From: danj1@ihspa.ATt.COM (Dan Jacobson)
Subject: Re: login should be a builtin
Organization: GNUs Not Usenet
Distribution: gnu
Date: Thu, 13 Aug 1992 15:43:00 GMT

>>>>> On Sat, 8 Aug 1992 11:53:07 GMT, jch+@cs.cmu.edu (Jonathan
>>>>> Hardwick) said:

JH> danj1@ihspa.ATt.COM (Dan Jacobson) writes
>>>>>>>>>>>>>>>>>>^Like, yo, yo, gnu list maintainers, your e-mail to
news gateway consistently downcases this letter in the "From:" header.

> login should be a builtin, because if jimmy, used to some other leading
> brands of shell, does
> bash$ login jenny
> as he turns over the terminal to jenny, and then later jenny logs out
> and walks away, jimmy's bash will be sitting there, so some baddie
> will take advantage of it

JH>   [ deleted ]

> Plus it's unreasonable to expect jimmy to memorize "'exec login' when
> under bash".

JH> It's unreasonable for jenny not to expect a trojan horse when jimmy types
JH> 	bash$ login jenny
JH> at his terminal and then says "there you go, it's all yours".  Both
JH> jimmy and jenny appear to be in dire need of a basic computer security
JH> course.  Even something as simple as:
JH> 	1. "always log out when you leave your terminal"
JH> 	2. "never log in unless you're sure a trojan isn't running"**
JH> would do.  If they can't even master these basic points, they have a
JH> whole heap more trouble to worry about than login not being a builtin
JH> in some shells. 

But even if jimmy & jenny are best of trusting friends, the problem is
the 3rd party baddie...

JH> Jonathan H.

JH> ** For arbitrary definitions of "sure".

>>>>> On Sat, 8 Aug 1992 23:47:23 GMT, friedman@gnu.ai.mit.edu (Noah Friedman) said:

NF> In article <1992Aug7Fr000428a.danj1@ihspa.att.com> danj1@ihspa.ATt.COM (Dan Jacobson) writes:
>login should be a builtin, because if jimmy, used to some other leading
>brands of shell, does
>bash$ login jenny
>as he turns over the terminal to jenny, and then later jenny logs out
>and walks away, jimmy's bash will be sitting there, so some baddie
>will take advantage of it, and then the whole school will hear some
>rumor that bash is a security hazard.  

NF>    I used to feel this way too, but lately I've decided I don't like for
NF> shells to be that clever.  It's even worse for some shells to recognize
NF> "newgrp" and do the same thing they do for login.  It's a misfeature in
NF> those shells. 

Thanks for reminding me about that massive drag "newgrp" crap in some
shells, I hereby rescind [withdraw] my original complaint.  One less
special twist for "security" is one more step towards a cleaner shell.

>                                        Plus, two out of three selected
>big name shells do it:

NF>    "If a million people do a foolish thing, it is still a foolish thing."  :-)

>Plus it's unreasonable to expect jimmy to memorize "'exec login' when
>under bash".

NF>    If it's really that much of a problem, then I'd suggest putting the
NF> following in /etc/profile:

NF>         if [ -n "${PS1}" -a -n "${BASH_VERSION}" ]; then
NF>            alias login='exec login'
NF>         fi

Probably best put in a specific parinoid person's .profile.

NF> But think about whether you really want to do this, instead of doing the
NF> Right Thing and getting users to learn about how the shell behaves in the
NF> first place.  If the users are lazy even after that, then they can make
NF> their own aliases.

Cool, I agree.  [Like, wowsky... I did a 180 degree viewpoint change.]
-- 
danj1@ihspa.att.com (Dan Jacobson) Naperville IL USA
+17089796364 Chinese~{;}5$Da~}Ji1Dan1ni2

Newsgroups: gnu.bash.bug