V2 Add support for ssh authentication methods

* podman --remote ssh://<user>:<password>@<host>:<port><path>
* podman --remote ssh://<user>:<password>@<host>:<port><path> \
  --identity <path> --passphrase <phrase>
* ssh-add <key>
  podman --remote ssh://<user>@<host><path>
* Fix `podman help` to run even if podman missing components
* Prompt for passphrase on stdin IFF key is protected and passphrase
  not given via any other configuration

* cobra flags do not support optional value flags therefore refactored
  --remote to be a boolean and --url will now contain the URI to Podman
  service

Signed-off-by: Jhon Honce <jhonce@redhat.com>

cmd/podman/root.go

@@ -103,6 +103,11 @@ func persistentPreRunE(cmd *cobra.Command, args []string) error {
 
 	cfg := registry.PodmanConfig()
 
+	// Help is a special case, no need for more setup
+	if cmd.Name() == "help" {
+		return nil
+	}
+
 	// Prep the engines
 	if _, err := registry.NewImageEngine(cmd, args); err != nil {
 		return err
@@ -150,6 +155,11 @@ func persistentPostRunE(cmd *cobra.Command, args []string) error {
 	// TODO: Remove trace statement in podman V2.1
 	logrus.Debugf("Called %s.PersistentPostRunE(%s)", cmd.Name(), strings.Join(os.Args, " "))
 
+	// Help is a special case, no need for more cleanup
+	if cmd.Name() == "help" {
+		return nil
+	}
+
 	cfg := registry.PodmanConfig()
 	if cmd.Flag("cpu-profile").Changed {
 		pprof.StopCPUProfile()
@@ -191,8 +201,11 @@ func loggingHook() {
 
 func rootFlags(opts *entities.PodmanConfig, flags *pflag.FlagSet) {
 	// V2 flags
-	flags.StringVarP(&opts.Uri, "remote", "r", registry.DefaultAPIAddress(), "URL to access Podman service")
-	flags.StringSliceVar(&opts.Identities, "identity", []string{}, "path to SSH identity file")
+	flags.BoolVarP(&opts.Remote, "remote", "r", false, "Access remote Podman service (default false)")
+	// TODO Read uri from containers.config when available
+	flags.StringVar(&opts.Uri, "url", registry.DefaultAPIAddress(), "URL to access Podman service (CONTAINER_HOST)")
+	flags.StringSliceVar(&opts.Identities, "identity", []string{}, "path to SSH identity file, (CONTAINER_SSHKEY)")
+	flags.StringVar(&opts.PassPhrase, "passphrase", "", "passphrase for identity file (not secure, CONTAINER_PASSPHRASE), ssh-agent always supported")
 
 	cfg := opts.Config
 	flags.StringVar(&cfg.Engine.CgroupManager, "cgroup-manager", cfg.Engine.CgroupManager, "Cgroup manager to use (\"cgroupfs\"|\"systemd\")")

docs/source/markdown/podman.1.md

@@ -61,6 +61,9 @@ Podman and libpod currently support an additional `precreate` state which is cal
 **--identity**=*path*
 Path to SSH identity file
 
+**--passphrase**=*secret*
+pass phrase for SSH identity file
+
 **--log-level**=*level*
 
 Log messages above specified level: debug, info, warn, error (default), fatal or panic (default: "error")
@@ -73,18 +76,21 @@ When namespace is set, created containers and pods will join the given namespace
 **--network-cmd-path**=*path*
 Path to the command binary to use for setting up a network.  It is currently only used for setting up a slirp4netns network.  If "" is used then the binary is looked up using the $PATH environment variable.
 
-**--remote**, **-r**=*url*
-URL to access Podman service (default "unix:/run/user/3267/podman/podman.sock")
+**--remote**, **-r**
+Access Podman service will be remote
+
+**--url**=*value*
+URL to access Podman service (default from `containers.conf`, rootless "unix://run/user/$UID/podman/podman.sock" or as root "unix://run/podman/podman.sock).
 
 **--root**=*value*
 
 Storage root dir in which data, including images, is stored (default: "/var/lib/containers/storage" for UID 0, "$HOME/.local/share/containers/storage" for other users).
-Default root dir is configured in `/etc/containers/storage.conf`.
+Default root dir configured in `/etc/containers/storage.conf`.
 
 **--runroot**=*value*
 
 Storage state directory where all state information is stored (default: "/var/run/containers/storage" for UID 0, "/var/run/user/$UID/run" for other users).
-Default state dir is configured in `/etc/containers/storage.conf`.
+Default state dir configured in `/etc/containers/storage.conf`.
 
