Merge pull request #5439 from pkilar/socks5_proxy

SOCKS5 proxy support

communicator/ssh/connect.go

@@ -6,6 +6,7 @@ import (
 	"time"
 
 	"golang.org/x/crypto/ssh"
+	"golang.org/x/net/proxy"
 )
 
 // ConnectFunc is a convenience method for returning a function
@@ -27,6 +28,25 @@ func ConnectFunc(network, addr string) func() (net.Conn, error) {
 	}
 }
 
+// ConnectFunc is a convenience method for returning a function
+// that connects to a host using SOCKS5 proxy
+func ProxyConnectFunc(socksProxy string, socksAuth *proxy.Auth, network, addr string) func() (net.Conn, error) {
+	return func() (net.Conn, error) {
+		// create a socks5 dialer
+		dialer, err := proxy.SOCKS5("tcp", socksProxy, socksAuth, proxy.Direct)
+		if err != nil {
+			return nil, fmt.Errorf("Can't connect to the proxy: %s", err)
+		}
+
+		c, err := dialer.Dial(network, addr)
+		if err != nil {
+			return nil, err
+		}
+
+		return c, nil
+	}
+}
+
 // BastionConnectFunc is a convenience method for returning a function
 // that connects to a host over a bastion connection.
 func BastionConnectFunc(

helper/communicator/config.go

@@ -33,6 +33,10 @@ type Config struct {
 	SSHBastionPassword        string        `mapstructure:"ssh_bastion_password"`
 	SSHBastionPrivateKey      string        `mapstructure:"ssh_bastion_private_key_file"`
 	SSHFileTransferMethod     string        `mapstructure:"ssh_file_transfer_method"`
+	SSHProxyHost              string        `mapstructure:"ssh_proxy_host"`
+	SSHProxyPort              int           `mapstructure:"ssh_proxy_port"`
+	SSHProxyUsername          string        `mapstructure:"ssh_proxy_username"`
+	SSHProxyPassword          string        `mapstructure:"ssh_proxy_password"`
 
 	// WinRM
 	WinRMUser               string        `mapstructure:"winrm_username"`
@@ -141,6 +145,12 @@ func (c *Config) prepareSSH(ctx *interpolate.Context) []error {
 		}
 	}
 
+	if c.SSHProxyHost != "" {
+		if c.SSHProxyPort == 0 {
+			c.SSHProxyPort = 1080
+		}
+	}
+
 	if c.SSHFileTransferMethod == "" {
 		c.SSHFileTransferMethod = "scp"
 	}
@@ -174,6 +184,10 @@ func (c *Config) prepareSSH(ctx *interpolate.Context) []error {
 			c.SSHFileTransferMethod))
 	}
 
+	if c.SSHBastionHost != "" && c.SSHProxyHost != "" {
+		errs = append(errs, errors.New("please specify either ssh_bastion_host or ssh_proxy_host, not both"))
+	}
+
 	return errs
 }
 

helper/communicator/step_connect_ssh.go

@@ -15,6 +15,7 @@ import (
 	"github.com/mitchellh/multistep"
 	gossh "golang.org/x/crypto/ssh"
 	"golang.org/x/crypto/ssh/agent"
+	"golang.org/x/net/proxy"
 )
 
 // StepConnectSSH is a step that only connects to SSH.
@@ -88,6 +89,8 @@ func (s *StepConnectSSH) waitForSSH(state multistep.StateBag, cancel <-chan stru
 	// do this one before entering the retry loop.
 	var bProto, bAddr string
 	var bConf *gossh.ClientConfig
+	var pAddr string
+	var pAuth *proxy.Auth
 	if s.Config.SSHBastionHost != "" {
 		// The protocol is hardcoded for now, but may be configurable one day
 		bProto = "tcp"
@@ -101,6 +104,16 @@ func (s *StepConnectSSH) waitForSSH(state multistep.StateBag, cancel <-chan stru
 		bConf = conf
 	}
 
