1 files changed, 128 insertions, 0 deletions
diff --git a/services/asymkey/ssh_key_authorized_principals.go b/services/asymkey/ssh_key_authorized_principals.go
new file mode 100644
index 0000000000..9154db7dbb
--- /dev/null
+++ b/services/asymkey/ssh_key_authorized_principals.go
@@ -0,0 +1,128 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package asymkey
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+
+	asymkey_model "code.gitea.io/gitea/models/asymkey"
+	"code.gitea.io/gitea/models/db"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/util"
+)
+
+// This file contains functions for creating authorized_principals files
+//
+// There is a dependence on the database within RewriteAllPrincipalKeys & RegeneratePrincipalKeys
+// The sshOpLocker is used from ssh_key_authorized_keys.go
+
+const (
+	authorizedPrincipalsFile = "authorized_principals"
+	tplCommentPrefix         = `# gitea public key`
+)
+
+// RewriteAllPrincipalKeys removes any authorized principal and rewrite all keys from database again.
+// Note: db.GetEngine(ctx).Iterate does not get latest data after insert/delete, so we have to call this function
+// outside any session scope independently.
+func RewriteAllPrincipalKeys(ctx context.Context) error {
+	// Don't rewrite key if internal server
+	if setting.SSH.StartBuiltinServer || !setting.SSH.CreateAuthorizedPrincipalsFile {
+		return nil
+	}
+
+	return asymkey_model.WithSSHOpLocker(func() error {
+		return rewriteAllPrincipalKeys(ctx)
+	})
+}
+
+func rewriteAllPrincipalKeys(ctx context.Context) error {
+	if setting.SSH.RootPath != "" {
+		// First of ensure that the RootPath is present, and if not make it with 0700 permissions
+		// This of course doesn't guarantee that this is the right directory for authorized_keys
+		// but at least if it's supposed to be this directory and it doesn't exist and we're the
+		// right user it will at least be created properly.
+		err := os.MkdirAll(setting.SSH.RootPath, 0o700)
+		if err != nil {
+			log.Error("Unable to MkdirAll(%s): %v", setting.SSH.RootPath, err)
+			return err
+		}
+	}
+
+	fPath := filepath.Join(setting.SSH.RootPath, authorizedPrincipalsFile)
+	tmpPath := fPath + ".tmp"
+	t, err := os.OpenFile(tmpPath, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0o600)
+	if err != nil {
+		return err
+	}
+	defer func() {
+		t.Close()
+		os.Remove(tmpPath)
+	}()
+
+	if setting.SSH.AuthorizedPrincipalsBackup {
+		isExist, err := util.IsExist(fPath)
+		if err != nil {
+			log.Error("Unable to check if %s exists. Error: %v", fPath, err)
+			return err
+		}
+		if isExist {
+			bakPath := fmt.Sprintf("%s_%d.gitea_bak", fPath, time.Now().Unix())
+			if err = util.CopyFile(fPath, bakPath); err != nil {
+				return err
+			}
+		}
+	}
+
+	if err := regeneratePrincipalKeys(ctx, t); err != nil {
+		return err
+	}
+
+	t.Close()
+	return util.Rename(tmpPath, fPath)
+}
+
+func regeneratePrincipalKeys(ctx context.Context, t io.StringWriter) error {
+	if err := db.GetEngine(ctx).Where("type = ?", asymkey_model.KeyTypePrincipal).Iterate(new(asymkey_model.PublicKey), func(idx int, bean any) (err error) {
+		_, err = t.WriteString((bean.(*asymkey_model.PublicKey)).AuthorizedString())
+		return err
+	}); err != nil {
+		return err
+	}
+
+	fPath := filepath.Join(setting.SSH.RootPath, authorizedPrincipalsFile)
+	isExist, err := util.IsExist(fPath)
+	if err != nil {
+		log.Error("Unable to check if %s exists. Error: %v", fPath, err)
+		return err
+	}
+	if isExist {
+		f, err := os.Open(fPath)
+		if err != nil {
+			return err
+		}
+		scanner := bufio.NewScanner(f)
+		for scanner.Scan() {
+			line := scanner.Text()
+			if strings.HasPrefix(line, tplCommentPrefix) {
+				scanner.Scan()
+				continue
+			}
+			_, err = t.WriteString(line + "\n")
+			if err != nil {
+				f.Close()
+				return err
+			}
+		}
+		f.Close()
+	}
+	return nil
+}