[RFC] PEP 3143: supplementary group list concerns

Discussion in 'Python' started by Jan Pokorný, Mar 11, 2012.

  1. Jan Pokorný

    Jan Pokorný Guest


    in the light of a recent spot in Python Paste [1], I've come across
    the python-daemon [2] implementation and found it also lacks support
    for supplementary groups.

    First, I just wanted to post a patch to the author, but realized
    the broader context of PEP 3143 that would probably deserve
    revisiting at the first place. As the target Python version
    seems not to be decided yet, I see a space for it.

    If the spirit of solution [2] was to be followed (i.e., initialize
    this list with all groups of which user derived from `uid` is
    a member + group derived from `gid` (regardless if `uid`/`gid`
    is explicit), no change of the PEP would be necessary.
    This fact of intented handling of supplementary groups under the hood
    still could be mentioned so the users and authors of compatible
    interfaces are aware of this "detail".

    Another way (in the spirit of systemd [3]) is to extend the interface
    with an option (named, e.g., supplementary_groups) for optional
    specification of supplemental groups. The default would be something
    as in the previous paragraph.

    To be honest, I am not sure how consistently is the concept of
    supplementary groups used across various *nixes.
    POSIX seems to admit variances, e.g. (via [4]):
    The System Interfaces volume of IEEE Std 1003.1-2001 does not specify
    whether the effective group ID of a process is included in its
    supplementary group list.

    But I believe this should be addressed before the PEP in question is
    brought into effect.

    [2] http://groups.google.com/group/paste-users/browse_thread/thread/2aa651ba331c2471
    [3] http://0pointer.de/public/systemd-man/systemd.exec.html
    [4] http://pubs.opengroup.org/onlinepubs/000095399/utilities/newgrp.html

    Jan Pokorný, Mar 11, 2012
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  2. Jan Pokorný

    Jan Pokorný Guest

    On 12/03/12 09:27 +1100, Ben Finney wrote:
    > Jan Pokorný <> writes:
    >> in the light of a recent spot in Python Paste [1], I've come across
    >> the python-daemon [2] implementation and found it also lacks support
    >> for supplementary groups.

    > Thank you for your interest in ‘python-daemon’.
    > To know specifically what you're referring to in most of this message,
    > I think your reference ‘[1]’ is necessary; but you didn't provide it.

    My bad, I've sent it with unfinished renumbering.
    Please swap [1]+[2] in the quoted part and the missing reference is
    (for some reason, this points to 1.5.5, even though 1.6 is also there:
    http://pypi.python.org/pypi/python-daemon/1.6 ).
    Jan Pokorný, Mar 11, 2012
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