Date: Sun, 14 Jan 1996 12:34:30 -0500 (EST) From: Sujal Patel <smpatel@wam.umd.edu> To: Bruce Evans <bde@zeta.org.au> Cc: freebsd-bugs@freefall.freebsd.org Subject: Re: ports/944: Security fixes for Fvwm 1.24r Message-ID: <Pine.BSF.3.91.960114122859.818E-100000@sl-015.sl.cybercomm.net> In-Reply-To: <199601140740.XAA19336@freefall.freebsd.org>
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On Sat, 13 Jan 1996, Bruce Evans wrote:
> >+ /* make a directory to guard against following symlinks */
> >+ if (mkdir(tmp_name, 0700) != 0) {
> >+ perror("exclusive open for tmp_name failed in m4_defs");
> >+ exit(0377);
> >+ }
> >+ strcat(tmp_name, "/data"); /* what actual tmp file is to be called */
>
> I think the O_EXCL method is better. Except of course if you really
> want a directory or another type of non-regular file. It's surprisingly
> hard to get the interface for temporary file [name] creation right.
> FreeBSD has 5 BAD interfaces: tempnam(), tmpfile(), tmpnam(), mktemp()
> and mkstemp().
I didn't like the idea of making a directory either. It looked pretty
ugly when I first looked at this patch-- But there is precedent for this
kind of protection (even in BSD code: df.c). Also, this temporary file
is going to be used when FVWM runs 'm4 > tempfile', so this doesn't allow
the use of mkstemp(). Overall, this whole part of FVWM is a big ugly mess--
But at least this fixes the security problems.
Sujal
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