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Date:      Wed, 24 Mar 2004 13:21:49 -0500 (EST)
From:      Andre Guibert de Bruet <andy@siliconlandmark.com>
To:        Rafal Skoczylas <nils@secprog.org>
Cc:        freebsd-current@freebsd.org
Subject:   Re: [UFS] Broken suiddir? (+patch)
Message-ID:  <20040324130129.A93167@alpha.siliconlandmark.com>
In-Reply-To: <20040323223020.GA2931@secprog.org>
References:  <20040323223020.GA2931@secprog.org>

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On Tue, 23 Mar 2004, Rafal Skoczylas wrote:

> from mount(8):
> [...]
> suiddir
>         A directory on the mounted file system will respond to
>         the SUID bit being set, by setting the owner of any new
>         files to be the same as the owner of the directory.  New
>         directories will inherit the bit from their parents.
>         Execute bits are removed from the file, and it will not
>         be given to root.
>
>         This feature is designed for use on fileservers serving
>         PC users via ftp, SAMBA, or netatalk.  It provides secu-
>         rity holes for shell users and as such should not be used
>         on shell machines, especially on home directories.
> [...]
>
> Additionaly, would someone be so kind to describe the risk caused by using
> SUIDDIR (mentioned in man) in more detail? Is there any "hidden" risk
> except those obvious (like created files that look like if someone else
> created them)? I tried searching google for such information but with
> no luck so far.

Imagine a scenario where a user uploads via SMB a windows executable and
another trojans it. User 1 has no idea that the file has been tampered
with and runs it. You've got yourself a problem.

Regards,

> Andre Guibert de Bruet | Enterprise Software Consultant >
> Silicon Landmark, LLC. | http://siliconlandmark.com/    >



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