Re: [AppArmor 01/41] Pass struct vfsmount to the inode_create LSM hook

Pavel Machek
2007-05-29T23:30:54Z

Hi!

> >>>If we want "/etc/shadow" to be the only way to access the shadow file
> >>>we could label the data with "/etc/shadow". Any attempts to access
> >>>this data using a renamed file or link would be denied (attempts to
> >>>link or rename could also be denied).
> >>Eloquently put.
> >>
> >>AppArmor actually does something similar to this, by mediating all of
> >>the ways that you can make an alias to a file. These are:
> >...
> >> * Hard links: AppArmor explicitly mediates permission to make a hard
> >
> >Unfortunately, aparmor is by design limited to subset of distro
> >(network daemons). Unfortunately, some other programs (passwd, vi)
> >routinely make hardlinks. So AA mediating hardlink is not enough, as
> >vi will happily hardlink /etc/shadow into /etc/.vi-shadow-1234.
>
> but with the AA design of default deny this isn't a big problem unless you
> specificly allow some network daemon to access /etc/.vi-shadow-1234

...or unless vi decides to hardlink into /tmp or something.

> no, this won't help you much against local users, but there are a _lot_ of
> boxes out there with few, if any, local users who don't also have the root
> password. AA helps the admin be safer when configuring netwrok daemons.

Hmm, I guess I'd love "it is useless on multiuser boxes" to become
standard part of AA advertising.
Pavel
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