toml Python package v0.10.0 is buggy; need v0.10.2

[dimakuv]

Description of the problem

While testing #671, I encountered this bug.

#671 introduces a rather complex format for IOCTL data structures. Example from device_ioctl.manifest.template from #671:

sgx.ioctl_structs.gramine_test_dev_ioctl_write = [
    { size=8, type="out", name="buf_size" },     # buf_size
    { ptr=[ {size="buf_size", type="out"} ] },   # buf
    { size=8, type="inout" },                    # off
    { adjust=-4, size=12, type="in" },           # copied; adjust is just for testing
]

Gramine uses the toml Python package, including for manifest.template rendering:

• gramine/python/gramine-manifest

  Line 29 in db86ad2

  manifest = Manifest.from_template(template, define)

• gramine/python/graminelibos/manifest.py

  Line 84 in db86ad2

  manifest = toml.loads(manifest_str)

The toml Python package on Ubuntu 20.04 is taken from apt install:

gramine/.ci/ubuntu20.04.dockerfile

Line 67 in db86ad2

python3-toml \

On Ubuntu 18.04, it is taken from pip3 install:

gramine/.ci/ubuntu18.04.dockerfile

Line 89 in db86ad2

'toml>=0.10' \

So on Ubuntu 18.04, we get v0.10.2. But on Ubuntu 20.04, we get v0.10.0.

Unfortunately, v0.10.0 had a bug that directly affects my TOML snippet above: "Parsing fails on inline array of tables containing a nested table". This bug was fixed in v0.10.2 though.

So on Ubuntu 20.04, if the toml Python package is installed as apt install python3-toml (from Ubuntu repos), then such TOML manifests fail.

Proposed solutions:

1. Switch to another TOML parser in Python. One suggestion was tomli.
2. Require to use toml Python package v0.10.2. For this:
   • If Gramine is built from source, then the package must be installed via pip3 install toml.
   • If Gramine is installed via our packages, then all packages must contain python3-toml package with v0.10.2 -- this can be taken from e.g. Ubuntu 22.04.

@dimakuv and @woju are fine with solution 2, at least in the short-term. But we should discuss it during the Gramine meeting.

Steps to reproduce

Try #671 on Ubuntu 20.04 with toml Python package installed via apt install python3-toml.

Expected results

device_ioctl.manifest.template from #671 is rendered correctly by toml Python package.

Actual results

This is what I observed in #671 in Ubuntu 20.04 Jenkins jobs:

16:11:59  gramine-manifest -Darch_libdir=/lib/x86_64-linux-gnu -Dcoreutils_libdir=/usr/lib/x86_64-linux-gnu/coreutils -Dentrypoint=device_ioctl -Dbinary_dir=/home/jenkins/workspace/graphene-20.04/usr/lib/x86_64-linux-gnu/gramine/tests/libos/regression -Dlibc=glibc device_ioctl.manifest.template device_ioctl.manifest
16:11:59  Traceback (most recent call last):
16:11:59    File "/usr/lib/python3/dist-packages/toml/decoder.py", line 455, in loads
16:11:59      ret = decoder.load_line(line, currentlevel, multikey,
16:11:59    File "/usr/lib/python3/dist-packages/toml/decoder.py", line 725, in load_line
16:11:59      value, vtype = self.load_value(pair[1], strictly_valid)
16:11:59    File "/usr/lib/python3/dist-packages/toml/decoder.py", line 802, in load_value
16:11:59      return (self.load_array(v), "array")
16:11:59    File "/usr/lib/python3/dist-packages/toml/decoder.py", line 938, in load_array
16:11:59      nval, ntype = self.load_value(a[i])
16:11:59    File "/usr/lib/python3/dist-packages/toml/decoder.py", line 805, in load_value
16:11:59      self.load_inline_object(v, inline_object)
16:11:59    File "/usr/lib/python3/dist-packages/toml/decoder.py", line 621, in load_inline_object
16:11:59      raise ValueError("Invalid inline table value encountered")
16:11:59  ValueError: Invalid inline table value encountered
16:11:59  
16:11:59  During handling of the above exception, another exception occurred:
16:11:59  
16:11:59  Traceback (most recent call last):
16:11:59    File "/home/jenkins/workspace/graphene-20.04/usr/bin/gramine-manifest", line 33, in <module>
16:11:59      main() # pylint: disable=no-value-for-parameter
16:11:59    File "/usr/lib/python3/dist-packages/click/core.py", line 764, in __call__
16:11:59      return self.main(*args, **kwargs)
16:11:59    File "/usr/lib/python3/dist-packages/click/core.py", line 717, in main
16:11:59      rv = self.invoke(ctx)
16:11:59    File "/usr/lib/python3/dist-packages/click/core.py", line 956, in invoke
16:11:59      return ctx.invoke(self.callback, **ctx.params)
16:11:59    File "/usr/lib/python3/dist-packages/click/core.py", line 555, in invoke
16:11:59      return callback(*args, **kwargs)
16:11:59    File "/home/jenkins/workspace/graphene-20.04/usr/bin/gramine-manifest", line 29, in main
16:11:59      manifest = Manifest.from_template(template, define)
16:11:59    File "/home/jenkins/workspace/graphene-20.04/usr/lib/python3.8/site-packages/graminelibos/manifest.py", line 142, in from_template
16:11:59      return cls(_env.from_string(template).render(**(variables or {})))
16:11:59    File "/home/jenkins/workspace/graphene-20.04/usr/lib/python3.8/site-packages/graminelibos/manifest.py", line 84, in __init__
16:11:59      manifest = toml.loads(manifest_str)
16:11:59    File "/usr/lib/python3/dist-packages/toml/decoder.py", line 458, in loads
16:11:59      raise TomlDecodeError(str(err), original, pos)
16:11:59  toml.decoder.TomlDecodeError: Invalid inline table value encountered (line 34 column 1 char 1547)

Gramine commit hash

d3b65ab (in #671)

[mkow]

Let's just move to tomli instead of adding another hacks. The current toml library seems to be of really bad quality (see gramineproject/gsc#101).

[dimakuv]

Ok, I will create a PR to move to tomli.