+	if s.Config.SSHProxyHost != "" {
+		pAddr = fmt.Sprintf("%s:%d", s.Config.SSHProxyHost, s.Config.SSHProxyPort)
+		if s.Config.SSHProxyUsername != "" {
+			pAuth = new(proxy.Auth)
+			pAuth.User = s.Config.SSHBastionUsername
+			pAuth.Password = s.Config.SSHBastionPassword
+		}
+
+	}
+
 	handshakeAttempts := 0
 
 	var comm packer.Communicator
@@ -146,6 +159,9 @@ func (s *StepConnectSSH) waitForSSH(state multistep.StateBag, cancel <-chan stru
 			// We're using a bastion host, so use the bastion connfunc
 			connFunc = ssh.BastionConnectFunc(
 				bProto, bAddr, bConf, "tcp", address)
+		} else if pAddr != "" {
+			// Connect via SOCKS5 proxy
+			connFunc = ssh.ProxyConnectFunc(pAddr, pAuth, "tcp", address)
 		} else {
 			// No bastion host, connect directly
 			connFunc = ssh.ConnectFunc("tcp", address)

vendor/golang.org/x/net/proxy/direct.go

@@ -0,0 +1,18 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proxy
+
+import (
+	"net"
+)
+
+type direct struct{}
+
+// Direct is a direct proxy: one that makes network connections directly.
+var Direct = direct{}
+
+func (direct) Dial(network, addr string) (net.Conn, error) {
+	return net.Dial(network, addr)
+}

vendor/golang.org/x/net/proxy/per_host.go

@@ -0,0 +1,140 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proxy
+
+import (
+	"net"
+	"strings"
+)
+
+// A PerHost directs connections to a default Dialer unless the host name
+// requested matches one of a number of exceptions.
+type PerHost struct {
+	def, bypass Dialer
+
+	bypassNetworks []*net.IPNet
+	bypassIPs      []net.IP
+	bypassZones    []string
+	bypassHosts    []string
+}
+
+// NewPerHost returns a PerHost Dialer that directs connections to either
+// defaultDialer or bypass, depending on whether the connection matches one of
+// the configured rules.
+func NewPerHost(defaultDialer, bypass Dialer) *PerHost {
+	return &PerHost{
+		def:    defaultDialer,
+		bypass: bypass,
+	}
+}
+
+// Dial connects to the address addr on the given network through either
+// defaultDialer or bypass.
+func (p *PerHost) Dial(network, addr string) (c net.Conn, err error) {
+	host, _, err := net.SplitHostPort(addr)
+	if err != nil {
+		return nil, err
+	}
+
+	return p.dialerForRequest(host).Dial(network, addr)
+}
+
+func (p *PerHost) dialerForRequest(host string) Dialer {
+	if ip := net.ParseIP(host); ip != nil {
+		for _, net := range p.bypassNetworks {
+			if net.Contains(ip) {
+				return p.bypass
+			}
+		}
+		for _, bypassIP := range p.bypassIPs {
+			if bypassIP.Equal(ip) {
+				return p.bypass
+			}
+		}
+		return p.def
+	}
+
+	for _, zone := range p.bypassZones {
+		if strings.HasSuffix(host, zone) {
+			return p.bypass
+		}
+		if host == zone[1:] {
+			// For a zone "example.com", we match "example.com"
+			// too.
+			return p.bypass
+		}
+	}
+	for _, bypassHost := range p.bypassHosts {
+		if bypassHost == host {
+			return p.bypass
+		}
+	}
+	return p.def
+}
+
+// AddFromString parses a string that contains comma-separated values
+// specifying hosts that should use the bypass proxy. Each value is either an
+// IP address, a CIDR range, a zone (*.example.com) or a host name
+// (localhost). A best effort is made to parse the string and errors are
+// ignored.
+func (p *PerHost) AddFromString(s string) {
+	hosts := strings.Split(s, ",")
+	for _, host := range hosts {
+		host = strings.TrimSpace(host)
+		if len(host) == 0 {
+			continue
+		}
+		if strings.Contains(host, "/") {
+			// We assume that it's a CIDR address like 127.0.0.0/8
+			if _, net, err := net.ParseCIDR(host); err == nil {
+				p.AddNetwork(net)
+			}
+			continue
+		}
+		if ip := net.ParseIP(host); ip != nil {
+			p.AddIP(ip)
+			continue
+		}
+		if strings.HasPrefix(host, "*.") {
+			p.AddZone(host[1:])
+			continue
+		}
+		p.AddHost(host)
+	}
+}
+
+// AddIP specifies an IP address that will use the bypass proxy. Note that
+// this will only take effect if a literal IP address is dialed. A connection
+// to a named host will never match an IP.
+func (p *PerHost) AddIP(ip net.IP) {
+	p.bypassIPs = append(p.bypassIPs, ip)
+}
+
+// AddNetwork specifies an IP range that will use the bypass proxy. Note that
+// this will only take effect if a literal IP address is dialed. A connection
+// to a named host will never match.
+func (p *PerHost) AddNetwork(net *net.IPNet) {
+	p.bypassNetworks = append(p.bypassNetworks, net)
+}
+
+// AddZone specifies a DNS suffix that will use the bypass proxy. A zone of
+// "example.com" matches "example.com" and all of its subdomains.
+func (p *PerHost) AddZone(zone string) {
+	if strings.HasSuffix(zone, ".") {
+		zone = zone[:len(zone)-1]
+	}
+	if !strings.HasPrefix(zone, ".") {
+		zone = "." + zone
+	}
+	p.bypassZones = append(p.bypassZones, zone)
+}
+
+// AddHost specifies a host name that will use the bypass proxy.
+func (p *PerHost) AddHost(host string) {
+	if strings.HasSuffix(host, ".") {
+		host = host[:len(host)-1]
+	}
+	p.bypassHosts = append(p.bypassHosts, host)
+}

