Re: [PATCH 2/3] binfmt_elf: Verify signature of signed elf binary

[Vivek Goyal <vgoyal@redhat.com>]

On Wed, Jan 16, 2013 at 02:37:24PM -0500, Mimi Zohar wrote:
> On Wed, 2013-01-16 at 13:57 -0500, Vivek Goyal wrote:
> > On Wed, Jan 16, 2013 at 01:45:12PM -0500, Mimi Zohar wrote:
> > 
> > [..]
> > > > Given the fact that signatures are stored in extended attributes, to me
> > > > the only way to sign executables in current IMA framework would to be
> > > > prepare file system image at build server and ship that image. And
> > > > then installer simply mounts that image (after making sure that proper
> > > > verification keys have been loaded in kernel).
> > > 
> > > That is one scenario.  Another scenario is to update packages to include
> > > extended attributes and to write those extended attributes on
> > > installation.
> > 
> > Ok, that's the point I am missing. So I can sign a file and signatures
> > are in a separate file. And these signatures are installed in extended
> > attributes at file installation time (IOW rpm installation time) on
> > target.
> > 
> > If all this works, this sounds reasonable so far. Except the point of
> > disabling ptrace and locking down memory. 
> > 
> > So what's the state of above work. Is there something I can play with.
> 
> Sorry, I'm not sure of the RPM implementation details of where/how the
> signatures are stored in the package, nor of the status of these
> changes.  Perhaps someone else on the mailing list knows.

So irrespective of fact how RPM does it. What are basic commands/steps to
generate signature of a file and how to store it later in an extended
attribute?

Thanks
Vivek