Adjust error handling in kernfs rename.

Read-only directories (e.g. under /sys, /proc) should return EPERM for rename.

PiperOrigin-RevId: 339979022

1 files changed, 7 insertions, 2 deletions

diff --git a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
index 4f78437d2..d83c17f83 100644
--- a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
+++ b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
@@ -578,13 +578,18 @@ func (o *OrderedChildren) RmDir(ctx context.Context, name string, child Inode) e
 //
 // Postcondition: reference on any replaced dentry transferred to caller.
 func (o *OrderedChildren) Rename(ctx context.Context, oldname, newname string, child, dstDir Inode) error {
+	if !o.writable {
+		return syserror.EPERM
+	}
+
 	dst, ok := dstDir.(interface{}).(*OrderedChildren)
 	if !ok {
-		return syserror.ENODEV
+		return syserror.EXDEV
 	}
-	if !o.writable || !dst.writable {
+	if !dst.writable {
 		return syserror.EPERM
 	}
+
 	// Note: There's a potential deadlock below if concurrent calls to Rename
 	// refer to the same src and dst directories in reverse. We avoid any
 	// ordering issues because the caller is required to serialize concurrent