Date: Mon, 17 Feb 1997 05:20:02 -0800 (PST) From: mark thompson <thompson@tgsoft.com> To: freebsd-bugs Subject: Re: bin/2747: at cannot be run in an atjob Message-ID: <199702171320.FAA14460@freefall.freebsd.org>
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The following reply was made to PR bin/2747; it has been noted by GNATS.
From: mark thompson <thompson@tgsoft.com>
To: joerg_wunsch@uriah.heep.sax.de
Cc: FreeBSD-gnats-submit@freebsd.org
Subject: Re: bin/2747: at cannot be run in an atjob
Date: Mon, 17 Feb 1997 05:12:03 -0800 (PST)
Date: Sun, 16 Feb 1997 20:48:18 +0100
From: j@uriah.heep.sax.de (J Wunsch)
As mark thompson wrote:
> You cannot submit an at job from within an at job, since the submitted
> job will have the wrong mail address, and atrun will reject it. The
People might consider this a feature. :-) So you can't defeat a
cron.deny entry with just an at.allow one.
I take it from the ascii winky that you are joking.
> comments suggest that the code in question (see below) is a hangover
> from an earlier day, and no longer appropriate.
No, the comments don't suggest this to me, sorry.
> - /* Get the userid to mail to, first by trying getlogin(), which reads
> - * /etc/utmp, then from LOGNAME, finally from getpwuid().
> + /* Get the userid to mail to, first by LOGNAME, then from getpwuid().
> */
> - mailname = getlogin();
> - if (mailname == NULL)
> - mailname = getenv("LOGNAME");
> + mailname = getenv("LOGNAME");
No, sorry, the preference of getlogin() over LOGNAME is a normal
sequence. getlogin() is much harder to fake.
The comment 'which reads /etc/utmp' does not suggest that it is a
holdover from previous times? In any case, let us assume just for a
moment that the user does set LOGNAME, then run at to try to spoof the
system. WHAT HARM DOES THAT DO? The mailname is the mailbox that the job
log is sent to - and atrun verifies that it matches the owner of the
submitted job in any case (that's why this fails in the first place).
-mark
ps. Now mind you - atrun has a buffer size overflow problem in the
fscanf that reads this... [HMMM... (looks at 2.2) no, the buffer
overflow is still there - AND - someone removed the check of mailname
against the file's owner! This seems to be going downhill. ]
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