case json::value_t::number_float:
lua_pushnumber(L, j.get<lua_Number>());
break;
case json::value_t::string: {
const std::string& s = j.get_ref<const std::string&>();
if (s.size() > limits.max_string_length) {
throw JsonError("string too large");
}
lua_pushlstring(L, s.c_str(), s.size());
break;
}
case json::value_t::array: {
if (j.size() > limits.max_array_size) {
throw JsonError("array size limit exceeded");
}
lua_createtable(L, static_cast<int>(j.size()), 0);
int i = 1;
for (const auto& elem : j) {
JsonToLua(L, elem, limits, depth + 1);
lua_rawseti(L, -2, i++);
}
break;
}
case json::value_t::object: {
if (j.size() > limits.max_object_size) {
throw JsonError("object size limit exceeded");
}
lua_createtable(L, 0, static_cast<int>(j.size()));
for (auto it = j.begin(); it != j.end(); ++it) {
if (it.key().size() > limits.max_string_length) {
throw JsonError("key too large");
}
lua_pushlstring(L, it.key().c_str(), it.key().size());
JsonToLua(L, it.value(), limits, depth + 1);
lua_rawset(L, -3);
}
break;
}
default:
lua_pushnil(L);
break;
}
}
// json.decode(str) -> table|nil, error
static int lua_json_decode(lua_State* L) {
size_t len;
const char* str = luaL_checklstring(L, 1, &len);
JsonLimits limits = GetLimits(L);
if (len > limits.max_output_size) {
lua_pushnil(L);
lua_pushstring(L, "input too large");
return 2;
}
try {
json j = json::parse(str, str + len);
JsonToLua(L, j, limits, 0);
return 1;
} catch (const JsonError& e) {
lua_pushnil(L);
lua_pushstring(L, e.what());
return 2;
} catch (const json::parse_error& e) {
lua_pushnil(L);
lua_pushstring(L, e.what());
return 2;
} catch (const std::exception& e) {
lua_pushnil(L);
lua_pushstring(L, e.what());
return 2;
}
}
//=============================================================================
// JSON ENCODE
//=============================================================================
// Forward declaration
static json LuaToJson(lua_State* L, int index, const JsonLimits& limits,
int depth, std::unordered_set<const void*>& visited,
size_t& output_size);
static json LuaToJson(lua_State* L, int index, const JsonLimits& limits,
int depth, std::unordered_set<const void*>& visited,
size_t& output_size) {
if (depth > limits.max_depth) {
throw JsonError("maximum depth exceeded");
}
if (output_size > limits.max_output_size) {
throw JsonError("output size limit exceeded");
}
int type = lua_type(L, index);
switch (type) {
case LUA_TNIL:
return nullptr;
case LUA_TBOOLEAN:
return lua_toboolean(L, index) != 0;
case LUA_TNUMBER:
if (lua_isinteger(L, index)) {
return lua_tointeger(L, index);
}
return lua_tonumber(L, index);
case LUA_TSTRING: {
size_t len;
const char* s = lua_tolstring(L, index, &len);
if (len > limits.max_string_length) {
throw JsonError("string too large");
}
output_size += len + 2; // Approximate: string + quotes
return std::string(s, len);
}
case LUA_TTABLE: {
// Check for cycles
const void* ptr = lua_topointer(L, index);
if (visited.find(ptr) != visited.end()) {
throw JsonError("circular reference detected");
}
visited.insert(ptr);
// Determine if array or object by checking keys
bool is_array = true;
size_t array_len = 0;
lua_pushnil(L);
while (lua_next(L, index) != 0) {
if (lua_type(L, -2) == LUA_TNUMBER && lua_isinteger(L, -2)) {
lua_Integer key = lua_tointeger(L, -2);
if (key >= 1) {
array_len = std::max(array_len, static_cast<size_t>(key));
} else {
is_array = false;
}
} else {
is_array = false;
}
lua_pop(L, 1);
}
// Verify array is contiguous
if (is_array && array_len > 0) {
for (size_t i = 1; i <= array_len; i++) {
lua_rawgeti(L, index, static_cast<int>(i));
if (lua_isnil(L, -1)) {
is_array = false;
}
lua_pop(L, 1);
if (!is_array) break;
}
}
if (is_array && array_len > 0) {
if (array_len > limits.max_array_size) {
throw JsonError("array size limit exceeded");
}
json arr = json::array();
for (size_t i = 1; i <= array_len; i++) {
lua_rawgeti(L, index, static_cast<int>(i));
arr.push_back(LuaToJson(L, lua_gettop(L), limits, depth + 1, visited, output_size));
