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    SubjectRe: Time to remove LSM (was Re: [RESEND][RFC][PATCH 2/7] implementation of LSM hooks)
    On 4/20/06, Valdis.Kletnieks@vt.edu <Valdis.Kletnieks@vt.edu> wrote:
    > On Wed, 19 Apr 2006 17:19:04 PDT, Crispin Cowan said:
    > > Valdis.Kletnieks@vt.edu wrote:
    > > > In other words, it's quite possible to accidentally introduce a vulnerability
    > > > that wasn't exploitable before, by artificially restricting the privs in a way
    > > > the designer didn't expect. So this is really just handing the sysadmin
    > > > a loaded gun and waiting.
    > > >
    > > While that is true of the voluntary model of acquiring and dropping
    > > privs, it is not true of AppArmor containment, which will just not give
    > > you the priv if it is not in your policy.
    >
    > The threat model is that you can take a buggy application, and constrain its
    > access to priv A in a way that causes a code failure that allows you to abuse
    > an unconstrained priv B.

    So you are talking about a 2 prong attack. One in where you somehow
    trick program A to do something that it's allowed to. That then would
    cause an error in program B ? Or cause program B to do something
    wonky.

    I guess a good example of this would be if you sent an email to
    sendmail (which is constrained) to write the message to my mailbox
    (which is allowed, obviously).

    Then I use an imap daemon (which would not be constrained, in the
    hypothetical, personally I constrain everything I can). To retrieve
    that message but the payload of the message causes the imap daemon to
    delete /lib ?

    Is that a proper example? or do you mean something else?

    -Ken
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