Re: [RFC] [Patch 1/1] IBAC Patch

From: Seth Arnold
Date: Wed Mar 14 2007 - 14:49:07 EST


On Wed, Mar 14, 2007 at 07:25:26AM -0400, Mimi Zohar wrote:
> It's a little bit of both. :-) Initially it was written to help me with

:)

> implementing and testing the integrity provider. But it could definitely stand
> on it's own. As Serge Hallyn commented http://lkml.org/lkml/2007/3/13/220, by
> adding the mmap hook, IBAC could replace the LSM aspect of digsig and a gpg
> based integrity provider, could be written, instead of EVM, which is TPM based.

Thanks.

> > > + if (status != INTEGRITY_PASS) { /* FAIL | NO_LABEL */
> > > + if (!is_kernel_thread(current)) {
> >
> > Please remind me why kernel threads are exempt?
>
> You really don't want to prevent kernel threads from working. Nasty things
> happen.

But under what conditions would a kernel thread not pass integrity? I
guess if it doesn't have an associated dentry... or the dentry refers
to something else? (What does knfsd do -- it is started by a userland
program which causes the kernel to start up some tasks for NFS..)

> For integrity_measure(), EVM calls IMA, if enabled, to extend the
> measurement list with the hash value it provides. In most cases, EVM
> has already calculated the hash value, when it was called to verify the
> data. integrity_measure() is not meant to be intrusive, so it is defined
> as void.

Oh, ok, thanks.

> Thank you for your comments.

My pleasure, thanks for the quick responses.

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