Messages in this thread | | | Subject | Re: Time to remove LSM (was Re: [RESEND][RFC][PATCH 2/7] implementation of LSM hooks) | From | Arjan van de Ven <> | Date | Mon, 24 Apr 2006 16:07:13 +0200 |
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On Mon, 2006-04-24 at 08:54 -0500, Serge E. Hallyn wrote: > Quoting Arjan van de Ven (arjan@infradead.org): > > On Mon, 2006-04-24 at 08:29 -0500, Serge E. Hallyn wrote: > > > Quoting Arjan van de Ven (arjan@infradead.org): > > > > On Mon, 2006-04-24 at 08:09 -0500, Serge E. Hallyn wrote: > > > > > Quoting Arjan van de Ven (arjan@infradead.org): > > > > > > for all such things in the first place. In fact, we already know that to > > > > > > do auditing, LSM is the wrong thing to do (and that's why audit doesn't > > > > > > use LSM). It's one of those fundamental linux truths: Trying to be > > > > > > > > > > As I recall it was simply decided that LSM must be "access control > > > > > only", and that was why it wasn't used for audit. > > > > > > > > no you recall incorrectly. > > > > Audit needs to audit things that didn't work out, like filenames that > > > > don't exist. Audit needs to know what is going to happen before the > > > > entire "is this allowed" chain is going to be followed. SELInux and > > > > other LSM parts are just one part of that chain, and there's zero > > > > guarantee that you get to the LSM part in the chain..... Now of course > > > > > > Ah yes. It needed to be authoritative. I did recall incorrectly. > > > > > > I suspect some would argue that you are right that LSM is broken, but > > > only because it wasn't allowed to be authoritative. > > > > authoritative isn't enough; think about it. The VFS isn't ever going to > > ask "can I open this file" if the file doesn't exist in the first place; > > Current audit doesn't do that either, does it?
As far as I know, it actually does. (assuming you configure it do audit such events obviously)
> It labels the parent > inode, so if /var/spool/mail doesn't exist, and you look up > /var/spool/mail/hallyn, you won't get an audit record.
> You'd have to do > that by auditing all open syscalls at the syscall level.
That's a wrong assumption. There is one level below the syscall level as well in Linux, and that is where you need to audit for this, and afaik audit actually does that.
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