From: "Michael Kjörling" <michael@kjorling.se>
To: tuhs@tuhs.org
Subject: Re: [TUHS] Set-uid shell scripts
Date: Sun, 4 Aug 2019 16:30:00 +0000 [thread overview]
Message-ID: <20190804163000.GB19836@h-178-80.A328.priv.bahnhof.se> (raw)
In-Reply-To: <20190804155854.C22CA18C096@mercury.lcs.mit.edu>
On 4 Aug 2019 11:58 -0400, from jnc@mercury.lcs.mit.edu (Noel Chiappa):
>> until someone realised that you could do:
>> ln -s /bin/scriptname ./-i
>> "-i" # assuming that "." is already in your path
>> ...and get a root shell.
>
> I'm clearly not very awake this morning, because I don't understand how this
> works. Can you break it down a little? Thanks!
I'm guessing a little here, but could it be related to poor command
line argument parsing in some shell, where "-i" forces the shell to
start in interactive mode and the shell looks for parameters
_anywhere_ in its argv[] (including argv[0]), not just at argv[1] and
later?
That would match the result described by Alec, and my modern dash's
man page does give that meaning for "-i", but it also feels like a
trivial bug to fix in the shell without prohibiting setuid scripts...
--
Michael Kjörling • https://michael.kjorling.se • michael@kjorling.se
“The most dangerous thought that you can have as a creative person
is to think you know what you’re doing.” (Bret Victor)
next prev parent reply other threads:[~2019-08-04 16:38 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-04 7:36 Dave Horsfall
2019-08-04 7:43 ` Alec Muffett
2019-08-04 15:58 ` Noel Chiappa
2019-08-04 16:30 ` Michael Kjörling [this message]
2019-08-04 16:48 ` Alec Muffett
2019-08-04 17:48 ` Michael Kjörling
2019-08-04 19:45 ` Alec Muffett
2019-08-04 16:50 ` Rico Pajarola
2019-08-04 7:46 ` arnold
2019-08-04 20:18 Noel Chiappa
2019-08-04 20:29 ` Clem Cole
2019-08-04 20:42 ` Richard Salz
2019-08-04 23:58 ` Dave Horsfall
2019-08-04 21:18 Norman Wilson
2019-08-04 21:27 Norman Wilson
2019-08-06 8:28 ` jason-tuhs
2019-08-06 9:55 ` arnold
2019-08-06 22:48 ` Dave Horsfall
2019-08-06 22:56 ` ron minnich
2019-08-07 1:21 ` Dave Horsfall
[not found] ` <40c92e85142fe7e3@orthanc.ca>
2019-08-07 21:33 ` Dave Horsfall
2019-08-08 6:39 ` Peter Jeremy
2019-08-07 12:56 ` Chet Ramey
2019-08-07 21:40 ` Dave Horsfall
2019-08-08 5:16 ` Adam Thornton
2019-08-14 5:41 ` Efton Collins
2019-08-05 0:13 Noel Chiappa
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