podman ssh work, using new c/common interface

implement new ssh interface into podman

this completely redesigns the entire functionality of podman image scp,
podman system connection add, and podman --remote. All references to golang.org/x/crypto/ssh
have been moved to common as have native ssh/scp execs and the new usage of the sftp package.

this PR adds a global flag, --ssh to podman which has two valid inputs `golang` and `native` where golang is the default.
Users should not notice any difference in their everyday workflows if they continue using the golang option. UNLESS they have been using an improperly verified ssh key, this will now fail. This is because podman was incorrectly using the
ssh callback method to IGNORE the ssh known hosts file which is very insecure and golang tells you not yo use this in production.

The native paths allows for immense flexibility, with a new containers.conf field `SSH_CONFIG` that specifies a specific ssh config file to be used in all operations. Else the users ~/.ssh/config file will be used.
podman --remote currently only uses the golang path, given its deep interconnection with dialing multiple clients and urls.

My goal after this PR is to go back and abstract the idea of podman --remote from golang's dialed clients, as it should not be so intrinsically connected. Overall, this is a v1 of a long process of offering native ssh, and one that covers some good ground with podman system connection add and podman image scp.

Signed-off-by: Charlie Doern <cdoern@redhat.com>

1 files changed, 20 insertions, 131 deletions

diff --git a/pkg/bindings/connection.go b/pkg/bindings/connection.go
index b994a5857..6d7b052b7 100644
--- a/pkg/bindings/connection.go
+++ b/pkg/bindings/connection.go
@@ -14,11 +14,9 @@ import (
 	"time"
 
 	"github.com/blang/semver/v4"
-	"github.com/containers/podman/v4/pkg/terminal"
+	"github.com/containers/common/pkg/ssh"
 	"github.com/containers/podman/v4/version"
 	"github.com/sirupsen/logrus"
-	"golang.org/x/crypto/ssh"
-	"golang.org/x/crypto/ssh/agent"
 )
 
 type APIResponse struct {
@@ -74,8 +72,7 @@ func NewConnection(ctx context.Context, uri string) (context.Context, error) {
 // or ssh://<user>@<host>[:port]/run/podman/podman.sock?secure=True
 func NewConnectionWithIdentity(ctx context.Context, uri string, identity string) (context.Context, error) {
 	var (
-		err    error
-		secure bool
+		err error
 	)
 	if v, found := os.LookupEnv("CONTAINER_HOST"); found && uri == "" {
 		uri = v
@@ -85,11 +82,6 @@ func NewConnectionWithIdentity(ctx context.Context, uri string, identity string)
 		identity = v
 	}
 
-	passPhrase := ""
-	if v, found := os.LookupEnv("CONTAINER_PASSPHRASE"); found {
-		passPhrase = v
-	}
-
 	_url, err := url.Parse(uri)
 	if err != nil {
 		return nil, fmt.Errorf("value of CONTAINER_HOST is not a valid url: %s: %w", uri, err)
@@ -99,11 +91,26 @@ func NewConnectionWithIdentity(ctx context.Context, uri string, identity string)
 	var connection Connection
 	switch _url.Scheme {
 	case "ssh":
-		secure, err = strconv.ParseBool(_url.Query().Get("secure"))
+		port, err := strconv.Atoi(_url.Port())
 		if err != nil {
-			secure = false
+			return nil, err
 		}
-		connection, err = sshClient(_url, secure, passPhrase, identity)
+		conn, err := ssh.Dial(&ssh.ConnectionDialOptions{
+			Host:     uri,
+			Identity: identity,
+			User:     _url.User,
+			Port:     port,
+		}, "golang")
+		if err != nil {
+			return nil, err
+		}
+		connection = Connection{URI: _url}
+		connection.Client = &http.Client{
+			Transport: &http.Transport{
+				DialContext: func(ctx context.Context, _, _ string) (net.Conn, error) {
+					return ssh.DialNet(conn, "unix", _url)
+				},
+			}}
 	case "unix":
 		if !strings.HasPrefix(uri, "unix:///") {
 			// autofix unix://path_element vs unix:///path_element
@@ -184,124 +191,6 @@ func pingNewConnection(ctx context.Context) (*semver.Version, error) {
 	return nil, fmt.Errorf("ping response was %d", response.StatusCode)
 }
 
