add ssh dialer

pkg/handler/forward/ssh/metadata.go

@@ -0,0 +1,94 @@
+package ssh
+
+import (
+	"io/ioutil"
+	"strings"
+
+	"github.com/go-gost/gost/pkg/auth"
+	tls_util "github.com/go-gost/gost/pkg/common/util/tls"
+	md "github.com/go-gost/gost/pkg/metadata"
+	"golang.org/x/crypto/ssh"
+)
+
+type metadata struct {
+	authenticator  auth.Authenticator
+	signer         ssh.Signer
+	authorizedKeys map[string]bool
+}
+
+func (h *forwardHandler) parseMetadata(md md.Metadata) (err error) {
+	const (
+		users          = "users"
+		authorizedKeys = "authorizedKeys"
+		privateKeyFile = "privateKeyFile"
+		passphrase     = "passphrase"
+	)
+
+	if v, _ := md.Get(users).([]interface{}); len(v) > 0 {
+		authenticator := auth.NewLocalAuthenticator(nil)
+		for _, auth := range v {
+			if s, _ := auth.(string); s != "" {
+				ss := strings.SplitN(s, ":", 2)
+				if len(ss) == 1 {
+					authenticator.Add(ss[0], "")
+				} else {
+					authenticator.Add(ss[0], ss[1])
+				}
+			}
+		}
+		h.md.authenticator = authenticator
+	}
+
+	if key := md.GetString(privateKeyFile); key != "" {
+		data, err := ioutil.ReadFile(key)
+		if err != nil {
+			return err
+		}
+
+		pp := md.GetString(passphrase)
+		if pp == "" {
+			h.md.signer, err = ssh.ParsePrivateKey(data)
+		} else {
+			h.md.signer, err = ssh.ParsePrivateKeyWithPassphrase(data, []byte(pp))
+		}
+		if err != nil {
+			return err
+		}
+	}
+	if h.md.signer == nil {
+		signer, err := ssh.NewSignerFromKey(tls_util.DefaultConfig.Clone().Certificates[0].PrivateKey)
+		if err != nil {
+			return err
+		}
+		h.md.signer = signer
+	}
+
+	if name := md.GetString(authorizedKeys); name != "" {
+		m, err := parseAuthorizedKeysFile(name)
+		if err != nil {
+			return err
+		}
+		h.md.authorizedKeys = m
+	}
+
+	return
+}
+
+// parseSSHAuthorizedKeysFile parses ssh authorized keys file.
+func parseAuthorizedKeysFile(name string) (map[string]bool, error) {
+	authorizedKeysBytes, err := ioutil.ReadFile(name)
+	if err != nil {
+		return nil, err
+	}
+	authorizedKeysMap := make(map[string]bool)
+	for len(authorizedKeysBytes) > 0 {
+		pubKey, _, _, rest, err := ssh.ParseAuthorizedKey(authorizedKeysBytes)
+		if err != nil {
+			return nil, err
+		}
+		authorizedKeysMap[string(pubKey.Marshal())] = true
+		authorizedKeysBytes = rest
+	}
+
+	return authorizedKeysMap, nil
+}