[RFC PATCH 8/9] LSM: x86/sgx: Introduce ->enclave_load() hook for Intel SGX

[Xing, Cedric]

> From: Christopherson, Sean J
> Sent: Tuesday, June 04, 2019 1:37 PM
> 
> On Tue, Jun 04, 2019 at 01:29:10PM -0700, Andy Lutomirski wrote:
> > On Fri, May 31, 2019 at 4:32 PM Sean Christopherson
> > <sean.j.christopherson at intel.com> wrote:
> > >  static int sgx_encl_add_page(struct sgx_encl *encl, unsigned long
> > > addr, diff --git a/include/linux/lsm_hooks.h
> > > b/include/linux/lsm_hooks.h index 47f58cfb6a19..0562775424a0 100644
> > > --- a/include/linux/lsm_hooks.h
> > > +++ b/include/linux/lsm_hooks.h
> > > @@ -1446,6 +1446,14 @@
> > >   * @bpf_prog_free_security:
> > >   *     Clean up the security information stored inside bpf prog.
> > >   *
> > > + * Security hooks for Intel SGX enclaves.
> > > + *
> > > + * @enclave_load:
> > > + *     On success, returns 0 and optionally adjusts @allowed_prot
> > > + *     @vma: the source memory region of the enclave page being
> loaded.
> > > + *     @prot: the initial protection of the enclave page.
> >
> > What do you mean "initial"?  The page is always mapped PROT_NONE when
> > this is called, right?  I feel like I must be missing something here.
> 
> Initial protection in the EPCM.  Yet another reason to ignore SECINFO.

I know you guys are talking in the background that all pages are mmap()'ed PROT_NONE. But that's an unnecessary limitation. And @prot here should be @target_vma->vm_flags&(VM_READ|VM_WRITE|VM_EXEC).