Re: Question about chsh/chfn/passwd patches

[Thorsten Kukuk <kukuk@suse.de>]

On Wed, Oct 15, Stephen Smalley wrote:

> On Wed, 2003-10-15 at 14:31, Thorsten Kukuk wrote:
> > Ok, since I copy always all attributes if I modify /etc/passwd and
> > /etc/shadow (to make sure to preserve ACLs and security attributes),
> > I don't need it.
> 
> The problem with simply preserving attributes via setxattr is that you
> cannot create the new file immediately with the desired attributes, so
> there is a window where the new file exists with the default attribute
> value, typically inherited from the parent directory.  Note that this is
> particularly a concern for /etc/passwd and /etc/shadow, since they live
> in the same parent directory but have differing protection requirements.

Ok, I think it is trivial to do a getfscreatecon, call setfscreatecon
with the permissions of the passwd file and restore the original
fscreate values afterwards.

But it would be interesting to know how somebody could be able to do
something forbidden with the following:

Create temporary file with mkstemp, mode 0600, owner root:root.
Copy EA attributes.

  Thorsten

-- 
Thorsten Kukuk       http://www.suse.de/~kukuk/        kukuk@suse.de
SuSE Linux AG        Deutschherrnstr. 15-19        D-90429 Nuernberg
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