-func sshClient(_url *url.URL, secure bool, passPhrase string, identity string) (Connection, error) {
-	// if you modify the authmethods or their conditionals, you will also need to make similar
-	// changes in the client (currently cmd/podman/system/connection/add getUDS).
-
-	var signers []ssh.Signer // order Signers are appended to this list determines which key is presented to server
-
-	if len(identity) > 0 {
-		s, err := terminal.PublicKey(identity, []byte(passPhrase))
-		if err != nil {
-			return Connection{}, fmt.Errorf("failed to parse identity %q: %w", identity, err)
-		}
-
-		signers = append(signers, s)
-		logrus.Debugf("SSH Ident Key %q %s %s", identity, ssh.FingerprintSHA256(s.PublicKey()), s.PublicKey().Type())
-	}
-
-	if sock, found := os.LookupEnv("SSH_AUTH_SOCK"); found {
-		logrus.Debugf("Found SSH_AUTH_SOCK %q, ssh-agent signer(s) enabled", sock)
-
-		c, err := net.Dial("unix", sock)
-		if err != nil {
-			return Connection{}, err
-		}
-
-		agentSigners, err := agent.NewClient(c).Signers()
-		if err != nil {
-			return Connection{}, err
-		}
-		signers = append(signers, agentSigners...)
-
-		if logrus.IsLevelEnabled(logrus.DebugLevel) {
-			for _, s := range agentSigners {
-				logrus.Debugf("SSH Agent Key %s %s", ssh.FingerprintSHA256(s.PublicKey()), s.PublicKey().Type())
-			}
-		}
-	}
-
-	var authMethods []ssh.AuthMethod
-	if len(signers) > 0 {
-		var dedup = make(map[string]ssh.Signer)
-		// Dedup signers based on fingerprint, ssh-agent keys override CONTAINER_SSHKEY
-		for _, s := range signers {
-			fp := ssh.FingerprintSHA256(s.PublicKey())
-			if _, found := dedup[fp]; found {
-				logrus.Debugf("Dedup SSH Key %s %s", ssh.FingerprintSHA256(s.PublicKey()), s.PublicKey().Type())
-			}
-			dedup[fp] = s
-		}
-
-		var uniq []ssh.Signer
-		for _, s := range dedup {
-			uniq = append(uniq, s)
-		}
-		authMethods = append(authMethods, ssh.PublicKeysCallback(func() ([]ssh.Signer, error) {
-			return uniq, nil
-		}))
-	}
-
-	if pw, found := _url.User.Password(); found {
-		authMethods = append(authMethods, ssh.Password(pw))
-	}
-
-	if len(authMethods) == 0 {
-		callback := func() (string, error) {
-			pass, err := terminal.ReadPassword("Login password:")
-			return string(pass), err
-		}
-		authMethods = append(authMethods, ssh.PasswordCallback(callback))
-	}
-
-	port := _url.Port()
-	if port == "" {
-		port = "22"
-	}
-
-	callback := ssh.InsecureIgnoreHostKey()
-	if secure {
-		host := _url.Hostname()
-		if port != "22" {
-			host = fmt.Sprintf("[%s]:%s", host, port)
-		}
-		key := terminal.HostKey(host)
-		if key != nil {
-			callback = ssh.FixedHostKey(key)
-		}
-	}
-
-	bastion, err := ssh.Dial("tcp",
-		net.JoinHostPort(_url.Hostname(), port),
-		&ssh.ClientConfig{
-			User:            _url.User.Username(),
-			Auth:            authMethods,
-			HostKeyCallback: callback,
-			HostKeyAlgorithms: []string{
-				ssh.KeyAlgoRSA,
-				ssh.KeyAlgoDSA,
-				ssh.KeyAlgoECDSA256,
-				ssh.KeyAlgoECDSA384,
-				ssh.KeyAlgoECDSA521,
-				ssh.KeyAlgoED25519,
-			},
-			Timeout: 5 * time.Second,
-		},
-	)
-	if err != nil {
-		return Connection{}, fmt.Errorf("connection to bastion host (%s) failed: %w", _url.String(), err)
-	}
-
-	connection := Connection{URI: _url}
-	connection.Client = &http.Client{
-		Transport: &http.Transport{
-			DialContext: func(ctx context.Context, _, _ string) (net.Conn, error) {
-				return bastion.Dial("unix", _url.Path)
-			},
-		}}
-	return connection, nil
-}
-
 func unixClient(_url *url.URL) Connection {
 	connection := Connection{URI: _url}
 	connection.Client = &http.Client{