/
ssh.go
356 lines (312 loc) · 8.42 KB
/
ssh.go
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package ssh
import (
"bytes"
"crypto/rand"
"fmt"
"io"
"io/ioutil"
"net"
"os"
"path/filepath"
"strings"
"sync"
"time"
"github.com/oliverkofoed/dogo/neaterror"
"golang.org/x/crypto/ssh"
"golang.org/x/crypto/ssh/agent"
)
type SSHConnection struct {
connection *ssh.Client
}
func NewSSHConnection(host string, port int, username string, password string, privatekey []byte, timeout time.Duration) (*SSHConnection, error) {
authMethods := make([]ssh.AuthMethod, 0, 3)
if password != "" {
// authenticate with password?
authMethods = append(authMethods, ssh.Password(password))
} else if privatekey != nil {
// authenticate with private key?
key, err := ssh.ParsePrivateKey(privatekey)
if err != nil {
return nil, fmt.Errorf("Could not parse keyfile. Error: %v", err)
}
authMethods = append(authMethods, ssh.PublicKeys(key))
} else {
// authenticate with ssh-agent?
if sshAgent, err := net.Dial("unix", os.Getenv("SSH_AUTH_SOCK")); err == nil {
authMethods = append(authMethods, ssh.PublicKeysCallback(agent.NewClient(sshAgent).Signers))
defer sshAgent.Close()
}
}
// connect to server
connection, err := ssh.Dial("tcp", fmt.Sprintf("%v:%v", host, port), &ssh.ClientConfig{
HostKeyCallback: ssh.InsecureIgnoreHostKey(), // TODO: should implement something better.
User: username,
Auth: authMethods,
Timeout: timeout,
})
if err != nil {
return nil, fmt.Errorf("Failed to connect to SSH on %v:%v. Error: %v", host, port, err)
}
return &SSHConnection{
connection: connection,
}, nil
}
func (s *SSHConnection) Close() error {
return s.connection.Close()
}
func WaitForSSH(host string, port int, username string, password string, privatekey []byte, timeout time.Duration) error {
start := time.Now()
step := timeout / 2
if step < time.Second {
step = time.Second
}
var lastError error
for time.Since(start) < timeout {
conn, err := NewSSHConnection(host, port, username, password, privatekey, step)
lastError = err
if err != nil {
if !strings.Contains(err.Error(), "Failed to connect to SSH on ") {
return err
}
time.Sleep(time.Millisecond * 100)
} else {
conn.Close()
return nil
}
}
return fmt.Errorf("Could not establish an SSH connection connection in the given time %v. Last error: %v", timeout, lastError)
}
func (s *SSHConnection) Shell(cmd string, stderr, stdout io.Writer, stdin io.Reader, width, height int) error {
// create a session
session, err := s.connection.NewSession()
if err != nil {
return fmt.Errorf("Failed to create SSH session: %v", err)
}
defer session.Close()
// assign input/output
session.Stdout = stdout
session.Stderr = stderr
session.Stdin = stdin
// create pty
err = session.RequestPty("xterm-256color", height, width, ssh.TerminalModes{
ssh.ECHO: 1, // enable echoing
ssh.TTY_OP_ISPEED: 14400, // input speed = 14.4kbaud
ssh.TTY_OP_OSPEED: 14400, // output speed = 14.4kbaud
})
if err != nil {
return err
}
// run shell
if cmd == "" {
err = session.Shell()
if err != nil {
return err
}
return session.Wait()
}
return session.Run(cmd)
}
func (s *SSHConnection) ExecutePipeCommand(command string, pipesFunc func(reader io.Reader, errorReader io.Reader, writer io.Writer) error) error {
// create a session
session, err := s.connection.NewSession()
if err != nil {
return fmt.Errorf("Failed to create SSH session: %v", err)
}
defer session.Close()
// create writer
writer, err := session.StdinPipe()
defer writer.Close()
if err != nil {
return err
}
// create reader
reader, err := session.StdoutPipe()
if err != nil {
return err
}
// create errorReader
errorReader, err := session.StderrPipe()
if err != nil {
return err
}
// start
runErr := session.Start(command)
if runErr != nil {
return errWrap(err, errorReader) //fmt.Errorf("Cmd.RunErr: %v", runErr)
}
// run pipesFunc
pipesErr := pipesFunc(reader, errorReader, writer)
if pipesErr != nil {
return errWrap(pipesErr, errorReader)
}
waitErr := session.Wait()
if waitErr != nil {
return errWrap(waitErr, errorReader)
}
return nil
}
func errWrap(err error, errorReader io.Reader) error {