vendor/golang.org/x/net/proxy/proxy.go

@@ -0,0 +1,134 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package proxy provides support for a variety of protocols to proxy network
+// data.
+package proxy // import "golang.org/x/net/proxy"
+
+import (
+	"errors"
+	"net"
+	"net/url"
+	"os"
+	"sync"
+)
+
+// A Dialer is a means to establish a connection.
+type Dialer interface {
+	// Dial connects to the given address via the proxy.
+	Dial(network, addr string) (c net.Conn, err error)
+}
+
+// Auth contains authentication parameters that specific Dialers may require.
+type Auth struct {
+	User, Password string
+}
+
+// FromEnvironment returns the dialer specified by the proxy related variables in
+// the environment.
+func FromEnvironment() Dialer {
+	allProxy := allProxyEnv.Get()
+	if len(allProxy) == 0 {
+		return Direct
+	}
+
+	proxyURL, err := url.Parse(allProxy)
+	if err != nil {
+		return Direct
+	}
+	proxy, err := FromURL(proxyURL, Direct)
+	if err != nil {
+		return Direct
+	}
+
+	noProxy := noProxyEnv.Get()
+	if len(noProxy) == 0 {
+		return proxy
+	}
+
+	perHost := NewPerHost(proxy, Direct)
+	perHost.AddFromString(noProxy)
+	return perHost
+}
+
+// proxySchemes is a map from URL schemes to a function that creates a Dialer
+// from a URL with such a scheme.
+var proxySchemes map[string]func(*url.URL, Dialer) (Dialer, error)
+
+// RegisterDialerType takes a URL scheme and a function to generate Dialers from
+// a URL with that scheme and a forwarding Dialer. Registered schemes are used
+// by FromURL.
+func RegisterDialerType(scheme string, f func(*url.URL, Dialer) (Dialer, error)) {
+	if proxySchemes == nil {
+		proxySchemes = make(map[string]func(*url.URL, Dialer) (Dialer, error))
+	}
+	proxySchemes[scheme] = f
+}
+
+// FromURL returns a Dialer given a URL specification and an underlying
+// Dialer for it to make network requests.
+func FromURL(u *url.URL, forward Dialer) (Dialer, error) {
+	var auth *Auth
+	if u.User != nil {
+		auth = new(Auth)
+		auth.User = u.User.Username()
+		if p, ok := u.User.Password(); ok {
+			auth.Password = p
+		}
+	}
+
+	switch u.Scheme {
+	case "socks5":
+		return SOCKS5("tcp", u.Host, auth, forward)
+	}
+
+	// If the scheme doesn't match any of the built-in schemes, see if it
+	// was registered by another package.
+	if proxySchemes != nil {
+		if f, ok := proxySchemes[u.Scheme]; ok {
+			return f(u, forward)
+		}
+	}
+
+	return nil, errors.New("proxy: unknown scheme: " + u.Scheme)
+}
+
+var (
+	allProxyEnv = &envOnce{
+		names: []string{"ALL_PROXY", "all_proxy"},
+	}
+	noProxyEnv = &envOnce{
+		names: []string{"NO_PROXY", "no_proxy"},
+	}
+)
+
+// envOnce looks up an environment variable (optionally by multiple
+// names) once. It mitigates expensive lookups on some platforms
+// (e.g. Windows).
+// (Borrowed from net/http/transport.go)
+type envOnce struct {
+	names []string
+	once  sync.Once
+	val   string
+}
+
+func (e *envOnce) Get() string {
+	e.once.Do(e.init)
+	return e.val
+}
+
+func (e *envOnce) init() {
+	for _, n := range e.names {
+		e.val = os.Getenv(n)
+		if e.val != "" {
+			return
+		}
+	}
+}
+
+// reset is used by tests
+func (e *envOnce) reset() {
+	e.once = sync.Once{}
+	e.val = ""
+}

