# Lua Sandbox System

The sandbox provides secure, isolated Lua environments for third-party apps.

## Security Features

| Feature | Implementation |
|---------|----------------|
| Dangerous globals removed | `os`, `io`, `loadfile`, `dofile`, `debug` |
| Memory limits | Configurable per-app (default 10MB) |
| CPU limits | Instruction counting with timeout |
| Bytecode rejected | Only source code allowed |
| Metatables protected | Cannot modify string/table metatables |
| Path traversal blocked | `../` and absolute paths rejected |

## Permission Categories

| Category | Auto-Grant | Examples |
|----------|------------|----------|
| Normal | Yes | `storage`, `network` |
| Dangerous | User consent | `camera`, `microphone`, `location`, `contacts` |
| Signature | System apps only | `system_settings`, `install_packages` |

## Available APIs

**Core APIs** (always available):
```lua
-- Timers
local id = setTimeout(function() end, 1000)
clearTimeout(id)
local id = setInterval(function() end, 500)
clearInterval(id)

-- JSON
local obj = json.decode('{"key": "value"}')
local str = json.encode({key = "value"})

-- Crypto
local bytes = crypto.randomBytes(16)
local hash = crypto.sha256("data")
local hmac = crypto.hmac("sha256", "key", "data")
```

**Storage APIs** (requires `storage` permission):
```lua
-- Virtual filesystem (sandboxed to app directory)
fs.write("data.txt", "content")
local content = fs.read("data.txt")
local files = fs.list("/")
local stat = fs.stat("data.txt")
fs.delete("data.txt")

-- SQLite database
local db = database.open("mydb")
db:execute("CREATE TABLE IF NOT EXISTS items (id INTEGER PRIMARY KEY, name TEXT)")
db:execute("INSERT INTO items (name) VALUES (?)", {"item1"})
local rows = db:query("SELECT * FROM items WHERE id = ?", {1})
```

**Network APIs** (requires `network` permission):
```lua
-- HTTP (HTTPS only, private IPs blocked)
local response = http.get("https://api.example.com/data")
local response = http.post("https://api.example.com/data", {
    headers = {["Content-Type"] = "application/json"},
    body = json.encode({key = "value"})
})

-- WebSocket
local ws = websocket.connect("wss://example.com/ws")
ws:send("message")
ws:onMessage(function(data) end)
ws:close()
```

**Hardware APIs** (requires dangerous permissions + user gesture):
```lua
-- Camera (requires camera permission)
camera.start(function(frame) end)
camera.stop()

-- Microphone (requires microphone permission)
microphone.start(function(samples) end)
microphone.stop()

-- Location (requires location permission)
location.getCurrentPosition(function(pos)
    print(pos.latitude, pos.longitude)
end)

-- Sensors (requires sensors permission)
sensors.subscribe("accelerometer", function(data)
    print(data.x, data.y, data.z)
end)
```

## Running Sandbox Tests

```bash
cd sandbox-test
cmake -B build -DCMAKE_TOOLCHAIN_FILE=%VCPKG_ROOT%/scripts/buildsystems/vcpkg.cmake
cmake --build build --config Debug
./build/Debug/sandbox-test.exe

# Output: 149 tests, all passing
```

## Test Categories

| Category | Tests | Description |
|----------|-------|-------------|
| Security | 11 | Globals removal, bytecode, metatables |
| Resources | 8 | Memory, CPU limits, instruction counting |
| Permissions | 7 | Normal/dangerous/signature grants |
| Rate Limiting | 6 | API call throttling |
| Timers | 7 | setTimeout/setInterval behavior |
| JSON | 5 | Encode/decode, depth limits |
| Crypto | 4 | Random, SHA256, HMAC |
| VirtualFS | 8 | Read/write, quotas, traversal |
| Database | 8 | SQLite operations, injection prevention |
| Network | 8 | URL validation, private IP blocking |
| WebSocket | 7 | Connection limits, message size |
| Hardware | 42 | Camera, mic, location, sensors, bluetooth |
| IPC | 7 | Message bus between apps |
| Integration | 9 | Full app lifecycle |
| Fuzzing | 3 | Random input crash testing |
