full-disclosure - Re: File system recursion and symlinks: A never-ending story (and how to bring it to an end for me)

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Date: Mon, 30 May 2011 16:27:31 -0700
From: coderman <coderman@...il.com>
To: halfdog <me@...fdog.net>
Cc: full-disclosure@...ts.grok.org.uk
Subject: Re: File system recursion and symlinks: A
 never-ending story (and how to bring it to an end for me)

On Mon, May 30, 2011 at 6:56 AM, halfdog <me@...fdog.net> wrote:
> ...
> It seems that quite a few backup applications are (or were) vulnerable
> to special combined symlink/timing attacks on pathname components before
> the last one (so O_NOFOLLOW does not help).
> ...
> Please let me know, if ... you
> have good reason, that the kernel interface is not the point, where this
> issue could be addressed most efficiently.

use lvm snapshots for backups, either directly at volume level or
mounting a read-only snapshot and running backup over that static
filesystem state.

running backups on live filesystems? not a great idea even if these
issues resolved.

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