vendor/golang.org/x/net/proxy/socks5.go

@@ -0,0 +1,214 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proxy
+
+import (
+	"errors"
+	"io"
+	"net"
+	"strconv"
+)
+
+// SOCKS5 returns a Dialer that makes SOCKSv5 connections to the given address
+// with an optional username and password. See RFC 1928 and 1929.
+func SOCKS5(network, addr string, auth *Auth, forward Dialer) (Dialer, error) {
+	s := &socks5{
+		network: network,
+		addr:    addr,
+		forward: forward,
+	}
+	if auth != nil {
+		s.user = auth.User
+		s.password = auth.Password
+	}
+
+	return s, nil
+}
+
+type socks5 struct {
+	user, password string
+	network, addr  string
+	forward        Dialer
+}
+
+const socks5Version = 5
+
+const (
+	socks5AuthNone     = 0
+	socks5AuthPassword = 2
+)
+
+const socks5Connect = 1
+
+const (
+	socks5IP4    = 1
+	socks5Domain = 3
+	socks5IP6    = 4
+)
+
+var socks5Errors = []string{
+	"",
+	"general failure",
+	"connection forbidden",
+	"network unreachable",
+	"host unreachable",
+	"connection refused",
+	"TTL expired",
+	"command not supported",
+	"address type not supported",
+}
+
+// Dial connects to the address addr on the network net via the SOCKS5 proxy.
+func (s *socks5) Dial(network, addr string) (net.Conn, error) {
+	switch network {
+	case "tcp", "tcp6", "tcp4":
+	default:
+		return nil, errors.New("proxy: no support for SOCKS5 proxy connections of type " + network)
+	}
+
+	conn, err := s.forward.Dial(s.network, s.addr)
+	if err != nil {
+		return nil, err
+	}
+	if err := s.connect(conn, addr); err != nil {
+		conn.Close()
+		return nil, err
+	}
+	return conn, nil
+}
+
+// connect takes an existing connection to a socks5 proxy server,
+// and commands the server to extend that connection to target,
+// which must be a canonical address with a host and port.
+func (s *socks5) connect(conn net.Conn, target string) error {
+	host, portStr, err := net.SplitHostPort(target)
+	if err != nil {
+		return err
+	}
+
+	port, err := strconv.Atoi(portStr)
+	if err != nil {
+		return errors.New("proxy: failed to parse port number: " + portStr)
+	}
+	if port < 1 || port > 0xffff {
+		return errors.New("proxy: port number out of range: " + portStr)
+	}
+
+	// the size here is just an estimate
+	buf := make([]byte, 0, 6+len(host))
+
+	buf = append(buf, socks5Version)
+	if len(s.user) > 0 && len(s.user) < 256 && len(s.password) < 256 {
+		buf = append(buf, 2 /* num auth methods */, socks5AuthNone, socks5AuthPassword)
+	} else {
+		buf = append(buf, 1 /* num auth methods */, socks5AuthNone)
+	}
+
+	if _, err := conn.Write(buf); err != nil {
+		return errors.New("proxy: failed to write greeting to SOCKS5 proxy at " + s.addr + ": " + err.Error())
+	}
+
+	if _, err := io.ReadFull(conn, buf[:2]); err != nil {
+		return errors.New("proxy: failed to read greeting from SOCKS5 proxy at " + s.addr + ": " + err.Error())
+	}
+	if buf[0] != 5 {
+		return errors.New("proxy: SOCKS5 proxy at " + s.addr + " has unexpected version " + strconv.Itoa(int(buf[0])))
+	}
+	if buf[1] == 0xff {
+		return errors.New("proxy: SOCKS5 proxy at " + s.addr + " requires authentication")
+	}
+
+	// See RFC 1929
+	if buf[1] == socks5AuthPassword {
+		buf = buf[:0]
+		buf = append(buf, 1 /* password protocol version */)
+		buf = append(buf, uint8(len(s.user)))
+		buf = append(buf, s.user...)
+		buf = append(buf, uint8(len(s.password)))
+		buf = append(buf, s.password...)
+
+		if _, err := conn.Write(buf); err != nil {
+			return errors.New("proxy: failed to write authentication request to SOCKS5 proxy at " + s.addr + ": " + err.Error())
+		}
+
+		if _, err := io.ReadFull(conn, buf[:2]); err != nil {
+			return errors.New("proxy: failed to read authentication reply from SOCKS5 proxy at " + s.addr + ": " + err.Error())
+		}
+
+		if buf[1] != 0 {
+			return errors.New("proxy: SOCKS5 proxy at " + s.addr + " rejected username/password")
+		}
+	}
+
+	buf = buf[:0]
+	buf = append(buf, socks5Version, socks5Connect, 0 /* reserved */)
+
+	if ip := net.ParseIP(host); ip != nil {
+		if ip4 := ip.To4(); ip4 != nil {
+			buf = append(buf, socks5IP4)
+			ip = ip4
+		} else {
+			buf = append(buf, socks5IP6)
+		}
+		buf = append(buf, ip...)
+	} else {
+		if len(host) > 255 {
+			return errors.New("proxy: destination host name too long: " + host)
+		}
+		buf = append(buf, socks5Domain)
+		buf = append(buf, byte(len(host)))
+		buf = append(buf, host...)
+	}
+	buf = append(buf, byte(port>>8), byte(port))
+
+	if _, err := conn.Write(buf); err != nil {
+		return errors.New("proxy: failed to write connect request to SOCKS5 proxy at " + s.addr + ": " + err.Error())
+	}
+
+	if _, err := io.ReadFull(conn, buf[:4]); err != nil {
+		return errors.New("proxy: failed to read connect reply from SOCKS5 proxy at " + s.addr + ": " + err.Error())
+	}
+
+	failure := "unknown error"
+	if int(buf[1]) < len(socks5Errors) {
+		failure = socks5Errors[buf[1]]
+	}
+
+	if len(failure) > 0 {
+		return errors.New("proxy: SOCKS5 proxy at " + s.addr + " failed to connect: " + failure)
+	}
+
+	bytesToDiscard := 0
+	switch buf[3] {
+	case socks5IP4:
+		bytesToDiscard = net.IPv4len
+	case socks5IP6:
+		bytesToDiscard = net.IPv6len
+	case socks5Domain:
+		_, err := io.ReadFull(conn, buf[:1])
+		if err != nil {
+			return errors.New("proxy: failed to read domain length from SOCKS5 proxy at " + s.addr + ": " + err.Error())
+		}
+		bytesToDiscard = int(buf[0])
+	default:
+		return errors.New("proxy: got unknown address type " + strconv.Itoa(int(buf[3])) + " from SOCKS5 proxy at " + s.addr)
+	}
+
+	if cap(buf) < bytesToDiscard {
+		buf = make([]byte, bytesToDiscard)
+	} else {
+		buf = buf[:bytesToDiscard]
+	}
+	if _, err := io.ReadFull(conn, buf); err != nil {
+		return errors.New("proxy: failed to read address from SOCKS5 proxy at " + s.addr + ": " + err.Error())
+	}
+
+	// Also need to discard the port number
+	if _, err := io.ReadFull(conn, buf[:2]); err != nil {
+		return errors.New("proxy: failed to read port from SOCKS5 proxy at " + s.addr + ": " + err.Error())
+	}
+
+	return nil
+}

