Disable SSH key deletion of externally managed Keys (#13985)

* Disable SSH key addition and deletion when externally managed

When a user has a login source which has SSH key management
key addition and deletion using the UI should be disabled.

Fix #13983

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Make only externally managed keys disabled

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

models/ssh_key.go

@@ -665,6 +665,82 @@ func deletePublicKeys(e Engine, keyIDs ...int64) error {
 	return err
 }
 
+// PublicKeysAreExternallyManaged returns whether the provided KeyID represents an externally managed Key
+func PublicKeysAreExternallyManaged(keys []*PublicKey) ([]bool, error) {
+	sources := make([]*LoginSource, 0, 5)
+	externals := make([]bool, len(keys))
+keyloop:
+	for i, key := range keys {
+		if key.LoginSourceID == 0 {
+			externals[i] = false
+			continue keyloop
+		}
+
+		var source *LoginSource
+
+	sourceloop:
+		for _, s := range sources {
+			if s.ID == key.LoginSourceID {
+				source = s
+				break sourceloop
+			}
+		}
+
+		if source == nil {
+			var err error
+			source, err = GetLoginSourceByID(key.LoginSourceID)
+			if err != nil {
+				if IsErrLoginSourceNotExist(err) {
+					externals[i] = false
+					sources[i] = &LoginSource{
+						ID: key.LoginSourceID,
+					}
+					continue keyloop
+				}
+				return nil, err
+			}
+		}
+
+		ldapSource := source.LDAP()
+		if ldapSource != nil &&
+			source.IsSyncEnabled &&
+			(source.Type == LoginLDAP || source.Type == LoginDLDAP) &&
+			len(strings.TrimSpace(ldapSource.AttributeSSHPublicKey)) > 0 {
+			// Disable setting SSH keys for this user
+			externals[i] = true
+		}
+	}
+
+	return externals, nil
+}
+
+// PublicKeyIsExternallyManaged returns whether the provided KeyID represents an externally managed Key
+func PublicKeyIsExternallyManaged(id int64) (bool, error) {
+	key, err := GetPublicKeyByID(id)
+	if err != nil {
+		return false, err
+	}
+	if key.LoginSourceID == 0 {
+		return false, nil
+	}
+	source, err := GetLoginSourceByID(key.LoginSourceID)
+	if err != nil {
+		if IsErrLoginSourceNotExist(err) {
+			return false, nil
+		}
+		return false, err
+	}
+	ldapSource := source.LDAP()
+	if ldapSource != nil &&
+		source.IsSyncEnabled &&
+		(source.Type == LoginLDAP || source.Type == LoginDLDAP) &&
+		len(strings.TrimSpace(ldapSource.AttributeSSHPublicKey)) > 0 {
+		// Disable setting SSH keys for this user
+		return true, nil
+	}
+	return false, nil
+}
+
 // DeletePublicKey deletes SSH key information both in database and authorized_keys file.
 func DeletePublicKey(doer *User, id int64) (err error) {
 	key, err := GetPublicKeyByID(id)