b, err := ioutil.ReadAll(errorReader)
if len(b) != 0 {
return fmt.Errorf("%v: %v", err, string(b))
}
return err
}
func (s *SSHConnection) ExecuteCommand(command string) (string, error) {
// create a session
session, err := s.connection.NewSession()
if err != nil {
return "", fmt.Errorf("Failed to create SSH session: %v", err)
}
defer session.Close()
// run command
var buf bytes.Buffer
session.Stdout = &buf
session.Stderr = &buf
if err := session.Run(command); err != nil {
return "", fmt.Errorf("%v: %v", err, string(buf.Bytes()))
}
return buf.String(), nil
}
func (s *SSHConnection) WriteFile(path string, mode os.FileMode, contentLength int64, content io.Reader, sudo bool, progress func(p float64)) error {
// create a session
session, err := s.connection.NewSession()
if err != nil {
return fmt.Errorf("Failed to create SSH session: %v", err)
}
defer session.Close()
// create writer
writer, err := session.StdinPipe()
if err != nil {
return err
}
defer writer.Close()
var buf bytes.Buffer
session.Stdout = &buf
session.Stderr = &buf
// write data in seperate go routine
go func() {
fmt.Fprintln(writer, fmt.Sprintf("C%04d", int(mode)), contentLength, filepath.Base(path))
arr := make([]byte, 32*1024)
written := int64(0)
for {
nr, er := content.Read(arr)
if nr > 0 {
nw, ew := writer.Write(arr[0:nr])
if nw > 0 {
written += int64(nw)
}
if ew != nil {
err = ew
break
}
if nr != nw {
err = io.ErrShortWrite
break
}
p := float64(written) / float64(contentLength)
progress(p)
}
if er == io.EOF {
break
}
if er != nil {
err = er
break
}
}
fmt.Fprint(writer, "\x00")
writer.Close()
}()
command := "/usr/bin/scp -t " + filepath.Dir(path)
if sudo {
command = "sudo -n " + command
}
err = session.Run(command)
if err != nil && buf.Len() != 0 {
return fmt.Errorf("%v: %v", err, string(buf.Bytes()))
}
return err
}
func (s *SSHConnection) StartTunnel(localPort int, remotePort int, remoteHost string, reverse bool) (listeningPort int, err error) {
if remoteHost == "" {
remoteHost = "127.0.0.1"
}
//remoteHost = "127.0.0.1"
if reverse {
if localPort == 0 {
return 0, neaterror.New(nil, "the local port can't be %v for reverse tunnels. Must know what to connect to.", localPort)
}
return tunnel(fmt.Sprintf("127.0.0.1:%v", localPort), fmt.Sprintf("%v:%v", remoteHost, remotePort), localPort, net.Dial, s.connection.Listen)
} else {
if remotePort == 0 {
return 0, neaterror.New(nil, "the remote port can't be %v for tunnels. Must know what to connect to.", remotePort)
}
return tunnel(fmt.Sprintf("%v:%v", remoteHost, remotePort), fmt.Sprintf("0.0.0.0:%v", localPort), remotePort, s.connection.Dial, net.Listen)
}
return 0, nil
}
func tunnel(dialAddress, listenAddress string, dialPort int, dial func(n, addr string) (net.Conn, error), listen func(n, addr string) (net.Listener, error)) (int, error) {
// test address
b, err := dial("tcp", dialAddress)
if err != nil {
if strings.Contains(err.Error(), "Connection refused") {
return 0, fmt.Errorf("Could not connect to port %v when pre-testing the tunnel. Perhaps nothing is listening on the port?", dialPort)
}
return 0, err
}
b.Close()
// start a listener
listener, err := listen("tcp", listenAddress)
if err != nil {
return 0, err
}
// get the listening port used
listeningPort := listener.Addr().(*net.TCPAddr).Port
// accept and manage connections
go func() {
defer listener.Close()
for {
a, err := listener.Accept()
if err != nil {
return
}
b, err := dial("tcp", dialAddress)
if err != nil {
a.Close()
continue
}
var wg sync.WaitGroup
wg.Add(2)
go func() {
io.Copy(a, b)
wg.Done()
}()
go func() {
io.Copy(b, a)
wg.Done()
}()
go func() {
wg.Wait()
a.Close()
b.Close()
}()
}
}()
return listeningPort, nil
}
const letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
func GenerateRandomPassword(length int) (string, error) {
b := make([]byte, length)
n, err := rand.Read(b)
if err != nil {
return "", err
}
if n != length {
return "", fmt.Errorf("could not read %v random bytes for generating password", n)
}
for i := range b {
b[i] = letterBytes[b[i]%byte(len(letterBytes))]
}
return string(b), nil
}