Create AuthorizedKeysCommand (#5236)

7 files changed, 136 insertions, 19 deletions

diff --git a/cmd/cmd.go b/cmd/cmd.go
index 15dd085247..1ca885a42b 100644
--- a/cmd/cmd.go
+++ b/cmd/cmd.go
@@ -27,10 +27,14 @@ func argsSet(c *cli.Context, args ...string) error {
 }
 
 func initDB() error {
+	return initDBDisableConsole(false)
+}
+
+func initDBDisableConsole(disableConsole bool) error {
 	setting.NewContext()
 	models.LoadConfigs()
 
-	setting.NewXORMLogService(false)
+	setting.NewXORMLogService(disableConsole)
 	if err := models.SetEngine(); err != nil {
 		return fmt.Errorf("models.SetEngine: %v", err)
 	}
diff --git a/cmd/keys.go b/cmd/keys.go
new file mode 100644
index 0000000000..66565cc563
--- /dev/null
+++ b/cmd/keys.go
@@ -0,0 +1,85 @@
+// Copyright 2018 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package cmd
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/setting"
+
+	"github.com/urfave/cli"
+)
+
+// CmdKeys represents the available keys sub-command
+var CmdKeys = cli.Command{
+	Name:   "keys",
+	Usage:  "This command queries the Gitea database to get the authorized command for a given ssh key fingerprint",
+	Action: runKeys,
+	Flags: []cli.Flag{
+		cli.StringFlag{
+			Name:  "expected, e",
+			Value: "git",
+			Usage: "Expected user for whom provide key commands",
+		},
+		cli.StringFlag{
+			Name:  "username, u",
+			Value: "",
+			Usage: "Username trying to log in by SSH",
+		},
+		cli.StringFlag{
+			Name:  "type, t",
+			Value: "",
+			Usage: "Type of the SSH key provided to the SSH Server (requires content to be provided too)",
+		},
+		cli.StringFlag{
+			Name:  "content, k",
+			Value: "",
+			Usage: "Base64 encoded content of the SSH key provided to the SSH Server (requires type to be provided too)",
+		},
+		cli.StringFlag{
+			Name:  "config, c",
+			Value: "custom/conf/app.ini",
+			Usage: "Custom configuration file path",
+		},
+	},
+}
+
+func runKeys(c *cli.Context) error {
+	if c.IsSet("config") {
+		setting.CustomConf = c.String("config")
+	}
+
+	if !c.IsSet("username") {
+		return errors.New("No username provided")
+	}
+	// Check username matches the expected username
+	if strings.TrimSpace(c.String("username")) != strings.TrimSpace(c.String("expected")) {
+		return nil
+	}
+
+	content := ""
+
+	if c.IsSet("type") && c.IsSet("content") {
+		content = fmt.Sprintf("%s %s", strings.TrimSpace(c.String("type")), strings.TrimSpace(c.String("content")))
+	}
+
+	if content == "" {
+		return errors.New("No key type and content provided")
+	}
+
+	if err := initDBDisableConsole(true); err != nil {
+		return err
+	}
+
+	publicKey, err := models.SearchPublicKeyByContent(content)
+	if err != nil {
+		return err
+	}
+	fmt.Println(publicKey.AuthorizedString())
+	return nil
+}
diff --git a/custom/conf/app.ini.sample b/custom/conf/app.ini.sample
index 1a85f9364d..a5925b48da 100644
--- a/custom/conf/app.ini.sample
+++ b/custom/conf/app.ini.sample
@@ -154,6 +154,9 @@ SSH_PORT = 22
 SSH_LISTEN_PORT = %(SSH_PORT)s
 ; Root path of SSH directory, default is '~/.ssh', but you have to use '/home/git/.ssh'.
 SSH_ROOT_PATH =
+; Gitea will create a authorized_keys file by default when it is not using the internal ssh server
+; If you intend to use the AuthorizedKeysCommand functionality then you should turn this off.
+SSH_CREATE_AUTHORIZED_KEYS_FILE = true
 ; For the built-in SSH server, choose the ciphers to support for SSH connections,
 ; for system SSH this setting has no effect
 SSH_SERVER_CIPHERS = aes128-ctr, aes192-ctr, aes256-ctr, aes128-gcm@openssh.com, arcfour256, arcfour128
diff --git a/docs/content/doc/usage/command-line.md b/docs/content/doc/usage/command-line.md
index 90e1ae2514..904a395e8c 100644
--- a/docs/content/doc/usage/command-line.md
+++ b/docs/content/doc/usage/command-line.md
@@ -163,3 +163,24 @@ for automatic deployments.
             - `gitea generate secret INTERNAL_TOKEN`
             - `gitea generate secret LFS_JWT_SECRET`
             - `gitea generate secret SECRET_KEY`
+
+#### keys
+
+Provides an SSHD AuthorizedKeysCommand. Needs to be configured in the sshd config file:
+
+```ini
+...
+# The value of -e and the AuthorizedKeysCommandUser should match the
+# username running gitea
+AuthorizedKeysCommandUser git
+AuthorizedKeysCommand /path/to/gitea keys -e git -u %u -t %t -k %k
+```
+
+The command will return the appropriate authorized_keys line for the
+provided key. You should also set the value
+`SSH_CREATE_AUTHORIZED_KEYS_FILE=false` in the `[server]` section of
+`app.ini`.
+
+NB: opensshd requires the gitea program to be owned by root and not
+writable by group or others. The program must be specified by an absolute
+path.
diff --git a/main.go b/main.go
index a0a52c3ae8..ccfc884b1c 100644
--- a/main.go
+++ b/main.go
@@ -13,6 +13,7 @@ import (
 	"code.gitea.io/gitea/cmd"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
+
 	// register supported doc types
 	_ "code.gitea.io/gitea/modules/markup/csv"
 	_ "code.gitea.io/gitea/modules/markup/markdown"
@@ -48,6 +49,7 @@ arguments - which can alternatively be run by running the subcommand web.`
 		cmd.CmdAdmin,
 		cmd.CmdGenerate,
 		cmd.CmdMigrate,
+		cmd.CmdKeys,
 	}
 	app.Flags = append(app.Flags, cmd.CmdWeb.Flags...)
 	app.Action = cmd.CmdWeb.Action
diff --git a/models/ssh_key.go b/models/ssh_key.go
index 0368ffad33..5d046c0201 100644
--- a/models/ssh_key.go
+++ b/models/ssh_key.go
@@ -558,7 +558,7 @@ func DeletePublicKey(doer *User, id int64) (err error) {
 // outside any session scope independently.
 func RewriteAllPublicKeys() error {
 	//Don't rewrite key if internal server
-	if setting.SSH.StartBuiltinServer {
+	if setting.SSH.StartBuiltinServer || !setting.SSH.CreateAuthorizedKeysFile {
 		return nil
 	}
 
