Polish code

sshutil/ssh.go

@@ -0,0 +1,97 @@
+package sshutil
+
+import (
+	"bytes"
+	"context"
+	"crypto/rand"
+	"crypto/rsa"
+	"fmt"
+	"time"
+
+	"github.com/AlexSSD7/linsk/utils"
+	"github.com/pkg/errors"
+	"golang.org/x/crypto/ssh"
+)
+
+func GenerateSSHKey() (ssh.Signer, []byte, error) {
+	privateKey, err := rsa.GenerateKey(rand.Reader, 4096)
+	if err != nil {
+		return nil, nil, errors.Wrap(err, "generate rsa private key")
+	}
+
+	signer, err := ssh.NewSignerFromKey(privateKey)
+	if err != nil {
+		return nil, nil, errors.Wrap(err, "create signer from key")
+	}
+
+	return signer, ssh.MarshalAuthorizedKey(signer.PublicKey()), nil
+}
+
+func RunSSHCmd(ctx context.Context, sc *ssh.Client, cmd string) ([]byte, error) {
+	var ret []byte
+	err := NewSSHSession(ctx, time.Second*15, sc, func(sess *ssh.Session) error {
+		stdout := bytes.NewBuffer(nil)
+		stderr := bytes.NewBuffer(nil)
+
+		sess.Stdout = stdout
+		sess.Stderr = stderr
+
+		err := sess.Run(cmd)
+		if err != nil {
+			return utils.WrapErrWithLog(err, "run cmd", stderr.String())
+		}
+
+		ret = stdout.Bytes()
+
+		return nil
+	})
+
+	return ret, err
+}
+
+func NewSSHSession(ctx context.Context, timeout time.Duration, sc *ssh.Client, fn func(*ssh.Session) error) error {
+	return NewSSHSessionWithDelayedTimeout(ctx, timeout, sc, func(sess *ssh.Session, startTimeout func()) error {
+		startTimeout()
+		return fn(sess)
+	})
+}
+
+func NewSSHSessionWithDelayedTimeout(ctx context.Context, timeout time.Duration, sc *ssh.Client, fn func(sess *ssh.Session, startTimeout func()) error) error {
+	s, err := sc.NewSession()
+	if err != nil {
+		return errors.Wrap(err, "create new ssh session")
+	}
+
+	done := make(chan struct{})
+	defer close(done)
+
+	var timedOut bool
+
+	// Start a thread to handle context cancelation.
+	go func() {
+		select {
+		case <-ctx.Done():
+			timedOut = true
+			_ = sc.Close()
+		case <-done:
+		}
+	}()
+
+	err = fn(s, func() {
+		// Now start a thread which will close the session
+		// down when the timeout hits.
+		go func() {
+			select {
+			case <-time.After(timeout):
+				timedOut = true
+				_ = sc.Close()
+			case <-done:
+			}
+		}()
+	})
+	if timedOut {
+		return fmt.Errorf("timed out (%w)", err)
+	}
+
+	return err
+}

sshutil/unix.go

@@ -0,0 +1,57 @@
+package sshutil
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/AlexSSD7/linsk/utils"
+	"github.com/alessio/shellescape"
+	"github.com/pkg/errors"
+	"go.uber.org/multierr"
+	"golang.org/x/crypto/ssh"
+)
+
+func ChangeUnixPass(ctx context.Context, sc *ssh.Client, user string, pwd string) error {
+	if !utils.ValidateUnixUsername(user) {
+		return fmt.Errorf("invalid unix username")
+	}
+
+	return NewSSHSession(ctx, time.Second*10, sc, func(sess *ssh.Session) error {
+		stderr := bytes.NewBuffer(nil)
+		sess.Stderr = stderr
+
+		stdinPipe, err := sess.StdinPipe()
+		if err != nil {
+			return errors.Wrap(err, "stdin pipe")
+		}
+
+		err = sess.Start("passwd " + shellescape.Quote(user))
+		if err != nil {
+			return errors.Wrap(err, "start change user password cmd")
+		}
+
+		pwdBytes := []byte(pwd + "\n")
+		defer func() {
+			// Clearing the memory up for security.
+			for i := range pwdBytes {
+				pwdBytes[i] = 0
+			}
+		}()
+
+		go func() {
+			// Writing the password. We're doing this two times
+			// as we need to confirm the password.
+			_, _ = stdinPipe.Write(pwdBytes)
+			_, _ = stdinPipe.Write(pwdBytes)
+		}()
+
+		err = sess.Wait()
+		if err != nil {
+			return multierr.Combine(utils.WrapErrWithLog(err, "wait for change user password cmd", stderr.String()))
+		}
+
+		return nil
+	})
+}