On Fri, Jun 14, 2019 at 10:53:39AM -0700, Sean Christopherson wrote:

On Fri, Jun 14, 2019 at 10:45:56AM -0700, Sean Christopherson wrote:

quoted

The state tracking of #2/#3 doesn't scare me, it's purely the auditing.
Holding an audit message for an indeterminate amount of time is a
nightmare.

Here's a thought.  What if we simply require FILE__EXECUTE or AA_EXEC_MAP
to load any enclave page from a file?  Alternatively, we could add an SGX
specific file policity, e.g. FILE__ENCLAVELOAD and AA_MAY_LOAD_ENCLAVE.
As in my other email, SELinux's W^X restrictions can be tied to the process,
i.e. they can be checked at mmap()/mprotect() without throwing a wrench in
auditing.

We would also need to require VM_MAYEXEC on all enclave pages, or forego
enforcing path_noexec() for enclaves.

Scratch that thought.   Tying W^X restrictions to the process only works
if its done at load time.  E.g. If process A maps a page W and process B
maps the same page X, then which process needs W^X depends on the order of
mmap()/mprotect() between the two processes.