Re: [PATCH 00/25] x86/sgx and selftests/sgx: Support SGX2

[Dave Hansen]

On 12/1/21 11:22 AM, Reinette Chatre wrote:
> * Support modifying permissions of regular enclave pages belonging to an
>   initialized enclave. New permissions are not allowed to exceed the
>   originally vetted permissions. Modifying permissions is accomplished
>   with a new ioctl SGX_IOC_PAGE_MODP.

It's probably also worth noting that this effectively punts on the issue
of how to allow enclaves to relax the permissions on pages, like taking
a page from R=>RW, or R=>RX.  RX isn't allowed unless the page was
*added* originally with RX or RWX.

Since dynamically added pages start with initial RW permissions, they
can *never* be RX or RWX since they did not start with execute
permissions.  That's a limitation, of course, but it's one that can be
dealt with separately from this set.

Does that sound sane to everyone?