[Emacs-diffs] emacs/lisp ChangeLog server.el

[Juanma Barranquero]

CVSROOT:        /cvsroot/emacs
Module name:    emacs
Changes by:     Juanma Barranquero <lektu>      09/09/19 14:56:07

Modified files:
        lisp           : ChangeLog server.el 

Log message:
        This fixes bug#4197 (merged to bug#865, though not identical).
        
        * server.el (server-auth-dir): Add docstring note about FAT32.
          (server-ensure-safe-dir): Accept FAT32 directories as "safe",
          but warn against using them.

CVSWeb URLs:
http://cvs.savannah.gnu.org/viewcvs/emacs/lisp/ChangeLog?cvsroot=emacs&r1=1.16209&r2=1.16210
http://cvs.savannah.gnu.org/viewcvs/emacs/lisp/server.el?cvsroot=emacs&r1=1.196&r2=1.197

Patches:
Index: ChangeLog
===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/ChangeLog,v
retrieving revision 1.16209
retrieving revision 1.16210
diff -u -b -r1.16209 -r1.16210
--- ChangeLog   19 Sep 2009 11:45:10 -0000      1.16209
+++ ChangeLog   19 Sep 2009 14:56:04 -0000      1.16210
@@ -1,3 +1,11 @@
+2009-09-19  Juanma Barranquero  <address@hidden>
+           Eli Zaretskii  <address@hidden>
+
+       This fixes bug#4197 (merged to bug#865, though not identical).
+       * server.el (server-auth-dir): Add docstring note about FAT32.
+       (server-ensure-safe-dir): Accept FAT32 directories as "safe",
+       but warn against using them.
+
 2009-09-19  Nick Roberts  <address@hidden>
 
        * progmodes/gdb-mi.el (gdb-var-update-handler-1): Include case of

Index: server.el
===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/server.el,v
retrieving revision 1.196
retrieving revision 1.197
diff -u -b -r1.196 -r1.197
--- server.el   18 Sep 2009 16:55:24 -0000      1.196
+++ server.el   19 Sep 2009 14:56:07 -0000      1.197
@@ -113,7 +113,12 @@
 (put 'server-host 'risky-local-variable t)
 
 (defcustom server-auth-dir (locate-user-emacs-file "server/")
-  "Directory for server authentication files."
+  "Directory for server authentication files.
+
+NOTE: On FAT32 filesystems, directories are not secure;
+files can be read and modified by any user or process.
+It is strongly suggested to set `server-auth-dir' to a
+directory residing in a NTFS partition instead."
   :group 'server
   :type 'directory
   :version "22.1")
@@ -453,11 +458,31 @@
     (unless attrs
       (letf (((default-file-modes) ?\700)) (make-directory dir t))
       (setq attrs (file-attributes dir 'integer)))
+
     ;; Check that it's safe for use.
-    (unless (and (eq t (car attrs)) (eql (nth 2 attrs) (user-uid))
-                 (or (eq system-type 'windows-nt)
-                     (zerop (logand ?\077 (file-modes dir)))))
-      (error "The directory %s is unsafe" dir))))
+    (let* ((uid (nth 2 attrs))
+          (w32 (eq system-type 'windows-nt))
+          (safe (catch :safe
+                  (unless (eq t (car attrs))   ; is a dir?
+                    (throw :safe nil))
+                  (when (and w32 (zerop uid))  ; on FAT32?
+                    (display-warning
+                     'server
+                     (format "Using `%s' to store Emacs-server authentication 
files.
+Directories on FAT32 filesystems are NOT secure against tampering.
+See variable `server-auth-dir' for details."
+                             (file-name-as-directory dir))
+                     :warning)
+                    (throw :safe t))
+                  (unless (eql uid (user-uid)) ; is the dir ours?
+                    (throw :safe nil))
+                  (when w32                    ; on NTFS?
+                    (throw :safe t))
+                  (unless (zerop (logand ?\077 (file-modes dir)))
+                    (throw :safe nil))
+                  t)))
+      (unless safe
+       (error "The directory `%s' is unsafe" dir)))))
 
 ;;;###autoload
 (defun server-start (&optional leave-dead)