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From: jnc@mercury.lcs.mit.edu (Noel Chiappa)
To: tuhs@tuhs.org
Cc: jnc@mercury.lcs.mit.edu
Subject: Re: [TUHS] Set-uid shell scripts
Date: Sun,  4 Aug 2019 16:18:37 -0400 (EDT)
Message-ID: <20190804201838.0246918C08C@mercury.lcs.mit.edu> (raw)

    > From: Alec Muffett

    >>>  ln -s /bin/scriptname ./-i
    >>>  "-i" # assuming that "." is already in your path

'scriptname' (above) would have to be a shell script which was SETUID root?
That was part of what I was missing, along with the below.

    > The cited filename is passed as argv[1]

I wonder why it passed the link name, instead of the actual filename of the
target (script)? Perhaps to allow one script to have multiple functions,
depending on the name it was called with? But that could have been done with
hard links? (Adding a hard link must require write access, because the link
count in the inode has to be updated? So it would be equally secure as not
having an SUID program with write access.)

Part of the problem is having the kernel involved in starting shell scripts;
convenient in some ways, but V6 etc worked fine without that 'feature'.

       Noel

         reply index

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   ` jnc
2019-08-04 16:30     ` Michael Kjörling
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 jnc [this message]
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 jnc

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