hermes/backend/sshappbackend/local-code/main.go

355 lines
8.3 KiB
Go

package main
import (
"bytes"
"crypto/md5"
"encoding/hex"
"encoding/json"
"fmt"
"os"
"strings"
"sync"
"git.terah.dev/imterah/hermes/backend/backendutil"
"git.terah.dev/imterah/hermes/backend/commonbackend"
"github.com/charmbracelet/log"
"github.com/go-playground/validator/v10"
"github.com/pkg/sftp"
"golang.org/x/crypto/ssh"
)
type SSHAppBackendData struct {
IP string `json:"ip" validate:"required"`
Port uint16 `json:"port" validate:"required"`
Username string `json:"username" validate:"required"`
PrivateKey string `json:"privateKey" validate:"required"`
ListenOnIPs []string `json:"listenOnIPs"`
}
type SSHAppBackend struct {
config *SSHAppBackendData
conn *ssh.Client
clients []*commonbackend.ProxyClientConnection
arrayPropMutex sync.Mutex
}
func (backend *SSHAppBackend) StartBackend(configBytes []byte) (bool, error) {
log.Info("SSHAppBackend is initializing...")
var backendData SSHAppBackendData
if err := json.Unmarshal(configBytes, &backendData); err != nil {
return false, err
}
if err := validator.New().Struct(&backendData); err != nil {
return false, err
}
backend.config = &backendData
if len(backend.config.ListenOnIPs) == 0 {
backend.config.ListenOnIPs = []string{"0.0.0.0"}
}
signer, err := ssh.ParsePrivateKey([]byte(backendData.PrivateKey))
if err != nil {
log.Warnf("Failed to initialize: %s", err.Error())
return false, err
}
auth := ssh.PublicKeys(signer)
config := &ssh.ClientConfig{
HostKeyCallback: ssh.InsecureIgnoreHostKey(),
User: backendData.Username,
Auth: []ssh.AuthMethod{
auth,
},
}
conn, err := ssh.Dial("tcp", fmt.Sprintf("%s:%d", backendData.IP, backendData.Port), config)
if err != nil {
log.Warnf("Failed to initialize: %s", err.Error())
return false, err
}
backend.conn = conn
log.Info("SSHAppBackend has connected successfully.")
log.Info("Getting CPU architecture...")
session, err := backend.conn.NewSession()
if err != nil {
log.Warnf("Failed to create session: %s", err.Error())
conn.Close()
backend.conn = nil
return false, err
}
var stdoutBuf bytes.Buffer
session.Stdout = &stdoutBuf
err = session.Run("uname -m")
if err != nil {
log.Warnf("Failed to run uname command: %s", err.Error())
conn.Close()
backend.conn = nil
return false, err
}
cpuArchBytes := make([]byte, stdoutBuf.Len())
stdoutBuf.Read(cpuArchBytes)
cpuArch := string(cpuArchBytes)
cpuArch = cpuArch[:len(cpuArch)-1]
var backendBinary string
// Ordered in (subjective) popularity
if cpuArch == "x86_64" {
backendBinary = "remote-bin/rt-amd64"
} else if cpuArch == "aarch64" {
backendBinary = "remote-bin/rt-arm64"
} else if cpuArch == "arm" {
backendBinary = "remote-bin/rt-arm"
} else if len(cpuArch) == 4 && string(cpuArch[0]) == "i" && strings.HasSuffix(cpuArch, "86") {
backendBinary = "remote-bin/rt-386"
} else {
log.Warn("Failed to determine executable to use: CPU architecture not compiled/supported currently")
conn.Close()
backend.conn = nil
return false, fmt.Errorf("CPU architecture not compiled/supported currently")
}
log.Info("Checking if we need to copy the application...")
var binary []byte
needsToCopyBinary := true
session, err = backend.conn.NewSession()
if err != nil {
log.Warnf("Failed to create session: %s", err.Error())
conn.Close()
backend.conn = nil
return false, err
}
session.Stdout = &stdoutBuf
err = session.Start("[ -f /tmp/sshappbackend.runtime ] && md5sum /tmp/sshappbackend.runtime | cut -d \" \" -f 1")
if err != nil {
log.Warnf("Failed to calculate hash of possibly existing backend: %s", err.Error())
conn.Close()
backend.conn = nil
return false, err
}
fileExists := stdoutBuf.Len() != 0
if fileExists {
remoteMD5HashStringBuf := make([]byte, stdoutBuf.Len())
stdoutBuf.Read(remoteMD5HashStringBuf)
remoteMD5HashString := string(remoteMD5HashStringBuf)
remoteMD5HashString = remoteMD5HashString[:len(remoteMD5HashString)-1]
remoteMD5Hash, err := hex.DecodeString(remoteMD5HashString)
if err != nil {
log.Warnf("Failed to decode hex: %s", err.Error())
conn.Close()
backend.conn = nil
return false, err
}
binary, err = binFiles.ReadFile(backendBinary)
if err != nil {
log.Warnf("Failed to read file in the embedded FS: %s", err.Error())
conn.Close()
backend.conn = nil
return false, fmt.Errorf("(embedded FS): %s", err.Error())
}
localMD5Hash := md5.Sum(binary)
log.Infof("remote: %s, local: %s", remoteMD5HashString, hex.EncodeToString(localMD5Hash[:]))
if bytes.Compare(localMD5Hash[:], remoteMD5Hash) == 0 {
needsToCopyBinary = false
}
}
if needsToCopyBinary {
log.Info("Copying binary...")
