Date: Wed, 29 May 2002 15:41:13 -0700 From: "Crist J. Clark" <crist.clark@attbi.com> To: "Jacques A. Vidrine" <nectar@freebsd.org> Cc: security@freebsd.org Subject: Re: FreeBSD Security Advisory FreeBSD-SA-02:27.rc Message-ID: <20020529154113.D12700@blossom.cjclark.org> In-Reply-To: <20020529210334.GA5544@madman.nectar.cc>; from nectar@freebsd.org on Wed, May 29, 2002 at 04:03:34PM -0500 References: <200205291636.g4TGaZX40801@freefall.freebsd.org> <20020529133852.B12700@blossom.cjclark.org> <20020529210334.GA5544@madman.nectar.cc>
next in thread | previous in thread | raw e-mail | index | archive | help
On Wed, May 29, 2002 at 04:03:34PM -0500, Jacques A. Vidrine wrote: > On Wed, May 29, 2002 at 01:38:52PM -0700, Crist J. Clark wrote: > > > /bin/sh -c 'echo -e "/.X11-unix/s/^/#/\nw\nq\n" | /bin/ed -s /etc/rc' > > > > Ick. How about, > > > > # /usr/bin/printf "/.X11-unix/s/^/#/\nw\nq\n" | /bin/ed -s /etc/rc > > > > Next time? > > *shrug* One could prescribe any number of alternatives to achieve the > modification. I chose this way, because /bin/sh and /bin/ed are both > statically linked and should always be available on all systems in > single user mode. It seems unlikely that this will be an issue for > anyone, but hey - you never know. I guess I should have explained my concern more. I'm thinking some l33t kid out there is going to look at that and say, "I can just do, # echo -e "/.X11-unix/s/^/#/\nw\nq\n" | /bin/ed -s /etc/rc And not have to worry about all of that /bin/sh stuff at the front..." and thus outsmart himself. He wouldn't realize you are counting on features of the echo builtin in sh(1) and not /bin/echo or the csh(1) echo builtin. The above commands don't work as desired for a non-sh(1)-ish shell. I'm curious to see how many posts to the list might appear as people do just that. -- Crist J. Clark | cjclark@alum.mit.edu | cjclark@jhu.edu http://people.freebsd.org/~cjc/ | cjc@freebsd.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-security" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20020529154113.D12700>