Path: utzoo!attcan!uunet!yale!Ram-Ashwin
From: Ram-Ashwin@cs.yale.edu (Ashwin Ram)
Newsgroups: comp.emacs
Subject: Re: Mode of autosave files
Message-ID: <48674@yale-celray.yale.UUCP>
Date: 25 Jan 89 17:49:28 GMT
References: <15179@oddjob.UChicago.EDU>
Sender: root@yale.UUCP
Reply-To: Ram-Ashwin@cs.yale.edu (Ashwin Ram)
Organization: Computer Science, Yale University, New Haven, CT 06520-2158
Lines: 20
In-reply-to: pearce@oddjob.UChicago.EDU (Eric C. Pearce)

In article <15179@oddjob.UChicago.EDU>, pearce@oddjob.UChicago.EDU (Eric C. Pearce) writes:
> Emacs 18.52 (running under Sun OS 3.5) sets the mode of the autosave
> files to the value derived from umask upon entry to emacs.  Thus, if
> you are editing a file which is non publically readable, and your
> umask is set to a typical Unix value, your file, say "foo", is visible
> to everyone in the form of its autosave file #foo#.
> 
> I would call this a bug and a security problem.  Backfiles
> automatically receive the same mode as the original file.  Autosave
> files should too.

I agree.  I use (setq backup-by-copying t) to force Emacs to preserve the
mode (ACLs on the Apollos) and date/time on the file, but this is a
workaround at best.  If backup-by-copying is nil, Emacs renames the original
file to make the backup, but the new file that is created in its place gets a
new mode derived afresh from the umask (at least in 18.48 on the Apollos)
rather than the mode it had previously.  This is another problem along the
lines you mentioned.

-- Ashwin.