Re: [PATCH 6/6] ima: Support appended signatures for appraisal

From: Thiago Jung Bauermann
Date: Thu Apr 27 2017 - 17:42:02 EST


Am Mittwoch, 26. April 2017, 18:18:34 BRT schrieb Mehmet Kayaalp:
> > On Apr 20, 2017, at 7:41 PM, Thiago Jung Bauermann
> > <bauerman@xxxxxxxxxxxxxxxxxx> wrote:
> >
> > This patch introduces the appended_imasig keyword to the IMA policy syntax
> > to specify that a given hook should expect the file to have the IMA
> > signature appended to it. Here is how it can be used in a rule:
> >
> > appraise func=KEXEC_KERNEL_CHECK appraise_type=appended_imasig
> > appraise func=KEXEC_KERNEL_CHECK appraise_type=appended_imasig|imasig
> >
> > In the second form, IMA will accept either an appended signature or a
> > signature stored in the extended attribute. In that case, it will first
> > check whether there is an appended signature, and if not it will read it
> > from the extended attribute.
> >
> > The format of the appended signature is the same used for signed kernel
> > modules. This means that the file can be signed with the scripts/sign-file
>
> > tool, with a command line such as this:
> I would suggest naming the appraise_type as modsig (or some variant) to
> clarify that the format is defined by how module signatures are handled.
> Maybe we'd like to define a different appended/inline signature format for
> IMA in the future.

I like the suggestion. Would that mean that we will keep refering to it as
"module signature format", and thus nothing changes in patch 5?

--
Thiago Jung Bauermann
IBM Linux Technology Center