[PATCH v23 12/24] x86/sgx: Linux Enclave Driver

[Sean Christopherson]

On Fri, Nov 01, 2019 at 09:28:17AM -0400, Stephen Smalley wrote:
> On 11/1/19 9:16 AM, Stephen Smalley wrote:
> >So, IIUC, that means that merging the driver will create a regression with
> >respect to LSM control over executable mappings that will only be
> >rectified at some future point in time if/when someone submits LSM hooks
> >or calls to existing hooks to restore such control.  That doesn't seem
> >like a good idea.  Why can't you include at least that basic level of
> >control now?  It is one thing to defer finer grained control or
> >SGX-specific access controls to the future - that I can understand.  But
> >introducing a regression in the existing controls is not really ok.
> 
> Unless you are arguing that the existing checks on mmap/mprotect of
> /dev/sgx/enclave are a coarse-grained approximation (effectively requiring
> WX to the file or execmem for any user of SGX).

Yes, that's the argument as running any enclave will require RWX access to
/dev/sgx/enclave.  EXECMEM won't trigger for SGX users as /dev/sgx/enclave
must be MAP_SHARED and it's a non-private file (not backed by anonymous
inode, in case I got the file terminology wrong).