Dave Young <dyo...@redhat.com> wrote:

> > > > +       /* Don't permit images to be loaded into trusted kernels if 
> > > > we're not
> > > > +        * going to verify the signature on them
> > > > +        */
> > > > +       if (!IS_ENABLED(CONFIG_KEXEC_VERIFY_SIG) && 
> > > > kernel_is_locked_down())
> > > > +               return -EPERM;
> > > > +
> > > >  
> > 
> > IMA can be used to verify file signatures too, based on the LSM hooks
> > in  kernel_read_file_from_fd().  CONFIG_KEXEC_VERIFY_SIG should not be
> > required.
> 
> Mimi, I remember we talked somthing before about the two signature 
> verification. One can change IMA policy in initramfs userspace,
> also there are kernel cmdline param to disable IMA, so it can break the
> lockdown? Suppose kexec boot with ima disabled cmdline param and then
> kexec reboot again..

I guess I should lock down the parameter to disable IMA too.

David

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