Re: [PATCH v3] Add systemd socket launching support

[Stefan Monnier <monnier@iro.umontreal.ca>]

>> In other similar functionality I've seen over the years, an alternative
>> was to pass the fd as an additional argument on the command line, but in
>> any case whether it's received from the environment or the command line,
>> the file-descriptor to use will just be an integer, and it's already
>> exposed to Lisp.
> It's an attack vector expecting to happen, so we should try to avoid
> that.

I'm not sure what kind of attack you're thinking about.  And I'm not
sure how the latest patch would address it (you can still cause Emacs
to use an arbitrary FD by providing the corresponding envvars).

>> AFAICT, only the first part is systemd-specific, so I think it would
>> make sense to try and avoid having systemd-specific details leak to the
>> other parts.
> I agree, and the last version of the patch already does that: it only
> requires a boolean flag exposed to other APIs.

But the process part of the patch could theoretically be used in other
contexts, fundamentally, whereas it ends up being tied to systemd, so
although it's code that can be compiled and could work regardless of
systemd, it ends up being systemd-specific since it only works when used
in the systemd-way and only if you linked with the systemd library.


        Stefan