[Pkg-shadow-devel] Bug#628843: crippling su -c is very troubling - first bug reports

[IgnorantGuru]

I agree that simply crippling su -c is a very troubling 'solution' to this problem.  Obviously anyone can close a problem by simply crippling the program.

Bugs from so-called 'fixes' related to this in shadow are now appearing in my file manager, this one from a Slackware user:
https://github.com/IgnorantGuru/spacefm/issues/394

su doesn't even return an error message there, it silently ignores the -c command, making troubleshooting difficult.  In this case, the SpaceFM file manager allows the user to run quick commands as root, open a root terminal, etc.  The user selects the su front-end to use, such as su in a terminal, gksu, kdesu, etc.  All of these front-ends support running a command, and the shadow 4.1.5  'fix' seems to break all of them in some circumstances (without PAM?)  In that case, Slackware users are encountering it when KDE is not installed.
http://seclists.org/oss-sec/2013/q2/374

Thus far I have not seen a problem in Debian on this, and I hope Debian takes a more reasonable approach.  Red Hat is very heavy-handed in their so-called fixes and they cause widespread breakage (eg udev, etc).  Hardly a good example to follow.

I'm not following all the technical details here, but in your rush to close a hole, be mindful not to cause such breakage.  There aren't a lot of alternatives to su.  su is less secure by nature and we all know this - you assume some risk by using it.  Yet simply removing the functionality is not a viable solution.  The approach to this is not considering all use cases of the widely-used su program and the implications of merely crippling it.

Thanks for considering this carefully.  I think if you don't you're opening a pandora's box of more issues.