 **--runtime**=*value*
 

pkg/bindings/bindings.go

@@ -9,7 +9,13 @@
 package bindings
 
 import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+
 	"github.com/blang/semver"
+	"golang.org/x/crypto/ssh/terminal"
 )
 
 var (
@@ -25,3 +31,40 @@ var (
 	// _*YES*- podman will fail to run if this value is wrong
 	APIVersion = semver.MustParse("1.0.0")
 )
+
+// readPassword 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.
+func readPassword(prompt string) (pw []byte, err error) {
+	fd := int(os.Stdin.Fd())
+	if terminal.IsTerminal(fd) {
+		fmt.Fprint(os.Stderr, prompt)
+		pw, err = terminal.ReadPassword(fd)
+		fmt.Fprintln(os.Stderr)
+		return
+	}
+
+	var b [1]byte
+	for {
+		n, err := os.Stdin.Read(b[:])
+		// terminal.ReadPassword 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.ReadPassword accepts EOF-terminated passwords
+			// if non-empty, so we do the same
+			if err == io.EOF && len(pw) > 0 {
+				err = nil
+			}
+			return pw, err
+		}
+	}
+}

pkg/bindings/connection.go

@@ -13,13 +13,15 @@ import (
 	"path/filepath"
 	"strconv"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/blang/semver"
 	jsoniter "github.com/json-iterator/go"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 	"golang.org/x/crypto/ssh"
+	"golang.org/x/crypto/ssh/agent"
 	"k8s.io/client-go/util/homedir"
 )
 
@@ -29,6 +31,8 @@ var (
 		Host:   "d",
 		Path:   "/v" + APIVersion.String() + "/libpod",
 	}
+	passPhrase []byte
+	phraseSync sync.Once
 )
 
 type APIResponse struct {
@@ -61,6 +65,10 @@ func JoinURL(elements ...string) string {
 	return "/" + strings.Join(elements, "/")
 }
 
+func NewConnection(ctx context.Context, uri string) (context.Context, error) {
+	return NewConnectionWithIdentity(ctx, uri, "")
+}
+
 // NewConnection takes a URI as a string and returns a context with the
 // Connection embedded as a value.  This context needs to be passed to each
 // endpoint to work correctly.
@@ -69,23 +77,28 @@ func JoinURL(elements ...string) string {
 // For example tcp://localhost:<port>
 // or unix:///run/podman/podman.sock
 // or ssh://<user>@<host>[:port]/run/podman/podman.sock?secure=True
-func NewConnection(ctx context.Context, uri string, identity ...string) (context.Context, error) {
+func NewConnectionWithIdentity(ctx context.Context, uri string, passPhrase string, identities ...string) (context.Context, error) {
 	var (
 		err    error
 		secure bool
 	)
-	if v, found := os.LookupEnv("PODMAN_HOST"); found {
+	if v, found := os.LookupEnv("CONTAINER_HOST"); found && uri == "" {
 		uri = v
 	}
 
-	if v, found := os.LookupEnv("PODMAN_SSHKEY"); found {
-		identity = []string{v}
+	if v, found := os.LookupEnv("CONTAINER_SSHKEY"); found && len(identities) == 0 {
+		identities = append(identities, v)
+	}
+
+	if v, found := os.LookupEnv("CONTAINER_PASSPHRASE"); found && passPhrase == "" {
+		passPhrase = v
 	}
 
 	_url, err := url.Parse(uri)
 	if err != nil {
-		return nil, errors.Wrapf(err, "Value of PODMAN_HOST is not a valid url: %s", uri)
+		return nil, errors.Wrapf(err, "Value of CONTAINER_HOST is not a valid url: %s", uri)
 	}
+	// TODO Fill in missing defaults for _url...
 
 	// Now we setup the http Client to use the connection above
 	var connection Connection
@@ -95,7 +108,7 @@ func NewConnection(ctx context.Context, uri string, identity ...string) (context
 		if err != nil {
 			secure = false
 		}
-		connection, err = sshClient(_url, identity[0], secure)
+		connection, err = sshClient(_url, secure, passPhrase, identities...)
 	case "unix":
 		if !strings.HasPrefix(uri, "unix:///") {
 			// autofix unix://path_element vs unix:///path_element
@@ -172,10 +185,31 @@ func pingNewConnection(ctx context.Context) error {
 	return errors.Errorf("ping response was %q", response.StatusCode)
 }
 
