Re: SGX vs LSM (Re: [PATCH v20 00/28] Intel SGX1 support)

On May 24, 2019, at 10:07 AM, Sean Christopherson [off-list ref] wrote:

quoted

On Fri, May 24, 2019 at 09:43:27AM -0700, Andy Lutomirski wrote:

quoted

On Fri, May 24, 2019 at 12:24 AM Xing, Cedric [off-list ref] wrote:
/**
* Summary:
* - The enclave file resembles a shared object that contains RO/RX/RW segments
* - FILE__* are assigned to /dev/sgx/enclave, to determine acceptable permissions to mmap()/mprotect(), valid combinations are
*   + FILE__READ - Allow SGX1 enclaves only
*   + FILE__READ|FILE__WRITE - Allow SGX2 enclaves to expand data segments (e.g. heaps, stacks, etc.)

I think this is a non-starter :(  FILE__WRITE also means that you can
write to the file, and the admin / policy author will almost never
want to allow that.

Why would FILE__WRITE on /dev/sgx/enclave be a problem?  An actual
write to /dev/sgx/enclave would yield -EINVAL, no?

Bah, read it wrong — FILE__WRITE on the enclave file on disk is no good.