Pylint output was filtered so that many files with existing pylint
violations were allowed to stay broken.
I made sure all files pass pylint, but whitelisted some rules that
we commonly disable:
* missing docstrings: most of the code is tests/internal anyway
* invalid-name: too many violations, and we commonly use one- or
two-character names (like "a, b" or "t1, t2") which is
disallowed by this rule; we could tweak it and then fix
remaining violations such as camel-case or lowercase constants
* fixme: we leave TODOs as a matter of practice, same as in C
* high-level style rules like too-few-* and too-many-*,
no-self-use
Hopefully that will make using pylint less annoying, while also
catching serious issues (such as unused variables or imports).
Previously, it was possible to use Graphene without the main executable
(e.g. having only preloaded libraries). We aren't aware of anyone using
this weird option, but worse, it led to a very bad UX when the user made
mistakes - e.g. having a typo in the manifest or executable name could
lead to Graphene starting without errors, but doing nothing.
Supporting these options complicates the design of Graphene and loading
logic significantly, providing little useful functionality:
- loader.exec:
- the main user of it were our tests
- worked only for the first process spawned inside Graphene, as it
was a unidirectional manifest->binary mapping, so the child
process didn't know about the corresponding manifest.
- sgx.sigfile:
- probably all existing usages of it were completely redundant
- was resolved relatively to CWD instead of the executable location,
which made it mostly useless
From now on, the correct location of the files is:
- either place the manifest and sigfile next to the binary, with a
matching name, or
- create a symlink to the binary in the folder where manifests are
stored and launch it through this symlink
Running a subset of regression tests, or a single test, is
currently rather annoying, as you cannot simply run 'pytest':
you need to override PYTHONPATH and specify several environment
variables.
Instead, move the whole boilerplate to a wrapper script that
allows running pytest with any command line options. Use it in
Makefiles as well, so that it doesn't go out of sync with CI.
Graphene had some paths to internal files generated at compile time and
hardcoded into the output binary, which disallowed e.g. moving the
Graphene directory after compilation.
Protected files (PF) are a new type of file that can be specified in
the manifest (SGX only). They are encrypted on disk and transparently
decrypted when accessed by the Graphene payload.
Other features:
- data is integrity protected (tamper resistance)
- file swap protection (a PF can only be accessed when in a specific path)
- transparency (Graphene payload sees PFs as regular files, no need to modify
the payload)
See Linux-SGX/protected-files directory for implementation. PF format is
based on protected files from the SGX SDK:
https://github.com/intel/linux-sgx/tree/master/sdk/protected_fs
The following new manifest elements are added:
sgx.protected_files_key = <16-byte hex value>
sgx.protected_files.<name> = file:<host path>
sgx.protected_files_key specifies the encryption key and is only a temporary
implementation. This key should be provisioned with local/remote attestation
in the future.
Paths specifying PF entries can be files or directories. If a directory is
specified, all files/directories within are registered as protected
recursively (and are expected to be encrypted in the PF format).
Linux-SGX/tools directory contains the pf_crypt utility that converts files
to/from the protected format.
Unlike /usr/bin/env which is a Posix standard, there is no guarentee
that /bin/bash exists. This is the case for operating systems such
as FreeBSD, NixOS and Guix. By using /usr/bin/env we also give
the user the option to provide their own bash in a different path
by setting the $PATH environemnt variable.
Distributions usually provide their own packaging wrappers
to fixup shebangs upon installation, however those are not convienent
to use when developing in the source tree.
See also other upstream discussions about the topic:
- https://github.com/systemd/systemd/pull/5816
We don't use it in tests, plus it didn't work on SGX - there was a
warning about autogeneration inserted before the autogenerated shebang.
Also, test_106_manifest_with_shebang didn't actually test the shebang
but ran the binary through the loader, so it was meaningless. We'll need
to fix it and implement again after cleaning up Graphene invocation.
Adapt the python constants so that python-simple also works on
Fedora 31. python-scipy-insecure misses some shared libraries on
Fedora 31, so it does not work there yet.
Adapt Scripts/Makefile.configs so that we can build and test on
Fedora. Most of the tests in Examples are now also runable on
Fedora. Also add a dependency installation target for Fedora to
TensorFlow example.
Extend Makefile.configs and define several variables for make to use
derived from 'gcc -dumpmachine'. In particular:
- ARCH as the architecture, e.g., x86_64
- ARCH_LONG as the long version of the architecture, e.g., x86_64-linux-gnu
- ARCH_LIBDIR as the directory where libraries are located,
e.g., /lib/x86_64-linux-gnu
In Makefiles and manifest templates, replace the hard-coded
x86_64-linux_gnu and /lib/x86_64-linux-gnu through these variables.
Extend the already existing sed scripts to replace the necessary
variables.
The goal of `$(SYS)` check in Makefiles is to skip all targets on
unsupported systems. This commit defines a default goal `all` as
a no-op for simplicity.
Instead of implementing downloading of external resources in every
Makefile again, use one script. This script adds the following
features:
- Always check the download against a known SHA-256 hash.
- Support caching of downloaded resources (set DL_CACHE=/some/dir).
- Allow offline builds if all files are cached. If DL_OFFLINE=true the
build will never attempt to download anything.
For detection of SGX/non-SGX (for example in regression tests) always
use the SGX environment variable. To generate launch/EINIT tokens use
the new 'sgx-tokens' Make target.
Paweł Marczewski