Setting to disable authorized_keys backup (#1856)

* Add setting to disable authorized_keys backup when rewriting public keys

Signed-off-by: Magnus Lindvall <magnus@dnmgns.com>

* Update default value to comply with documentation

Signed-off-by: Magnus Lindvall <magnus@dnmgns.com>

* Use tmp-file instead of bak-file for saving manually added keys.

Signed-off-by: Magnus Lindvall <magnus@dnmgns.com>

* Change casing

Signed-off-by: Magnus Lindvall <magnus@dnmgns.com>

* Change casing and build bakpath with sprintf only

Signed-off-by: Magnus Lindvall <magnus@dnmgns.com>

* Only close file once

Signed-off-by: Magnus Lindvall <magnus@dnmgns.com>

* Do not modify calcFingerprint

Signed-off-by: Magnus Lindvall <magnus@dnmgns.com>

* Fix casing

Signed-off-by: Magnus Lindvall <magnus@dnmgns.com>

* Change style from disable to enable

Signed-off-by: Magnus Lindvall <magnus@dnmgns.com>

* Change name, just SSH_BACKUP_AUTHORIZED_KEYS

Signed-off-by: Magnus Lindvall <magnus@dnmgns.com>

* Do not check for directory existence if backup is disabled

Signed-off-by: Magnus Lindvall <magnus@dnmgns.com>

3 files changed, 35 insertions, 31 deletions

diff --git a/conf/app.ini b/conf/app.ini
index 2f9c3cdb11..8f04435b5f 100644
--- a/conf/app.ini
+++ b/conf/app.ini
@@ -124,6 +124,8 @@ SSH_ROOT_PATH =
 SSH_KEY_TEST_PATH =
 ; Path to ssh-keygen, default is 'ssh-keygen' and let shell find out which one to call.
 SSH_KEYGEN_PATH = ssh-keygen
+; Enable SSH Authorized Key Backup when rewriting all keys, default is true
+SSH_BACKUP_AUTHORIZED_KEYS = true
 ; Indicate whether to check minimum key size with corresponding type
 MINIMUM_KEY_SIZE_CHECK = false
 ; Disable CDN even in "prod" mode
diff --git a/models/ssh_key.go b/models/ssh_key.go
index 947b2dabfd..f70e16c62a 100644
--- a/models/ssh_key.go
+++ b/models/ssh_key.go
@@ -324,8 +324,8 @@ func appendAuthorizedKeysToFile(keys ...*PublicKey) error {
 	sshOpLocker.Lock()
 	defer sshOpLocker.Unlock()
 
-	fpath := filepath.Join(setting.SSH.RootPath, "authorized_keys")
-	f, err := os.OpenFile(fpath, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0600)
+	fPath := filepath.Join(setting.SSH.RootPath, "authorized_keys")
+	f, err := os.OpenFile(fPath, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0600)
 	if err != nil {
 		return err
 	}
@@ -558,53 +558,53 @@ func RewriteAllPublicKeys() error {
 	sshOpLocker.Lock()
 	defer sshOpLocker.Unlock()
 
-	fpath := filepath.Join(setting.SSH.RootPath, "authorized_keys")
-	tmpPath := fpath + ".tmp"
-	f, err := os.OpenFile(tmpPath, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600)
+	fPath := filepath.Join(setting.SSH.RootPath, "authorized_keys")
+	tmpPath := fPath + ".tmp"
+	t, err := os.OpenFile(tmpPath, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600)
 	if err != nil {
 		return err
 	}
 	defer func() {
-		f.Close()
+		t.Close()
 		os.Remove(tmpPath)
 	}()
 
+	if setting.SSH.AuthorizedKeysBackup && com.IsExist(fPath) {
+		bakPath := fmt.Sprintf("%s_%d.gitea_bak", fPath, time.Now().Unix())
+		if err = com.Copy(fPath, bakPath); err != nil {
+			return err
+		}
+	}
+
 	err = x.Iterate(new(PublicKey), func(idx int, bean interface{}) (err error) {
-		_, err = f.WriteString((bean.(*PublicKey)).AuthorizedString())
+		_, err = t.WriteString((bean.(*PublicKey)).AuthorizedString())
 		return err
 	})
 	if err != nil {
 		return err
 	}
 
-	if com.IsExist(fpath) {
-		bakPath := fpath + fmt.Sprintf("_%d.gitea_bak", time.Now().Unix())
-		if err = com.Copy(fpath, bakPath); err != nil {
-			return err
-		}
-
-		p, err := os.Open(bakPath)
+	if com.IsExist(fPath) {
+		f, err := os.Open(fPath)
 		if err != nil {
 			return err
 		}
-		defer p.Close()
-
-		scanner := bufio.NewScanner(p)
+		scanner := bufio.NewScanner(f)
 		for scanner.Scan() {
 			line := scanner.Text()
 			if strings.HasPrefix(line, tplCommentPrefix) {
 				scanner.Scan()
 				continue
 			}
-			_, err = f.WriteString(line + "\n")
+			_, err = t.WriteString(line + "\n")
 			if err != nil {
 				return err
 			}
 		}
+		defer f.Close()
 	}
 
-	f.Close()
-	if err = os.Rename(tmpPath, fpath); err != nil {
+	if err = os.Rename(tmpPath, fPath); err != nil {
 		return err
 	}
 
diff --git a/modules/setting/setting.go b/modules/setting/setting.go
index a51e0e7599..d07dce39a0 100644
--- a/modules/setting/setting.go
+++ b/modules/setting/setting.go
@@ -87,17 +87,18 @@ var (
 	EnablePprof          bool
 
 	SSH = struct {
-		Disabled            bool           `ini:"DISABLE_SSH"`
-		StartBuiltinServer  bool           `ini:"START_SSH_SERVER"`
-		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"`
-		KeyTestPath         string         `ini:"SSH_KEY_TEST_PATH"`
-		KeygenPath          string         `ini:"SSH_KEYGEN_PATH"`
-		MinimumKeySizeCheck bool           `ini:"-"`
-		MinimumKeySizes     map[string]int `ini:"-"`
+		Disabled             bool           `ini:"DISABLE_SSH"`
+		StartBuiltinServer   bool           `ini:"START_SSH_SERVER"`
+		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"`
+		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:"-"`
 	}{
 		Disabled:           false,
 		StartBuiltinServer: false,
@@ -703,6 +704,7 @@ func NewContext() {
 			SSH.MinimumKeySizes[strings.ToLower(key.Name())] = key.MustInt()
 		}
 	}
+	SSH.AuthorizedKeysBackup = sec.Key("SSH_AUTHORIZED_KEYS_BACKUP").MustBool(true)
 
 	if err = Cfg.Section("server").MapTo(&LFS); err != nil {
 		log.Fatal(4, "Failed to map LFS settings: %v", err)