emacs-28 56caf1c: Use restrictive umask when creating image-dired data

[Stefan Kangas]

branch: emacs-28
commit 56caf1c9b887ccbb6d35a95ca257f633bb71d1d3
Author: Stefan Kangas <stefan@marxist.se>
Commit: Stefan Kangas <stefan@marxist.se>

    Use restrictive umask when creating image-dired data
    
    * lisp/image-dired.el (image-dired-dir)
    (image-dired-sane-db-file): Create thumbnail directory and
    .image-dired_db with umask 077.  This avoids creating world readable
    copies of private data, and is in fact mandated by the Thumbnail
    Managing Standard that we aim to support.
---
 lisp/image-dired.el | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/lisp/image-dired.el b/lisp/image-dired.el
index 2af0c66..e5fbfcf 100644
--- a/lisp/image-dired.el
+++ b/lisp/image-dired.el
@@ -538,7 +538,8 @@ Create the thumbnails directory if it does not exist."
   (let ((image-dired-dir (file-name-as-directory
                     (expand-file-name image-dired-dir))))
     (unless (file-directory-p image-dired-dir)
-      (make-directory image-dired-dir t)
+      (with-file-modes #o700
+        (make-directory image-dired-dir t))
       (message "Creating thumbnails directory"))
     image-dired-dir))
 
@@ -1070,10 +1071,12 @@ Signal error if there are problems creating it."
       (let (dir buf)
         (unless (file-directory-p (setq dir (file-name-directory
                                              image-dired-db-file)))
-          (make-directory dir t))
+          (with-file-modes #o700
+            (make-directory dir t)))
         (with-current-buffer (setq buf (create-file-buffer
                                         image-dired-db-file))
-          (write-file image-dired-db-file))
+          (with-file-modes #o600
+            (write-file image-dired-db-file)))
         (kill-buffer buf)
         (file-exists-p image-dired-db-file))
       (error "Could not create %s" image-dired-db-file)))
@@ -2515,6 +2518,7 @@ when using per-directory thumbnail file storage"))
     (if (file-exists-p image-dired-gallery-dir)
         (if (not (file-directory-p image-dired-gallery-dir))
             (error "Variable image-dired-gallery-dir is not a directory"))
+      ;; FIXME: Should we set umask to 077 here, as we do for thumbnails?
       (make-directory image-dired-gallery-dir))
     ;; Open index file
     (with-temp-file index-file