vendor/vendor.json

@@ -1235,6 +1235,12 @@
 			"revision": "1c05540f6879653db88113bc4a2b70aec4bd491f",
 			"revisionTime": "2017-08-04T00:04:37Z"
 		},
+		{
+			"checksumSHA1": "S4QRxs3K4notNO97Um4sA2IvHaM=",
+			"path": "golang.org/x/net/proxy",
+			"revision": "a04bdaca5b32abe1c069418fb7088ae607de5bd0",
+			"revisionTime": "2017-10-03T05:09:24Z"
+		},
 		{
 			"checksumSHA1": "mktBVED98G2vv+OKcSgtnFVZC1Y=",
 			"path": "golang.org/x/oauth2",

website/source/docs/templates/communicator.html.md

@@ -104,6 +104,15 @@ The SSH communicator has the following options:
 
 -   `ssh_username` (string) - The username to connect to SSH with. Required
     if using SSH.
+-   `ssh_proxy_host` (string) - A SOCKS proxy host to use for SSH connection
+
+-   `ssh_proxy_port` (Integer) - A port of the SOCKS proxy, defaults to 1080
+
+-   `ssh_proxy_username` (string) - The username to authenticate with the proxy
+    server. Optional.
+
+-   `ssh_proxy_password` (string) - The password to use to authenticate with
+    the proxy server. Optional.
 
 ## WinRM Communicator