Refactor: page-fault abstraction in libsgxstep

[jovanbulck]

Currently, page-fault attack code is rather unclean and has a lot of code duplication to setup fault handlers and revoke enclave page permissions through either mprotect calls and/or PTE remapping + editing..

Goal: Offer a simple and intuitive abstraction in libsgxstep/pf.c to mount page-fault controlled-channel attacks on enclaves so applications need only to focus on the actual attack logic (state machines) to interpret page-fault sequences.

[w-woloszyn]

Looks like a file pf.c does not exist and has never existed in the repository. (The output of git log --all --name-only --pretty=format: | grep 'pf.c' is empty.) Did you mean to write libsgxstep/pt.c?

EDIT: Oh, or do you mean to create such a file?

[jovanbulck]

yes, the idea indeed would be to create a new pf.c file but it's not here yet. This issue is open already way too long -- ideally I should make some time to cleanup the code and extract the common logic in a proper abstraction 😅

FWIW: you may want to have a look at an (unmaintained) tutorial I made long time ago with some support for page faults:

https://github.com/jovanbulck/sgx-tutorial-space18/blob/master/common/pf.c