sftpInstance, err := sftp.NewClient(conn)
if err != nil {
log.Warnf("Failed to initialize SFTP: %s", err.Error())
conn.Close()
backend.conn = nil
return false, err
}
defer sftpInstance.Close()
if len(binary) == 0 {
binary, err = binFiles.ReadFile(backendBinary)
if err != nil {
log.Warnf("Failed to read file in the embedded FS: %s", err.Error())
conn.Close()
backend.conn = nil
return false, fmt.Errorf("(embedded FS): %s", err.Error())
}
}
var file *sftp.File
if fileExists {
file, err = sftpInstance.Create("/tmp/sshappbackend.runtime")
} else {
file, err = sftpInstance.OpenFile("/tmp/sshappbackend.runtime", os.O_WRONLY)
}
if err != nil {
log.Warnf("Failed to create file: %s", err.Error())
conn.Close()
backend.conn = nil
return false, err
}
_, err = file.Write(binary)
if err != nil {
log.Warnf("Failed to write file: %s", err.Error())
conn.Close()
backend.conn = nil
return false, err
}
err = file.Chmod(775)
if err != nil {
log.Warnf("Failed to change permissions on file: %s", err.Error())
conn.Close()
backend.conn = nil
return false, err
}
log.Info("Done copying file.")
} else {
log.Info("Skipping copying as there's a copy on disk already.")
}
log.Info("Starting process...")
session, err = backend.conn.NewSession()
if err != nil {
log.Warnf("Failed to create session: %s", err.Error())
conn.Close()
backend.conn = nil
return false, err
}
session.Stdout = WriteLogger{}
session.Stderr = WriteLogger{}
go session.Run("/tmp/sshappbackend.runtime")
log.Info("SSHAppBackend has initialized successfully.")
return true, nil
}
func (backend *SSHAppBackend) StopBackend() (bool, error) {
err := backend.conn.Close()
if err != nil {
return false, err
}
return true, nil
}
func (backend *SSHAppBackend) GetBackendStatus() (bool, error) {
return backend.conn != nil, nil
}
func (backend *SSHAppBackend) StartProxy(command *commonbackend.AddProxy) (bool, error) {
return true, nil
}
func (backend *SSHAppBackend) StopProxy(command *commonbackend.RemoveProxy) (bool, error) {
return false, fmt.Errorf("could not find the proxy")
}
func (backend *SSHAppBackend) GetAllClientConnections() []*commonbackend.ProxyClientConnection {
return backend.clients
}
func (backend *SSHAppBackend) CheckParametersForConnections(clientParameters *commonbackend.CheckClientParameters) *commonbackend.CheckParametersResponse {
return &commonbackend.CheckParametersResponse{
IsValid: true,
}
}
func (backend *SSHAppBackend) CheckParametersForBackend(arguments []byte) *commonbackend.CheckParametersResponse {
var backendData SSHAppBackendData
if err := json.Unmarshal(arguments, &backendData); err != nil {
return &commonbackend.CheckParametersResponse{
IsValid: false,
Message: fmt.Sprintf("could not read json: %s", err.Error()),
}
}
if err := validator.New().Struct(&backendData); err != nil {
return &commonbackend.CheckParametersResponse{
IsValid: false,
Message: fmt.Sprintf("failed validation of parameters: %s", err.Error()),
}
}
return &commonbackend.CheckParametersResponse{
IsValid: true,
}
}
func main() {
logLevel := os.Getenv("HERMES_LOG_LEVEL")
if logLevel != "" {
switch logLevel {
case "debug":
log.SetLevel(log.DebugLevel)
case "info":
log.SetLevel(log.InfoLevel)
case "warn":
log.SetLevel(log.WarnLevel)
case "error":
log.SetLevel(log.ErrorLevel)
case "fatal":
log.SetLevel(log.FatalLevel)
}
}
backend := &SSHAppBackend{}
application := backendutil.NewHelper(backend)
err := application.Start()
if err != nil {
log.Fatalf("failed execution in application: %s", err.Error())
}
}