diff --git a/modules/setting/setting.go b/modules/setting/setting.go
index 0eaf58988f..a15dc116af 100644
--- a/modules/setting/setting.go
+++ b/modules/setting/setting.go
@@ -118,23 +118,24 @@ var (
 	LetsEncryptEmail     string
 
 	SSH = struct {
-		Disabled             bool           `ini:"DISABLE_SSH"`
-		StartBuiltinServer   bool           `ini:"START_SSH_SERVER"`
-		BuiltinServerUser    string         `ini:"BUILTIN_SSH_SERVER_USER"`
-		Domain               string         `ini:"SSH_DOMAIN"`
-		Port                 int            `ini:"SSH_PORT"`
-		ListenHost           string         `ini:"SSH_LISTEN_HOST"`
-		ListenPort           int            `ini:"SSH_LISTEN_PORT"`
-		RootPath             string         `ini:"SSH_ROOT_PATH"`
-		ServerCiphers        []string       `ini:"SSH_SERVER_CIPHERS"`
-		ServerKeyExchanges   []string       `ini:"SSH_SERVER_KEY_EXCHANGES"`
-		ServerMACs           []string       `ini:"SSH_SERVER_MACS"`
-		KeyTestPath          string         `ini:"SSH_KEY_TEST_PATH"`
-		KeygenPath           string         `ini:"SSH_KEYGEN_PATH"`
-		AuthorizedKeysBackup bool           `ini:"SSH_AUTHORIZED_KEYS_BACKUP"`
-		MinimumKeySizeCheck  bool           `ini:"-"`
-		MinimumKeySizes      map[string]int `ini:"-"`
-		ExposeAnonymous      bool           `ini:"SSH_EXPOSE_ANONYMOUS"`
+		Disabled                 bool           `ini:"DISABLE_SSH"`
+		StartBuiltinServer       bool           `ini:"START_SSH_SERVER"`
+		BuiltinServerUser        string         `ini:"BUILTIN_SSH_SERVER_USER"`
+		Domain                   string         `ini:"SSH_DOMAIN"`
+		Port                     int            `ini:"SSH_PORT"`
+		ListenHost               string         `ini:"SSH_LISTEN_HOST"`
+		ListenPort               int            `ini:"SSH_LISTEN_PORT"`
+		RootPath                 string         `ini:"SSH_ROOT_PATH"`
+		ServerCiphers            []string       `ini:"SSH_SERVER_CIPHERS"`
+		ServerKeyExchanges       []string       `ini:"SSH_SERVER_KEY_EXCHANGES"`
+		ServerMACs               []string       `ini:"SSH_SERVER_MACS"`
+		KeyTestPath              string         `ini:"SSH_KEY_TEST_PATH"`
+		KeygenPath               string         `ini:"SSH_KEYGEN_PATH"`
+		AuthorizedKeysBackup     bool           `ini:"SSH_AUTHORIZED_KEYS_BACKUP"`
+		MinimumKeySizeCheck      bool           `ini:"-"`
+		MinimumKeySizes          map[string]int `ini:"-"`
+		CreateAuthorizedKeysFile bool           `ini:"SSH_CREATE_AUTHORIZED_KEYS_FILE"`
+		ExposeAnonymous          bool           `ini:"SSH_EXPOSE_ANONYMOUS"`
 	}{
 		Disabled:           false,
 		StartBuiltinServer: false,
@@ -863,6 +864,7 @@ func NewContext() {
 		}
 	}
 	SSH.AuthorizedKeysBackup = sec.Key("SSH_AUTHORIZED_KEYS_BACKUP").MustBool(true)
+	SSH.CreateAuthorizedKeysFile = sec.Key("SSH_CREATE_AUTHORIZED_KEYS_FILE").MustBool(true)
 	SSH.ExposeAnonymous = sec.Key("SSH_EXPOSE_ANONYMOUS").MustBool(false)
 
 	sec = Cfg.Section("server")