Drop -f/--config option from sympa_newaliases.pl

[Beuc]

Version

any

Installation method

any

Expected behavior

vulnerable dead code dropped

Actual behavior

vulnerable dead code present

Additional information

Following-up on #943 (comment)

One possible vulnerability you document in your patch, allowing *->root escalation, is passing an alternate configuration file to sympa_newaliases-wrapper.
However, sympa_newaliases.pl has an old bug, as it uses $main::options{config} which is undefined (unlike $options{config}), so it's not exploitable as it is AFAICS (though this would be better dropped entirely).

sympa_newaliases.pl, which is run through a setuid root wrapper, has a feature to read an arbitrary configuration file. Given that the configuration file is parsed as root, and can execute arbitrary commands through its backticks syntax, this would allow an escalation privilege.
In a standard installation, this would allow an unintentional privilege escalation from sympa to full root shell access.

Fortunately the feature has been broken for years. For clarity and to avoid introducing this later, I would suggest dropping the -f/--config option from sympa_newaliases.pl.

Credits goes to @lightsey .

[ikedas]

As @Beuc wrote, it is not a bug. Some command line options including --config were ineffective, and the behavior @lightsey described is not possible.

Submitted PR removes these options to clarify they were useless.