pack/cmd/docker_init.go

146 lines
3.6 KiB
Go

package cmd
import (
"bufio"
"bytes"
"encoding/base64"
"errors"
"fmt"
"io"
"net/http"
"net/url"
"os"
"strings"
dockerClient "github.com/moby/moby/client"
"golang.org/x/crypto/ssh"
"golang.org/x/term"
"github.com/buildpacks/pack/internal/sshdialer"
)
func tryInitSSHDockerClient() (*dockerClient.Client, error) {
dockerHost := os.Getenv("DOCKER_HOST")
_url, err := url.Parse(dockerHost)
isSSH := err == nil && _url.Scheme == "ssh"
if !isSSH {
return nil, nil
}
credentialsConfig := sshdialer.Config{
Identity: os.Getenv("DOCKER_HOST_SSH_IDENTITY"),
PassPhrase: os.Getenv("DOCKER_HOST_SSH_IDENTITY_PASSPHRASE"),
PasswordCallback: newReadSecretCbk("please enter password:"),
PassPhraseCallback: newReadSecretCbk("please enter passphrase to private key:"),
HostKeyCallback: newHostKeyCbk(),
}
dialContext, err := sshdialer.NewDialContext(_url, credentialsConfig)
if err != nil {
return nil, err
}
httpClient := &http.Client{
// No tls
// No proxy
Transport: &http.Transport{
DialContext: dialContext,
},
}
dockerClientOpts := []dockerClient.Opt{
dockerClient.WithHTTPClient(httpClient),
dockerClient.WithHost("http://dummy"),
dockerClient.WithDialContext(dialContext),
}
return dockerClient.New(dockerClientOpts...)
}
// readSecret prompts for a secret and returns value input by user from stdin
// Unlike terminal.ReadPassword(), $(echo $SECRET | podman...) is supported.
// Additionally, all input after `<secret>/n` is queued to podman command.
//
// NOTE: this code is based on "github.com/containers/podman/v3/pkg/terminal"
func readSecret(prompt string) (pw []byte, err error) {
fd := int(os.Stdin.Fd())
if term.IsTerminal(fd) {
fmt.Fprint(os.Stderr, prompt)
pw, err = term.ReadPassword(fd)
fmt.Fprintln(os.Stderr)
return pw, err
}
var b [1]byte
for {
n, err := os.Stdin.Read(b[:])
// terminal.readSecret discards any '\r', so we do the same
if n > 0 && b[0] != '\r' {
if b[0] == '\n' {
return pw, nil
}
pw = append(pw, b[0])
// limit size, so that a wrong input won't fill up the memory
if len(pw) > 1024 {
err = errors.New("password too long, 1024 byte limit")
}
}
if err != nil {
// terminal.readSecret accepts EOF-terminated passwords
// if non-empty, so we do the same
if err == io.EOF && len(pw) > 0 {
err = nil
}
return pw, err
}
}
}
func newReadSecretCbk(prompt string) sshdialer.SecretCallback {
var secretSet bool
var secret string
return func() (string, error) {
if secretSet {
return secret, nil
}
p, err := readSecret(prompt)
if err != nil {
return "", err
}
secretSet = true
secret = string(p)
return secret, err
}
}
func newHostKeyCbk() sshdialer.HostKeyCallback {
var trust []byte
return func(hostPort string, pubKey ssh.PublicKey) error {
if bytes.Equal(trust, pubKey.Marshal()) {
return nil
}
msg := `The authenticity of host %s cannot be established.
%s key fingerprint is %s
Are you sure you want to continue connecting (yes/no)? `
fmt.Fprintf(os.Stderr, msg, hostPort, pubKey.Type(), ssh.FingerprintSHA256(pubKey))
reader := bufio.NewReader(os.Stdin)
answer, err := reader.ReadString('\n')
if err != nil {
return err
}
answer = strings.TrimRight(answer, "\r\n")
answer = strings.ToLower(answer)
if answer == "yes" || answer == "y" {
trust = pubKey.Marshal()
fmt.Fprintf(os.Stderr, "To avoid this in future add following line into your ~/.ssh/known_hosts:\n%s %s %s\n",
hostPort, pubKey.Type(), base64.StdEncoding.EncodeToString(trust))
return nil
}
return errors.New("key rejected")
}
}