-func sshClient(_url *url.URL, identity string, secure bool) (Connection, error) {
-	auth, err := publicKey(identity)
-	if err != nil {
-		return Connection{}, errors.Wrapf(err, "Failed to parse identity %s: %v\n", _url.String(), identity)
+func sshClient(_url *url.URL, secure bool, passPhrase string, identities ...string) (Connection, error) {
+	var authMethods []ssh.AuthMethod
+
+	for _, i := range identities {
+		auth, err := publicKey(i, []byte(passPhrase))
+		if err != nil {
+			fmt.Fprint(os.Stderr, errors.Wrapf(err, "failed to parse identity %q", i).Error()+"\n")
+			continue
+		}
+		authMethods = append(authMethods, auth)
+	}
+
+	if sock, found := os.LookupEnv("SSH_AUTH_SOCK"); found {
+		logrus.Debugf("Found SSH_AUTH_SOCK %q, ssh-agent signer enabled", sock)
+
+		c, err := net.Dial("unix", sock)
+		if err != nil {
+			return Connection{}, err
+		}
+		a := agent.NewClient(c)
+		authMethods = append(authMethods, ssh.PublicKeysCallback(a.Signers))
+	}
+
+	if pw, found := _url.User.Password(); found {
+		authMethods = append(authMethods, ssh.Password(pw))
 	}
 
 	callback := ssh.InsecureIgnoreHostKey()
@@ -195,7 +229,7 @@ func sshClient(_url *url.URL, identity string, secure bool) (Connection, error)
 		net.JoinHostPort(_url.Hostname(), port),
 		&ssh.ClientConfig{
 			User:            _url.User.Username(),
-			Auth:            []ssh.AuthMethod{auth},
+			Auth:            authMethods,
 			HostKeyCallback: callback,
 			HostKeyAlgorithms: []string{
 				ssh.KeyAlgoRSA,
@@ -307,20 +341,38 @@ func (h *APIResponse) IsServerError() bool {
 	return h.Response.StatusCode/100 == 5
 }
 
-func publicKey(path string) (ssh.AuthMethod, error) {
+func publicKey(path string, passphrase []byte) (ssh.AuthMethod, error) {
 	key, err := ioutil.ReadFile(path)
 	if err != nil {
 		return nil, err
 	}
 
 	signer, err := ssh.ParsePrivateKey(key)
 	if err != nil {
-		return nil, err
+		if _, ok := err.(*ssh.PassphraseMissingError); !ok {
+			return nil, err
+		}
+		if len(passphrase) == 0 {
+			phraseSync.Do(promptPassphrase)
+			passphrase = passPhrase
+		}
+		signer, err = ssh.ParsePrivateKeyWithPassphrase(key, passphrase)
+		if err != nil {
+			return nil, err
+		}
 	}
-
 	return ssh.PublicKeys(signer), nil
 }
 
+func promptPassphrase() {
+	phrase, err := readPassword("Key Passphrase: ")
+	if err != nil {
+		passPhrase = []byte{}
+		return
+	}
+	passPhrase = phrase
+}
+
 func hostKey(host string) ssh.PublicKey {
 	// parse OpenSSH known_hosts file
 	// ssh or use ssh-keyscan to get initial key

pkg/domain/entities/engine.go

@@ -43,14 +43,16 @@ type PodmanConfig struct {
 	EngineMode     EngineMode       // ABI or Tunneling mode
 	Identities     []string         // ssh identities for connecting to server
 	MaxWorks       int              // maximum number of parallel threads
+	PassPhrase     string           // ssh passphrase for identity for connecting to server
 	RegistriesConf string           // allows for specifying a custom registries.conf
+	Remote         bool             // Connection to Podman API Service will use RESTful API
 	RuntimePath    string           // --runtime flag will set Engine.RuntimePath
+	Span           opentracing.Span // tracing object
 	SpanCloser     io.Closer        // Close() for tracing object
 	SpanCtx        context.Context  // context to use when tracing
-	Span           opentracing.Span // tracing object
 	Syslog         bool             // write to StdOut and Syslog, not supported when tunneling
 	Trace          bool             // Hidden: Trace execution
-	Uri            string           // URI to API Service
+	Uri            string           // URI to RESTful API Service
 
