Date: 16 Jan 1997 11:19:12 -0800 From: jdp@polstra.com (John Polstra) To: freebsd-hackers@freebsd.org Subject: Re: open () unlinked? Message-ID: <5bluvg$q4j@austin.polstra.com> References: <32DE6EAC.1A1B@vailsys.com>
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In article <32DE6EAC.1A1B@vailsys.com>, Hal Snyder <hal@vailsys.com> wrote:
> I was at Marcus Ranum's Usenix '97 tuturial on Coding for Hostile
> Environments, and the subject came up of creating temporary files
> securely. Open-then-unlink leaves a window for someone to get at the
> file.
>
> Has there been any discussion here of adding, e.g., an O_UNLINK flag to
> open (), that would effectively create an anonymous temp file?
It's hard to see what that would buy you that you can't already get by
the time honored method:
fd = open(path, O_RDWR|O_CREAT|O_TRUNC|O_EXCL, 0);
The key is the last argument 0, the file mode. A mode of 0 means that
nobody except root can open the file.
John
--
John Polstra jdp@polstra.com
John D. Polstra & Co., Inc. Seattle, Washington USA
"Self-knowledge is always bad news." -- John Barth
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