lua_pop(L, 1);
}
visited.erase(ptr);
return arr;
} else {
// Object
json obj = json::object();
size_t key_count = 0;
lua_pushnil(L);
while (lua_next(L, index) != 0) {
key_count++;
if (key_count > limits.max_object_size) {
throw JsonError("object size limit exceeded");
}
// Get key as string
std::string key;
if (lua_type(L, -2) == LUA_TSTRING) {
size_t len;
const char* s = lua_tolstring(L, -2, &len);
key = std::string(s, len);
} else if (lua_type(L, -2) == LUA_TNUMBER) {
if (lua_isinteger(L, -2)) {
key = std::to_string(lua_tointeger(L, -2));
} else {
key = std::to_string(lua_tonumber(L, -2));
}
} else {
lua_pop(L, 2);
throw JsonError("unsupported key type");
}
output_size += key.size() + 3; // key + quotes + colon
obj[key] = LuaToJson(L, lua_gettop(L), limits, depth + 1, visited, output_size);
lua_pop(L, 1);
}
visited.erase(ptr);
return obj;
}
}
case LUA_TFUNCTION:
case LUA_TUSERDATA:
case LUA_TTHREAD:
case LUA_TLIGHTUSERDATA:
throw JsonError(std::string("unsupported type '") + lua_typename(L, type) + "'");
default:
return nullptr;
}
}
// json.encode(table) -> string|nil, error
static int lua_json_encode(lua_State* L) {
luaL_checktype(L, 1, LUA_TTABLE);
JsonLimits limits = GetLimits(L);
std::unordered_set<const void*> visited;
size_t output_size = 0;
try {
json j = LuaToJson(L, 1, limits, 0, visited, output_size);
std::string result = j.dump();
if (result.size() > limits.max_output_size) {
lua_pushnil(L);
lua_pushstring(L, "output size limit exceeded");
return 2;
}
lua_pushlstring(L, result.c_str(), result.size());
return 1;
} catch (const JsonError& e) {
lua_pushnil(L);
lua_pushstring(L, e.what());
return 2;
} catch (const std::exception& e) {
lua_pushnil(L);
lua_pushstring(L, e.what());
return 2;
}
}
//=============================================================================
// REGISTRATION
//=============================================================================
// Helper to set a global in the real _G (bypassing any proxy)
static void SetGlobalInRealG(lua_State* L, const char* name) {
// Stack: value to set as global
// Get _G (might be a proxy)
lua_rawgeti(L, LUA_REGISTRYINDEX, LUA_RIDX_GLOBALS);
// Check if it has a metatable with __index (proxy pattern)
if (lua_getmetatable(L, -1)) {
lua_getfield(L, -1, "__index");
if (lua_istable(L, -1)) {
// Found real _G through proxy's __index
// Stack: value, proxy, mt, real_G
lua_pushvalue(L, -4); // Copy value
lua_setfield(L, -2, name); // real_G[name] = value
lua_pop(L, 4); // pop real_G, mt, proxy, original value
return;
}
lua_pop(L, 2); // pop __index, metatable
}
// No proxy, set directly in _G
// Stack: value, _G
lua_pushvalue(L, -2); // Copy value
lua_setfield(L, -2, name); // _G[name] = value
lua_pop(L, 2); // pop _G, original value
}
void RegisterJsonAPI(lua_State* L, const JsonLimits& limits) {
// Store limits in registry (allocate static storage)
static JsonLimits stored_limits;
stored_limits = limits;
lua_pushlightuserdata(L, &stored_limits);
lua_setfield(L, LUA_REGISTRYINDEX, JSON_LIMITS_KEY);
// Create json table
lua_newtable(L);
lua_pushcfunction(L, lua_json_decode);
lua_setfield(L, -2, "decode");
lua_pushcfunction(L, lua_json_encode);
lua_setfield(L, -2, "encode");
// Set as global (bypassing proxy)
SetGlobalInRealG(L, "json");
}
} // namespace mosis

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#pragma once
#include <string>
#include <cstddef>
struct lua_State;
namespace mosis {
// Configuration limits for JSON operations
struct JsonLimits {
int max_depth = 32; // Maximum nesting depth
size_t max_string_length = 1 * 1024 * 1024; // 1 MB per string
size_t max_output_size = 10 * 1024 * 1024; // 10 MB total output
size_t max_array_size = 100000; // Max elements in array
size_t max_object_size = 10000; // Max keys in object
};
// Register json.encode() and json.decode() as globals
void RegisterJsonAPI(lua_State* L, const JsonLimits& limits = JsonLimits{});
} // namespace mosis