 	Runroot       string
 	StorageDriver string

pkg/domain/infra/runtime_abi.go

@@ -20,7 +20,7 @@ func NewContainerEngine(facts *entities.PodmanConfig) (entities.ContainerEngine,
 		r, err := NewLibpodRuntime(facts.FlagSet, facts)
 		return r, err
 	case entities.TunnelMode:
-		ctx, err := bindings.NewConnection(context.Background(), facts.Uri, facts.Identities...)
+		ctx, err := bindings.NewConnectionWithIdentity(context.Background(), facts.Uri, facts.PassPhrase, facts.Identities...)
 		return &tunnel.ContainerEngine{ClientCxt: ctx}, err
 	}
 	return nil, fmt.Errorf("runtime mode '%v' is not supported", facts.EngineMode)
@@ -33,7 +33,7 @@ func NewImageEngine(facts *entities.PodmanConfig) (entities.ImageEngine, error)
 		r, err := NewLibpodImageRuntime(facts.FlagSet, facts)
 		return r, err
 	case entities.TunnelMode:
-		ctx, err := bindings.NewConnection(context.Background(), facts.Uri, facts.Identities...)
+		ctx, err := bindings.NewConnectionWithIdentity(context.Background(), facts.Uri, facts.PassPhrase, facts.Identities...)
 		return &tunnel.ImageEngine{ClientCxt: ctx}, err
 	}
 	return nil, fmt.Errorf("runtime mode '%v' is not supported", facts.EngineMode)

pkg/domain/infra/runtime_tunnel.go

@@ -16,7 +16,7 @@ func NewContainerEngine(facts *entities.PodmanConfig) (entities.ContainerEngine,
 	case entities.ABIMode:
 		return nil, fmt.Errorf("direct runtime not supported")
 	case entities.TunnelMode:
-		ctx, err := bindings.NewConnection(context.Background(), facts.Uri, facts.Identities...)
+		ctx, err := bindings.NewConnectionWithIdentity(context.Background(), facts.Uri, facts.PassPhrase, facts.Identities...)
 		return &tunnel.ContainerEngine{ClientCxt: ctx}, err
 	}
 	return nil, fmt.Errorf("runtime mode '%v' is not supported", facts.EngineMode)
@@ -28,7 +28,7 @@ func NewImageEngine(facts *entities.PodmanConfig) (entities.ImageEngine, error)
 	case entities.ABIMode:
 		return nil, fmt.Errorf("direct image runtime not supported")
 	case entities.TunnelMode:
-		ctx, err := bindings.NewConnection(context.Background(), facts.Uri, facts.Identities...)
+		ctx, err := bindings.NewConnectionWithIdentity(context.Background(), facts.Uri, facts.PassPhrase, facts.Identities...)
 		return &tunnel.ImageEngine{ClientCxt: ctx}, err
 	}
 	return nil, fmt.Errorf("runtime mode '%v' is not supported", facts.EngineMode)

test/e2e/libpod_suite_remote_test.go

@@ -36,23 +36,23 @@ func SkipIfRootlessV2() {
 
 // Podman is the exec call to podman on the filesystem
 func (p *PodmanTestIntegration) Podman(args []string) *PodmanSessionIntegration {
-	var remoteArgs = []string{"--remote", p.RemoteSocket}
+	var remoteArgs = []string{"--remote", "--url", p.RemoteSocket}
 	remoteArgs = append(remoteArgs, args...)
 	podmanSession := p.PodmanBase(remoteArgs, false, false)
 	return &PodmanSessionIntegration{podmanSession}
 }
 
 // PodmanExtraFiles is the exec call to podman on the filesystem and passes down extra files
 func (p *PodmanTestIntegration) PodmanExtraFiles(args []string, extraFiles []*os.File) *PodmanSessionIntegration {
-	var remoteArgs = []string{"--remote", p.RemoteSocket}
+	var remoteArgs = []string{"--remote", "--url", p.RemoteSocket}
 	remoteArgs = append(remoteArgs, args...)
 	podmanSession := p.PodmanAsUserBase(remoteArgs, 0, 0, "", nil, false, false, extraFiles)
 	return &PodmanSessionIntegration{podmanSession}
 }
 
 // PodmanNoCache calls podman with out adding the imagecache
 func (p *PodmanTestIntegration) PodmanNoCache(args []string) *PodmanSessionIntegration {
-	var remoteArgs = []string{"--remote", p.RemoteSocket}
+	var remoteArgs = []string{"--remote", "--url", p.RemoteSocket}
 	remoteArgs = append(remoteArgs, args...)
 	podmanSession := p.PodmanBase(remoteArgs, false, true)
 	return &PodmanSessionIntegration{podmanSession}

test/utils/utils.go

@@ -73,7 +73,7 @@ func (p *PodmanTest) PodmanAsUserBase(args []string, uid, gid uint32, cwd string
 		podmanBinary = p.RemotePodmanBinary
 	}
 	if p.RemoteTest {
-		podmanOptions = append([]string{"--remote", p.RemoteSocket}, podmanOptions...)
+		podmanOptions = append([]string{"--remote", "--url", p.RemoteSocket}, podmanOptions...)
 	}
 	if env == nil {
 		fmt.Printf("Running: %s %s\n", podmanBinary, strings.Join(podmanOptions, " "))