sandbox.go

// Copyright (C) 2024 Matt Dunleavy. All rights reserved.
// Use of this source code is subject to the MIT license 
// that can be found in the LICENSE file.

package pluginmanager

import (
    "os"
    "path/filepath"
    "syscall"
)

type Sandbox interface {
    Enable() error
    Disable() error
    VerifyPluginPath(path string) error
}

type LinuxSandbox struct {
    originalDir  string
    originalUmask int
    chrootDir    string
}

func NewLinuxSandbox(chrootDir string) *LinuxSandbox {
    if chrootDir == "" {
        chrootDir = "./sandbox"
    }
    return &LinuxSandbox{
        chrootDir: chrootDir,
    }
}

func (s *LinuxSandbox) Enable() error {
    var err error
    s.originalDir, err = os.Getwd()
    if err != nil {
        return err
    }

    if err := os.MkdirAll(s.chrootDir, 0755); err != nil {
        return err
    }

    if err := syscall.Chroot(s.chrootDir); err != nil {
        return err
    }

    if err := os.Chdir("/"); err != nil {
        return err
    }

    s.originalUmask = syscall.Umask(0)

    return nil
}

func (s *LinuxSandbox) Disable() error {
    syscall.Umask(s.originalUmask)

    if err := syscall.Chroot("."); err != nil {
        return err
    }

    if err := os.Chdir(s.originalDir); err != nil {
        return err
    }

    return nil
}

func (s *LinuxSandbox) VerifyPluginPath(path string) error {
    absPath, err := filepath.Abs(path)
    if err != nil {
        return err
    }

    if !filepath.HasPrefix(absPath, s.chrootDir) {
        return ErrPluginSandboxViolation
    }

    return nil
}