Previously, we introduced `sgx.zero_heap_on_demand` in Linux-SGX as a
knob to trade off runtime degradation on memory allocations for faster
enclave start-up times. This was an incorrect fix because Linux-SGX's
`_DkVirtualMemoryAlloc()` always zeroess the requested memory region,
so there was a double-zero of the heap at runtime. Note that LibOS
layer silently assumes that `_DkVirtualMemoryAlloc()` zeroes out the
memory, and many applications rely on this (Apache, Blender in my
experiments). Thus, this commit keeps the zero-out in
`_DkVirtualMemoryAlloc()` and removes zero-outs on enclave init and in
`get_enclave_pages()`. This renders `sgx.zero_heap_on_demand`
useless, so this manifest option is also removed. Also note that this
commit doesn't introduce any performance degradation (in fact, now
Graphene behaves as if `sgx.zero_heap_on_demand = 1` always).
The documentation currently specifies SGX_SIGNER_KEY as the parameter to
enable Graphene to find your keys.
Some examples don't use an environment parameter at all for the key to
sign the enclave, this commit fixes that.
Adapt the python constants so that python-simple also works on
Fedora 31. python-scipy-insecure misses some shared libraries on
Fedora 31, so it does not work there yet.
Extend Makefile.configs and define several variables for make to use
derived from 'gcc -dumpmachine'. In particular:
- ARCH as the architecture, e.g., x86_64
- ARCH_LONG as the long version of the architecture, e.g., x86_64-linux-gnu
- ARCH_LIBDIR as the directory where libraries are located,
e.g., /lib/x86_64-linux-gnu
In Makefiles and manifest templates, replace the hard-coded
x86_64-linux_gnu and /lib/x86_64-linux-gnu through these variables.
Extend the already existing sed scripts to replace the necessary
variables.
Michał Kowalczyk