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Date: Sun, 17 Apr 2016 16:25:31 +0200
From: none <ytrezq@...-eu.org>
To: oss-security@...ts.openwall.com
Subject: Re: CVE Request: cpio -- directory traversal

On 2015-02-02 20:48, Vitezslav Cizek wrote:
>> * Dne Friday 16. January 2015, 03:44:25 [CET] Alexander Cherepanov 
>> napsal:
>>> cpio is susceptible to a directory traversal vulnerability via 
>>> symlinks.
>> 
>> Here's a patch we use in SUSE for some time.

> Thanks for sharing!

>> It forbids to write over symlinks, similar to bsdtar.

> Nice, this is a simple and easy approach. But I wonder if it's widely
> acceptable. GNU tar follows symlinks which are not extracted from the
> archive and, in 
> http://www.openwall.com/lists/oss-security/2015/01/08/4,
> Florian Weimer said: "If [the current directory] already contains
> symbolic links, some users expect that those links are followed because
> they have used symlinks to move part of the file system tree to
> somewhere else (perhaps a large file system)."

A year later, I see this bug is still not fixed.

What about using the ɢɴᴜ tar way in that case. I mean delay the creation 
of symlinks until all fifo/device/regular files and directories are 
created ? (instead of following the oder in the archive)


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