From 6bac5068423972e82cb4e50acde67f1c9ce36202 Mon Sep 17 00:00:00 2001
From: Chris Lu <chrislusf@users.noreply.github.com>
Date: Sun, 11 Oct 2026 20:18:29 -0700
Subject: [PATCH] sftp: terminate the missing-ancestor permission walk at the
 root

A path whose ancestors are all absent recursed on the root forever,
since Dir("/") is "/".

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>
---
 weed/sftpd/sftp_permissions.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/weed/sftpd/sftp_permissions.go b/weed/sftpd/sftp_permissions.go
index 8eea53f60..1a3210783 100644
--- a/weed/sftpd/sftp_permissions.go
+++ b/weed/sftpd/sftp_permissions.go
@@ -67,6 +67,9 @@ func (fs *SftpServer) CheckFilePermission(path string, perm string) error {
 		// check permissions on the parent directory instead
 		if err == os.ErrNotExist {
 			parentPath := stdpath.Dir(path)
+			if parentPath == path {
+				return os.ErrPermission
+			}
 			// Check if user can write to the parent directory
 			return fs.CheckFilePermission(parentPath, perm)
 		}